American Journal of Orthodontics & Dentofacial Orthopedics

Is the education worth the debt?

W. Eugene Roberts — 2010-08-01

The average debt of a graduating orthodontist is about $250,000, but for some the figure exceeds $600,000. Depending on interest rates, these young orthodontists will pay thousands of dollars a month for 30 years or more just to service the debt. Most educational debt cannot be cancelled by bankruptcy. In the current economy, many recent graduates are struggling to find professional opportunities that are adequate to service their debt and support a desirable lifestyle. Fewer orthodontists have adequate resources to retire, many practices no longer have the patient volume to support an associate, and high debt makes a new graduate a poor risk for a loan to purchase a practice.

Teaching orthodontic residents and clinicians about cleft palate treatment

Samuel Berkowitz — 2010-08-01

Thank you for your comments (Turpin DL. Editor's comment. Am J Orthod Dentofacial Orthop 2010;137:578) on my Guest Editorial in the May issue (Berkowitz S. The need to establish an on-line cleft palate teaching program for orthodontic residents and practicing orthodontists. Am J Orthod Dentofacial Orthop 2010;137:577). A Craniofacial Anomalies and Special Needs Symposium is an excellent tool to improve the education of orthodontic residents and current practitioners in the treatment of children with special needs.

Self-ligating bracket claims

2010-08-01

Although the self-ligating edgewise bracket was introduced to orthodontists 75 years ago, recent advances in bracket technology have resulted in a number of new self-ligating bracket “systems” and greater interest in their use. Much of this interest is in response to information comparing the benefits of self-ligating systems with conventional edgewise brackets. Often, this information comes from marketing materials and nonrefereed sources claiming that self-ligating bracket systems provide superior treatment efficiency and efficacy. In response to and in support of these claims, there have been numerous articles in refereed journals.

Earn 3 hours of CE credit

Michael Rennert — 2010-08-01

Dehiscence and fenestration in patients with Class I and Class II Division 1 malocclusion assessed with cone-beam computed tomography

2010-08-01

Introduction: The aim of this study was to compare the presence of alveolar defects (dehiscence and fenestration) in patients with Class I and Class II Division 1 malocclusions and different facial types.Methods: Seventy-nine Class I and 80 Class II patients with no previous orthodontic treatment were evaluated using cone-beam computed tomography. The sample included 4319 teeth. All teeth were analyzed by 2 examiners who evaluated sectional images in axial and cross-sectional views to check for the presence or absence of dehiscence and fenestration on the buccal and lingual surfaces.Results: Dehiscence was associated with 51.09% of all teeth, and fenestration with 36.51%. The Class I malocclusion patients had a greater prevalence of dehiscence: 35% higher than those with Class II Division 1 malocclusion (P <0.01). There was no statistically significant difference between the facial types.Conclusions: Alveolar defects are a common finding before orthodontic treatment, especially in Class I patients, but they are not related to the facial types.

Editor's Comment and Q&A: Dehiscence and fenestration in patients with Class I and Class II Division 1 malocclusion assessed with cone-beam computed tomography

2010-08-01

Introduction: The aim of this study was to compare the presence of alveolar defects (dehiscence and fenestration) in patients with Class I and Class II Division 1 malocclusions and different facial types.Methods: Cone-beam computed tomography records of 79 patients with Class I and 80 patients with Class II Division 1 malocclusions and no previous orthodontic treatment were evaluated. The sample included 4319 teeth. All teeth were analyzed by 2 examiners who evaluated sectional images in axial and cross-sectional views to check for the presence or absence of dehiscence and fenestration on the buccal and lingual surfaces.Results: Dehiscence was associated with 51.09% of all teeth, and fenestration with 36.51%. The Class I malocclusion patients had a greater prevalence of dehiscence: 35% higher than those with Class II Division 1 malocclusion (P <0.01). There was no statistically significant difference between the facial types.Conclusions: Alveolar defects are a common finding before orthodontic treatment, especially in Class I patients, but they are not related to the facial types.

Orthodontic treatment-related white spot lesions: A 14-year prospective quantitative follow-up, including bonding material assessment

Dmitry Shungin, Alexandra Ioannidis Olsson, Maurits Persson — 2010-08-01

Introduction: White spots (WS) related to orthodontic treatment are severe cariologic and cosmetic complications, but they are shown to be partially reduced by remineralization or abrasion in short-term follow-ups. In this prospective study, we quantitatively analyzed changes in WS in general and in treatment-related white spot lesions (WSL) during orthodontic treatment and at a 12-year follow-up after treatment. In addition, we quantitatively compared the effects of an acrylic bonding material vs a glass ionomer cement (GIC) on WSL.Methods: Sum areas of WS and WSL were calculated on scans of standardized photos of the vestibular surfaces of 4 teeth in consecutive orthodontic patients (median treatment time, 1.7 years) bonded with the 2 materials in a split-mouth design. Comparisons were made in 59 patients before treatment (BF), at debonding (T0), at 1 year (T1), and at 2 years (T2), and in 30 patients at a 12-year follow-up (T3) with the Friedman test followed by pairwise comparisons with the Wilcoxon matched-pairs signed rank test. Differences of the effects of acrylic vs GIC on the sum areas of WSL were tested for each observation period with the Mann-Whitney U test.Results: Increases in the sum areas of WS and WSL from BF to T0 (P <0.001) were followed by significant decreases at T1 (P <0.001) and T2 (P <0.01 for WS; P <0.001 for WSL). Significant changes were also found in the sum areas for WS at T3 compared with T2 (P <0.01), but not for WSL (P = 0.328). The sum areas of WS and WSL at T3 did not return to BF levels (P <0.001). Sum areas of WSL were higher for surfaces bonded with acrylic compared with GIC for each observation period from BF to T2 (P >0.001), and from T2 to T3 (P >0.05).Conclusions: Although significantly reduced during the 12-year follow-up and significantly lower with the GIC than the acrylic material at bonding, WSL are a cariologic and cosmetic problem for many orthodontic patients.

Editor's Comment and Q&A: Orthodontic treatment-related white spot lesions: A 14-year prospective quantitative follow-up, including bonding material assessment

Dmitry Shungin, Alexandra Ioannidis Olsson, Maurits Persson — 2010-08-01

Efficiency of self-ligating vs conventionally ligated brackets during initial alignment

Emily Ong, Hugh McCallum, Mark P. Griffin, Christopher Ho — 2010-08-01

Introduction: The aim of this study was to compare the efficiency of self-ligating (SL) and conventionally ligated (CL) brackets during the first 20 weeks of extraction treatment.Methods: Study models of 50 consecutive patients who had premolar extractions in the maxillary and/or mandibular arch, 0.022 × 0.028-in slot brackets, and similar archwire sequences were examined. Forty-four arches received SL Damon 3MX brackets (Ormco, Glendora, Calif), and 40 arches received either CL Victory Series (3M Unitek, Monrovia, Calif) or Mini-Diamond (Ormco) brackets. The models were evaluated for anterior arch alignment, extraction spaces, and arch dimensions at pretreatment (T0), 10 weeks (T1), and 20 weeks (T2).Results: There were no significant differences between the SL and CL groups at 20 weeks in irregularity scores (mandibular arch, P = 0.54; maxillary arch, P = 0.81). There were no significant differences in passive extraction space closures between the SL and CL groups (mandibular arch, T0-T2, P = 0.85; maxillary arch, T0-T2, P = 0.33). Mandibular intercanine widths increased from T0 to T2: 1.96 and 2.86 mm in the SL and CL groups, respectively. This was not significant between the groups (P = 0.31). Logistic regression did not show a difference between the SL and CL bracket groups.Conclusions: SL brackets were no more efficient than CL brackets in anterior alignment or passive extraction space closure during the first 20 weeks of treatment. Ligation technique is only one of many factors that can influence the efficiency of treatment. Similar changes in arch dimensions occurred, irrespective of bracket type, that might be attributed to the archform of the archwires.

Editor's Comment and Q&A: Efficiency of self-ligating vs conventionally ligated brackets during initial alignment

Emily Ong, Hugh McCallum, Mark P. Griffin, Christopher Ho — 2010-08-01

Introduction: The aim of this study was to compare the efficiency of self-ligating (SL) and conventionally ligated (CL) brackets during the first 20 weeks of extraction treatment.Methods: Study models of 50 consecutive patients who had premolar extractions in the maxillary or mandibular arch, 0.022 × 0.028-in slot brackets, and similar archwire sequences were examined. Forty-four arches received SL Damon 3MX brackets (Ormco, Glendora, Calif), and 40 arches received either CL Victory Series (3M Unitek, Monrovia, Calif) or Mini-Diamond (Ormco) brackets. The models were evaluated for anterior arch alignment, extraction spaces, and arch dimensions at pretreatment (T0), 10 weeks (T1), and 20 weeks (T2).Results: There were no significant differences between the SL and CL groups at 20 weeks in irregularity scores (mandibular arch, P = 0.54; maxillary arch, P = 0.81). There were no significant differences in passive extraction space closures between the SL and CL groups (mandibular arch, T0-T2, P = 0.85; maxillary arch, T0-T2, P = 0.33). Mandibular intercanine widths increased from T0 to T2: 1.96 and 2.86 mm in the SL and CL groups, respectively. This was not significant between the groups (P = 0.31). Logistic regression did not show a difference between the SL and CL bracket groups.Conclusions: SL brackets were no more efficient than CL brackets in anterior alignment or passive extraction space closure during the first 20 weeks of treatment. Ligation technique is only one of many factors that can influence the efficiency of treatment. Similar changes in arch dimensions occurred, irrespective of bracket type, that might be attributed to the archform of the archwires.

Cherubism gene Sh3bp2 is important for optimal bone formation, osteoblast differentiation, and function

2010-08-01

Introduction: Cherubism is a human genetic disorder that causes bilateral symmetrical enlargement of the maxilla and the mandible in children. It is caused by mutations in SH3BP2. The exact pathogenesis of the disorder is an area of active research. Sh3bp2 knock-in mice were developed by introducing a Pro416Arg mutation (Pro418Arg in humans) in the mouse genome. The osteoclast phenotype of this mouse model was recently described.Methods: We examined the bone phenotype of the cherubism mouse model, the role of Sh3bp2 during bone formation, osteoblast differentiation, and osteoblast function.Results: We observed delays in early postnatal development of homozygous Sh3bp2KI/KI mice, which exhibited increased growth plate thickness and significantly decreased trabecular bone thickness and bone mineral density. Histomorphometric and microcomputed tomography analyses showed bone loss in the cranial and appendicular skeletons. Sh3bp2KI/KI mice also exhibited a significant decrease in osteoid formation that indicated a defect in osteoblast function. Calvarial osteoblast cell cultures had decreased alkaline phosphatase expression and mineralization, suggesting reduced differentiation potential. Gene expression of osteoblast differentiation markers such as collagen type I, alkaline phosphatase, and osteocalcin were decreased in osteoblast cultures from Sh3bp2KI/KI mice.Conclusions: These data suggest that Sh3bp2 regulates bone homeostasis through not only osteoclast-specific effects, but also through effects on osteoblast differentiation and function.

Editor's Comment and Q&A: Cherubism gene Sh3bp2 is important for optimal bone formation, osteoblast differentiation, and function

2010-08-01

Introduction: Cherubism is a human genetic disorder that causes bilateral symmetrical enlargement of the maxilla and the mandible in children. It is caused by mutations in SH3BP2. The exact pathogenesis of the disorder is an area of active research. Sh3bp2 knock-in mice were developed by introducing a Pro416Arg mutation (Pro418Arg in humans) in the mouse genome. The osteoclast phenotype of this mouse model was recently described.Methods: We examined the bone phenotype of the cherubism mouse model, the role of Sh3bp2 during bone formation, osteoblast differentiation, and osteoblast function.Results: We observed delays in early postnatal development of homozygous Sh3bp2KI/KI mice, which exhibited increased growth plate thickness and significantly decreased trabecular bone thickness and bone mineral density. Histomorphometric and microcomputed tomography analyses showed bone loss in the cranial and appendicular skeletons. Sh3bp2KI/KI mice also exhibited a significant decrease in osteoid formation that indicated a defect in osteoblast function. Calvarial osteoblast cell cultures had decreased alkaline phosphatase expression and mineralization, suggesting reduced differentiation potential. Gene expression of osteoblast differentiation markers such as collagen type I, alkaline phosphatase, and osteocalcin were decreased in osteoblast cultures from Sh3bp2KI/KI mice.Conclusions: These data suggest that Sh3bp2 function regulates bone homeostasis through not only osteoclast-specific effects, but also effects on osteoblast differentiation and function.

Force characteristics of nickel-titanium open-coil springs

Allyson Bourke, John Daskalogiannakis, Bryan Tompson, Philip Watson — 2010-08-01

Introduction: The objective of this study was to quantify the properties of commercially available nickel-titanium open-coil springs.Methods: Eleven springs from 3 manufacturers were tested 5 times over a 12-week period. A universal testing machine was used to measure the force generated when open-coil springs were compressed to half of their original length and then gradually allowed to decompress.Results: The average forces generated at the initial recording session for uniformly wound springs from GAC International (Bohemia, NY) and 3M Unitek (Monrovia, Calif) were 19.3% to 42.7% and 9.7% to 38.8% below the manufacturers' labeled force levels, respectively. GAC's 100-, 150-, and 200-g stop-wound coils demonstrated statistically and clinically significant stepwise force degradation over the 12-week experimental period (P <0.0001). GAC's uniformly wound light (100 g) coils generated the lowest load-deflection ratios (23.7 g/mm).Conclusions: Open coils might need to be compressed by more than one-third of their original length to produce the labeled forces. Uniformly wound coils generally produce lower load-deflection ratios and maximum forces, which are generally more acceptable for tooth movement.

Editor's Comment and Q&A: Force characteristics of nickel-titanium open-coil springs

Allyson Bourke, John Daskalogiannakis, Bryan Tompson, Philip Watson — 2010-08-01

Introduction: The objective of this study was to quantify the properties of commercially available nickel-titanium open-coil springs.Methods: Eleven springs from 3 manufacturers were tested 5 times over a 12-week period. A universal testing machine was used to measure the force generated when open-coil springs were compressed to half of their original length and then gradually allowed to decompress.Results: The average forces generated at the initial recording session for uniformly wound springs from GAC International (Bohemia, NY) and 3M Unitek (Monrovia, Calif) were 19.3% to 42.7% and 9.7% to 38.8% below the manufacturers' labeled force levels, respectively. GAC's 100, 150, and 200 g stop-wound coils demonstrated statistically and clinically significant stepwise force degradation over the 12-week experimental period (P <0.0001). GAC's uniformly wound light (100 g) coils generated the lowest load-deflection ratios (23.7 g/mm).Conclusions: Open coils might need to be compressed by more than one-third of their original length to produce the labeled forces. Uniformly wound coils generally produce lower load-deflection ratios and maximum forces, which are generally more acceptable for tooth movement.

Comparison of Twin-block and Dynamax appliances for the treatment of Class II malocclusion in adolescents: A randomized controlled trial

2010-08-01

Introduction: The aim of this study was to compare the effectiveness of Twin-block and Dynamax appliances for the treatment of Class II Division 1 malocclusion.Methods: This was a randomized controlled trial involving 32 boys and 32 girls aged 10 to 14 years with Class II Division 1 malocclusion. They were randomly allocated to either the Dynamax appliance group or the Twin-block appliance group. Treatment was provided by 4 clinicians at 2 centers. Records were taken at the start and the end of the functional phase and after all treatment. In addition, incisal overjet, the number of appliance breakages, and adverse events or side effects of the treatment were recorded at each patient visit.Results: The data monitoring committee in an interim analysis at 18 months after the start of the trial found significantly greater overjet reduction in the Twin-block group than in the Dynamax group and more breakages and adverse events with the Dynamax appliance. As a result, treatment with the Dynamax appliance was terminated, and those patients completed treatment with the Twin-block or a fixed appliance. Regression analysis showed a statistically significant difference in the performance over time between the Twin-block and Dynamax appliances in terms of reduction in overjet, with the Twin-block appliance performing significantly better than the Dynamax. The incidence of adverse events was greater in the Dynamax group (82%) than in the Twin-block group (16%), with a statistically significant difference (P <0.001) between the 2 groups.Conclusions: The Twin-block appliance was more effective than the Dynamax appliance when overjet was evaluated and the Dynamax appliance patients reported greater incidence of adverse events with their appliance than those who were treated with the Twin-block appliance.

Editor's Comment and Q&A: Comparison of Twin-block and Dynamax appliances for the treatment of Class II malocclusion in adolescents: A randomized controlled trial

2010-08-01

Occlusal stability of adult Class II Division 1 treatment with the Herbst appliance

Niko Christian Bock, Julia von Bremen, Sabine Ruf — 2010-08-01

Introduction: During recent years, some articles have been published on Herbst appliance treatment in adult patients, an approach that has been shown to be most effective in Class II treatment in both early and late adulthood. However, no results on stability have yet been published. Our objective was to analyze the short-term occlusal stability of Herbst therapy in adults with Class II Division 1 malocclusions.Methods: The subjects comprised 26 adults with Class II Division 1 malocclusions exhibiting a Class II molar relationship ≥0.5 cusp bilaterally or ≥1.0 cusp unilaterally and an overjet of ≥4.0 mm. The average treatment time was 8.8 months (Herbst phase) plus 14.7 months (subsequent multi-bracket phase). Study casts from before and after treatment and after an average retention period of 32 months were analyzed.Results: After retention, molar relationships were stable in 77.6% and canine relationships in 71.2% of the teeth. True relapses were found in 8.2% (molar relationships) and 1.9% (canine relationships) of the teeth. Overjet was stable in 92.3% and overbite in 96.0% of the patients; true relapse did not occur.Conclusions: Herbst treatment showed good occlusal stability 2.5 years after treatment in adults with Class II Division 1 malocclusions.

Oral health-related quality of life and orthodontic treatment seeking

2010-08-01

Introduction: The aim of this study was to assess oral health-related quality of life (OHQOL) in adolescents who sought orthodontic treatment. A comparison between these adolescents and their age-matched peers who were not seeking orthodontic treatment provided an assessment of the role of OHQOL in treatment seeking.Methods: The sample consisted of 225 subjects, 12 to 15 years of age; 101 had sought orthodontic treatment at a university clinic (orthodontic group), and 124, from a nearby public school, had never undergone or sought orthodontic treatment (comparison group). OHQOL was assessed with the Brazilian version of the short form of the oral health impact profile, and malocclusion severity was assessed with the index of orthodontic treatment need.Results: Simple and multiple logistic regression analysis showed that those who sought orthodontic treatment reported worse OHQOL than did the subjects in the comparison group (P <0.001). They also had more severe malocclusions as shown by the index of orthodontic treatment need (P = 0.003) and greater esthetic impairment, both when analyzed professionally (P = 0.008) and by self-perception (P <0.0001). No sex differences were observed in quality of life impacts (P = 0.22). However, when the orthodontic group was separately evaluated, the girls reported significantly worse impacts (P = 0.05). After controlling for confounding (dental caries status, esthetic impairment, and malocclusion severity), those who sought orthodontic treatment were 3.1 times more likely to have worse OHQOL than those in the comparison group.Conclusions: Adolescents who sought orthodontic treatment had more severe malocclusions and esthetic impairments, and had worse OHQOL than those who did not seek orthodontic treatment, even though severely compromised esthetics was a better predictor of worse OHQOL than seeking orthodontic treatment.

Evaluation of the effects of malocclusion and orthodontic treatment on self-esteem in an adolescent population

Min-Ho Jung — 2010-08-01

Introduction: The purpose of this study was to evaluate the effects of malocclusion and orthodontic treatment on adolescent self-esteem.Methods: A total of 4509 middle school students were clinically evaluated for dental crowding. Lip protrusion was also measured with a specially designed ruler. Rosenberg's self-esteem scale was used to determine each subject's level of self-esteem.Results: The results showed that sex played a role in the relationship between self-esteem and malocclusion. For the girls, crowding of the anterior teeth had significant effects on their self-esteem; however, there was no significant difference in the boys' self-esteem. After fixed orthodontic treatment, the girls had higher self-esteem than the untreated malocclusion group. Girls with an ideal profile and good tooth alignment also showed higher self-esteem than students with crowding or protrusion.Conclusions: This clinical study proved that malocclusion and fixed orthodontic treatment can affect self-esteem in adolescent girls.

Facial soft-tissue changes in skeletal Class III orthognathic surgery patients analyzed with 3-dimensional laser scanning

Hyoung-Seon Baik, Soo-Yeon Kim — 2010-08-01

Introduction: Patients undergoing orthognathic surgery show considerable changes in both hard and soft tissues. The purpose of this study was to use a 3-dimensional (3D) laser scanner to evaluate the soft-tissue changes after the correction of skeletal Class III malocclusions with orthognathic surgery.Methods: The subjects consisted of 20 Korean patients with skeletal Class III malocclusion who underwent LeFort I osteotomy with maxillary advancement and posterior nasal spine impaction, along with bilateral intraoral vertical ramus osteotomy for mandibular setback. Ten patients (group 1) had 2-jaw surgery with genioplasty, and the other 10 (group 2) had 2-jaw surgery without genioplasty. Three-dimensional images of the patients were acquired with a 3D laser scanner. The ratios of soft-tissue changes to hard-tissue movements were analyzed and compared between the 2 groups. In addition, the changes in the soft-tissue landmarks in the 3D coordinates and the 3D linear, angular, and proportional changes were measured preoperatively and postoperatively, and compared.Results: There was no significant difference between the groups in the horizontal ratios of the soft-tissue to hard-tissue changes. In both groups, the ratios of the horizontal changes in the paranasal area were higher than in the subnasale area. There were more changes in the subalar area than in the supracommissural area, and more changes in the chin and labiomental areas than in the subcommissural area. Ala moved anterolaterally, and cheilion moved posteroinferiorly. The distance between upper-lip point and cheilion increased significantly (P <0.05). In the 3D angles, transverse nasal prominence and transverse upper lip prominence increased significantly (P <0.05).Conclusions: The 3D analysis in this study can be used to estimate the soft-tissue changes in Class III patients who undergo orthognathic surgery.

Computed tomography evaluation of mandibular incisor bony support in untreated patients

Antonio Gracco, Lombardo Luca, Maria Cristina Bongiorno, Giuseppe Siciliani — 2010-08-01

Introduction: In this study, we aimed to verify, via computed volumetric tomography, a correlation between the morphology of the mandibular symphysis and the various facial types.Methods: From a sample of 148 digital volumetric tomographs, the subjects were classified as either short face (25 subjects), normal face (27 subjects), or long face (28 subjects) according to the average values of their Frankfort-mandibular plane angle. The 80 healthy subjects were between 12 and 40 years of age. Tomography was carried out using NewTom 3G volume scanner (QRsr1, Verona, Italy). The following parameters were measured on the sections corresponding to the 4 mandibular incisors: height, thickness, and area of the entire symphysis; height, thickness, and area of the cancellous bone of the symphysis; distance of the vestibular and lingual cortices from the apices of the 4 incisors; and possible inclination of each mandibular incisor, expressed in degrees. The F test or analysis of variance (ANOVA) and the Tukey HSD Test were subsequently used.Results: The total thickness of the symphysis was greater in the short-face subjects than in the long-face subjects. No statistically significant differences in the total and cancellous areas of the symphysis were found between the 3 facial types. In all 3 groups, the total and cancellous heights and areas were greater at the central incisors than at the lateral incisors.Conclusions: There is a statistically significant relationship between facial type and the total thickness of the mandibular symphysis.

Risk factors for incidence and severity of white spot lesions during treatment with fixed orthodontic appliances

2010-08-01

Introduction: The development of incipient caries, or white spot lesions (WSLs), is a significant clinical problem in orthodontics. The purpose of this study was to retrospectively determine the incidence and severity of WSLs by examining pretreatment and posttreatment digital photographs.Methods: A total of 332 consecutive finished patients from a university graduate orthodontic clinic were evaluated. Initial and final digital images were compared to assess WSLs. The facial surfaces of the anterior 8 maxillary teeth were analyzed. The percentage area of WSL per total facial tooth surface was calculated to control for magnification differences. Reliability of the method was assessed by comparison with direct clinical examination data. Patient and operator factors, and treatment complexity and outcomes were evaluated as predictors of WSL incidence and severity.Results: Agreement between direct clinical examination and digital photo data was excellent, with an intraclass correlation coefficient 0.88 and a 0.3% average difference between methods. The incidence of at least 1 WSL on the labial surface of the anterior 8 maxillary teeth was 36%. The order of incidence was lateral incisor (34%), canine (31%), premolar (28%), and central incisor (17%).Conclusions: Risk factors for the development of incipient caries during orthodontic treatment were young age (preadolescent) at the start of treatment, number of poor hygiene citations during treatment, unfavorable clinical outcome score, white ethnic group, and inadequate oral hygiene at the initial pretreatment examination. The use of computer software to evaluate digital photos retrospectively is a valid method for assessing the incidence and severity of WSLs on the maxillary anterior incisors, canines, and premolars.

Debonding of ceramic brackets by a new scanning laser method

Mehmet Oguz Oztoprak, Didem Nalbantgil, Ayşe Sine Erdem, Murat Tozlu, Tülin Arun — 2010-08-01

Introduction: The purpose of this in-vitro study was to develop a new method to debond ceramic brackets by scanning with an Er:YAG laser.Methods: Sixty bovine mandibular incisors were randomly divided into 2 groups of 30. Polycrystalline ceramic brackets were placed on their labial surfaces by using the orthodontic composite adhesive Transbond XT (3M Unitek, Monrovia, Calif) and light cured for a total of 40 seconds. The first group was the control group, with no laser application performed. The Er:YAG laser was used on each bracket in the study group at 4.2 W for 9 seconds with the scanning method. The force required for debonding the brackets was applied 45 seconds after laser exposure. Shear bond strengths were measured in megapascals with a universal testing machine, and adhesive remnant index scores were assigned to each specimen.Results: Statistically significant (P <0.001) lower shear bond strengths were found in the laser group (9.52 MPa) compared with the control group (20.75 MPa). Likewise, the adhesive remnant index scores were statistically different (P <0.001); the laser group had twice as many samples with adhesive, with the adhesive remnant index scores of 2 or 3.Conclusions: The application of the Er:YAG laser with the scanning method is effective for debonding ceramic brackets by degrading the adhesive through thermal softening.

Effects of high-intensity curing lights on microleakage under orthodontic bands

Tancan Uysal, Sabri Ilhan Ramoglu, Mustafa Ulker, Huseyin Ertas — 2010-08-01

Introduction: Our objective was to compare the effects of 3 light-curing units (LCUs) (quartz-tungsten-halogen [QTH], light-emitting diode [LED], and plasma-arc curing [PAC]) on the microleakage patterns of a polyacid-modified composite (PAMC) for band cementation between the cement-enamel and the cement-band interfaces from the buccal, lingual, occlusal, and gingival margins.Methods: Sixty freshly extracted third molars were randomly divided into 3 groups of 20 teeth each. Microetched molar bands were cemented in all groups with the PAMC (Ultra Band-Lok, Reliance Orthodontic Products, Itasca, Ill) and cured for 30 seconds with the QTH (Hilux 350, Express Dental Products, Toronto, Ontario, Canada), for 20 seconds with the LED (Elipar Freelight 2, 3M Espe, Seefeld, Germany), or for 6 seconds with the PAC (Power-Pac, American Medical Technologies, Hannover, Germany). A dye penetration method was used for microleakage evaluation. Microleakage was determined with a stereomicroscope for the cement-band and cement-enamel interfaces from the buccal and lingual sides at the occlusal and gingival margins. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was set at P <0.05.Results: The gingival sides in the LED and PAC groups had higher microleakage scores compared with those observed on the occlusal sides at both the cement-band and cement-enamel interfaces. The buccal sides had similar microleakage values compared with those on the lingual sides for the cement-enamel and cement-band interfaces in all LCU types. Statistical comparisons showed that there were statistically significant differences among the investigated LCUs at the cement-enamel interface (P <0.05). Post hoc comparisons showed statistically significant microleakage differences between the PAC (median, 0.950 mm), the QTH (median, 0.383 mm) (P <0.01), and the PAC and the LED (median, 0.558 mm) (P <0.05) LCUs at the cement-enamel interfaces.Conclusions: The high-intensity curing device PAC is associated with more microleakage than the LED and QTH at the cement-enamel interface.

Effect of early orthodontic force on shear bond strength of orthodontic brackets bonded with different adhesive systems

Yasser Lotfy Abdelnaby, Essam El Saeid Al-Wakeel — 2010-08-01

Introduction: This study was conducted to evaluate the effect of applying early orthodontic force on the shear bond strength (SBS) of orthodontic brackets bonded with 4 adhesive systems.Methods: Eighty stainless steel brackets were bonded to the enamel surfaces of extracted premolars with 4 adhesive systems. For each adhesive, 10 brackets were bonded without application of force (groups 1, 3, 5, and 7), and another 10 were subjected to a 120-g force with a coil spring (groups 2, 4, 6, and 8). This force was applied 30 minutes after bonding and maintained for 24 hours. Groups 1 and 2 had Rely-a-bond primer and Rely-a-bond adhesive (Reliance Orthodontic Products, Itasca, Ill). Groups 3 and 4 had Transbond XT primer and Transbond XT adhesive (3M Unitek, Monrovia, Calif). Groups 5 and 6 had Transbond Plus Self Etching Primer and Transbond XT adhesive (3M Unitek). Groups 7 and 8 had RelyX Unicem (3M ESPE, Seefeld, Germany). After thermocycling, SBS testing was performed by using a universal testing machine (Type 500, Lloyd Instruments Ltd, Fareham Hants, UK). The results of SBS testing for all adhesives were analyzed by 2-way analysis of variance and the Duncan test. The unpaired Student t test was used to compare the effect of force on the SBS of each adhesive.Results: Transbond XT primer and its adhesive had the highest values (without force, 11.2 ± 3.1 MPa; with force, 10.7 ± 2.7 MPa), and RelyX Unicem had the lowest (without force, 5.8 ± 1.5MPa; with force, 5.7 ± 1.6 MPa). Application of force yielded nonsignificant reductions in SBS for all adhesives; this reduction was less pronounced with RelyX Unicem.Conclusions: For all studied adhesive systems, orthodontic force up to 120 g can be applied within the first hour after bonding with no deleterious effects on bond strength.

Treatment of an ankylosed maxillary incisor by intraoral alveolar bone distraction osteogenesis

YongIl Kim, SooByung Park, WooSung Son, SeongSik Kim, YongDeok Kim, James Mah — 2010-08-01

An ankylosed tooth and adjacent alveolar process can lead to the development of an open bite, an unesthetic smile line, and abnormal function in mastication. Intraoral alveolar bone distraction osteogenesis is an option for treating an ankylosed tooth. The purpose of this clinical report was to show the treatment of a growing patient with an ankylosed maxillary central incisor. A simple tooth-borne intraoral distractor was made with an expansion screw and 0.9-mm stainless steel wire, which enabled it to move easily. Intraoral alveolar bone distraction osteogenesis will give the best results in patients with favorable root length and severely resorbed alveolar bone in the vertical dimension.

Class III subdivision malocclusion corrected with asymmetric intermaxillary elastics

2010-08-01

Correcting a Class III subdivision malocclusion is usually a challenge for an orthodontist, especially if the patient's profile does not allow for any extractions. One treatment option is to use asymmetric intermaxillary elastics to correct the unilateral anteroposterior discrepancy. However, the success of this method depends on the individual response of each patient and his or her compliance in using the elastics. The objectives of this article were to present a successful treatment of a Class III subdivision patient with this approach and to illustrate and discuss the dentoskeletal changes that contributed to the correction.

Interview with an innovator: SureSmile Chief Clinical Officer Rohit C. L. Sachdeva

Robert P. Scholz, Rohit C.L. Sachdeva — 2010-08-01

Robert P. Scholz: You have an interesting educational and work background. Where did you get started, and how did you end up with SureSmile? Rohit C. L. Sachdeva: I was born in Kenya and completed my dental education at the University of Nairobi in the mid 1970s. I took a position as a registrar in orthodontics at the Royal Dental Hospital, University of London, under Dr Bill Houston. There, I was exposed to many orthodontic philosophies, including both functional and Begg. I moved to the United States in the early 1980s and completed my orthodontic residency at the University of Connecticut Health Sciences Center under Dr Charles Burstone. I learned the segmental approach to orthodontics and also developed an interest in the bioengineering aspects of orthodontics. I joined the University of Connecticut faculty and then moved to Canada and joined the faculty at the University of Manitoba, which also had a strong focus on bioengineering research in orthodontics.

Current concepts on temporomandibular disorders

Alex Jacobson — 2010-08-01

Reviewed by Alex Jacobson This book was designed to bring together some renowned experts in the field to provide state-of-the-art information about temporomandibular disorders (TMD). The book is divided into 5 parts, the first of which pertains to “Fundamentals,” beginning with “Anatomy of the temporomandibular joint and masticatory muscles.” The next chapter discusses TMD classification and epidemiology, a system that provides an assessment of psychosocial impairment along with physical impairment, the research diagnostic criteria for temporomandibular disorders (RDC/TMD), which is currently being updated. Discussed in chapter 3, “TMD as a chronic pain disorder,” are the general biomedical concepts of TMD, the general biosocial and psychosocial features of chronic TMD pain, and the general principles of pain assessment and management.

Anna-Marie Gron, 1928-2010

Sheldon Peck — 2010-08-01

Anna-Marie Gron, a retired professor and research orthodontist at Harvard University and The Forsyth Institute, Boston, died on April 9, 2010, of complications of multiple myeloma at her home in Conway, Arkansas. She was 81. In her now-classic research studies, Dr Gron contributed significantly to the understanding of tooth emergence and osseous development as applied to the facial growth patterns of children.

Meeting announcements

2010-08-01

AAO Annual Sessions

Directory: AAO Officers and Organizations

2010-08-01

Editor's choice

David L. Turpin — 2010-08-01

You have just removed a patient's fixed appliances and noticed more than the usual signs of demineralization. You are considering calling a staff meeting to express your displeasure with the patient's esthetic outcome, when a staff member asks, “What causes white spot lesions in our patients? Could we have predicted that this would happen before the start of treatment?” This question brings to mind the objectives of this study from Indiana University. It is a retrospective evaluation of the incidence and severity of white spot lesions and the variables affecting many patients treated with fixed appliances. This interesting study attempts to identify the risk factors leading to incipient caries.

Editors

2010-08-01

Information for readers

2010-08-01

American Journal of Orthodontics & Dentofacial Orthopedics

Is the education worth the debt?

Teaching orthodontic residents and clinicians about cleft palate treatment

Self-ligating bracket claims

Earn 3 hours of CE credit

Dehiscence and fenestration in patients with Class I and Class II Division 1 malocclusion assessed with cone-beam computed tomography

Editor's Comment and Q&A: Dehiscence and fenestration in patients with Class I and Class II Division 1 malocclusion assessed with cone-beam computed tomography

Orthodontic treatment-related white spot lesions: A 14-year prospective quantitative follow-up, including bonding material assessment

Editor's Comment and Q&A: Orthodontic treatment-related white spot lesions: A 14-year prospective quantitative follow-up, including bonding material assessment

Efficiency of self-ligating vs conventionally ligated brackets during initial alignment

Editor's Comment and Q&A: Efficiency of self-ligating vs conventionally ligated brackets during initial alignment

Cherubism gene Sh3bp2 is important for optimal bone formation, osteoblast differentiation, and function

Editor's Comment and Q&A: Cherubism gene Sh3bp2 is important for optimal bone formation, osteoblast differentiation, and function

Force characteristics of nickel-titanium open-coil springs

Editor's Comment and Q&A: Force characteristics of nickel-titanium open-coil springs

Comparison of Twin-block and Dynamax appliances for the treatment of Class II malocclusion in adolescents: A randomized controlled trial

Editor's Comment and Q&A: Comparison of Twin-block and Dynamax appliances for the treatment of Class II malocclusion in adolescents: A randomized controlled trial

Occlusal stability of adult Class II Division 1 treatment with the Herbst appliance

Oral health-related quality of life and orthodontic treatment seeking

Evaluation of the effects of malocclusion and orthodontic treatment on self-esteem in an adolescent population

Facial soft-tissue changes in skeletal Class III orthognathic surgery patients analyzed with 3-dimensional laser scanning

Computed tomography evaluation of mandibular incisor bony support in untreated patients

Risk factors for incidence and severity of white spot lesions during treatment with fixed orthodontic appliances

Debonding of ceramic brackets by a new scanning laser method

Effects of high-intensity curing lights on microleakage under orthodontic bands

Effect of early orthodontic force on shear bond strength of orthodontic brackets bonded with different adhesive systems

Treatment of an ankylosed maxillary incisor by intraoral alveolar bone distraction osteogenesis

Class III subdivision malocclusion corrected with asymmetric intermaxillary elastics

Interview with an innovator: SureSmile Chief Clinical Officer Rohit C. L. Sachdeva

Current concepts on temporomandibular disorders

Anna-Marie Gron, 1928-2010

Meeting announcements

Directory: AAO Officers and Organizations

Table of Contents

Editor's choice

Editors

Information for readers