presents Vol.26 No.8 Orthodontics - Practical Reviews · Orthodontics. Oakstone Medical Publishing is committed to the free exchange iof dental and medical education. ... • Provide

Issue HighlightsThese articles have been selected by theCoordinating Editor as Key Reviews.

Critical Discussion and Commentary

Cognitive Behavioral TherapyIs Effective for Managing Orthodontic Pain

page 3

• Ideal Method for Rebondinga Lingual Retainer

page 4

Bolton Analysis? There’s anApp for That

page 5

more…

Literature Reviews

What Is the Effect of ToothBleaching on Shear BondStrength?

page 6

• How Common Is Caries inAdult Third Molars?

page 8

• Faces Judged as AestheticFall Within CephalometricNorms

page 10more…

Practice Quiz

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Vol. 26 No. 8

E-quiz code: 32053N

Dialogue

September 30, 2012 Original Rel.: September 2012 Termination: September 2014

White spot lesions/decalcificationare an orthodontic dilemma. Whatcan be done? It is gratifying to me

to see the recent interest in research relat-ing to prevention and resolution of whitespot lesions in patients undergoing fixed or-thodontic treatment. In fact, there were atleast six such presentationson this topic at our recentAmerican Association of Or-thodontists annual sessionin Hawaii. A white spot le-sion is a subsurface enamelporosity from carious dem-ineralization that presentsitself as a milky white opac-ity on smooth enamel sur-faces. White spot lesionsare the first visible signs ofenamel demineralization. They reflectchanges in the optical properties, giving thesurface an opaque chalky white appear-ance. They begin as subsurface demineral-izations, but may lead to surface cavitation.White spot lesions have been shown tooccur in as little as four weeks, althoughthey are not generally visible at this point.White spot lesions are most frequently seenon the gingival aspect of maxillary lateral in-cisors, mandibular canines and first premo-lars. Nothing is more frustrating to theclinical orthodontist than to remove bracesfrom an otherwise well-treated case andsee these enamel scars that could havebeen prevented by good oral hygiene dur-ing treatment. The patient came for ortho-dontic alignment, not permanent scars onthe teeth that may require restorative care.

Prevalence of visible white spot lesionsranges from 11–97% depending on the as-sessment method used and whether pre-treatment white spot lesions have been

controlled for. In the largest study of preva-lence conducted to date, approximately 23%of orthodontic patients developed white spotlesions during treatment. With one-fourth ofour patients developing white spot lesions,prevention should be foremost in the mind ofevery clinical orthodontist. It appears the

prevalence of white spotlesions has increased withthe advent of bonding onanterior teeth, possibly dueto acid etching of theseteeth prior to bonding,which increases the likeli-hood of decalcification.Acid etching prior to bond-ing orthodontic bracketsdemineralizes the enamelsurface, exposes enamel

rods and prisms and removes the acquiredpellicle to a depth of 5–25 microns. Thedeeper enamel is much softer than surfaceenamel, making it more acid soluble. Whilepartial remineralization occurs after acidetching, recovery is incomplete. Even withpartial remineralization, the unsightlyenamel scars remain as permanent seque-lae of poor oral hygiene during treatment.

Clinicians whose careers have spannedboth the banding and bonding eras of prac-tice have reported conflicting opinions con-cerning the prevalence of white spot lesionsduring each era. In my practice, there wasno doubt. This included nine years of fullbanding and 23 years of a combination ofbanding molars and bonding all other teeth.Surveys of successive finished cases dur-ing each era revealed a dramatic differencein prevalence of white spot lesions withbonded brackets, but also an exponentialincrease in severity that generally extendedall the way from the bracket to the free

Attempting to determine the

etiology of such a difference in

incidence of white spot lesions

between banding and bonding

continues to be challenging.

White Spot Lesions/Decalcification — An OrthodonticDilemmaAlthough usually caused by poor oral hygiene, it should be the goal ofall orthodontists to prevent white spot lesions to avoid remineralization

By Phillip M. Campbell, DDS, MSD

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presents

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Literature review and critical analysis from the publisher of Practical Reviews

Orthodontics

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Copyright 2012 Oakstone Publishing, LLC. Copyright strictly reserved. The content of this newsletter maynot be reproduced in whole or in part without written permission of Oakstone Publishing, LLC. Note: Content largely consists of abstracts from the medical literature and is not intended to be an exhaustivedissertation on the articles discussed.

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Coordinating Editor John S. Casko, DDS, MS, PhDProfessor, Department of OrthodonticsThe University of Iowa College of DentistryIowa City, IA

ReviewersVincent G. Kokich, Sr, DDS, MSDProfessor, Department of OrthodonticsUniversity of WashingtonSeattle, WA

Brent E. Larson, DDS, MSAssociate ProfessorDivision of OrthodonticsUniversity of MinnesotaMinneapolis, MN

Guest:Phillip M. Campbell, DDS, MSDRobert E. Gaylord Endowed ChairDepartment of OrthodonticsBaylor College of DentistryDallas, TX

gingival margins of the affected teeth, whereas white spot le-sions with bands usually involved the small line where thecement had washed out. Since there was absolutely no pos-sibility of returning to a full-banded appliance, I had to at-tempt to find a solution. The obvious question was: Whatwere the significant differences in the banding and bondingeras? During the full-banded era, for me 1973–82, preformedbands were generally well-fitted. However, due to the conicalshape of all teeth, there were consistently open margins gin-givally. When the cement washed out, the white spot lesionsthat occurred were much smaller and usually did not extendto the free gingival margin. The band cements used wereusually zinc oxyphosphate, which have been shown todemonstrate some antibacterial properties. There were someexceptions, for example, when a given band had been loosefor a long period of time and it was not detected and rece-mented. During the bonded area, for me from 1982–2005,brackets were generally bonded on all teeth except molarswith an obvious increase in white spot lesions following mytransition from banding to bonding, 3% versus 21%. I be-came concerned with the etiology of the significant increasein number and severity of white spot lesions.

Attempting to determine the etiology of such a difference inincidence of white spot lesions between banding and bond-ing continues to be challenging. There are a number of pos-sible reasons why white spots lesions are more prevalentand severe with bonded brackets: 1) acid etching removesthe pellicle and fluoride-rich layer and increases the solubilityof enamel, 2) affinity to and colonization by Streptococcusmutans around bonding resins adjacent to brackets, 3) bac-teriostatic cements like zinc oxyphosphate are no longerused to cement anterior bands, and 4) there appears to havebeen an increased consumption of sodas and sports drinksamong our patient population. Proposed methods for the pre-vention of white spot lesions include an excellent in-officeoral hygiene program including regular monitoring, grading orreward systems; an organized oral hygiene class for patientswith oral hygiene problems prior to initiation of treatment anda separate session for patients already in treatment withproblems; a prescription for a 1.1% sodium fluoride gel;monthly in-office fluoride rinses; regular application of fluo-ride varnish; an encouraged limitation of carbonated bever-ages and sports drinks; application of filled resin sealantsand reapplication as necessary; and development of abracket bonding adhesive that does not require acid etchingand is bacteriostatic.

Admittedly, remineralization of white spot lesions is a nobleundertaking, and there is some evidence of success. How-ever, the unsightly enamel scars are still mostly visible un-less cosmetic bonding or resin infiltration is done. Thesepermanent scars remain for costly follow-up care for manyyears to come and may precipitate negative comments fromassociates and even other dentists, such as, “It is obviousthat you had braces. I see those white spots on your teeth.”Certainly, the goal of all clinicians should be to prevent whitespot lesions from occurring in the first place rather than hav-ing to remineralization or restore them. Currently, we mustrely on excellent oral hygiene, fluorides and filled resinsealants. In lieu of excellent oral hygiene in every patient,filled resin sealants appear to be the best method for preven-tion of white spot lesions during active orthodontic treatment.Filled resin sealants placed on the smooth enamel surfacesof all adolescent patients prior to bonding of brackets

™

presents

in

Literature review and critical analysis from the publisher of Practical ReviewsOrthodontics

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provides a rain coat covering, which has been shown to beat least partially protective even in non-compliant patients.

Even though application of filled resin sealants may be timeconsuming for the clinician, we feel the benefits outweighthe chair time involved. In my opinion, prevention of a singlewhite spot lesion in one patient is worth the effort. The pa-tient came for orthodontic alignment, not permanent scarswhich require restorative care and follow-up maintenance.Was specific informed consent given and the risks thor-oughly explained in lay terms to both patients and parents?Was treatment discontinued when white spot lesions werefirst noticed? Was the oral hygiene so poor that treatmentshould not have been initiated in the first place?

White spot lesions do actually have litigious ramifications.Apparently, there have been some six-figure settlements orjudgments related to white spot lesions recently. Althoughpoor oral hygiene for the patient is the etiology, our solemnresponsibility as professionals is always to do no harm. Thediscipline of orthodontics has provided a wonderful servicefor millions of patients over the last century and is in greaterdemand today than ever before. We should not rest until wehave totally solved the problem of white spot lesions and thesolution should not require patient compliance. Our patientsand profession will be better served by our concerted efforts.

Cognitive Behavioral Therapy Is Ef-fective for Managing OrthodonticPain

Cognitive behavioral therapy is a useful toolfor managing orthodontic pain followingbracketing and archwire placement

By Vincent G. Kokich, Sr, DDS, MSDBased on: Wang J, Jian F, et al. Cognitive Behavioral Ther-apy for Orthodontic Pain Control: A Randomized Trial. JDent Res 2012; 91 (June): 580–585.

Suppose you are about to place orthodontic applianceson a 12-year-old female. The mother informs you thatthe child is highly susceptible to any sort of dental

pain. The mother is concerned that the pain from the initialarchwire placed after bracket bonding will be difficult for herdaughter. You suggest the mother give the daughter ibupro-fen after the orthodontic bonding to reduce the incidence ofpain. The mother states that she does not want to give herchild any sort of drugs. Are there any alternatives? How doyou help your patients to manage orthodontic pain followingappliance placement? That question was addressed in a re-cent study.

The purpose of this study was to assess the efficacy of cog-nitive behavioral therapy intervention for managed

orthodontic pain. This was a randomized clinical trial. Thesample consisted of 450 individuals who were receiving or-thodontic appliances. One hundred and fifty of these individ-uals received ibuprofen every six hours for the first dayfollowing orthodontic banding and wire placement. The sec-ond group of 150 subjects received cognitive behavioraltherapy coaching from a group of 15 therapists. The thirdgroup received no intervention. Brackets were placed on allteeth in this group of subjects who averaged around 12years of age, and an initial archwire was placed. A visualanalog scale was used for subjects to measure and for eval-uators to interpret the degree of orthodontic pain that theyperceived in each of the three groups.

Is it possible, with cognitive behavioral therapy teaching, toreduce the perception of orthodontic pain following applianceplacement to a level that matches the effect of ibuprofen ther-apy? The answer to that question is yes, definitely. Basedupon this large randomized clinical trial, the authors foundthat cognitive behavioral therapy was just as successful asibuprofen in reducing the perception of orthodontic pain fol-lowing appliance and initial archwire placement. Both of thesegroups performed equally well compared to the control sub-jects who received no drugs or cognitive behavioral therapy.

I would advise you to read this article, if possible. In the digi-tal format, there are references to the psychological inter-vention that is used in cognitive behavioral therapy, andthese references can be accessed directly by clicking on thelink following the reference. This is good information thatcould help any orthodontist.

Do You Have a Mission Statement forYour Practice?A mission statement can create a sense ofpurpose for the team members in your practice

By John S. Casko, DDS, MS, PhDBased on: Levin RP. Leadership and Purpose. J Am DentAssoc 2012; 143 (July): 793–794.

For as long as I have been reviewing articles on prac-tice management, it seems that the need for having amission statement for your practice is a topic repeat-

edly discussed. Do you have a mission statement for yourpractice? If so, how do you use it? I believe that for manypractices that do have a mission statement, it is eitherframed and hung on a wall or placed in an operations man-ual and rarely referred to. The important questions are doyou need a mission statement for your practice and, if youdo, why do you need it and how should you use it? Thesequestions are addressed in a recent article.

In this article, Dr. Levin discusses why it is important to havea mission statement for your practice and how the missionstatement should be used. He emphasizes that a missionstatement is an important tool of leadership for any practice

Critical Discussion and Commentary

and can be used to create and promote a clear sense of pur-pose for employees. When things get hectic, it is not uncommon for employees to concentrate on getting throughthe day and forget why they are there. Dr. Levin stated thathe has encountered many non-dental companies in whichthe first agenda item of every meeting is reading the missionstatement. This is simply to remind staff members why theycome to work each day. He also noted that many practicesstart each day reading the mission statement, which he sug-gests should be no more than two to four sentences.

As the leader in your practice, one of your more importantroles is to maintain a sense of purpose for your employees,and a mission statement which is regularly reviewed is oneway to do this. If you do not have a mission statement foryour practice or if you do have one and rarely refer to it, Iwould suggest that you read this article in detail.

Ideal Method for Rebonding a LingualRetainerRemoving all composite remnants is recom-mended prior to rebonding lingual retainers,as greater variability in bond strength existswhen composite remnants remain

By Brent E. Larson, DDS, MSBased on: van Westing K, Algera TJ, Kleverlaan CJ. RebondStrength of Bonded Lingual Wire Retainers. Eur J Orthod2012; 34 (June): 345–349.

Although lingual bonded retainers can provide a won-derful service for our patients that need constant re-tention following orthodontic treatment, maintenance

can be a clinical headache. If a retainer comes loose, wewould like to rebond it quickly and predictably to eliminate thechance that it will come loose again next week. One impor-tant clinical question to answer is whether complete removalof the old composite is necessary prior to rebonding, orwhether the retainer can be bonded to the composite rem-nants that remain. Researchers from the Netherlands re-cently published a paper to help us answer this clinicalquestion.

The study was conducted in the laboratory under controlledconditions. Lingual retainer wire was bonded to 38 bovineteeth etching for 30 seconds with 37% phosphoric acid, ap-plying a bonding adhesive and then a flowable composite. Ametal mold was used to standardize the bonding area to a di-ameter of 4 mm and a height of 2 mm. After curing for 20seconds, samples were stored for two weeks in distilledwater. Bond strength was tested on a universal testing ma-chine, and the strength was recorded for all samples. Afterdebonding, the teeth were randomly assigned to have thecomposite remnants roughened with a tungsten carbide buror to have all adhesive remnants removed. Bonding andbond strength testing was then repeated. Each tooth wasthen rebonded a second time using a repeated crossover de-

sign so the opposite composite removal technique was used.Therefore, each tooth was tested three times with differentenamel conditions — initial clean enamel, roughened com-posite and all composite remnants removed.

The researchers discovered there were no significant differ-ences in the average bond strength among the three testingconditions. However, rebonding teeth with adhesive rem-nants remaining showed a higher standard deviation in bondstrength, that is, more variability. They also found that mostbond failures occurred at the wire-composite interface. Theauthors’ conclusion is that complete removal of compositeprior to rebonding lingual retainers is recommended to re-duce variability in bond strength even though they found theaverage bond strength was not different. So, if you are look-ing for predictability in rebonding, it would seem to makesense to remove all composite remnants if possible. On theother hand, if some remnants remain, you still may have ade-quate strength but a bit less certainty.

It would be nice to have a clinical study to confirm these rec-ommendations, but for now it seems wise to follow the au-thors’ advice when feasible.

Is Ultrasonography Acceptable for Diagnosis of TMJ Disc Displacement?Ultrasonography provides an acceptablerange of accuracy for preliminary detection ofTMJ disc displacement, but positive findingsshould be confirmed by MRI

By Vincent G. Kokich, Sr, DDS, MSDBased on: Li C, Su N, et al. Ultrasonography for Detection ofDisc Displacement of Temporomandibular Joint: A SystematicReview and Meta-Analysis. J Oral Maxillofac Surg 2012; 70(June): 1300–1309.

How would you handle this situation? An adult patientwho has been in orthodontic treatment for about sixmonths complains to you of popping of the left tem-

poromandibular joint. She has recently been wearing Class IIelastics. You tell her to stop wearing the rubber bands andplan to check her in another month. After a month, the poppingof the left joint is continuing, and it occurs when she opens andcloses. She complains to you that this is painful. You suspectthat she has an anteriorly displaced disc that reduces whenshe closes. In order to confirm this diagnosis, you refer her tohave an MRI performed. However, when the patient finds outthe cost of the MRI, she suggests that her sister, who is an ul-trasound technician, could use sonography or ultrasound tocheck the temporomandibular joint for no fee. Is ultrasound anaccurate tool for determining anterior disc displacement? Thatquestion was addressed in a recent study.

The purpose of this study was to perform a systematic reviewto assess and explore the reliability of ultrasonography in di-agnosing disc displacement of the TMJ. Multiple databases

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were explored. The authors identified 15 studies to include inthe meta-analysis. All studies had used sonography to evalu-ate whether or not the disc had been displaced in a series ofpatients.

Most researchers regarded MRI as the gold standard. So,what was the diagnostic accuracy of MRI in predicting or de-termining a displaced disc? The MRI had an accuracy of 95%to detect disc displacement. What did the systematic reviewshow for the accuracy of ultrasound? Good question. The au-thors found that the diagnostic accuracy of ultrasonography inboth closed and open mouth positions was acceptable andwas in the range of between 79% and 90%. What does thismean? These authors believe that ultrasound provides astrong diagnostic basis but is not completely accurate.

The authors suggest that ultrasonography is an acceptablemethod that can be used as a rapid preliminary diagnostictool to exclude clinical suspicions. It is also much more rea-sonable in terms of cost compared to MRI. However, positiveultrasonographic findings should be confirmed by MRI. In ad-dition, the authors point out that ultrasonography has notbeen shown to accurately detect lateral or posterior displace-ment of the disc.

In the scenario that I described previously, it could be benefi-cial for your patient to have her sister use ultrasound to determine if the temporomandibular joint disc is being dis-placed. If this suspicion were positive, then an MRI might beperformed to validate this diagnosis.

Bolton Analysis? There’s an Appfor That

A new smartphone application allows calcula-tion of Bolton discrepancies and arch-lengthdiscrepancies by inputting the mesiodistal dimensions of the dentition

By Brent E. Larson, DDS, MSBased on: Pavan KM, Praveen KN, Vasu Murthy S. ModelAnalysis on a Smartphone. J Clin Orthod 2012; 46 (June):356–358.

As you walk down the street and nearly bump intosomeone who has her face buried in the screen of hersmartphone, do you wonder what impact mobile tech-

nology will have on orthodontics? We can access our recordsand schedules and communicate with our colleagues. Butnow I have an app, or application, for you that does all thecalculations for many model analyses. The app I am talkingabout is previewed in a recent article.

This new app for Android devices was developed by ortho-dontists in India and is capable of performing the followingcalculations: Bolton analysis, arch length discrepancies,Howes analysis, Pont and Linder Harth arch width analyses,and Tanaka-Johnston mixed dentition analysis. As you view

the home screen, the first link on the menu, labeled "Teeth Di-mensions", allows the user to input mesiodistal tooth widths.As you enter values, the program will automatically fill in thesame value for the contralateral tooth to save time. Once thetooth sizes have been entered, the Bolton analysis can be runby just selecting the "Bolton" link. Additional analyses requirethe input of measured arch lengths or arch widths. The pro-gram will prompt the user for the required measurement val-ues to complete the desired calculations. Additionally, a helpmenu describing the various methods of analysis is availablefor reference. The app is called iModelAnalysis and is avail-able for download from the Google Play store.

I was quickly and easily able to download this app and load itonto my Android phone using the QR code published in thearticle. It is actually quite easy to use, even though it requiresmanual input of tooth measurements to do the calculations. Iquickly entered the tooth size data for the upper and lower 3-3, and it immediately calculated the anterior Bolton toothsize discrepancy for me.

Although this specific app may not prove useful for you, it isjust the beginning of mobile applications we will see for oursmartphones to help us with orthodontic treatment planningand management. I think we will see a great deal more ofthese developments in the future as mobile devices continueto grow in popularity and performance.

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Background: Currently, increasingnumbers of adults are seeking ortho-dontic treatment. Many adults havebleached their teeth. Does toothbleaching prior to bonding of orthodon-tic brackets cause a problem withshear bond strength, especially if fluoride-releasing sealants are used?

Objective: To investigate the effects ofbleaching on shear bond strength oforthodontic attachments bonded withfluoride-releasing sealants.

Design/Methods: This was a labora-tory investigation. In total, 160 ex-tracted human molars were dividedinto 2 main groups. One group of mo-lars received 45% carbamide peroxide

bleaching simulating an in-office tech-nique, followed by 5 sessions of 20%carbamide peroxide bleaching to simu-late at-home bleaching. These teethwere then stored in water for 2 weeks.The other group was the unbleachedgroup. Then, both groups had thetooth surfaces etched with phosphoricacid, and some teeth were primed withPro Seal sealant containing fluoride.The remaining groups were primedwith Transbond XT primer. Thenbrackets were bonded to all teeth.After 24 hours, brackets were re-moved and shear bond strength wasrecorded for half the sample. After 3months, the remaining brackets weredebonded and the shear bondstrength was calculated.

Results: Shear bond strengths werealways greater in the patients whoseteeth were bleached compared to thegroup where bleaching was not per-formed. In addition, the Pro Sealsealant showed a reduction in shearbond strength after 3 months in the

unbleached group, but the shear bondstrength was still within clinically ac-ceptable limits.

Conclusions: Bleaching and waitingfor 2 weeks does not have a negativeeffect on shear bond strength of brack-ets when fluoride-releasing sealantsare used.

Reviewer’s Comments: This studyprovides valuable information for or-thodontists who treat adults. The keything to remember is that the teeth thatwere bleached did not have bracketsbonded immediately. A 2-week intervalallowed the residual oxygen presenton the tooth surface during the bleach-ing procedure to be removed. Theresidual oxygen can have an effect onthe curing of the composite.

Reviewer: Vincent G. Kokich, Sr, DDS,MSDArticle Reviewed: Phan X, Akyalcin S,et al. Effect of Tooth Bleaching on ShearBond Strength of a Fluoride-ReleasingSealant. Angle Orthod 2012; 82 (May):546–551.

Literature Reviews reviewsWhat Is the Effect of Tooth Bleaching on Shear Bond Strength?

Take Home Pearl:

Tooth bleaching prior to bond-ing of orthodontic bracketsdoes not reduce the shearbond strength when fluoride-releasing sealants are used.

Clinical

Background: When patients ask youwhat the benefits of orthodontic treat-ment are, what do you tell them?Would you have a valid basis fortelling them that it leads to an improve-ment in quality of life?

Objective: To assess the oral health-related quality of life of patients whocompleted orthodontic treatment com-pared with subjects awaiting orthodon-tic treatment.

Participants: The sample for thisstudy consisted of 2 groups of pa-tients. The treatment group consistedof 100 consecutive patients who

concluded orthodontic treatment atleast 6 months before the study, andthe second group was a control groupof 100 patients with similar orthodonticproblems who were awaiting the initia-tion of orthodontic treatment.

Methods: Data were collected throughface-to-face interviews, self-completedquestionnaires, and oral examinationsby a trained orthodontist. The oralhealth-related quality-of-life assess-ment (a validated assessment form)was administered to each subject andthe scores were statistically evaluated.

Results: Statistical analysis revealedthat the non-treated young adults hadmean oral health impact profile scoresover 5 times greater than the treatedgroup, indicating that the untreatedgroup had a significantly poorer oralhealth-related quality of life than didthe patients who received orthodontictreatment.

Conclusions: Patients who completeorthodontic treatment have a higheroral health-related quality of life thanpatients who do not receive orthodon-tic treatment.

Reviewer’s Comments: I thought thiswas an excellent study. From just see-ing the changes in patients that theyhave treated, I believe most orthodon-tists would feel comfortable saying thatorthodontic treatment usually results inan improved quality of life. It is helpful,however, to be able to refer to a validresearch study that reaches the sameconclusion when talking to patients.

Reviewer: John S. Casko, DDS, MS,PhDArticle Reviewed:Palomares NB, Ce-leste RK, et al. How Does OrthodonticTreatment Affect Young Adults’ OralHealth-Related Quality of Life? Am J Or-thod Dentofacial Orthop 2012; 141(June): 751–758.

Orthodontic Treatment Leads to Improvement in Quality of LifeTake Home Pearl:

This article provides a valid re-search basis for concluding thatorthodontic treatment does leadto an improvement in quality oflife.

Clinical

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Background: For a patient with ananterior deep bite due to a stepdownof the maxillary incisors, it is usuallyindicated to intrude the incisors. Whatdifference would it make if you used amaxillary depressing archwire or amini-implant system to intrude the incisors?

Objective: To compare the skeletaland dental effects of 2 intrusion sys-tems involving mini-implant and theConnecticut intrusion arch in patientswith deep bites.

Participants: The sample for thisstudy consisted of 45 adults who hadanterior deep bites due to upright max-illary incisors.

Methods: The 45 adult patients weredivided into 3 groups. One group usedConnecticut maxillary depressionarchwires to intrude the maxillary inci-sors. The second group used a mini-implant supported intrusion system tointrude the maxillary incisors. The thirdgroup received no treatment and actedas a control group. Cephalometric ra-diographs, panoramic radiographs,models, and intraoral and facial photo-graphs were used to evaluate dentaland skeletal changes after a maximumof 7 months intrusion with each system.

Results: Both systems effectively in-truded and protruded the maxillary inci-sors. The maxillary intrusion archwirealso had a reciprocal effect on the max-illary first molars extruding them due toa distal repositioning of the crown andmesial repositioning of the roots.

Conclusions: Both maxillary depress-ing archwires and mini-implant sys-tems can effectively intrude themaxillary incisors.

Reviewer’s Comments: I was not surprised that both of these systemscould effectively intrude the incisors.Because all of the patients had uprightmaxillary incisors, I was surprised thatthe maxillary depressing archwireswere cinched back distal to the molartubes. This is usually indicated whenyou are trying to intrude protrusivemaxillary incisors to put a distal forceon them. In patients who require intru-sion of the maxillary incisors and canbenefit from some maxillary molar ex-trusion, using the depressing archwirewould be a simpler and equally effec-tive way to intrude the incisors whencompared with the additional work ofplacing implants.

Reviewer: John S. Casko, DDS, MS,PhDArticle Reviewed:Senisik NE,Türkkahraman H. Treatment Effects ofIntrusion Arches and Mini-Implant Sys-tems in Deepbite Patients. Am J OrthodDentofacial Orthop 2012; 141 (June):723–333.

Intrusion Arches, Mini-Implant Systems Both Effectively Intrude Maxillary IncisorsTake Home Pearl:

Mini-implant supported maxillaryincisor intrusion systems do nothave a reciprocal effect on themaxillary first molars.

Clinical

Background: Root resorption is com-mon during orthodontic treatment. Thisfact has been substantiated in severalpast studies. However, the degree ofroot resorption that occurs during or-thodontics can be underestimated be-cause of the type of radiographs thatare typically used, ie, 2-dimensionalfilms. With cone-beam CT (CBCT) im-aging, perhaps the extent of root re-sorption and its location can beassessed more accurately.

Objective: To investigate the incidenceand severity of root resorption duringorthodontic treatment and to explorefactors that have a possible influenceon the degree of root shortening.

Design/Methods: This was aprospective study of 152 patients whohad orthodontic treatment with extrac-tion of at least 1 premolar in each

quadrant. All subjects had Class I mal-occlusions. About half the sample wasmale and the other half was female.The average patient age was 15 yearsat the start of treatment. The averagetime in orthodontic treatment was 20months. CBCT images were taken onall subjects before treatment, after 6months of treatment, and at the com-pletion of orthodontics. Assessmentsof the incidence and location of rootresorption were made at 6 months andat treatment completion.

Results: At 6 months, the highest fre-quencies of root resorption occurred inthe maxillary arch on the premolarsand lateral incisors. Very few roots hadshortening >2 mm and none hadshortening >4 mm. At the completionof orthodontics, the most significantroot resorption was found on maxillarylateral incisors followed by maxillarycentral incisors. Root shortenings >4 mm were found on 2.6% of themaxillary incisors. Of all patients,94.0% had at least 1 root with shorten-ing >1 mm and 6.6% of the samplehad ≥1 teeth with root shortening >4 mm. Root resorption of the incisors

was slanted, with greater resorptionoccurring on the palatal side.

Conclusions: CBCT imaging accu-rately assesses the amount and loca-tion of root resorption. The authorsbelieve that CBCT imaging more accu-rately represents the amount of rootresorption that occurs compared to 2-dimensional radiographs.

Reviewer’s Comments: The authorscould not make a direct comparison ofCBCT imaging and 2-dimensional radi-ographs because they did not includethe latter protocol. However, they con-clude that because the resorption, es-pecially on maxillary central incisors, isslanted with a greater amount occur-ring on the palatal surface, a 2-dimensional radiograph would under-estimate the true degree of root resorption. This is probably true.

Reviewer: Vincent G. Kokich, Sr, DDS,MSDArticle Reviewed: Lund H, Gröndahl K,et al. Apical Root Resorption During Or-thodontic Treatment: A ProspectiveStudy Using Cone Beam CT. Angle Or-thod 2012; 82 (May): 480–487.

Evaluating Root Resorption Using CBCT Imaging

Take Home Pearl:

Cone-beam CT imaging provides a more accurate as-sessment of root resorptioncompared to studies using two-dimensional radiographs.

Clinical

,

8

Background: Cleft lip and palate typi-cally is accompanied by underdevel-opment of the maxilla, especially ifsurgery to correct the cleft deformity isperformed during childhood. Due tothe scarring of the tissue after surgery,there can be a restriction of maxillaryforward growth. If the maxilla is re-stricted significantly, this can result in adeficient airway. Will distraction osteo-genesis of the maxilla improve the air-way space?

Objective: To determine if maxillarydistraction osteogenesis will increase

the pharyngeal airway space in adultsubjects with cleft lip and palate.

Design/Methods: This was a retro-spective analysis of 14 adult subjectswith cleft lip and palate. All subjectshad maxillary distraction osteogenesisto correct their malocclusion. Cephalo-metric radiographs were taken preop-eratively and postoperatively. Theairway space was measured and com-pared to the amount of distraction ofthe maxilla.

Results: Significant improvement oc-curred in the maxilla with an averageforward advancement of nearly 9 mm.As a result, the posterior nasal spinemoved forward about 7 mm on aver-age. There were mean increases inthe posterior pharyngeal airway of 7.5 mm and in the superoposterior air-way of 5.1 mm.

Conclusions: Maxillary distraction inadult cleft lip and palate patients re-sults in significant enlargement of thepharyngeal airway space.

Reviewer’s Comments: This was animpressive article. Distraction of themaxilla is not easy for the patient orthe clinician. However, this studyclearly shows that, if maxillary distrac-tion can be facilitated, this will result insubstantial increases in the posteriorpharyngeal space and airway for thepatient.

Reviewer: Vincent G. Kokich, Sr, DDS,MSDArticle Reviewed:Aksu M, Taner T, etal. Pharyngeal Airway Changes Associ-ated With Maxillary Distraction Osteoge-nesis in Adult Cleft Lip and PalatePatients. J Oral Maxillofac Surg 2012; 70(February): e133–e140.

How Does Maxillary Distraction Osteogenesis Affect Pharyngeal Airway Space?Take Home Pearl:

Maxillary distraction osteogene-sis results in significant in-creases in the posterior airway inadult cleft lip and palate patients.

Clinical

Background: A common decision thatmust be made at the end of orthodon-tic treatment is whether to extractmaxillary and/or mandibular third mo-lars. Often, the decision is clear be-cause of impaction. However, somethird molars erupt and function in oc-clusion. Because these teeth are fur-ther posterior in the oral cavity, do theyhave a higher incidence of periodontalproblems and/or caries?

Objective: To assess the prevalenceof caries and periodontal pathology inerupted third molars in young adults.

Design/Methods: This was a retro-spective assessment of the records of400 adults who had retained eruptedthird molars over a 5-year period. Peri-odontal pocket depths were measuredat 6 sites around all teeth. Caries wasassessed on all molars.

Results: The incidence of periodontalpocketing >4 mm was more frequentaround the third molars than it was onthe first or second molars in youngadults. The authors also found thatcaries on the occlusal surface wasmore prevalent on first molars than itwas on third molars.

Conclusions: Periodontal health maybe slightly compromised around third

molars, but the incidence of carieswas not greater than in other teeth.

Reviewer’s Comments: This studyfollows a long list of trials from the Uni-versity of North Carolina evaluatingthe potential problems that can occur ifthird molars are maintained and notextracted. This review clearly showsthat caries is not a problem in theseteeth; however, the potential for adeeper pocket depth may be moreprevalent.

Reviewer: Vincent G. Kokich, Sr, DDS,MSDArticle Reviewed:Garaas RN, FisherEL, et al. Prevalence of Third MolarsWith Caries Experience or PeriodontalPathology in Young Adults. J Oral Max-illofac Surg 2012; 70 (March): 507–513.

How Common Is Caries in Adult Third Molars?

Take Home Pearl:

Erupted and retained third mo-lars have a lower incidence ofcaries than do first or secondmolars and a higher incidenceof periodontal pocketing.

Clinical

9

Background: There are many bene-fits to receiving orthodontic treatment.Is there any basis for believing that im-provement of adolescents’ self-perception is one of them?

Objective: To evaluate “changes inaesthetic self-perception of Brazilianadolescents who were receiving fixedorthodontic treatment during a 2-yearperiod.”

Participants: 318 adolescents aged12 to 15 years were assigned to 1 of 3groups: a treatment group, a groupwaiting for treatment, or a schoolgroup.

Methods: All subjects completed 3 in-terviews and clinical evaluations. The

first data collection occurred before thebeginning of therapy for the treatmentgroup and was contemporaneous withthe first interviews of the waiting andschool groups. The second time ofdata collection occurred 1 year afterplacement of the fixed appliances forthe treatment group and 1 year afterthe first interviews for the school andwaiting groups. The third data collec-tion took place 2 years after treatmentof the fixed appliances for the treat-ment group and 2 years after the firstinterviews for the school and waitinggroups. The main outcome variableevaluated in this study was the index oforthodontic treatment need-aestheticcomponent of each subject analyzedas a discrete variable.

Results: At the 1- and 2-year post-initiation of treatment periods, therewas a significant improvement in theaesthetic component self scores in thegroup that received orthodontic treat-ment compared to the groups that did

not, each of which had no changes.Gender, age, and socioeconomic sta-tus were not associated with the ado-lescents’ aesthetic self-perception.

Conclusions: Fixed orthodontic treat-ment improves aesthetic self-percep-tions in Brazilian adolescents aged 12to 15 years who sought orthodonticcare.

Reviewer’s Comments: This is an-other trial you can use to support thebenefits of orthodontic treatment. Thisstudy was well conducted and clearlydemonstrated an improvement in self-perception for adolescents who re-ceived orthodontic care, whereasthose who did not receive treatmenthad significantly worse self-ratings.

Reviewer: John S. Casko, DDS, MS,PhDArticle Reviewed: Feu D, Oliveira BH,et al. Influence of Orthodontic Treatmenton Adolescents’ Self-Perceptions of Es-thetics. Am J Orthod Dentofacial Orthop2012; 141 (June): 743–750.

Orthodontic Treatment Can Improve Aesthetic Self-PerceptionTake Home Pearl:

Age and gender do not affect anadolescent’s aesthetic self-perception after orthodontictreatment.

Clinical

Background: Class II malocclusionmay be partially due to insufficientmandibular growth. Is it possible thatthe growth disturbance causing aClass II relationship could be unilateraland produce a skeletal asymmetry? Inother words, are Class II patients moreasymmetric than Class I skeletal patients?

Objective: To determine any differ-ences in skeletal asymmetry betweensubjects with Class I versus Class IIskeletal patterns.

Design/Methods: This was a retro-spective analysis of the records of 80consecutive subjects who underwentorthodontic treatment. The inclusion cri-teria were age 11 to 16 years andcone-beam CT (CBCT) films that fit intoa required ANB angle group. Patientsdid not have crossbites or posteriorCR/CO shifts. CBCT images weremade of these subjects, and an asym-metry assessment was conducted onthe cephalometric landmarks. The land-marks Sella, Nasion, and Dent wereused to create 3 reference planes tomeasure linear landmark distances todetermine symmetry or asymmetry.

Results: Discrepant jaw growth result-ing in Class II skeletal patterns has nomore skeletal asymmetry than Class Iskeletal patterns.

Conclusions: Class II skeletal patternsdo not have greater mandibular asym-metry than Class I skeletal patterns.

Reviewer’s Comments: I did not findthis to be an unexpected finding. Al-though the mandible grows insuffi-ciently in Class II subjects comparedto Class I subjects, I did not expectthis would be unilateral and producemore asymmetries. This study has ver-ified that finding.

Reviewer: Vincent G. Kokich, Sr, DDS,MSDArticle Reviewed:Sievers M, LarsonBE, et al. Asymmetry Assessment UsingCone Beam CT. A Class I and Class IIPatient Comparison. Angle Orthod 2012;82 (May): 410–417.

Is Mandibular Asymmetry Different in Class I &Class II Subjects?Take Home Pearl:

Class II skeletal patterns do nothave more skeletal asymmetrythan Class I skeletal patterns.

Clinical

Background: The goal of any ortho-dontic treatment would be to make theretraction of canines more efficient.Would nonconventional elastomericligatures improve the efficiency of ca-nine retraction?

Objective: To evaluate the clinical effi-ciency of nonconventional ligatureswith that of conventional elastomericligatures during canine retraction.

Participants: The sample consisted of20 patients who required individual

Nonconventional vs Conventional Elastomeric LigaturesTake Home Pearl:

Nonconventional elastomericligatures are more expensivebut not more efficient than con-ventional elastomeric ligatures.

Clinical

10

Background: The use of a thyroid col-lar is recommended to reduce radia-tion exposure to the thyroid when itdoes not alter the diagnostic value ofthe radiograph.

Objective: To evaluate the reductionin effective dose provided by a thyroidcollar during cone-beam CT (CBCT).

Design: In vitro study.

Methods: An adult male phantom(ART-210) with thermoluminescentdosimeter chips at 21 locations wasused to measure the average tissue-absorbed dose during CBCT scans.Five consecutive exposures were per-

formed on a NewTom 9000 CBCTscanner with a large field of view (15 cm × 15 cm cylinder), and the av-erage effective dose was calculated.Five different scan protocols were per-formed: no thyroid shielding; 1 collarloosely on the front of the neck; 2 col-lars loosely on the front and back ofthe neck; 1 collar tightly on the front ofthe neck; and 2 collars tightly on thefront and back of the neck.

Results: Without shielding, the effec-tive organ dose was 31.0 µSv to thethyroid gland and 2.4 µSv to the esoph-agus. The loosely placed collar or col-lars did not effectively lower the dose toindividual organs, but a tightly placedcollar reduced the dose to the thyroidand esophagus by nearly 50% (15.9 µSv and 1.4 µSv, respectively).Two tightly placed collars offered simi-lar protection to a single tight collar. Forall test conditions, there were no signifi-cant differences in total effective dose.

Conclusions: A tightly placed thyroidcollar reduces effective organ dose tothe thyroid and esophagus by approxi-mately 50% but does not significantlylower total effective dose.

Reviewer’s Comments: I was struckthat almost no dose reduction wasfound with a loosely placed thyroid col-lar, highlighting the need for properplacement if it is used. The authorsrecommend a single, tightly placedcollar if used, but due to the low over-all reduction in total effective dose (ap-proximately 1 µSv), it should only beused if it does not sacrifice diagnosticinformation.

Reviewer: Brent E. Larson, DDS, MSArticle Reviewed:Qu XM, Li G, et al.Dose Reduction of Cone Beam CTScanning for the Entire Oral and Maxillo-facial Regions With Thyroid Collars.Dentomaxillofac Radiol 2012; 41 (July):373–378.

Do Thyroid Collars Significantly Alter RadiationDose During CBCT Scans?Take Home Pearl:

A tight thyroid collar may reduceeffective organ dose to the thy-roid and esophagus by nearly50% but does not significantlyalter the total effective dose.

General

canine retraction into first premolar ex-traction spaces in each quadrant.

Methods: A split-mouth design wasused to randomly assign nonconven-tional or conventional ligatures to indi-vidual quadrants. The nonconventionalelastomeric ligatures were Slide liga-tures, which are an innovative ligaturemade of a special polyurethane mix formedical use manufactured by the in-jection molding technique. They wereintroduced in 2005 with a claim of low-ering the levels of friction in treatmentmechanics with preadjusted Edgewiseappliances. The ligature interacts withthe bracket slot to form a tube-likestructure taking the shape of a passiveself-ligating bracket. The rate of canineretraction was measured at monthly in-tervals and at the completion of retrac-tion. The differences in the rate ofretraction were statistically evaluated.

Results: No significant difference wasfound in the rate of canine retraction inthe maxillary arch between the conven-tional and nonconventional elastomericligatures. There was also no significantclinical advantage with nonconven-tional elastomeric ligatures over con-ventional elastomeric ligatures withrespect to the time required to com-plete canine retraction. While canineretraction in the mandibular arch wasslightly more efficient with the noncon-ventional ligatures, this difference didnot appear to be clinically significant.

Conclusions: Compared to conven-tional elastomeric ligatures, noncon-ventional elastomeric ligatures aremore costly and do not appear to bemore efficient.

Reviewer’s Comments: Although thisstudy had a small sample size, I

believe it was well designed. We needmore studies like this to evaluateclaims that manufacturers make re-garding the advantages of specificproducts that they sell. Based on theresults of this study, it does not appearthat nonconventional elastomeric liga-tures provide greater treatment effi-ciency to warrant their additional cost.

Reviewer: John S. Casko, DDS, MS,PhDArticle Reviewed:Dholakia KK, BhatSR. Clinical Efficiency of Nonconven-tional Elastomeric Ligatures in the Ca-nine Retraction Phase of PreadjustedEdgewise Appliance Therapy: An In-VivoStudy. Am J Orthod Dentofacial Orthop2012; 141 (June): 715–722.

Background: One of the key out-comes of orthodontic treatment is

improvement of facial aesthetics, soan orthodontist must have a properunderstanding of what is perceived asaesthetic.

Objective: To identify faces judged ashighly aesthetic and to investigate howtheir cephalometric measurementscompare with cephalometric norms.

Design: Survey.

Methods: Frontal relaxed, frontal smil-ing, and profile photographs weretaken of 89 dental students (77 fe-males and 12 males). Each set of 3photographs were displayed togetherin a Power Point presentation andevaluated by a panel of 34 lay people(30 females and 4 males who were

Faces Judged as Aesthetic Fall Within Cephalometric NormsTake Home Pearl:

The findings of this study showthat the faces considered moreattractive fulfilled the cephalo-metric and facial norms.

Other

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Background: Over the last few years,public awareness of radiation risk hasgrown, prompting the development ofa position paper to assist in choosingappropriate diagnostic imaging, espe-cially cone-beam CT (CBCT).

Objective: To clarify the risks of low-dose maxillofacial radiation.

Design: Editorial/expert opinion.

Discussion: Radiation risk falls into 2broad categories: (1) deterministic ef-fects that require a certain high doseof radiation over a short period tocause direct cell death or malfunction;and (2) stochastic effects that resultfrom low radiation levels that cause

irreversible alteration of the cell. Indentistry, only stochastic effects are arisk with diagnostic maxillofacial radiol-ogy. Although direct evidence is lack-ing, the safest assumption is that theseeffects are linearly related to dose,which creates a minor risk even with avery minimal exposure. However, thisrisk varies depending on the tissue ex-posed, leading to various tissueweighting factors that together definethe effective whole-body dose. In addi-tion, pediatric patients are at a higherrisk due to the greater cellular growthrate, the longer expected lifetime, thehigher specific organ doses found inchildren, and the lack of specific pedi-atric exposure-reduction techniques (inmany instances). Therefore, childrenare considered between 2 and 10times more sensitive to radiation car-cinogenesis compared to adults. Modi-fying exposure parameters for thesepatients is extremely important. To sim-plify explanation of radiation risk, theAmerican College of Radiology is

proposing a new 6-point scale to desig-nate risk with certain procedures.

Conclusions: Careful consideration ofradiation dose remains important whenordering diagnostic imaging, especiallywith pediatric patients.

Reviewer’s Comments: This editorialprovides a nice summary of the vari-ous elements of radiation risk. An im-portant quote regarding the risk fromthe low exposures used for maxillofa-cial imaging is that it “does not meanthat it is known that a risk exists atthese levels, but rather that, in the ab-sence of clear evidence of a thresholddose, it is prudent to assume that sucha risk exists.” I would be interested tosee further development of the pro-posed scale to help providers commu-nicate and understand radiation risk.

Reviewer: Brent E. Larson, DDS, MSArticle Reviewed:Scarfe WC. RadiationRisk in Low-Dose Maxillofacial Radiogra-phy. Oral Surg Oral Med Oral Pathol OralRadiol 2012; 114 (September): 277–280.

Risks With Low-Dose Radiation Exposure

Take Home Pearl:

It is best to assume that low-dose maxillofacial imaging ex-posure presents a small but realradiation risk to patients, espe-cially for pediatric patients.

Other

physiotherapy students aged 20 to 26years). Each slide was shown for 15seconds and ranked on a 5-point scalefrom 1 (very unattractive) to 5 (very at-tractive). Cephalometric analysis wasperformed on the 11 subjects rankedthe most aesthetic and compared tocephalometric norms.

Results: For the 11 most aestheticcases, cephalometric measurements allfell within the accepted norms for thecombined sample. However, significantgender differences were found, with fe-males tending to display more facialconvexity (2.1 mm vs –1.8 mm), asmaller face height ratio (66% vs 79%),

and a higher ANB angle (3.2° vs 0.5°)compared to males. Therefore, attrac-tive males had a slightly straighter pro-file with a stronger lower jaw and morehorizontal facial pattern compared to at-tractive females. None of the 11 mostaesthetic cases had a Class II or ClassIII skeletal relationship.

Conclusions: Attractive subjects hadcephalometric measurements withincephalometric norms, but gender dif-ferences did exist. Attractive femalestended to be slightly Class II with amore convex profile.

Reviewer’s Comments: I think it isimportant to remember when

assessing patients that gender differ-ences in cephalometric measurementsclearly do exist, and assessment of theindividuals’ facial aesthetics is essen-tial along with cephalometric charac-terization. For instance, Class IIIfemales may require surgical correc-tion more frequently than males to ob-tain optimal aesthetics.

Reviewer: Brent E. Larson, DDS, MSArticle Reviewed:Macías Gago AB,Romero Maroto M, Crego A. The Percep-tion of Facial Aesthetics in a YoungSpanish Population. Eur J Orthod 2012;34 (June): 335–339.

Background: Placement of mini-screws into nonkeratinized buccal mu-cosa may increase the risk for tissueirritation and overgrowth compared to

placement into the attached gingiva.On the other hand, miniscrews placedfurther apically are more likely to beplaced into good cortical bone and willhave greater distance from adjacenttooth roots.

Objective: To examine the current re-search on placement of miniscrewsinto unattached mucosa and offerguidelines for miniscrew placement.

Design: Expert opinion.

Discussion: When examining the re-cent literature, no clear consensuswas found on whether mucosal qualityaffects miniscrew failure rates. How-ever, many articles do not differentiatebetween various vertical positionswithin the unattached mucosa thatmay influence results. The nonkera-tinized tissue near the mucogingivaljunction may have very limited mobil-ity, while mucosa at the depth of thevestibule may be very mobile. There-fore, while extreme apical placement

What Is the Success of Miniscrews Above theMucogingival Junction?Take Home Pearl:

Miniscrews placed in the buccalmucosa near the mucogingivaljunction may have higher suc-cess than those placed fartherfrom the attached gingiva.

Surgical

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Background: Sleep bruxism may beassociated with muscle tenderness,muscle stiffness, dental attrition, dentalfractures, and locking of the temporo-mandibular joint. Oral appliances arecommonly used to treat sleep bruxism,but many different designs exist.

Objective: To compare the effects of 3different oral appliances on muscle ac-tivity during sleep.

Design: Randomized crossover trial.

Participants: 11 patients (4 males and7 females) with an average age of 26± 3 years and presenting with self-reported sleep bruxism were includedin the study.

Methods: The experimental protocollasted 30 days for all patients. For thefirst 9 days, no oral appliance wasused and electromyographic (EMG)activity was measured in the right andleft masseter muscles during the first 3days. The baseline EMG reading wastaken from the average of the secondand third nights. For the next week,patients were randomized to 1 of 3oral appliances: a restricted maxillaryand mandibular appliance (MMOA); afree MMOA; or a maxillary oral appli-ance only (MOA, flat-plane splint withcanine guidance). Patients changedappliances weekly until all 3 appli-ances were worn. EMG activity wasrecorded at the end of each week andcompared to baseline. EMG activitywas recorded as phasic (0.25 secondsto 2.0 seconds of activity) or tonic(>2.0 seconds of activity).

Results: The number of phasicepisodes was significantly reduced withall oral appliances, with no significant

differences between appliances. Inter-estingly, no significant changes in tonicactivity were noted with any appliance.

Conclusions: The presence of an oralappliance significantly reduced mas-seter muscle activity, but limitingmandibular movement did not appearto offer any added benefit.

Reviewer’s Comments: The shortlength of the study, limited sample size,and lack of a washout period may influ-ence the results of this study. However,overall, I feel that the findings are con-sistent with other sleep bruxism re-search. Oral appliances offer someimprovement, but it is difficult to differ-entiate between appliances.

Reviewer: Brent E. Larson, DDS, MSArticle Reviewed:Arima T, TomonagaA, et al. Does Restriction of MandibularMovements During Sleep Influence Jaw-Muscle Activity? J Oral Rehabil 2012; 39(July): 545–551.

Effects of Various Oral Appliances on Sleep Bruxism Fairly SimilarTake Home Pearl:

Phasic masseter muscle activityis reduced with the use of anoral appliance, but no significantdifferences exist between vari-ous appliance designs.

Treatment Outcome

may be contraindicated, miniscrewsplaced in limited-mobility mucosa nearthe mucogingival junction may give afavorable soft-tissue response. In addi-tion, this region typically offers goodprimary stability in cortical bone andallows adequate space between roots.

Conclusions: Implant placement innonkeratinized tissue should not be im-mediately disregarded, as placement

near the mucogingival junction may stillgive a favorable tissue response.

Reviewer’s Comments: I have occa-sionally placed miniscrews into mu-cosa near the mucogingival junction toobtain adequate root divergence andhad a good tissue response. Therefore,I tend to agree with this article, al-though little scientific evidence is pre-sented. Further investigation of these

concepts would benefit the clinicianand the patient by helping to provide abalance between adequate bone andsufficient tissue stability for health.

Reviewer: Brent E. Larson, DDS, MSArticle Reviewed:Baumgaertel S, TranTT. Buccal Mini-Implant Site Selection:The Mucosal Fallacy and Zones of Op-portunity. J Clin Orthod 2012; 46 (July):434–436.

13

To receive credit for this activity, answer the practicequiz questions below, read the content, and complete theonline post-activity quiz at www.practicalreviews.com.Log in using your email address and password, click on“Take a Quiz,” and enter the e-quiz code located below.

E-quiz code: 32053N

1. A recent study has shown that cognitive behavioraltherapy is a good tool for reducing and managing or-thodontic pain after initial archwire placement.

Practice: T F Answer Submitted: T F

2. A mission statement can help to motivate staff employees.


3. When rebonding a loose lingual retainer, removal ofall composite prior to rebonding appears to increasethe mean bond strength.


4. In a recent study, researchers showed that bleachingteeth 2 weeks prior to bonding of brackets always re-sults in a lower shear bond strength.


5. When analyzing faces seen as esthetic by lay people,Macías Gago et al found that females tended to haveslightly more convex facial profiles than males.


6. In a recent study, researchers found that ultrasoundwas reasonably accurate for a preliminary assess-ment of TMJ disc displacement.


7. Orthodontic treatment leads to an improved level oforal health-related quality of life.


8. Due to the increasing popularity of applications formobile devices, it is now possible to have a modelanalysis app to simplify the calculation of Boltontooth-size discrepancies and other tooth-size/arch-length relationships.


9. A recent study by Lund et al shows that cone-beamCT imaging accurately assesses the amount and lo-cation of root resorption during orthodontic treatment.


10. In patients with deep bites, maxillary depressingarchwire and mini-implant intrusion systems areequally effective in intruding maxillary incisors.


11. A single tight thyroid collar used during cone-beamCT imaging can reduce the total effective radiationdose by nearly 50%.


12. Miniscrews can be placed in nonkeratinized tissueto limit tissue movement if they are located closeenough to the mucogingival junction.


13. Children are considered less sensitive to radiationcarcinogenesis because they have more rapid cell re-pair mechanisms.


14. In patients with self-reported sleep bruxism, the pres-ence of an oral appliance significantly reduces mas-seter muscle activity, but limiting mandibularmovement does not appear to offer any added benefit.


15. Retained and erupted third molars have a slightlyhigher incidence of caries than do first or second mo-lars in young adults.


16. In a recent study, researchers showed that maxillarydistraction in adult cleft lip and palate patients doesnot significantly improve the pharyngeal airwayspace after surgery.


17. Subjects with Class II skeletal patterns have greateramounts of mandibular asymmetry than do thosewith Class I skeletal patterns.


18. Orthodontic treatment significantly improves self-perception in adolescents.


19. Compared to conventional elastomeric ligatures,nonconventional elastomeric ligatures are morecostly and do not appear to be more efficient for ca-nine retraction into first premolar extraction spaces.


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1. F Although Yang et al were able to demonstratedental expansion following alveolar bone graft-ing in cleft subjects, there was no evidence thatthe midsagittal suture was successfully opened.

2. T When root structure is penetrated by a tempo-rary anchorage device, cementum repair is likelyto occur over time.

3. T A recent study shows that if adenoidectomy isperformed in conjunction with Le Fort I os-teotomy and advancement, a significant increasein the nasopharyngeal airway will occur.

4. T The American Academy of Oral and Maxillofa-cial Radiology recommends cross-sectional im-aging for assessment of implant sites andsuggests that cone-beam CT is the best way toget this information.

5. F A recent study has shown that there is no sig-nificant increase in periodontopathogenic bacte-ria in the gingival sulcus following theplacement of orthodontic appliances in adolescents.

6. T Just like in many 2D landmark studies,Schlicher et al found that in 3D, the sella land-mark shows excellent precision.

7. T Having the “perfect” team in your office is notnecessary for building a successful practice.

8. F Researchers have shown that placing a bone graftand membrane over a mandibular third molar ex-traction site will have a minimal effect on improv-ing periodontal health distal to the adjacent secondmolar.

9. F A laboratory study by Hirai et al found no moretorque delivered with wire ligation compared toelastic ligation under any of their test conditions.

10. F In order to reduce the presence of white spot le-sions, there is no difference between etching for15 seconds versus 30 seconds.

11. T Autotransplantation of completely erupted teethin experimental animals requires root canal ther-apy and orthodontic force appliance 2 weeks afterautotransplantation to reduce root resorption, en-hance success, and prevent ankylosis.

12. F Common at-home bleaching procedures resultin the loss of calcium and phosphorus in toothenamel.

13. T The use of thermoplastic retainers increasesthe likelihood of Streptococcus mutans and Lac-tobacillus accumulation on tooth surfaces.

14. T Rapid maxillary expansion results in an in-crease in nasal cavity volume.

15. T Researchers have recently shown that placingplatelet-rich plasma in third molar extractionsockets compared to nongrafted control sites ac-celerates the formation and regeneration ofalveolar bone during the first 6 months.

16. T During the first 4 months of treatment, an in-direct bonding technique can be valuable in re-ducing plaque accumulation and white spotlesions in patients.

17. T The difference in profile change between extrac-tion and nonextraction in borderline crowdingcases is primarily realized in the perioral area.

18. T More instruments can be accommodated in asterilizer cycle by using pouches rather thanwrapped cassettes.

19. T According to a discussion of tooth replacementoptions for traumatically lost teeth, resin-bonded bridges have a 5-year survival of >85%.

20. T When implant supported teeth are designed,lower cusp inclinations should be favored tominimize lateral loading on the implant.

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