DENTALELLE TUTORING Vital Signs Dentalelle Tutoring @ 1

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DENTALELLE TUTORING

Vital Signs


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Recording of Vital Signs

At the New Patient Exam (and in some cases EVERY appointment) vital signs must be recorded

Often vital signs are only recorded for adults and older children – here is the normal range:

Blood pressure – 115/75 (or 120/80 depending on the text you read but 115/75 is the normal range under the ‘heart and stroke foundation’.

Pulse – 60-90 BPMRespiration – 14-20 RPMTemperature – 97-99 degrees


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Normal Results

A normal body temperature taken orally is 98.6°F (37°C), with a range of 97.8–99.1°F (36.5–37.2°C).

A fever is a temperature of 101°F (38.3°C) or higher in an infant younger than three months or above 102°F (38.9°C) for older children and adults. Hypothermia is recognized as a temperature below 96°F (35.5°C).

Respirations are quiet, slow, and shallow when the adult is asleep, and rapid, deeper, and noisier during and after activity.

Average respiration rates at rest are:infants, 34–40 per minutechildren five years of age, 25 per minuteTachypnea is rapid respiration above 20 per minute.


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Continuation

The strength of a heart beat is raised during conditions such as fever and lowered by conditions such as shock or elevated intracranial pressure. The average heart rate for older children (aged 12 and older) and adults is approximately 72 beats per minute (bpm). Tachycardia is a pulse rate over 100 bpm, while bradycardia is a pulse rate of under 60 bpm.


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Blood Pressure

To record blood pressure, a person should be seated with one arm bent slightly, and the arm bare or with the sleeve loosely rolled up. The cuff is placed level with the heart and wrapped around the upper arm, one inch above the elbow.

If the blood pressure is monitored manually, a cuff is placed level with the heart and wrapped firmly but not tightly around the arm one inch above the elbow over the brachial artery. Positioning a stethoscope over the brachial artery in front of the elbow with one hand and listening through the earpieces, the cuff is inflated well above normal levels (to about 200 mmHg), or until no sound is heard. Alternatively, the cuff should be inflated 10 mm Hg above the last sound heard. The valve in the pump is slowly opened. Air is allowed to escape no faster than 5 mmHg per second to deflate the pressure in the cuff to the point where a clicking sound is heard over the brachial artery. The reading of the gauge at this point is recorded as the systolic pressure.


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Blood Pressure Continuation

The sounds continue as the pressure in the cuff is released and the flow of blood through the artery is no longer blocked. At this point, the noises are no longer heard. The reading of the gauge at this point is noted as the diastolic pressure. "Lub-dub" is the sound produced by the normal heart as it beats. Every time this sound is detected, it means that the heart is contracting once. The noises are created when the heart valves click to close. When one hears "lub," the atrioventricular valves are closing. The "dub" sound is produced by the pulmonic and aortic valves.

With children, the clicking noise does not disappear but changes to a soft muffled sound. Because sounds continue to be heard as the cuff deflates to zero, the reading of the gauge at the point where the sounds change is recorded as the diastolic pressure.

Blood pressure readings are recorded with the systolic pressure first, then the diastolic pressure (e.g., 120/70).

Blood pressure should be measured using a cuff that is correctly sized for the person being evaluated. Cuffs that are too small are likely to yield readings that can be 10 to 50 millimeters (mm) Hg too high. Hypertension (high blood pressure) may be incorrectly diagnosed.


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Pulse – Heart Beat

The pulse can be recorded anywhere that a surface artery runs over a bone. The radial artery in the wrist is the point most commonly used to measure a pulse. To measure a pulse, one should place the index, middle, and ring fingers over the radial artery. It is located above the wrist, on the anterior or front surface of the thumb side of the arm.

Gentle pressure should be applied, taking care to avoid obstructing blood flow. The rate, rhythm, strength, and tension of the pulse should be noted. If there are no abnormalities detected, the pulsations can be counted for half a minute, and the result doubled. However, any irregularities discerned indicate that the pulse should be recorded for one minute. This will eliminate the possibility of error. Pulse results should be noted in the health chart.


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Respirations

An examiner's fingers should be placed on the person's wrist, while the number of breaths or respirations in one minute is recorded. Every effort should be made to prevent people from becoming aware that their breathing is being checked. Respiration results should be noted in the medical chart


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Temperature

Temperature is recorded to check for fever (pyrexia or a febrile condition), or to monitor the degree of hypothermia.

Manufacturer guidelines should be followed when recording a temperature with an electronic thermometer . The result displayed on the liquid crystal display (LCD) screen should be read, then recorded in a person's medical record. Electronic temperature monitors do not have to be cleaned after use. They have protective guards that are discarded after each use. This practice ensures that infections are not spread.


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Ergonomics


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Ergonomics for the Dental Assistant

As a dental assistant, ergonomics is important to your health and longevity in the profession.

Neutral-sitting position is ideal. This is sitting upright with your back straight and weight evenly distributed over the seat. Legs should be slightly separated with feet flat on the ring around the base of the chair. Your thighs should be parallel to the floor and front edge of the chair even with the patient's mouth. Position your chair close to the side of the patient with knees facing toward the patient's head. The height of the chair should be such that your eye level is 4 to 6 inches above the operator. This will give you a good line of vision into all areas of the patient's mouth.

If your chair has an arm support, it should be at the level of your abdomen and be used for reaching and leaning forward. The position of the mobile cart or cabinet top should be over your thighs and as close as possible.


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Five Categories of Motion

Class I is using fingers only such as flipping ends of the instrument.

Class II is using fingers and wrist. This could be transferring an instrument to the operator.

Movement of fingers, wrist and arm are Class III. Oral evacuation is in this classification.

Mixing of dental materials involves movement of the entire arm and shoulder. This is classified as Class IV.

Class V is movement of the arm and twisting of the body. Twisting behind you to adjust the dental light would be this classification.


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Zones

The work area around the patient is arranged into zones representing hours on a clock. The activity zone for the operator is 7 o'clock to 12 o'clock. All activities of the operator at the chairside are performed in this zone. The assisting zone is 2 o'clock to 4 o'clock.

In this zone, the assistant is positioned. The assistant transfers materials and instruments in the transfer zone, which is 4 o'clock to 7 o'clock.

Ergonomically, the design of the work area is a 20-inch radius. Keep frequently used items such as air-water syringe, high volume evacuator and saliva ejector within easy reach. All equipment and instruments should be within maximum vertical and horizontal reach. This is the sweep of your forearm in a reach of vertical and horizontal direction. Front delivery systems are best.


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Zones Diagram


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Patient Positioning

You should keep everything approximately waist high, not above shoulder level or below the waist. Those levels require twisting, turning of your back and shoulders. If a side delivery system is utilized, make it your dominant side. Again, this will require less overextending of your arm and shoulder

Do not overlook patient positioning. The position of the patient can greatly affect your posture. When reclining the patient, place his or her head in the same plane as their feet. Many dental practitioners try to perform procedures with the patient in an upright position. This causes practitioners to compensate by twisting their neck and back in order to see. Do not be afraid to ask patients to turn their heads or tilt their chins up or down. Patients are willing to comply if asked. This will allow better access and vision in the oral cavity.

Try using indirect vision for those hard to access areas such as buccal of the left side of the mouth and lingual of the right side.


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Other Areas to Consider

When deciding on a proper glove size, make sure the glove is not too tight across the palm or too constricting at the wrist. Also, the finger length should be adequate to allow for comfortable finger movement.

Handpieces and air/water syringes have hoses that are coiled and can be heavy. Their coiled cord places resistance against the wrist and hand. If the cord is long enough, place it in your lap so the excess is not dangling down. Swiveling devices can be placed on a handpiece. These devices reduce handpiece torque. Newer handpieces are much lighter than the older models. If your air/water syringe has a tightly coiled cord, consider replacing it with a lightweight hose.

Climate control of the workplace is important too. Exposure to cold air or drafts can cause muscles to constrict leading to fatigue or overworking of the muscles. This affects muscles of the neck, shoulders and back in particular. Always wash your hands in warm water to decrease hand fatigue.


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Stretching

Routine stretching exercises for your neck, shoulders, back, arms and fingers can prevent some work-related injuries and relax the body. Stretching should be performed every hour and slowly while exhaling into the stretch.


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Exercises to Perform

Neck Rotation Exercises 1. Head rotation * Drop your head forward * Rotate your head to the right shoulder * To left shoulder * Then return to front * Repeat this 3-5 times

Shoulder & Upper Back Exercises 1. Shoulder rotation * Rotate your right shoulder * Then rotate your left shoulder * Repeat this series 3-5 times 2. Shoulder shrug * Shrug your shoulders by raising them * Hold this position for 5 seconds * Repeat 3-5 times

Overhead reach * Place your hands and arms straight over your head and stretch * Hold for 5 seconds * Repeat 3-5 times 4. Elbow spread * Interlock fingers behind head * Move elbows backward * Hold for 5 seconds * Repeat 3-5 times


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Continuation of Exercises

Arm straightening * Interlock fingers behind your back and straighten arms * Hold for 5 seconds * Repeat 3-5 times Lower Back Exercises 1. Backward lean * Place hands on buttocks and lean backward * Hold for 5 seconds * Repeat 3-5 times

Spine rotation * While sitting, place your left hand on right knee * Look over the right shoulder causing spine rotation * Repeat other side * Repeat series 3-5 times 3. Forward bend * Bend forward at waist * Try to touch your toes * Hold for 5 seconds * Repeat 3-5 times Wrist & Finger Exercises

Finger curl * Stretch fingers out * Curl them toward palm of hand * Repeat 3-5 times 2. Finger pull * Pull fingertips of one hand back with the other * Repeat with other hand * Repeat 3-5 times


DENTALELLE TUTORING

Dental Procedures20


Sealants21


Sealants

A sealant is a protective, plastic coating that can be placed on the occlusal surfaces and buccal/lingual pits of the teeth

Usually done to seal the pits and fissures of the first and second year molars but can be placed on the premolars as well. Ages 6-7 or 11-14.

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Steps for placement of a sealant

Wash the tooth with pumice and water to ensure it is clean

Wash and dry the toothApply your cotton rolls, dry angles, etc. to the

areaApply etch and allow to sit for 10-30 seconds

depending on the manufacturers instructionsWash the etch very well, dry very well. To

ensure proper etching has taken place, the tooth must appear a chalky white and if not, re-etch for 10-20 seconds

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Continuation

Apply the sealant materialRun an explorer along the sealant to prevent

air bubbles from formingLight cure for 10-20 secondsCheck sealant with explorer to make sure no

voids are presentUse bite paper to check the bite

(articulation), if the sealant is high, the Dentist can smooth off with a high speed hand piece

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Recall Appointments

The sealants will need to be reviewed at recare appointments to make sure no voids or pieces of the sealant have come off

The patient and parents must be aware that proper brushing and flossing must still be maintained. A sealant only ‘helps’ prevent decay but will not stop it entirely

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Fillings26


Composite Fillings

Since they bond to the tooth, composite fillings restore most of the original strength of the tooth. Silver weakens the teeth, making them more susceptible to breaking. Since broken teeth are very expensive to restore, composites can save a lot of expense over the long run.

Composite fillings restore the natural appearance of the tooth. Teeth restored with white fillings are less sensitive to hot and cold

than teeth restored with amalgam, if correct techniques are used.

Composites are mercury-free. Mercury in the fillings is viewed by some as being toxic.

Composites require less removal of tooth structure. Especially with new cavities, the size of the hole made for the filling can be dramatically smaller with composites.

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Amalgam Fillings

They are generally less expensive. Composite fillings, if they are done correctly, take about 60% longer, require special expertise and expensive materials, and are more difficult to place, and so they cost considerably more than silver.

General dentists can place amalgam without extra training. Composite requires the use of special bonding technology that many dentists are uncomfortable with.

The proper placement of a white filling requires that the site for the filling be kept totally isolated from saliva while it is being placed. In the very back of the mouth, on some patients, it is difficult to keep the tooth isolated for the duration of the procedure. This can also be uncomfortable for some patients. A silver amalgam filling does not require this strict isolation of the tooth.

The filling by itself is a stronger material, although it weakens the tooth. Silver fillings have a longer history of use than mercury-free fillings, thus

some feel that they are more tried and tested.

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Composite vs Amalgam Fillings

If a patient has a cavity, the cavity must be removed and an amalgam or composite filling placed. Depending on the tooth and the patient, one might be better then the other

The procedure involves: Topical/Local anesthetic Application of the rubber dam Removal of decay using high speed and slow speed handpieces Etch, prime/bond and light cure of the materials Filling material placed and light cured (if composite) The bite is checked with articulating paper and polishing **This is a quick recap of the procedure, please review in your

notes from school the exact procedure – questions will be asked in your next session

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Dental Inlays and Onlays

Another form of a dental filling that can be used in place of an amalgam or composite

Porcelain or gold inlays are used to repair minor damages to the teeth and dental onlays for greater damage.

Simplified, one could describe dental fillings or dental inlays/onlays as ‘partial crowns’ that are used in cases when there is enough healthy enamel left on a tooth worth saving rather than inserting a completely new, artificial dental crown.

One can say that the dental inlays resemble a small piece of puzzle which is customised, fitted and glued into the remaining enamel in order to restore the tooth’s strength and longevity. The inlays are normally made from either porcelain or gold.

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Inlay and Onlay Procedure

To receive dental inlays or dental onlays requires two dentist appointments. During the first one the tooth that is to have the dental inlay is examined and prepared.

Once the tooth is prepared an impression is made and sent to a dental technological laboratory where the porcelain or gold inlay/onlay is made. Finally the dentist will fit you with a temporary dental filling and book a time for your next appointment.

During the second appointment the temporary dental filling is removed. The porcelain or gold inlay/onlay is then tried out to make sure it fits perfectly. Once the fit is how it should be, it is then cemented into place.

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Crown and Bridge Procedure32



What are Dental Crowns and Tooth Bridges?Both crowns and most bridges are fixed prosthetic devices.

Crowns and bridges are cemented onto existing teeth or implants, and can only be removed by a dentist.

Crowns are placed on teeth that have very large fillings to begin with and a concern with chipping is apparent, a crown will go over the tooth given it strength

Bridges are in place of a tooth – if a tooth is missing and a space results. Bridges are placed to prevent shifting of the teeth and to maintain the proper bite.


Crowns34

The dentist may recommend a crown to:Replace a large filling when there isn't

enough tooth remainingProtect a weak tooth from fracturingRestore a fractured toothAttach a bridgeCover a dental implantCover a discolored or poorly shaped toothCover a tooth that has had root

canal treatment



Before either a crown or a bridge can be made, the tooth (or teeth) must be reduced in size so that the crown or bridge will fit over it properly. Normally a rubber dam is placed for this but after the teeth have been reduced in size, the rubber dam is removed to finish.

After reducing the tooth/teeth, the dentist will take an impression to provide an exact mold for the crown or bridge. If porcelain is to be used, your dentist will determine the correct shade for the crown or bridge to match the color of your existing teeth.

Using this impression, a dental lab then makes your crown or bridge, in the material your dentist specifies. A temporary crown or bridge will be put in place to cover the prepared tooth while the permanent crown or bridge is being made.

When the permanent crown or bridge is ready, the temporary crown or bridge is removed, and the new crown or bridge is cemented over your prepared tooth or teeth. Normally it takes two weeks at the most for a crown or bridge to be made.


Dental Implants36


Dental Implants37

A Dental Implant is a small titanium screw that serves as the replacement for the root portion of a missing natural tooth. It is available in various sizes (both width and height) for different clinical situations.

Dental Implants may be used to replace one or more missing teeth. In case of completely edentulous patients, implants may be used to fix the dentures to the underlying bone. Alternately, implants may be used to provide fixed tooth to edentulous patients without the use of dentures. Needless to say, an implant offers several advantages over conventional treatment options.


Benefits of Implants38

Implant supported teeth are more comfortable than conventional dentures because there is no slipping or movement, because the implants are fixed they feel and function like natural teeth. This eliminates some of the key worries of denture wearers and improves self-confidence.

Dental implants are an alternative to conventional bridgework. They eliminate the need to prepare healthy teeth and do not place additional loads on the teeth supporting the bridge.

When teeth are missing the surrounding bone shrinks. Implants stimulate the bone to be maintained which helps keep shape and structure of the jaw stable.


Contraindications for Implants39

Implants are not for everyone!There must be enough bone in the area to hold a

dental implant or it will failA lot of dental surgeons will not perform the

implant procedure on a smoker due to the dealing in healing time

Also your diabetic patients, healing is reduced so an implant may not be the best option

For your dental hygienist – plastic scalers can only be used on and around the implant to avoid scratches


Root Canal40


Root Canal41

The root canal procedure can be the most daunting to a new dental assistant, we have outlined some of the basic steps for you:

Think of the procedure in steps, what you will be doing will determine what you will need


Steps42

Anesthesia. Rubber dam application. Making the area aseptic. Access to pulp chamber. Pulp extirpation. Trial radiograph with instrument in place. Calculating exact measurement. Reaming and filing of root canal to measurement. Irrigation. Desiccation. Selecting, sterilizing, and fitting the point. Trial radiograph with point in place. Cementation of point. Sealing of access opening. Final radiograph.


Preparing the canal43

Preparing the Root Canal. In gaining access, provide high and low speed burs. A barbed broach is used for extirpation of the pulp. A monojet syringe or some type of syringe is typically used to irrigate the tooth with sodium hypochlorite. Desiccation or drying of the root canal is done by the use of paper absorbent points: Extra fine, fine, medium, or coarse. The endodontic assistant should set out an assortment of paper points for the dentist. A radiograph with the measured instrument placed in the canal is exposed to determine the exact length of the root canal. The dental assistant then should provide a sequential assortment of reamers and files of increasing size. The beginning size is determined by the dentist. The reamers and files should be provided with rubber stops. A corresponding size point, either silver or gutta-percha, is selected and trial-fitted.

Once the point passes the trial fit, it is ready for cementation. The dental assistant should now be prepared to mix the root canal cement. If the zinc oxide and eugenol technique is used, relatively large portions of powder are added to the liquid and spatulated until a heavy, creamy, nongranular mix is obtained. When the mix is complete, the cement should be drawn up from the mixing slab about 1 inch without separating. This test is done by dabbing the spatula into the mix and drawing it up slowly. The cement is given to the dentist who places it in the canal with a reamer. The point is coated with cement and seated into place.


Filling and Sealing44

Filling and Sealing the Root Canal. When gutta-percha points are used, cotton forceps are used to place the point. Depending on the technique, a plugger, a spreader, or both, are used to condense the gutta-percha in the canal.

In other techniques, both gutta-percha and silver points are used at the same time. A trial radiograph of the root canal filling is taken and, if it is satisfactory, a thick mix of zinc oxide and eugenol or zinc phosphate cement is made and plugged into the access area to completely seal the canal. A number three Ladmore plugger is the instrument of choice for plugging the access opening with the cement.


Other Method45

The sequence of treatment for the multiappointment method of endodontic therapy differs from the single appointment method in that the sequence is interrupted at various stages to allow for drainage of infected material, for changing of medications in the root canal, or to alleviate a lengthy appointment.

Medications commonly used in endodontic techniques include cresatin and camphorated paramonochlorophenol, which are placed in dappen dishes and then placed into the root canal by using paper points or into the pulp chamber by using cotton pellets. The tooth is then sealed and kept sealed until the next appointment.


Continued46

Follow-up Appointments. Upon completion of the treatment by either method, arrangements should be made to recall the patient 6 months later for a follow-up radiograph to determine the success of the treatment. If an abscess forms, the root canal treatment will have to be redone.

Sterilization. Successful endodontics depends greatly upon sterility. Anything placed into the tooth must be sterilized.


Orthodontics47


Orthodontics48

Orthodontics is done by a specialist – additional training is needed. Working as a dental assistant in an orthodontic office is an exciting experience. Often you will be trained on the job for this but it is wise to know the basics for regular practice.

If your patient does not have a ‘Class I’ bite, this will likely need to be corrected.

Acquired malocclusions are caused by:Trauma (including delayed weaning from thumb, finger, or

pacifier sucking)Mouthbreathing (due to enlarged tonsils or adenoids, blocked

nasal passages etc.)Premature loss of baby or adult teeth


Malocclusions49

Regardless of whether malocclusions are inherited or acquired, many of these problems affect not only alignment of the teeth but also facial development and appearance as well.

A poor bite does not DIRECTLY cause tooth decay, or periodontal disease. It may, however, make it difficult to brush and floss properly which increases the likelihood of dental disease.

Although a majority of the population have some type of malocclusion, not all people require or seek orthodontic treatment. For example, with or without a history of orthodontic treatment, 65% of adults develop crowded, crooked lower front teeth. This is a natural result of change over time and does not necessarily require orthodontic treatment.


Symptoms that may require Orthodontics

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Permanent teeth coming in (erupting) out of their normal position;

Problems with biting the cheek or roof of the mouth; or

Difficulty chewing or difficulty aligning teeth;Facial muscle or jaw pain, or speech difficulties.Obvious rotations and crowding of the teethRemember – LOTS of space, teeth far apart, in

a child is a good thing – meaning more room for the permanent teeth to come in


Desensitization of Teeth51

Tooth sensitivity is a very common issue and can happen from a variety of reasons:

Recession – seems to be the main reason, if a patient is brushing too hard over a number of years can result in recession. Using a soft toothbrush is especially important in preventing further recession

Clenching/grinding – if a patient clenches his or her teeth as well as grinding this can result in very sensitive teeth. A nightguard is the only solution to this other than stopping the grinding/clenching.

Erosion – if a patient has been vomiting or eating/drinking acidic foods this can cause erosion resulting in sensitivity. Chronic erosion may no longer be sensitive*


Toothpastes52

Desensitizing toothpastes work by blocking transmission of sensations through the tubules of the dentin layer so that they are unable to reach the nerve. In addition to regular brushing with a desensitizing toothpaste, Discovery Health recommends placing a small amount onto sensitive areas and leaving it overnight. Consistent overnight use should bring some relief within a few weeks.

Duraflor, or a different type of desensitizing agent can be applied directly to the area in the dental office.

Some sensitivity may be caused by vigorous brushing with a hard toothbrush. This can wear away the enamel, exposing the tubules that lead to the tooth's nerve. Harsh brushing can also cause the gums to recede, exposing the roots of the teeth. Although enamel cannot be restored once it is lost, using a soft-bristled toothbrush can prevent the damage from progressing. This will also help with sensitivity.


Fluoride53

Fluoride is found in most toothpastes, but a special rinse or treatment may be used when teeth are sensitive. Fluoride rinses are available over-the-counter, or the dentist can prescribe a stronger rinse or varnish.

The American Dental Association indicates that fluoride strengthens the tooth's protective enamel layer and reduces the transmission of sensations.

Custom trays can be made for the patient to be worn at home with fluoride if the sensitivity is extreme.


Bleaching54


Bleaching (Teeth Whitening)55

Teeth whitening procedures have been performed for over one hundred years. As far back as 1877, procedures involving the use of oxalic acid to whiten teeth were reported. Hydrogen peroxide was introduced as a tooth bleaching agent back in 1884 and in 1918, the use of high-intensity lights in conjunction with the hydrogen peroxide was used to speed up the bleaching process, according to a report by the ADA.

No significant adverse health effects have been associated with the use of dentist-prescribed home use whiteners. Minor side effects from the procedures may include transient mild tooth sensitivity to temperature changes and mucosal irritation. Most side effects associated with the teeth whitening procedures disappear within seven days.


Staining56

Stains can happen both intrinsically and extrinsically. Smoking, coffee, tea, aging, medications, etc., all play a part

A blue/gray hue to the teeth will not whiten well and patients with this hue should be made aware of this.

A yellow/brown stain will likely whiten well to any type of procedure Everyone responds differently in the length of time it takes to see

results. This is why it is important for you to carefully discuss in advance with your dentist what the causes of the discolorations are.

For people with intrinsic staining (from fluorosis, tetracycline staining or tooth trauma inside the pulp), the results may take longer and it may be necessary to have a few sessions, or discuss other options for the more intense stains. Typically these are the streaks or the purplish discolorations that are harder to lighten. Patients with intense streaks in their teeth will find that the intensity fades, however, it is almost impossible to totally remove the streaks, especially using only the home bleaching techniques.


Take-Home Whitening57

This is the most common option and often cheaper than the in-office whitening

Custom trays are made of the teeth using alginate impressions, impressions poured up and whitening trays are made (using a vacuum former for whitening)

The patient comes back to the office and is given instructions for us along with the bleaching syringes required


In-Office Whitening58

This is a popular option to get quick results, often the same bleaching material is used as the take-home whitening but a stronger concentration

A light is often used to speed up the process as well but keep in mind this can lead to additional sensitivity

It is often recommended that the patient brushes with a sensitivity type toothpaste two weeks prior and two weeks after the whitening procedure to limit the sensitivity as much as possible


Extractions59


Extractions60

Why are teeth extracted? If a tooth has been broken or damaged by decay, your dentist will try to fix it with a filling, crown or other treatment. Sometimes, though, there's too much damage for the tooth to be repaired. In this case, the tooth needs to be extracted.

The dental assistants role in this is often to help the dentist during the procedure and provide post-op instructions afterwards


Additional Reasons to Extract61

Some people have extra teeth that block other teeth from coming in. Sometimes baby teeth don't fall out in time to allow the permanent teeth to come

in. People getting braces may need teeth extracted to create room for the teeth that

are being moved into place. Infected teeth may need to be extracted. Some teeth may need to be extracted if they could become a source of infection

after an organ transplant. People with organ transplants have a high risk of infection because they must take drugs that decrease or suppress the immune system.

Wisdom teeth, also called third molars, are often extracted either before or after they come in. They commonly come in during the late teens or early 20s. They need to be removed if they are decayed, cause pain or have a cyst or infection. These teeth often get stuck in the jaw (impacted) and do not come in. This can irritate the gum, causing pain and swelling. In this case, the tooth must be removed. If you need all four wisdom teeth removed, they are usually taken out at the same time.


Preparations62

An x-ray of the area will be taken to help plan the best way to remove the tooth.

If the wisdom teeth are being removed, you may need to take a panoramic x-ray. This x-ray takes a picture of all the teeth at once. It can show several things that help to guide an extraction:

The relationship of the wisdom teeth to the other teethThe upper teeth's relationship to the sinusesThe lower teeth's relationship to a nerve in the jawbone

that gives feeling to the lower jaw, lower teeth, lower lip and chin. This nerve is called the inferior alveolar nerve.

Any infections, tumors or bone disease that may be present


Antibiotics63

Some doctors prescribe antibiotics to be taken before and after surgery. This practice varies by the dentist or oral surgeon. Antibiotics are more likely to be given if:

An infection at the time of surgeryDue to a weakened immune systemSpecific medical conditions are present


Telling your Patient64

You may have intravenous (IV) anesthesia, which can range from conscious sedation to general anesthesia. If so, your doctor will have give you instructions to follow. You should wear clothing with short sleeves or sleeves that can be rolled up easily. This allows access for an IV line to be placed in a vein. Don't eat or drink anything for six or eight hours before the procedure.

If you have a cough, stuffy nose or cold up to a week before the surgery, call your doctor. He or she may want to avoid anesthesia until you are over the cold. If you had nausea and vomiting the night before the procedure, call the doctor's office first thing in the morning. You may need a change in the planned anesthesia or the extraction may have to be rescheduled.

After the extraction, someone will need to drive you home and stay there with you. You will be given post-surgery instructions.


Types of Extractions65

There are two types of extractions:A simple extraction is performed on a tooth that can be seen

in the mouth. General dentists commonly do simple extractions. In a simple extraction, the dentist loosens the tooth with an instrument called an elevator. Then the dentist uses an instrument called a forceps to remove the tooth.

A surgical extraction is a more complex procedure. It is used if a tooth may have broken off at the gum line or has not come into the mouth yet. Surgical extractions commonly are done by oral surgeons. However, they are also done by general dentists. The doctor makes a small incision (cut) into your gum. Sometimes it's necessary to remove some of the bone around the tooth or to cut the tooth in half in order to extract it.


Types66

Most simple extractions can be done using just an injection (a local anesthetic). For a surgical extraction, you will receive a local anesthetic, and you may also have anesthesia through a vein (intravenous). Some people may need general anesthesia. They include patients with specific medical or behavioral conditions and young children.

If you are receiving conscious sedation, you may be given steroids as well as other medicines in your IV line. The steroids help to reduce swelling and keep you pain-free after the procedure.

During a tooth extraction, you can expect to feel pressure, but no pain. If you feel any pain or pinching, tell your doctor.


Post-Op Instructions67

Having a tooth taken out is surgery.. Research has shown that taking nonsteroidal anti-inflammatory drugs (NSAIDs) can greatly decrease pain after a tooth extraction. These drugs include ibuprofen, such as Advil, Motrin and others. Take the dose your doctor recommends, 3 to 4 times a day. Take the first pills before the local anesthesia wears off. Continue taking them for 3 days.

Surgical extractions generally cause more pain after the procedure than simple extractions. The level of discomfort and how long it lasts will depend on how difficult it was to remove the tooth. Your dentist may prescribe pain medicine for a few days and then suggest an NSAID. Most pain disappears after a couple of days.

After an extraction, you'll be asked to bite on a piece of gauze for 20 to 30 minutes. This pressure will allow the blood to clot. You still have a small amount of bleeding for the next 24 hours or so. It should taper off after that. Don't disturb the clot that forms on the wound.


Continued68

You can put ice packs on your face to reduce swelling. Typically, they are left on for 20 minutes at a time and removed for 20 minutes. If your jaw is sore and stiff after the swelling goes away, try warm compresses.

Eat soft and cool foods for a few days. A gentle rinse with warm salt water, started 24 hours after the surgery,

can help to keep the area clean. Use one-half teaspoon of salt in a cup of water. Most swelling and bleeding end within a day or two after the surgery. Initial healing takes at least two weeks.

If you need stitches, your doctor may use the kind that dissolve on their own. This usually takes one to two weeks. Rinsing with warm salt water will help the stitches to dissolve. Some stitches need to be removed by the dentist or surgeon.

You should not smoke, use a straw or spit after surgery. These actions can pull the blood clot out of the hole where the tooth was.


Risks Involved69

A problem called a dry socket develops in about 3% to 4% of all extractions. This occurs when a blood clot doesn't form in the hole or the blood clot breaks off or breaks down too early.

In a dry socket, the underlying bone is exposed to air and food. This can be very painful and can cause a bad odor or taste. Typically dry sockets begin to cause pain the third day after surgery.

Dry socket occurs up to 30% of the time when impacted teeth are removed. It is also more likely after difficult extractions. Smokers and women who take birth control pills are more likely to have a dry socket.

A dry socket needs to be treated with a medicated dressing to stop the pain and encourage the area to heal.

Infection can set in after an extraction. However, you probably won't get an infection if you have a healthy immune system.


Other Problems70

Accidental damage to nearby teeth, such as fracture of fillings or teeth An incomplete extraction, in which a tooth root remains in the jaw — Your

dentist usually removes the root to prevent infection, but occasionally it is less risky to leave a small root tip in place.

A fractured jaw caused by the pressure put on the jaw during extraction — This occurs more often in older people with osteoporosis (thinning) of the jaw bone.

A hole in the sinus during removal of an upper back tooth (molar) — A small hole usually will close up by itself in a few weeks. If not, more surgery may be required.

Soreness in the jaw muscles and/or jaw joint — It may be tough for you to open your mouth wide. This can happen because of the injections, keeping your mouth open and/or lots of pushing on your jaw.

Long-lasting numbness in the lower lip and chin — This is an uncommon problem. It is caused by injury to the inferior alveolar nerve in your lower jaw. Complete healing may take three to six months. In rare cases, the numbness may be permanent.


Calling a Professional71

The swelling gets worse instead of better. You have fever, chills or redness You have trouble swallowing You have uncontrolled bleeding in the area The area continues to ooze or bleed after the first 24 hours Your tongue, chin or lip feels numb more than 3 to 4 hours after the

procedure The extraction site becomes very painful -- This may be a sign that

you have developed a dry socket.


Tooth Impactions72


Wisdom Teeth73

Wisdom teeth are known as “third molars,” and generally develop in a person between the ages of 17 and 25, although approximately 25% to 35% of the population never develops wisdom teeth. More often than not, however, wisdom teeth need to be extracted because of problems and complications.

Impaction of the Wisdom Teeth The majority of wisdom teeth fall into this category, primarily because there isn’t enough

room in your jaw to accommodate the teeth. A horizontal impaction occurs when the wisdom tooth grows in sideways, approximately ninety degrees in direction from the rest of the teeth.

With a horizontal impaction, the wisdom tooth grows towards the rest of the teeth. A distal impaction occurs when the tooth grows in at approximately a forty-five degree angle, opposite the direction of the other teeth. Finally, vertical impaction occurs when the tooth is growing upright.

Aside from impaction, there are several other problems that can result if these teeth are left in your mouth. Even though the age-old justification for the removal of wisdom teeth is the misalignment or shifting of other teeth in your mouth if wisdom teeth are left to grow, some of these justifications are debatable and up for interpretation. It’s certainly the case that not everyone’s wisdom teeth need to be extracted.


Incision and Drainage74


Surgical Incision and Drainage75

Dr. Reena Talwar says that Surgical incision and drainage is a commonly used technique in oral surgery to treat dental infections which have progressed to oral swellings. If cavities of the teeth are left untreated, they can eventually progress to infections that spread into the jaw bones and later into the surrounding soft tissues. Not only is this process extremely painful for the individual, but it is also extremely dangerous. This is because untreated dental infections which have penetrated into the surrounding tissues can lead to a spreading of the infection to the brain or heart in a short period of time, causing severe illness and potentially death.

The first sign of a dental infection that has penetrated through the jaw bone into the surrounding soft tissues, other than pain, is a noticeable swelling of the individual’s mouth and/or face.

The way in which these types of infections are treated first begins with a

complete review of the patient’s medical and dental history. It is crucial for the clinician to know the history of the current infection in order to develop an appropriate treatment plan to treat the infection.


Continuation76

In some situations, the tooth responsible for the infection may be salvaged. This is based on clinical assessment of the tooth and the relative prognosis for treating the infection by retaining the tooth. In most instances however, the tooth in question is often extracted in conjunction with performing the incision and drainage procedure. In this case, the extraction is performed at the same time as the surgical incision and drainage procedure.

The procedure is generally performed in an out patient

setting under local anesthetic. For those individuals who are extremely apprehensive, oral and or intravenous sedation can be utilized in conjunction with the local anesthetic.


Infection77

In general, once the region of the infection has been appropriately anesthetized or “frozen”, a small incision/cut is made in the gums at the most prominent point of the oral swelling. The pus (purulence) is then drained and the site is irrigated with sterile saline solution. In certain instances where a significant amount of swelling and pus are present or when the infection has been long standing, the clinician may elect to place a rubber drain to keep the surgical site patent. This allows for any residual drainage of pus to occur and prevents the need for any further surgery at this site. The drain must be removed by the clinician in 24 to 72 hours after placement. The patient is required to follow-up with the clinician on a regular basis during the healing period. The timeline for follow-up is determined by the clinician based on his/her clinical assessment of the patient.

The patients are often placed on antibiotic therapy following the surgical procedure for a period of 7 to 10 days. A prescription for pain medication is also often provided.

Surgical incision and drainage is a routinely performed procedure for locally

spreading dental infections which has demonstrated excellent outcome for patients.


Dental Assisting Anatomy78

Dentalelle Tutoring @ www.dentalelle.com 79




Paired Cranial Bones82


Parietals

The Parietals are paired left and right. Externally, each possess a Superior, and Inferior Temporal Line, to which the temporal muscle is attached. The lines run from the Frontal Crest of the anterior frontal bone to the Supra-Mastoid Crest on the posterior portion of the temporal bone. The parietals articulate with each other by way of the Mid-Sagittal Suture, and with the frontal bone anteriorly by way of the Coronal Suture. These two sutures generally form a right angle with one another. Posteriorly, the parietals articulate with the Occipital Bone by way of the Lambdoid Suture. The intersection of the Lambdoid and Sagittal Sutures approximate a 120 degree angle on each of the parietals and the occipital bone. Among the sutures the Lambdoid is by far more serrated than either the Sagittal or the Coronal. Inferiorly the Parietal articulates with the temporal bone by way of the Squamosal and Parieto-Mastoid Sutures. On the external surface near the center of the bone is the Parietal Eminence. Slightly posterior to the eminence there may be a Parietal Foramen.

Internally, the bones possess a number of Meningeal Groves as well as perhaps some number of Arachnoid Foveae. The groves generally branch from the inferior/anterior edge of the bone to superior/posterior, while the foveae are frequently found along the sagittal suture. At the area of intersection of the lambdoid and parieto-mastoid sutures there is a brief portion of the Sigmoid (i.e., Transverse) Sulcus.

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Temporal Bone

The Temporal Bone is another paired cranial bone which is difficult to describe due to its various features, and projections. It consists of two major portions, the Squamous Portion, which is flat or fan-like and projects superiorly from the other, very thick and rugged portion, the Petrosal Portion.

The squamous portion assists in forming the Squamous Suture which separates the temporal bone from the adjacent and partially underlying parietal bone. The petrosal portion contains the cavity of the middle ear and all the ear ossicles; the Malleus, Incas and Stapes. This portion projects anterior and medially beneath the skull. Projecting inferiorly from the petrosal portion is the slender Styloid Process which is of variable length. The styloid process serves as a muscle attachment for various thin muscles to the tongue and other structures in the throat. Externally the petrosal portion possesses the External Auditory Meatus while internally there is an Internal Auditory Meatus. Anterior to the external meatus the Zygomatic Process has its origin. This process projects forward toward the face and its articulation with the temporal process of the zygomatic. Just anterior of the external meatus and inferior of the origin of the zygomatic process is the Glenoid or Mandibular Fossa which assists in forming the shallow socket of the Tempro-Mandibular Joint. Posterior to the external auditory meatus is the inferiorly projecting Mastoid Process which serves as an attachment for the sternocleidomastoid muscle. Above the mastoid process is the Supramastoid Crest to which the posterior portion of the temporal muscle is attached.

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Unpaired Cranial Bones85


The Frontal Bone

The frontal bone may be divided into two main portions, a vertical squamous portion which articulates with the paired parietals along the Coronal Suture and forms the forehead, and two orbital plates, which contribute to the ceiling and lateral walls of the left and right eye orbits. On the external surface the squamous portion frequently possesses a left and right Frontal Eminence. Additionally, the bone possesses two Supra-Orbital Ridges (i.e., Superciliary or Brow Ridges) which are bumps above each of the eye orbits. In early hominids these ridges formed a Torus or large shelf-like process protruding from above the eyes. Associated with each Superior Orbital Margin of the eye orbit the frontal bone may posses a Supra-Orbital Notch or if completely surrounded by bone, a Supra-Orbital Foramen. Above the fronto-nasal suture which allows articulation between the frontal and nasal bones there is generally a trace of the vertical Metopic Suture. In early life the metopic suture divided the frontal bone into left and right halves. With in the bone, and above and the metopic suture, is the Frontal Sinus. The left and right Frontal Crest, begins at each Zygomatic Process of the frontal bone, and provides the anterior origin of the Temporal Line to which the left and right temporal muscle is attached.

Internally, the frontal bone possesses the Median Sagittal (i.e., Sagittal-Frontal) Crest which separates the two frontal hemispheres of the brain.

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The Occipital Bone

The Occipital Bone consists of a large squamous, or flattened portion separated from a small thick basal portion by the Foramen Magnum on either side of which is a left or right Occipital Condyle. The occipital condyles articulate with the first cervical vertebrae (the Atlas). Externally, the squamous portion of the bone possesses Superior, Middle, and Inferior Nuchal Lines to which the muscles at the back of the neck are attached. The External Occipital Protuberance lies on the superior nuchal line in the mid-sagittal plain. Lateral to each occipital condyle are the Condylar Fossae and Foramen while the Hypoglossal Canal is medial to them.

Internally, are the Sagittal and Transverse Sulci, or grooves which converge at the Confluence of Sinuses. A single internal Occipital Protuberance or Cruciform Eminence is also found in this area. Running inferior from the eminence to the foramen magnum is the Internal Occipital Crest which separates the Cerebellar Fossae. The transverse sulci assist in directing the developing jugular vein to the Jugular Notch on either side of the basilar portion of the occipital.

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The Sphenoid

The Sphenoid has a number of features and projections, which allow it to be seen from various views of the skull. It is a single bone that runs through the mid-sagittal plane and aids to connect the cranial skeleton to the facial skeleton. It consists of a hollow body, which contains the Sphenoidal Sinus, and three pairs of projections: the more superior Lesser Wings, the intermediate Greater Wings, and the most inferior projecting Pterygoid Processes. Internally upon the body is the Sella Turcica where the pituitary gland rests in life. The smaller lesser wings possesses the Optic Foramen through which the optic or second cranial nerve passes before giving rise to the eye.

The Supra-Orbital Fissure separates the lesser wing superiorly from the greater wing below and can best be viewed on the posterior wall of each eye orbit. The left and right greater wings assist in forming the posterior wall of each of the eye orbits where it forms an Orbital Plate.

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Continued89

Just inferior to the supra-orbital fissure near the body of the sphenoid, each of the greater wings also possess a Foramen Rotundum which in life transmits the maxillary branch of the fifth, or trigeminal, cranial nerve. Each of these wings also possesses a much larger Foramen Ovale more laterally, which transmits the mandibular branch of the same nerve. More posteriorly is the smallest of the three pairs of foramena, the Foramen Spinosum which transmits the middle meningeal vessels and nerve to the tissues covering the brain.

The left and right pterygoid processes project inferiorly from near the junction of each of the greater wings with the body of the sphenoid. These processes run along the posterior portion of the nasal passage toward the palate. Each process is formed from a Medial and Lateral Pterygoid Plate to which the respective medial and lateral pterygoid muscle is attached during life. In life the muscles assist in creating the grinding motion associated with chewing.


The Ethmoid

It has a number of features and projections, but unlike the sphenoid it cannot be seen from various views of the skull. It is a single bone that runs through the mid-sagittal plane and aids to connect the cranial skeleton to the facial skeleton. It consists of various plates and paired projections. The most superior projection is the Crista Galli, found within the cranium. It assists in dividing the left and right frontal lobes of the brain. Lateral projections from the Crista Galli are the left and right Cribriform Plates which in life cradle the first cranial nerves i.e., the olfactory nerves. The nerves brachiate through the porosity of these plates into the nasal cavity below. Directly inferior to the Crista Galli and running in the mid-sagittal plane is the Perpendicular Plate of the ethmoid which articulates with the vomer more inferiorly and assists in separating the left and right nasal passages. The Perpendicular Plate can be viewed anteriorly through the nasal cavity.

Descending off each of the Cribriform Plates is a left or right Orbital Plate which aids to form the medial wall of the respective eye orbit. Each Orbital Plate is rectangular in shape and gives rise to two medial projections, the Superior and Middle Nasal Concha. These projections, like the separate Inferior Nasal Concha, assist in increasing the surface area within the nasal cavity and thereby the exposure of the brachiating olfactory nerve to inhaled odors. The Superior or Supreme Nasal Conche are smaller, and cannot be viewed through the anterior nasal opening because it is blocked from view by the more inferior Middle Nasal Conche.

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Paired Facial Bones91


The Lacrimal Bone

The Lacrimal bones are the smallest and most fragile of the facial bones. They are paired left and right and assist in forming the anterior portion of the medial wall of each eye orbit. They are basically rectangular with two surfaces and four borders. Each of the borders articulate with the bones that surround the Lacrimal. The Orbital or Lateral Surface contributes to the eye orbit, while the Medial Surface assists in forming a small portion of the nasal passage. The orbital surface possesses a sharp superior-inferior running ridge called the Posterior Lacrimal Crest which divides this surface into an Orbital Plate and the Lacrimal Sulcus. The sulcus, along with a contiguous sulcus on the maxillae, assists in forming the lacrimal fossa which contains the lacrimal duct in life. The duct connects the medial corner of the eye to the nasal passage and allows tears from the eye to be shunted into the nasal passage.

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The Nasal Bones

Each of the nasal bones is a small rectangular bone which together form the bridge of the nose above the Nasal Cavity also called the Piriform Aperture. They articulate with each other by way of the Internasal Suture and with the frontal bone superiorly by way of the Fronto-Nasal Suture just below the glabellar region of the frontal bone. The intersection of these two sutures marks the anatomical landmark called Nasion. Laterally, each of the nasal bones articulates with the frontal process of the maxilla.

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The Zygomatic Bones

Each cheek or zygomatic bone possesses three major processes which articulate with the bones which surround it.

The Frontal Process of the zygomatic forms the lateral margin and wall of the eye orbit and projects superiorly to articulate with the zygomatic process of the frontal bone. This portion of the bone separates the eye orbit from the temporal fossa and possesses a posterior projecting edge called the Marginal Process. The Temporal Process of the zygomatic runs lateral and posterior toward an articulation with the zygomatic process of the temporal bone. Together these two processes assist in forming the zygomatic arch which serves as the attachment for the masseter muscle in life, one of the primary muscles used in mastication. The temporal muscle runs beneath the arch and is also a primary mover of the mandible in chewing. The Maxillary Process of the zygomatic articulates with the zygomatic portion of the maxilla by way of the Zygo-Maxillary Suture.

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The Maxillary Bone

The Maxillae are the paired facial bones which contain the upper dentition and thus form the upper jaw. Each is basically hollow with a large Maxillary Sinus. A superior projection, the Frontal Process, assists in forming the lateral margin of the nasal aperture and ends by articulating with the frontal bone. An Orbital Plate forms the floor of the eye orbit, while the Zygomatic Process articulates with the zygomatic bone. On the anterior surface of the bone, near the maxillo-zygomatic suture, there is an Infra-Orbital Foramen. The Alveolar Process of the Maxilla contains the upper dentition and assists in giving rise to the Palatine Portion which forms the anterior half of the hard palate. The left and right Maxillae articulate with one another by way of the Inter-Maxillary Suture. The superior end of this suture frequently terminates with the Nasal Spine.

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The Palatine Bones

The Palatine Bones are paired left and right and articulate with one another in the mid-sagittal plane at the Interpalatine Suture. Both bones assist in forming the posterior portion of the hard palate as well as a portion of the nasal cavity. Each bone possesses a Horizontal Part, with an inferior surface which forms the posterior portion of the hard palate and a superior surface that assists in forming the posterior portion of the floor of the nasal cavity. The Vertical Part of each contributes to the lateral wall of the nasal cavity. Near the posterior junction of the Vertical and Horizontal Parts on the palatal surface is a Palatine Foramen. Each bone possesses a number of processes and articular surfaces which touch the bones that surround it.

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The Inferior Nasal Concha

The Inferior Nasal Concha is a very thin, porous, and fragile, paired bone basically elongated and curled upon itself. It lays in the horizontal plane and is attached to the lateral wall of the nasal cavity. By way of the Maxillary Process on the bone's lateral surface, it is attached to the maxilla, and by way of the Lacrimal, Ethmoid and Palatine Processes to each of the bones which assist in forming the lateral wall of the nasal cavity. By projecting into the nasal cavity, the medial surface of the Inferior Nasal Concha assists in increasing the surface area within the cavity and thus increases the amount of mucus membrane and olfactory nerve endings exposed to inhaled odors.

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Unpaired Facial Bones98


The Vomer Bone

The Vomer is a single relatively flat bone located in the mid-sagittal plane. It articulates with the perpendicular plate of the ethmoid superiorly and together aid in forming the nasal septum. While it is frequently deflected slightly to the left or right, in general the septum is aligned perpendicularly and divides the nasal aperture into the left and right nasal passages. In addition to the Perpendicular Portion, superiorly the Vomer mushrooms out into a pair of Alae which terminate and articulate with the sphenoid in a heart shaped process. Inferiorly the Vomer rests on both the maxillae and the palatines.

99


The Mandible

The Mandible or lower jaw consists to four major portions, a left and right Mandibular Ramus and the left and right Body. The Alveolar Process of the body is that portion of the mandible which contains the lower dentition. The junction of the ramus and the body occurs at the Gonial Angle where externally one of the masseter muscles is attached. The left and right masseters make up a set of two sets of muscles used in chewing. At the gonial angle on the internal surface the Pterygoid Attachments are found. These attachments are for the medial and lateral pterygoid muscles which assist in the grinding motion of chewing.

The external surface of the mandibular body possesses the Mental Foramen and at the midline, the Mental Protuberance or chin. The internal surface of the body possesses the Lingual Foramen, the Mandibular Canal, and the longitudinal running Mylohyoid Ridge. The Genio Tubercle is located in the mid-sagittal plane on the internal surface of the mandible. The superior margin of each ramus possesses both a Mandibular Condyle or Head, for articulation with the temporal bone at the tempro-mandibular joint, and the Coronoid Process, for the attachment of the temporalis muscle (one in the set of primary muscles used in mastication). The mandible articulates with each of the Maxillae by way of their contained respective lower and upper dentition.

100


The Hyoid Bone

The hyoid is a single small "U" shaped bone in the adult which does not articulate with any other bone. It is suspended from the styloid process of each temporal bone by means of the stylohyoid ligaments. It is located in the mid-sagittal plane, at the front of the throat, and beneath the mandible but above the larynx near the level of the third cervical vertebrae. It is formed from three separate parts (i.e., the Body, and the left and right Greater and Lesser Cornu) which fuse in early adulthood. The base of the "U" shaped bone is located anteriorly while the Cornu project posteriorly.

101



The Hard Palate

The hard palate is vaulted. Its bony skeleton is made up of the palatine processes of the maxillae (anterior two thirds) and the horizontal plates of the palatine bones (posterior third). The mucosa of the hard palate is tightly bound to the underlying bone.

At the anterior end of the hard palate are transverse palatine folds which assist with the manipulation of food during chewing. In the midline is a narrow whitish streak, the palatine raphe, which marks the site of fusion of the embryonic palatal processes. The blood supply is chiefly from the greater palatine artery of each side. The greater palatine vessels emerge from the greater palatine foramina. There is one of these on each side in the lateral border of the hard palate, medial to the upper 3rd molar tooth. The nasopalatine nerve supplies the mucous membrane of the anterior part of the hard palate. The nasopalatine nerve passes from the nose through incisive canals that open into the incisive foramen which is posterior to the central incisor teeth. Behind each greater palatine foramen and more laterally, is the pterygoid hamulus of each side.

The most posterior end of the hard palate is extended a little bit in the midline and this process is called the posterior nasal spine.

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TMJ104




TMJ

There are three basic types of joints in the human body, and the TMJ incorporates characteristics of all three.

1. The hinge joint, like a knee or elbow, the joint moves like a door opening and closing.

2. The ball and socket joint, like the hip or shoulder, a wide range of motion is achieved by circular motion around a central point.

3. The glide joint, like the wrist wherein motion is achieved when bones essentially glide together and apart.

The TMJ acts like a ball and socket joint when you chew your food, and it acts like a gliding joint when you jut your jaw forward.

To add to the complexity of the TMJ, it is the only joint in the body wherein its motion directly affects the other joint on the other side of the head.

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More about the TMJ

TMJ is the abbreviation used to represent the jaw joint. It stands for temporomandibular joint. TMJ is an anatomical term but is often used to refer to any problem with this joint or the associated jaw muscles. Dentists will generally use the term temporomandibular disorders (TMD) to refer to abnormalities that affect the TMJ or the associated jaw muscles.

The upper part of the mandibular joint is a hollow (mandibular fossa) formed by the temporal bone of the skull. The lower part is formed by the mandibular condyle (end of the lower jaw), hence the term temporomandibular joint. The right and left lower joint bones are joined together by the body of the mandible, and are able to rotate and also move in and out of the upper part of the fossa. This makes the mechanics of jaw movement complex. When one joint is not working well the other is often affected.

There are 3 paired and powerful muscles that close the jaw and bring the teeth together for the biting and grinding of food: the masseter, temporalis, and medial pterygoid muscles. The paired lateral pterygoids protrude the lower jaw and produces jaw opening.

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…

Mandibular fossa - the hollow formed from the temporal bone of the skull where the mandibular condyle (lower joint bone) sits when the mouth is closed.

Mandibular condyle - the lower joint bone that is rounded and moves in and out of the fossa during mouth opening and closing. The right and left condyles are joined together by the mandible (lower jaw).

Articular disc - a firm pad of tissue occupying the space between the upper and lower joint bones. The disc helps to maintain smooth movement and position between the 2 joint bones. Changes in disc position are often the cause of noises occurring in the joint during mouth movements. The disc itself does not have sensation but the surrounding ligaments such as the posterior attachment are sensitive and may become painful due to a disc disorder. The posterior attachment connects the disc to the mandibular fossa.

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…

Temporalis muscle - one of the large jaw-closing muscles that when strained can cause headache in and around the temples.

Masseter muscle - one of the powerful jaw-closing muscles that is attached on the outside of the lower jaw.

Mandible (lower jaw) - ends on both sides of the face to form the mandibular condyle, the lower joint bones.

Lateral pterygoid muscle - when this muscle contracts the condyle is pulled forward and down producing mouth opening.

A firm pad of tissue (the articular disc) occupies the space between the upper and lower joint bones. Ligaments attach the disc to the lower bone and the upper fossa. Changes in disc position are common and can cause jaw clicking and locking. A ligament attached to the upper and lower joint bones surrounds the joint parts. Ligaments help to provide stability to the disc and condyle during movements.

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