10. diag. & planning in orthog. (88) Dr. RAHUL TIWARI

05/02/2023 12:14:08 AM 1RT/10/DIAG. & PLANNING IN ORTHO. SRUG./88

Rahul TiwariIII yr OMFS PG

DIAGNOSIS & PLANNING

for ORTHOGNATHIC

SURGERY

GOOD MORNING


Introduction Indications Psychological implications Collection of recordsFacial analysisCephalometric analysis Model surgery PlanningConclusionReferences

CONTENTS


INTRODUCTIONORTHOGNATHIC SURGERY is the art and science of diagnosis treatment planning and execution of treatment by combining orthodontics and oral and maxillofacial surgery to correct musculoskeletal, dento osseous and soft tissue deformity of the jaws and associated structures .

It is indicated in patients who have skeletal problems, dento alveolar problems that are too severe to be corrected by orthodontics alone, in whom growth is completed and growth modifications cannot be done.


When a jaw discrepancy accompanies a severe malocclusion, there are three broad possibilities for correction:

(1) growth modification,

(2) camouflage (orthodontic positioning of the teeth to compensate for the jaw discrepancy),

or (3) orthognathic surgery in conjunction with

orthodontics to reposition the jaws and/or dentoalveolar segments.


Growth modification, generally referred to as dentofacial orthopedics, is the most desirable approach to a severe skeletal problem when the potential for further growth exists.

Although the pattern of growth can be favorably modified for some patients, the capacity for major increments in growth is rather limited.

The variation in response of individual patients, however, suggests growth modification should be attempted in preadolescent patients.


When a moderate skeletal discrepancy exists and there is no potential for further growth (or if more change is required than can be accomplished through growth modification alone), orthodontic camouflage should be considered.

The teeth are repositioned to establish normal overjet and overbite in an effort to compensate for the jaw discrepancy .


The final treatment option for a severe skeletal discrepancy is orthognathic

surgery. Once growth has ceased, surgery becomes the only means of

correcting a severe jaw discrepancy. Although surgery may allow greater

changes, there are still limitations to the surgical options, depending on the

type of problem and direction of desired jaw movement, and certain

problems are more receptive to surgical correction than others.


The term reverse orthodontics is often used in reference to the deliberate movement of teeth in a direction that appears to make the worse initially when preparing the dentition for orthognathic surgery.. When dental compensations exist, they limit the distance the jaws can be repositioned to achieve a desirable esthetic result.


First mandibular osteotomy : HULLIHEN (1849) done to correct a protrusive malposition of a mandibular alveolar segment.

In 1927, WASSMUND introduced total maxillary osteotomy and inverted “L” ramal osteotomy, by external approach.

In 1959, TRAUNER and OBWEGESER introduced sagittal split osteotomy as the beginning of a new era of orthognathic surgery.

The beginning of the early orthognathic surgery was in St.Louis where the orthodontist Edward Angle and the surgeon Vilray Blair worked together

HISTORY


Epker, Bell and Wolford developed Lefort-1 maxillary downward fracture, so that we can keep the maxilla stable in all 3 planes of spaces.

By 1980 progress has reached to such an extent that, it is possible to reposition either or both the jaws and to move the chin in all 3 planes of spaces & Rigid internal fixation made it possible for comfort and better immobilization after surgery.

AJODO. 2007 Feb;131(2):263-7


ETIOLOGIC FACTORS

Dentofacial deformity Developmental problem.

ETIOLOGY

KNOWN SPECIFIC

CAUSEHEREDITARY

FACTORSENVIRONMENT

ALINFLUENCES

Occasionally the deformity is due to a single specific cause, much more frequently they result from a complex interaction among multiple factors that influence growth and development.


Respiratory influenceMouth breathing has been blamed for altered dentofacial development

Harvold et al, showed that total blocking the nares led to Various moderate to severe malocclusions, Because the lower jaw was positioned forward , the deformity always included a component of mandibular prognathism along with various displacements of teeth

Total nasal obstruction

Downward backward rotation

Long face deformity

(AJODO, vol 79. 1981).


Why Orthognathic Surgery?1.When orthodontic treatment alone cannot

correct a problem. 2.To improve jaw function. 3.To enhance the long term orthodontic result

(stability). 4.Reduction in overall treatment time. 5.Change in facial appearance. 6.Improved breathing. 7.Improved speech. 8.Improvement in jaw pain.


Indications for Surgical-Orthodontic Treatment

One answer to the question of "When is a problem too severe for orthodontic treatment only?" is "When the combination of tooth movement and growth modification does not have the potential to bring the patient to normal occlusion."


Psycological Implications of orthognathic patients.

PSYCHOLOGICAL IMPLICATIONS

Facial deformity is defined as “ a physiognomic form that is sufficiently negatively marked, so as to set the individual apart from the general population”.

A dentofacial anomaly may have an adverse effect on an individuals self esteem and self confidence as well as evoke an undesirable social response .

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FACE IS THE INDEX OF MIND

The area of the body which maximally determines physical attractiveness is the face. It is a primary means of identification , expression and non-verbal communication.

There is a high value of cosmetic characteristics in the current society and severe cranio-facial deformity may cause significant psychosocial problems.


Concept of “Body image” ( Schilder and Schonfeld ) 2 components of body image are 1. Body sense 2. Body conceptBody sense The actual appearance the person sees when viewing

himself in a mirror or photograph.

Body conceptThe internal process of how the patient feels about his

appearance.

Generally those patients with a good body image in spite of having a deformity are better candidates for surgery

EXTERNAL & INTERNAL PRESSURE Edgerton & knorr pointed out the importance of external

versus internal motivation.

Internal pressure’ would be that originating within the patient and usually involves depression and a sense of inadequacy.

‘External pressure’ would include the need to please others and a desire to overcome career or social problems through a change in appearance.



Psychological support for orthognathic patients

Selection of patients for orthognathic treatment involves various factors that may ultimately influence levels of patient satisfaction.

These include: physiological; medical; interpersonal and psychological.

The majority of studies investigating the psychological aspects of patients undergoing orthognathic treatment, have shown that patients seeking orthognathic treatment are psychologically well adjusted prior to surgery, and appear to have fewer deficits in their personality dimensions than those patients seeking other ‘cosmetic-type’ procedures.


Who is the patient for orthognathic surgery?

An orthodontist must determine at an early stage why the patient is seeking treatment and what the patient hopes to achieve .

The surgeon must then decide whether this demand can be met surgically.


Lavell et al, emphasized that satisfaction begins with selection of appropriate patients.

The selection can be represented by the acronym .....

‘SAFE’S- Self-assessment of attractivenessA-AnxietyF- FearE- Expectations

Journal of Orthodontics, Vol. 33, 2006, 107–115


High satisfaction with most of orthognathic patients treated can be related to:-

Realistic expectations with regard to outcome.

Patients with a realistic expectation of post-operative discomfort and recovery.

Effective pre-operative preparation of the patient.

Good psychological adjustment both pre- and post-operatively.


DIAGNOSIS AND PLANNING


Data base (case history, patient examination,

Radiographic and model analysis)

Problem list in priority order – Diagnosis

Possible solution to the problem – Tentative treatment plan.

Discussed with the patient & modified

Optimal treatment plan

Execution of treatment


Diagnosis & Treatment Planning - Steps

Patient HistoryClinical Examination

Analysis of Diagnostic Records

Classification Problem List = Diagnosis

Treat pathology(caries, gingivitis etc.)

Problems inpriorityorder

ABCD

Possiblesolution toindividualproblems

Optimal Treatment Plan

DataBase

ABCD


Systematic patient evaluation1. ESSENTIAL PATIENT EVALUATIONS

2.ADJUNCTIVE EVALUATIONS.


ESSENTIAL PATIENT EVALUATIONS A. General patient evaluation.

1.Medical history2.Dental evaluation.a.Dental history.b.Dental health.

B. Social-psychological evalution

C. Esthetic facial evaluation.1.Front face analysis2. Profile analysis

D.Cephalometric evaluation.1.soft tissue.2.Skeletal relation3.dental relation.


E. Panoramic or full-mouth peri apical evaluation.

F. Occlusal evaluation.1.Functional2.Static.

G. Masticatory muscle & TMJ evaluation1.Masticatory muscle.2.Mandibular movements.3.TMJ symptoms.4.TMJ signs

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ADJUNCTIVE EVALUATIONSA. Comprehensive psychologic evaluation.

B. Additional photographs.1.symmetric view2.submental view3.superior view.4.three quarter face view.

C. Computed assited analysis1.video manipulation2.Three dimentional CT scan reconstruction.


D. Additional Radiographs1. Lateral cephalometric radiograph in Rest position.2. P-A view.

E. Diagnostic Occlusal splints.

F. velvopharyngeal evalutions1.speech evaluation.2,Nasoendoscopy.

G.Tongue Evalution1 speech evaluation2.Radographic evaluation of tongue posture.3.clinical evaluation of tongue posture


Demographic data Consists of basic chart information of name, address (home, work or school), age, sex, marital status and type of employment or school attended.

Chief complaint The first goal of the interview is to establish the

patient’s major reason for seeking treatment, which is the chief complaint.

Collection of Data base:


Socio psychological evaluation

Psychological makeup of the patient is important because, despite on objectively favorable treatment result, certain patients will express dissatisfaction with their results due to unrealistic patient expectations regarding the result of the treatment .


Unrealistic expectations are most likely to occur in two types of patients,

patients with acquired deformities and Those with external motivations.

Treatment of such patients must be entered into only after careful consideration and psychologic consultation.

Frequently it is best not to treat the patients since they are generally unhappy with the results achieved. These kind of patients can be distinguished by a deliberate social psychologic evaluation.


Classification of patients Highly positive reactive / group IPatients who respond positively to all questions and

are good candidates for surgeryNeutral reactors / group IIPatients who had given positive responses with 2 or 3

negative or slightly negative responses belong to this group. In general these patients require more than the usual amounts of attention and counseling during the preoperative phase to prevent difficulty later.

Negative reactors / group IIIPatients who gives negative responses to most of the

questions are unlikely to be satisfied by the results of surgery.


Medical history

Patient’s medical information must aim to obtain information regarding medical conditions like history of medication, allergies to drug, bleeding disorder or other congenital abnormalities .

Respiratory problem, cardiac problem, asthma, diabetics, anemia, rheumatic fever etc that may complicate correction of a skeletal deformities.


Family historyIncludes information regarding the marriage

of the parents consanguineous/ non consanguineous marriage, about the siblings, sibling’s general and dental conditions, history of familial disease if any and Parent’s concern for treatment.

Dental history. Knowledge about previous orthodontic therapy, or existing

active orthodontic treatment carries important. Any previous records if available or narrative description about treatment from the previous dentist regarding the nature of treatment and evaluation of results should be reviewed


Pre and post surgical Diagnostic Records:- Study models.- Panoramic and lateral cephalometric radiographs- PA cephalogram in patients with significant

asymmetry- Photographs: extra oral & intra oral


ESTHETIC FACIAL EVALUATION Facial proportions and esthetics.

A precise and detailed soft tissue evaluation is always essential to derive proper diagnosis and accurate treatment plan which maximizes the patient’s benefit.

The most important point in proper analysis of facial esthetics is the use of a clinical format.

Examination should not be based on static laboratory x-ray film and photographic representation of the patient alone.

Frontal face analysis1.Outline form & symmetry

2. Facial level

3. Midline alignment.

4. Facial one thirds

5. Lower one-third evaluation

6. Upper & lower lip lengths

7. Upper tooth to lip relationship

8. Inter labial gap


Profile face analysis

1. Soft tissue profile angle

2. Naso labial angle 3. Orbital rim 4. Cheekbone contour 5. Nasal base-lip contour 6. Nasal projection 7. Throat contour 8. Subnasale-pogonion line

( sn-pg’)



Frontal face analysisOutline form & symmetry.

General outline form & symmetry of face are noted. The widest dimension of the face is the zygomatic width.

According to the normal values established by Farkas with Anthropometric studies the bigonial width is approximately 30% less than the bizygomatic dimension.


CRANIAL TYPES- s.w/s.h x 100 Brachycephalic – 75.9%Mesocephalic – 76-80.9%Dolicocephalic – 81%

Euryproscopic - 97% Mesoproscopic – 97-104%Leptoproscopic – 104%

FACIAL TYPES – f.h/bzw x 100


Facial level To examine facial levels a reliable horizontal landmark is necessary. With the patient in natural head posture, the pupils are assessed for level with the horizon. If pupils are level, they are used as the horizontal reference line and adjacent structures are measured relative to this line. Structures compared with the pupil line are:-

Upper canine level Lower canine level Chin & jaw level

MIDLINE ALIGNMENTSThe relative positions of soft

tissue landmarks (nasal bridge, nasal tip, philtrum, and chin point) and dental midline landmarks (upper incisor midline, lower incisor midline) are assessed for midline alignment..

Philtrum is usually a reliable midline structure and can be used as the basis for midline assessment most often.


Transverse Facial Proportions:

Facial Thirds

SYMMETRY

BALANCE

MORPHOLOGY


Mesurements of intercanthal and interpupilary distances.

The Central Fifth: Delineated by the inner

canthus of the eyes.

Inner canthal distance= alar base of nose

The Medial Fifth:

Width of mouth= interpupillary distance

Line from the outer canthus should coincide with the gonial angles

Outer fifth From the pinna

RULE OF FIFTHS


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UPPER & LOWER LIP The lips are measured

independently in a relaxed position. The normal length from subnasale to upper lip inferior is 19 to 22mm.

The lower lip is measured from lower lip superior to soft tissue menton and normally measure in a range of 38 to 44mm.


Upper tooth to lip relationship Increased or decreased anatomic upper lip length Increased or decreased maxillary skeletal length Thick upper lip expose less incisor than thin upper lips,all

other factors being equal. The angle of view changes the amount of incisor visible to the viewer.

The distance from upper lip inferior to maxillary incisal edge is measured. The normal range is 1 to 5 mm. Women show more within this range. Surgical and orthodontic vertical changes are based primarily on this measurement .

Increase in inter labial gap are seen with anatomic short upper lip, vertical maxillary excess, and mandibular protrusion with open bite secondary to cuspal interferences.

Decreased interlabial gap is found with vertical maxillary deficiency, anatomically long upper lip (natural change with ageing, esp. in males) and mandibular retrusion with deep bite.


Smile position lip level

Ideal exposure with smile is three-quarters of the crown height to 2mm of gingiva. Females show more gingival exposure than males.

Reveals 75% to 100% of the maxillary anterior teeth and the interproximal gingiva



Soft tissue profile angle This angle is formed

by connecting soft tissue glabella, subnasale, and soft tissue pogonion.

General harmony of forehead , midface ,and lower face is appraised with this angle

Nasolabial angle

This angle is formed by the intersection of the

upper lip anterior and columella at subnasale.

This angle can change noticeably with orthodontic and surgical procedures that alter the antero-posterior position or inclination of the maxillary anterior teeth.

Desirable range of 90 to 110 degrees


Evaluation of nose Bell described three type of noseLeptorrhine-long, high and narrow nostrils.

Mesorrhine-lack of dorsal height and columellar support.

Platirrhine-flat broad nose and wide nostrils

Alar base width is equal to the intercanthal width of eye of which is influenced by inherited ethnic characters.

Lefort 1 osteotomies affect the alar base width, superior repositioning is associated with widening of alar base.

simultaneous rhinoplasty is indicated if siginificant change in alar base width is expected during surgery.



The nasal projection measured horizontally from subnasale to nasal tip is normally 16 to20mm ,

. Nasal projection is an indicator of maxillary antero posterior position.

This length becomes particularly important when planning for anterior movement of maxilla.

Nasal projection

Orbital rim

The orbital rim is an antero-posterior indicator of maxillary position.

Deficient orbital rims may correlate positionally with a retruded maxillary position because the osseous structures are often deficient as groups ,rather than in isolation.

The Eye globe normally is positioned 2-4mm anterior to the orbital rim.



The surgical maxillary versus mandibular decision is influenced by the orbital rim position.

Deficient orbital rims dictates the need for maxillary advancement with all other parameters being normal..

Maxillary sulcus contour

Normally this sulcus is gently curved and gives information regarding upper lip tension

Maxilla should not be retracted significantly when a deeply curved thick lip is present since this produces poor lip support.

If possible maxilla should be moved forward towards the curved lip to improve lip support.



LOWER 3RD

Lip projection.Labio-mental sulcus.Lip-chin –throat angle.Lip-chin throat length.Chin neck angle.


Angle between lower lip ,chin ,C- point,Should be approximately 900.

Increased in-Chin deficiencyLower lip procumbency.Excessive sub mental fat.Low hyoid bone position.

Lip-chin throat angle

CHIN-NECK ANGLEAlso termed cervicomental

angleVaries between 105-120º.Absolute 110 o.

Distance Between pogonian to neck chin angle is 50mm.



The relationship of lips to the sn-pg’ line is an important aid in soft tissue analysis and treatment.

Tooth movement changes the relationship of the lips to the sn-pg’ line and therefore the esthetic result.

SUBNASALE - POGONION LINE ( SN-PG’)


CEPHALOMETRICS FOR ORTHOGNATHIC SURGERY


COGS – Cephalometrics for Orthognathic SurgeryDeveloped by Charles Burstone et alPresented first in Journal of Oral Surgery. 1978 April.

Followed by Soft tissue Cephalometric Analysis for Orthognathic surgery in Journal of Oral Surgery. 1980 .

Data derived from samples obtained from Child Research Centre, Univ. of Colorado school of medicine.

Sample type: Northern european descentSample Size = 27

16 females 11 males


A constructed plane called Horizontal Plane which is surrogate Frankfort Horizontal plane constructed by drawing a line 70 from SN plane

Most measurements will be made from projections either parallel or perpendicular to the Horizontal Plane


Chosen landmarks and measurements can be altered by various surgical procedures.

The appraisal includes all facial bones and a cranial base reference.

Rectilinear measurements can be readily transferred to a study cast for mock surgery.

Critical facial components can be examined.

Consists of a series of measurements that can be

computerised.



GLABELLA NASION

ANS PNS

POINT A POINT B

SELLA PORION

BASION POGONION

GNATHION

MENTON

GONION

ORBITALE

CEPHALOMETRIC LANDMARKS


69

Maxillary and Mandibular measurements

ANS-PNS

Ar-Go

Go-Pg

Gonial Angle and Chin Prominence

Ar-Go-Gn


Dental Angular Measurements

Upper Incisor – Nasal Floor angle

Lower Incisor – Mandibular Plane Angle

Burstone’s Soft Tissue Analysis

Legan & Burstone (1980)J oral Surg. 1980




Dr.Aravind.M

G-Sn-Pg angle=12 °

G-Sn=6mm

G-Pg=0mm


Dr.Aravind.M

Vertical Height Ratio=1:1

G - Sn

Sn - Me

Nasolabial Angle=110 °


Interlabial Gap=2mm

Mentolabial Sulcus=4mm

Upper lip protrusion=3mm

Lower lip protrusion=2mm


Maxillary Incisor Exposure=2mm

Stms-Upper incisor


Soft tissue Cephalometric AnalysisBy William Arnett and Robert Bergman

AJODO 1999

Sequale to Facial keys to orthodontic diagnosis and treatment planning. Part I and II

AJODO 1993


“We only treat what we are

educated to see. The more we

see, the better the treatment

we render our patients”-Arnett.


Model surgery is the dental cast version of cephalometric prediction of surgical results.

Typically model surgery is done just prior to the actual surgery, after orthodontic preparation has been completed, so there is no need to reposition teeth on casts, but a simulation of the final occlusion can be seen prior to any treatment if a diagnostic setup has been done.

Mandibular advancement can be simulated, for instance, by sliding the lower cast forward relative to the upper cast.

MODEL SURGERY


It is easier to study the possible tooth relationships if the casts are mounted temporarily on an arbitrary articulator so that they are held in the desired position. The better the occlusion without any tooth movement, the easier it is to articulate the casts by hand and vice versa.

If the maxilla will be repositioned vertically, it is

important to use a face-bow transfer to mount the casts on a semi-adjustable articulator so that the condyle-tooth relationships are recorded and mandibular rotation is correctly accounted for doing the cephalometric prediction.


Model SurgeryPurpose of model surgery.

1) To verify that the planned movements are possible

2) To relate the mandibular and maxillary dentitions in the position where the surgical splint will be made.


Model Surgery - 2 jaw surgery Impressions

Face-bow record

Wax bite to record Pre surgical occlusion


Model Surgery -

Casts mounted on semi-adjustable articulator

Requirements of the splintFit the teeth accurately.

Minimum thickness – not more than 2 mm.

Excess acrylic should be trimmed off the buccal aspect, to allow for proper visual verification during surgery and oral hygiene maintenance.



Final splint made


The goal of the treatment plan is develop the plan that will maximise the patient benefit. It is completely based upon diagnostic truth.

Surgical treatment possibilities Logical sequence in planning surgical

orthodontic treatment Treatment plan techniques of cephalometric

prediction and cast prediction


BELL & PROFITTPETERSON PRINCIPLES OF ORAL SURGERY PETER WARD BOOTH REYENEKEFONSECADIMITROULIS

REFERENCES


THANK YOU

Health & Medicine

10. diag. & planning in orthog. (88) Dr. RAHUL TIWARI