Current status of undergraduate orthodontic education in Canada

PURPOSE

This study evaluated teaching hours and mode of instruction of undergraduate orthodontic education dental students in Canada receive, changes implemented by each educational dental institution (EDI) in response to the COVID-19 pandemic, and plans for mode of orthodontic education delivery post-COVID-19.

METHODS

An electronic survey was administered to the program directors of undergraduate orthodontics at each EDI to reveal details regarding the (i) time and details of didactic, preclinical, and clinical experience provided to students and (ii) perceptions of undergraduate program directors about the adequacy of the current curricula.

RESULTS

All 10 Canadian EDIs participated in the survey during the year 2021. Most EDIs deliver their orthodontic curricula beginning in the second year of the program (7, 70.0%), continuing through third (7, 70.0%) and fourth (6, 60.0%) years. The number of hours of didactic, preclinical, and clinical instruction varied by as much as 50 h per academic year across different EDIs. In response to the COVID-19 pandemic, almost all EDIs (9, 90.0%) maintained the same amount of didactic lecture time yet most switched to synchronous (5, 50.0%) or asynchronous (3, 30.0%) online delivery format. Most EDIs (8, 80.0%) indicated the quality of education was maintained during the pandemic.

CONCLUSIONS

There exists significant variation in undergraduate orthodontic time allotment among Canadian EDIs. During the COVID-19 pandemic, most Canadian EDIs maintained a consistent amount of teaching hours while transitioning to some form of online course delivery. Most program directors indicated they believed students received the same quality of education after the change in mode of course delivery. The future of undergraduate orthodontic education will likely continue the accelerated trend toward online education.

Cephalometric effects of Twin-block and van Beek Headgear-Activator in the correction of Class II malocclusion

INTRODUCTION

The Twin-block (TB) and the van Beek Headgear-Activator (vBHGA) are indicated for patients with Class II malocclusion with a retrognathic mandible. Although the former is commonly prescribed for horizontally growing patients, the latter is often recommended for those growing vertically. This study aimed to compare the skeletal, dentoalveolar, and soft-tissue short-term effects of TB and vBHGA, taking growth patterns into account.

METHODS

Immediate prefunctional (T1) and postfunctional appliance (T2) lateral cephalometric radiographs were retrospectively obtained for vBHGA (n = 46), TB (n = 45), and untreated control (n = 45) groups. The interaction of several variables at T1, T2, and T2 - T1, as well as the resultant treatment effect, were analyzed using the analysis of covariance regression models at the 5% significance level.

RESULTS

Except for a greater reduction in Wits measurement (3.0 mm; P <0.0001) in the TB group, no anteroposterior (AP) skeletal difference was observed between the 2 appliances (ANB, 0.530; P = 0.07) (Harvold, 0.13 mm; P = 0.81). Both improved the AP skeletal relationship (ANB and Harvold) compared with the control (P <0.05). Although this mostly occurred because of the forward positioning of the mandible with the TB (SNB, 0.960; P = 0.01), the maxillary restriction was the main mechanism with the vBHGA (SNA, 1.590; P <0.01). Dentoalveolar compensations were more pronounced with the TB (IMPA, 1.92; P = 0.02), leading to greater overbite and overjet correction. Only the inclination of the maxillary incisors showed interaction with the growth pattern, with the TB horizontal growers experiencing more retroclination (U1-NA°. 3.620; P = 0.0067).

CONCLUSIONS

Both appliances produced similar modest AP skeletal changes that, together with dentoalveolar compensations, were able to correct the Class II malocclusion regardless of growth pattern.

Comparison of AdvanSync and intermaxillary elastics in the correction of Class II malocclusions: A retrospective clinical study

INTRODUCTION

Our objectives were to compare the skeletal, dentoalveolar, and soft tissue effects of the AdvanSync appliance (Ormco, Glendora, Calif) with intermaxillary elastics in the correction of Class II malocclusions in growing patients.

METHODS

A retrospective study was conducted using lateral cephalograms of patients taken before and after comprehensive orthodontic treatment; 41 patients consecutively treated with the AdvanSync were compared with 41 similar patients treated with intermaxillary Class II elastics. All patients had significant growth potential during treatment, as assessed by cervical vertebral maturation. A comparison group was generated from historical data bases and matched to the experimental groups for skeletal age, sex, and craniofacial morphology. Treatment changes were evaluated between the time points using a custom cephalometric analysis generating 31 variables as well as regional superimpositions. Data were analyzed using 1-way analysis of variance and Tukey-Kramer tests.

RESULTS

The effects of the AdvanSync and fixed orthodontics included maxillary growth restriction, protrusion, proclination, and intrusion of the mandibular incisors as well as mesialization of the mandibular molars (P <0.01). The effects of Class II elastics and fixed orthodontics were similar to AdvanSync, with the exceptions of less maxillary growth restriction and greater retrusion and retroclination of the maxillary incisors (P <0.01). Significant mandibular growth stimulation, relative to the untreated controls, did not occur with either modality.

CONCLUSION

AdvanSync and intermaxillary elastics were effective in normalizing Class II malocclusions during comprehensive fixed orthodontics. AdvanSync produced its effects through maxillary skeletal growth restriction and mandibular dentoalveolar changes. Class II elastics worked primarily through dentoalveolar changes in both the maxilla and the mandible.

Changes in mandibular incisor position and arch form resulting from Invisalign correction of the crowded dentition treated nonextraction

OBJECTIVE

To investigate changes in mandibular incisor position resulting from Invisalign correction of the crowded dentition without extraction.

MATERIALS AND METHODS

A retrospective chart review was completed on 61 adult White patients. Patients were categorized into three groups based on the value of pretreatment crowding of the lower dentition: 20 mild (2.0-3.9 mm), 22 moderate (4.0-5.9 mm), and 19 severe (>6.0 mm). Cephalometric radiographs were measured to determine lower incisor changes. Interproximal reduction and changes in arch width were also measured. Statistical evaluation of T0 and T1 values using paired t-tests and analysis of covariance were applied to evaluate mean value changes.

RESULTS

Lower incisor position and angulation changes were statistically significant in the severe crowding group. There were no statistically significant differences in lower incisor position between the mild and moderate crowding groups. There was a statistically significant increase in buccal expansion in each of the three groups.

CONCLUSIONS

Invisalign(®) treatment can successfully resolve mandibular arch crowding using a combination of buccal arch expansion, interproximal reduction, and lower incisor proclination. When there is <6 mm of crowding, lower incisor position remained relatively stable. The lower incisors proclined and protruded in the more severely crowded dentitions (>6 mm).

An investigation into bisphenol-A leaching from orthodontic materials

OBJECTIVE

To quantitatively determine the bisphenol-A (BPA) leached from orthodontic materials during simulated intraoral exposure.

MATERIALS AND METHODS

Samples of orthodontic materials were subjected to simulated abrasion, immersion in artificial saliva, thermal shock via temperature cycling, and simulated intraoral exposure. Sample aliquots were collected for up to 2 weeks after artificial saliva immersion, derivatized, then analyzed for BPA by gas chromatography/mass spectroscopy.

RESULTS

Quantifiable amounts of leached BPA were observed from a thermoformed orthodontic retainer material (7.63 µg/g of material) and an orthodontic adhesive (2.75 µg/g of material). BPA leaching was only observed within the first 3 days of artificial saliva immersion.

CONCLUSIONS

Under the test conditions, BPA was observed to leach from two orthodontic materials. While the quantities of leached BPA were below the reference dose for daily intake, existing data of low-dose effects and medical disorders associated with elevated urinary BPA levels suggest that BPA exposure, and thus the use of the leaching materials identified in this study, should be reduced or eliminated.

Differences in the gingival crevicular fluid composition between adults and adolescents undergoing orthodontic treatment

OBJECTIVES

To investigate differences in the gingival crevicular fluid (GCF) composition between adolescent and adult patients undergoing orthodontic treatment with fixed appliances.

MATERIALS AND METHODS

Ten adolescents (14.4 ± 1.43) and 10 adults (28.5 ± 7.83) with Class I malocclusions and minor upper incisor crowding were allocated to two different age groups. Brackets were bonded only in the upper arch over the 20-week period of the experiment. Samples of GCF were collected from the labial sides of the upper incisors (experimental sites) and lower incisors (control sites) of each subject at five time points. Aliquots from diluted GCF were screened for the presence of receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), interleukin-1 (IL-1), interleukin-1 receptor antagonist (IL-1RA), and metalloproteinase-9 (MMP-9) using a microarray technique. The values were statistically analyzed.

RESULTS

In adults, the ratio of IL-1 to IL-1RA decreased significantly (P  =  .033) in experimental sites 3 weeks after appliance placement and first archwire activation. In adolescents, the ratio of RANKL to OPG peaked 6 weeks after the insertion of the first rectangular archwire. This ratio peak found in adolescents was a consequence of a decrease in the mean concentration of OPG. No significant changes over time were observed in the concentration of MMP-9.

CONCLUSION

This study demonstrates age trends in the GCF levels of IL-1, IL-1RA, RANKL, and OPG that may be used to track differences in tissue response between adults and adolescents undergoing orthodontic treatment.

Graduate orthodontic education in Turkey: the residents' perspective

The aim of the present study was to explore residents' perceptions of their educational and clinical treatment experiences including the number of clinical cases undertaken, patient completion rates, techniques utilised and the scientific component of Turkish graduate orthodontic programmes. Residents recorded in the list of Turkish Orthodontic Society were sent an e-mail to participate in a survey containing 46 multiple-choice questions and ten one-line answers. An e-mail with a personalised online link was sent to a total of 227 residents throughout the Turkey. Data were categorised, and basic statistics including chi-square comparative analyses were performed. A total of 136 (response rate of 59.91%) residents completed the survey. The majority of residents (58.08%) were either 'very satisfied' or 'satisfied' with their programme. Respondents said they have just the right amount of formal didactic teaching sessions or dedicated and protected academic time. Most residents (69.11%) indicated their programme offers training in numerous philosophies; whilst 97.79% said they have sufficient clinically based training and 42.64% said they have sufficient research-based training. Overall, residents in the Turkey are satisfied with their orthodontic programme. They receive comprehensive training with the opportunity to start and complete a significant number of their patients. The survey findings suggest that orthodontic programmes in Turkey are deficient in providing care to underserviced populations and disabled patients. Programmes could improve the opportunity for residents to treat patients requiring interdisciplinary treatment.

Digital analysis of staining properties of clear aesthetic brackets

OBJECTIVE

To analyse the staining properties of clear orthodontic brackets using a digital analysis.

DESIGN

In vitro, laboratory study

MATERIAL AND METHODS

A total of 500 tooth-coloured brackets from 10 brands (five ceramic and five plastic) were investigated. The cumulative discolouring effect of staining agents (tea, coffee, curry and red wine) were analysed at two consumption levels: light and heavy, based on a 6-month period of exposure. Study group brackets were immersed in the agents consecutively at 37°C. The control group was only exposed to artificial saliva. Samples were analysed digitally to obtain L*, a* and b* (lightness, red-green and yellow-blue) colour readings. Using these values, total colour change (ΔE*) at each level was also calculated. Three-way analysis of variance (ANOVA) test was used for statistical comparisons.

RESULTS

L* and b* colour parameters showed significant differences (P<0·001) between different bracket groups, consumption levels and the type of exposure. However, the a* value only differed between bracket groups (P<0·001). According to the ΔE* values, ceramic brackets had less colour change than plastic brackets at the end of phase 1 for both the study and control groups. However, as consumption time increased, the rate of colour change decreased for the plastic brackets. In general, ceramic brackets demonstrated much more resistance to staining agents than plastic brackets.

CONCLUSIONS

Both plastic and ceramic brackets showed changes in colour when exposed to heavy consumption of staining agents, with plastic brackets being the most affected.

Relapse of orthodontically corrected deepbites in accordance with growth pattern

INTRODUCTION

A common orthodontic problem is a deep overbite malocclusion. Because of its high relapse tendency, it is also one of the most challenging problems to treat. To minimize relapse, the morphologic characteristics of patients need to be considered. The aim of this study was to compare deepbite relapse in 3 groups of patients categorized by vertical growth type.

METHODS

The total sample included 60 patients treated at the University of Washington in Seattle, all with initial overbites greater than 50%. Data were collected from casts and cephalometric radiographs at 3 time points: pretreatment, posttreatment, and 10 years postretention. A mixed-effects model (analysis of variance) and post-hoc t tests were used for the statistical evaluations.

RESULTS

The high-angle subjects showed the least deepbite relapse (0.1 ± 1.1 mm), whereas the low-angle (1.2 ± 0.9 mm) and the normal-angle (1.4 ± 1.3 mm) subjects had statistically significant relapses P <0.001. This overbite relapse might be partially due to changes in the mandibular and interincisal angles, which were also observed in these 2 groups.

CONCLUSIONS

High-angle subjects tend to relapse less in overbite than do low-angle and normal-angle subjects in the long term.

Impact of orthodontic retainers on periodontal health status assessed by biomarkers in gingival crevicular fluid

OBJECTIVE

To evaluate whether biomarkers of inflammation and periodontal remodeling are differentially expressed in the gingival crevicular fluid (GCF) of patients wearing different types of orthodontic retainers.

MATERIALS AND METHODS

Thirty-one adult subjects (17 men and 14 women with an age range of 20 to 35 years) were allocated to three different groups. Group 1 consisted of 10 patients wearing fixed retainers, group 2 included 11 patients using lower removable retainers, and group 3 comprised 10 patients without retainers (control). Periodontal health assessment and GCF collection were carried out at two sites per subject: the lingual side of a central lower incisor and the lingual side of a lower second premolar. Aliquots from diluted GCF were screened for the presence of biomarkers using a microarray technique.

RESULTS

Group 1 patients exhibited a higher percentage of sites with visible plaque in the incisor region than the other groups (P = .03); no differences were noted in gingival bleeding and probing depths. The median concentrations (pg/mL) of interferon-gamma and interleukin-10 were significantly higher in the premolar sites of patients in group 2 (P = .01 and P = .04, respectively), whereas the concentration of matrix metalloproteinase-9 was significantly higher at the incisors of patients wearing fixed retainers (P = .02). A significant difference between the two sites was seen only in group 2.

CONCLUSIONS

The presence of different orthodontic retainers may promote specific alterations in the GCF composition. With retention periods potentially becoming longer, this finding may be of clinical significance.

Effect of tooth bleaching on shear bond strength of a fluoride-releasing sealant

OBJECTIVE

To evaluate the effect of an in-office plus at-home bleaching protocol on shear bond strength of orthodontic buttons when using a fluoride-releasing sealant.

MATERIALS AND METHODS

Extracted human molars (160) were randomly divided into bleached (n  =  80) and unbleached groups (n  =  80). The bleached group was treated with 45% carbamide peroxide for 30 minutes, followed by five applications of 20% carbamide peroxide at 24-hour intervals. After 2 weeks, lingual buttons were bonded on the teeth in both groups using either Transbond XT primer or Pro Seal sealant. The teeth were then stored in artificial saliva and subjected to shear testing at 24 hours and 3 months using a Zwick Universal Test Machine. Comparisons of mean shear bond strength values were made with the analysis of variance test. The Fisher's exact test was used to evaluate the adhesive remnant index scores.

RESULTS

The analysis of variance of the 24-hour results indicated a significant difference between the four subgroups (P < .0011). Further simple t-tests indicated that the differences were significant only between bleached and unbleached subgroups (P < .0011). The 3-month results showed the mean shear bond strengths of the unbleached group using Pro Seal sealant was significantly lower than that of the other, though still greater than clinically minimal suggested bond strengths. Interestingly, 15% of the bleached teeth exhibited enamel fracture at the 3-month testing.

CONCLUSION

Both Pro Seal sealant and Transbond XT primer demonstrated reliable shear bond strength values on both bleached and unbleached teeth over time.

Motivations of orthodontic residents in Canada and the United States to treat patients with craniofacial anomalies, cleft lip/palate, and special needs

OBJECTIVES

To determine the motivation of orthodontic residents in Canada and the United States to treat patients with cleft lip/palate (CLP), craniofacial anomalies (CFA), and special needs (SN).

METHODS

In March 2009, an e-mail with a link to a 41-item survey was sent to all orthodontic residents in Canada and the United States (n  =  944).

RESULTS

Of 944 residents contacted, 339 viewed and 208 completed the survey (22.03%). Using a seven-point Likert scale, residents recognized the importance of treating patients with CLP/CFA/SN. When asked if they plan to treat patients with CLP/CFA/SN, 54.48% responded yes, 13.46% no, and 36.06% were unsure. A total of 38.05% said they would charge the same fee as a typical multiarch case, while 58.05% would charge more, and 60% of fourth-year residents would charge twice the fee. Of the respondents, 43.00% were aware of the established fellowship programs in CLP/CFA/SN. Canadian residents (67.9%) were more enthusiastic about completing a fellowship than Americans were. Of the respondents, 29.33% would complete a 1-year fellowship, while 70.67% would not. A total of 78.4% of male respondents and 77.4% of American residents indicated they would not pursue a fellowship.

CONCLUSIONS

Residents supported the importance of treating patients with CLP/CFA/SN, and more than 54% indicated they plan to treat these patients. Residents who indicated that they would not treat these patients sited limited experience and inadequate expertise as the reasons. Less than 30% indicated a willingness to pursue a fellowship program.

Motivational factors and future life plans of orthodontic residents in the United States

INTRODUCTION

The purposes of this study were to investigate factors influencing career choice and identify future life plans of orthodontic residents in the United States.

METHODS

Program chairs and directors of all 65 orthodontic residency programs in the United States were contacted by e-mail and telephone for permission to e-mail their residents and invite them to take part in on online survey. A total of 335 residents from 37 programs were invited to complete an anonymous 57-item questionnaire in May 2007. Data were categorized, and basic statistics including chi-square comparative analyses were performed.

RESULTS

A total of 136 (40.60%) residents completed the survey. A "passion for orthodontics" emerged as the most important factor (20.29%) influencing the decision to pursue orthodontics as a career, followed by "intellectual stimulation or challenge" (18.12%). Most residents decided to become an orthodontist before they were in dental school (44.93%). Most residents (89.05%) plan to engage in private practice, and only 2 intend to pursue primarily an academic career. The average resident debt was $165,226 at the end of their program.

CONCLUSIONS

The decision to become an orthodontist is often made early in life, before dental school, and a passion for orthodontics is the motivational factor. Residents plan to enter private practice and not pursue a career in academia. The current shortage of academics and orthodontic researchers will not be resolved from the current pool of orthodontic residents. A possible solution to the academic crisis is to change the selection criteria in programs to accept orthodontic residents who develop a passion for orthodontics while in dental school or to recruit primary researchers and teachers to the specialty. Residents plan to practice in an urban setting. Rural and underserviced areas will probably continue to experience shortages of orthodontists in the future.

Future provision of orthodontic care for patients with craniofacial anomalies and cleft lip and palate

OBJECTIVE

To determine whether Canadian and United States (US) orthodontic programs provide training in treating patients with cleft lip and palate (CLP) and craniofacial anomalies (CFA) and whether residents will treat these patients in their future practices.

METHODS

An email with a personalized link to an anonymous, multi-item, online questionnaire was sent to all 54 Canadian and 335 of the approximately 700 US orthodontic residents. The two questions asked were: "Do you plan to include the treatment of CLP and CFA patients in your practice?" and "Does your program contain formal training in treating patients with CLP and CFA?"

RESULTS

A total of 44 Canadian and 136 US residents responded. In Canada, 30% plan to treat patients with CLP and CFA after graduation, 14% said no, 48% said maybe, and 9% were unsure. In the US, 53% said yes, 7% said no, 36% said maybe, and 4% were unsure. When asked if their program offers formal training in the treatment of these patients, 45% of Canadian residents said yes, 34% said no, and 20% were unsure, whereas 82% of US residents said yes, 12% said no, and 5% were unsure.

CONCLUSION

Most programs in the US and approximately half in Canada provide training in CLP and CFA, and more than half of US and almost one-third of Canadian residents plan to be involved in the care of patients with CLP and CFA, which is considerably less than those receiving training. Orthodontic programs need to increase the number of postgraduate students who are interested in providing care to CLP and CFA patients after becoming orthodontists.

Motivations and future plans of Canadian orthodontic residents

INTRODUCTION

Our purposes were to investigate factors influencing career choice and to identify future plans of Canadian orthodontic residents.

METHODS

All orthodontic residents in the 5 Canadian residency training programs were invited to complete an anonymous online survey in November 2006. Data were categorized by demographic variables, and basic statistics including chi-square comparative analyses were performed.

RESULTS

Forty-four of the 54 residents in Canada (81.48%) completed the survey. "Intellectual stimulation/challenge" emerged as the most important factor (40%) influencing the decision to pursue specialty training in orthodontics, followed by a "passion for orthodontics" (29%). The decision to become an orthodontist was made by 42% of respondents while they were in dental school; 33% had decided after completing dental school, and 24% had already decided before starting their dental school studies. Most residents (82%) planned to work in a private practice environment. Only 2 (4.5%) indicated that they will most likely practice primarily in an academic setting. Eighty percent said that they will use self-ligating brackets in private practice, and almost 80% said they will use Invisalign (Align Technology, Santa Clara, Calif). A total of 55% indicated that orthodontic residents should be required to undertake research leading to a masters of science degree as part of their orthodontic program. A total of 77% thought that a 24- to 30-month program was too short to adequately prepare them for private practice.

CONCLUSIONS

Intellectual stimulation was the major attraction of most applicants to orthodontic programs, and the decision to become an orthodontist was normally made during dental school or even earlier. Most residents intended to enter an urban or suburban private practice after graduation, with few considering academic career choices. Modern techniques such as self-ligating brackets and Invisalign are expected to be popular among future orthodontists in Canada.

Resident evaluation of orthodontic programs in the United States

The objective of this study was to investigate the satisfaction of orthodontic residents in the United States with their programs and determine the scope of their training. Program chairs/directors of all sixty-five U.S. orthodontic graduate programs were contacted for permission to email their residents. A total of 335 residents from thirty-seven programs were invited to complete an anonymous, online, fifty-seven-item survey in May 2007. Data were categorized, and basic statistics were performed. A total of 136 (40.60 percent) residents completed the survey. Overall, 75.74 percent were satisfied with their program. Residents said they feel they receive appropriate didactic teaching sessions and dedicated academic time (60.29 percent). Most residents (92.70 percent) indicated their program offers training in numerous philosophies, while 80.29 percent said they have sufficient clinically based training and 59.85 percent said they have sufficient research-based training. A total of 57.66 percent said they will not complete more than thirty cases from start to finish and on average treat two orthognathic surgery, thirteen extraction, twenty-four nonextraction, and nine adult patients. Most (92.70 percent) said their program contains care for disabled or underserved patients; most (92.70 percent) said they feel they will be adequately prepared to provide unsupervised orthodontic care after graduation; and 54.41 percent said they think other specialties have a positive view of orthodontics. Only 58.09 percent indicated they have a formal interdisciplinary program for treating patients. We conclude that U.S. orthodontic residents are satisfied with their programs. They receive training in a variety of approaches; however, inadequacies in exposure to interdisciplinary teaching and a limitation of the number of cases started and completed were identified. These observations may be a result of program length due to the preponderance of twenty-four- to thirty-month programs.

Future practice plans of orthodontic residents in the United States

INTRODUCTION

The purpose of this study was to investigate the future clinical practice plans of orthodontic residents in the United States.

METHODS

All program chairs and directors of the 65 US orthodontic residency programs were contacted by e-mail and telephone and asked for permission to e-mail their residents and invite them to take part in an anonymous 57-item questionnaire online. A total of 335 e-mails from 37 programs were obtained, and the survey was sent in May 2007. Basic statistics including chi-square comparative analyses were performed by sex, age, and year of program.

RESULTS

A total of 63.04% of orthodontic residents plan to use self-ligating brackets; 84.06% plan to use Invisalign (Align Technology, Santa Clara, Calif); 92.03% plan to use temporary anchorage devices, and 72.26% plan on placing them themselves; 28.26% plan to use cone-beam computerized tomography; 92.75% plan to use a digital imaging program; 45.65% plan to use indirect bonding; and 10.87% plan to use lingual orthodontics. A total of 70.07% plan to use 2-phase treatment, and 61.59% said they will use functional appliances. A total of 81.16% plan to become certified by the American Board of Orthodontics, but only 18.12% thought certification should be mandatory for licensure; 36.50% indicated that a master of science degree should be required in their program, and 77.94% believe that a 24- to 30-month program adequately prepares them for future orthodontic practice.

CONCLUSIONS

Newer orthodontic technologies such as self-ligating brackets, temporary anchorage devices, and Invisalign as well as functional appliances are expected to grow in popularity in the United States because of projected future use by orthodontic residents. Two-phase orthodontic treatment with functional appliance mechanics will continue to be used. Most orthodontic residents will become certified by the American Board of Orthodontics but do not believe it should be necessary for licensure. Orthodontic residents in the United States believe that a 2-year program adequately prepares them for private practice.

Resident evaluation of orthodontic programs in Canada

The purpose of this study was to investigate the satisfaction of Canadian orthodontic residents with their programs and determine the scope of their training. An anonymous online questionnaire was sent to all Canadian orthodontic residents in November 2006. Data were assembled and categorized by different variables, and chi-square comparative analyses were performed. Forty-four out of fifty-four residents responded, giving a participation rate of 81.48 percent. Overall, 86.36 percent of responding residents were satisfied with their program. Respondents said they felt they received the appropriate amount of formal didactic teaching sessions and dedicated and protected academic time. All residents indicated their programs offered training in numerous treatment philosophies: 93.18 percent said they have sufficient clinically based training, and 72.73 percent indicated that their research-based training was sufficient. All responding residents indicated they will complete more than thirty patients from start to finish, and 25 percent estimated completion of more than seventy patients by graduation. Residents said they will complete on average five orthognathic surgery, twenty-four extraction, thirty-one non-extraction, eight adult, and thirteen patients in the mixed dentition. Only 50 percent said their programs contained care for disabled or underserved patients. Most (86.36 percent) said they feel they will be adequately prepared to provide unsupervised orthodontic care after graduation. These orthodontic residents indicated they collaborate most with the disciplines of oral surgery, periodontics, and prosthodontics. However, only 52.27 percent indicated they have a formal interdisciplinary program for treating patients. We conclude from the study that Canadian orthodontic residents are satisfied with the didactic, clinical, and research aspects of their programs. They receive comprehensive instruction with the opportunity to complete a significant number of patients, employing a variety of treatment approaches.

Profile changes in orthodontic patients treated with mandibular advancement surgery

INTRODUCTION

The potential to improve facial esthetics is often the deciding factor in treatment planning of borderline orthodontic patients who can be treated with either orthognathic surgery or dental camouflage. The purpose of this study was to determine the degree of skeletal and soft-tissue Class II disharmony necessary before a significant esthetic benefit is derived from mandibular advancement surgery.

METHODS

Twenty laypeople, 20 orthodontists, and 20 oral surgeons rated the attractiveness of before and after treatment profiles of 20 mandibular advancement patients using a 5-point Likert scale. The Spearman rank correlation tested for relationships between amount of profile change and varying pretreatment ANB and profile angles. Plots of the distribution of profile changes with varying ANB and profile angles were then examined.

RESULTS

There was a tendency for inverse correlations between profile change and profile angle, and for positive correlations between profile change and ANB angles, but only the relationship between profile change and ANB angles judged by the orthodontists was statistically significant (P <0.05). Orthodontists, oral surgeons, and laypeople found that profiles consistently improved when profile angles were < or = 159 degrees, < or = 158 degrees, and < or = 157 degrees, respectively. Orthodontists and oral surgeons found profiles consistently improved when ANB angles were > or = 5.5 degrees and > or = 6.5 degrees, respectively, whereas laypeople showed no trend between ANB angle and profile change. The incidence of having less desirable profiles after treatment was 2.6 to 5.0 times higher when the pretreatment profile angles were larger than the threshold profile angles, and 4.5 to 7.9 times higher when the pretreatment ANB angles were less than threshold ANB angles.

CONCLUSIONS

Pretreatment profile angles < 160 degrees and ANB angles > 6 degrees are necessary for profiles to be consistently perceived as improved after surgery and to minimize the incidence of the profile worsening after treatment.

Healing of periodontal tissues following transplantation of cells in a rat orthodontic tooth movement model

OBJECTIVE

To determine the fate and differentiation of transplanted periodontal ligament (PL) precursor cells and mouse embryonic stem (ES) cells and their relative capacity to regenerate wounded periodontium.

MATERIALS AND METHODS

Orthodontic tooth movement was introduced 24 hours before transplantation of PL or ES cells, and rats were euthanized either 24 hours or 72 hours after cell transplantation. The control rats received either no tooth movement and no cell transplantation or tooth movement and no cell transplantation. Differentiation of transplanted cells was assessed from mandibular periodontal histological tissue sections by immunohistochemical methods using monoclonal antibodies against PL cell differentiation markers. Data were analyzed using Student's t-test at a significance level of P = .05.

RESULTS

Transplantation of PL and ES cells resulted in a higher number of osteopontin, bone sialoprotein, and alpha-smooth muscle actin labeled transplanted cells, predominantly around the blood vessels of the periodontium in study rats compared with control rats (cell transplantation but no orthodontic tooth movement, P = .05). Combined treatments of tooth movement and cell transplantation resulted in enhanced regeneration of the periodontium as a result of tooth movement. Transplantation of PL cells induced a higher number of differentiating cells in the PL and alveolar bone than did transplantation of ES cells.

CONCLUSIONS

Orthodontic tooth movement promotes the differentiation of transplanted cells, and the differentiation occurs predominantly in the paravascular areas of the periodontium. In terms of regeneration of wounded periodontium, transplantation of PL cells produced a higher level of regeneration than ES cells, possibly because of PL cell plasticity and the capacity to undergo effective differentiation in the periodontal cellular microenvironment.

In Vivo Bonding of Orthodontic Brackets to Fluorosed Enamel using an Adhesion Promotor

Objectives: To determine the success of bracket retention using an adhesion promoter with and without the additional microabrasion of enamel.

Materials and Methods: Fifty-two teeth with severe dental fluorosis were bonded in vivo using a split-mouth design where the enamel surfaces of 26 teeth were microabraded with 50 μm of aluminum silicate for 5 seconds under rubber dam and high volume suction. Thirty-seven percent phosphoric acid was then applied to the enamel, washed and dried, and followed by placement of Scotchbond Multipurpose Plus Bonding Adhesive. Finally, precoated 3M Unitek Victory brackets were placed and light cured. The remaining teeth were bonded using the same protocol but without microabrasion.

Results: After 9 months of intraoral service, only one bond failure occurred in the control group where microabrasion was used. Chi-square analysis revealed P = .31, indicating no statistical significance between the two groups.

Conclusions: Bonding orthodontic attachments to fluorosed enamel using an adhesion promoter is a viable clinical procedure that does not require the additional micro-mechanical abrasion step.

Diagnosis and management of the infraerupted primary molar

An infraerupted tooth is a tooth that has failed to erupt to be in line with adjacent teeth in the vertical plane of occlusion. The general dentist may be faced with this predicament which requires careful attention and thoughtful consideration in terms of long-term patient goals. It is important to diagnose infraerupted teeth and treat them in a timely fashion to help prevent unwelcome sequelae. Important interdisciplinary communication is vital between the dentist and the orthodontist to ensure that precious space and time are not lost. Here we present a review article of complications and considerations that must be taken into account when faced with a patient who has an infraerupted tooth.

Diagnosis and clinical management of patients with skeletal Class III dysplasia

This paper summarizes the current literature on the diagnosis and treatment of a patient with Class III skeletal dysplasia. It also includes a report of two siblings with Class III skeletal dysplasia, although each received different treatment due to different causes of the condition. This review illustrates that early appropriate diagnosis, including cephalometric analysis, is important for identifying the location of the dysplasia. If the dysplasia is in the maxilla, treatment may prevent the need for future orthognathic surgery. Treatment for mandibular prognathism usually involves waiting for the patient's growth to complete (this could occur past the age of 18 in women and the age of 20 in men) and performing orthognathic surgery at that time.

Shear/peel bond strength of orthodontic attachments to moist and dry enamel

INTRODUCTION

The purpose of this study was to evaluate the in-vitro shear-peel bond strength of orthodontic attachments bonded to moist and dry enamel surfaces with orthodontic resin.

METHODS

Two stainless-steel mesh-based buttons were bonded to pumiced and etched enamel of each of 60 human molars mounted in cylindrical molds with Transbond XT (3M/Unitek, St Paul, Minn) (control), Smartbond (Gestenco International, Goteborg, Sweden), or Assure (Reliance Orthodontic Products, Itasca, Ill) according to each manufacturer's instructions. Half of the teeth were bonded under dry conditions, and half were given a thick layer of whole, unstimulated, fresh human saliva just before bonding. The teeth were stored in distilled deionized water at 37 degrees C. The shear-peel bond strength of 1 button on each tooth was evaluated in a testing device (Zwick, Ulm, Germany) at 24 hours; the remaining button on each tooth was evaluated at 6 months.

RESULTS

Statistically significant differences (P < .05) were evident in button adhesion to the tooth surface between moisture variations for Transbond XT, but not for Assure and Smartbond. Superior bond strengths were obtained for Transbond XT on dry enamel; the bond strength of Assure to saliva-contaminated enamel was better than that of the other materials.

CONCLUSIONS

Bonding to moist and dry enamel appears to be material-specific. Adequate in-vitro bonding to moist, saliva-contaminated enamel is possible with certain bonding materials.

Preventive and interceptive orthodontic treatment needs of an inner-city group of 6- and 9-year-old Canadian children

OBJECTIVE

Early recognition of developing malocclusions and the potential for uncomplicated orthodontic treatment procedures can minimize or eliminate future costly treatment. This study was designed to assess the potential for this approach in children living in a limited-income environment. A modified index for preventive and interceptive orthodontic needs (IPION) was used to determine the need for such treatment in schoolchildren aged 6 and 9 years.

METHODS

Two calibrated examiners examined each child independently and assessed several components of his or her occlusion, including molar relationship, crossbite, open bite, overbite and overjet. Dental variables such as presence of caries and early loss of teeth were also noted. Informed consent was obtained and all children present at school on the day of the field study were included. A total of 395 children were divided into 2 groups, aged 6 and 9 years.

RESULTS

A high prevalence of caries in the deciduous dentition (30.4% for 6 year olds; 20.6% for 9 year olds) and early loss of primary teeth (11.9% for 6 year olds; 29.4% for 9 year olds) was observed. A large percentage of children had crossbite in the anterior or posterior segments, or both. Open bites were also a common finding. Future orthodontic problems were identified in 28% of this population by using the modified IPION. No statistically significant differences (p > 0.05) were found between sexes or age groups using the chi2 test.

CONCLUSIONS

Most of the developing malocclusions identified in this study would be amenable to interceptive orthodontics, consisting of space maintenance, crossbite correction and arch expansion.

Increasing general dentists' provision of care to child patients through changes in the undergraduate pediatric dentistry program

Reduced caries rates and an increased percentage of children with dental insurance have made it more difficult for dental schools to provide undergraduates with sufficient numbers of pediatric dental patients requiring restorative procedures. This may result in graduates who are not competent and are reluctant to treat children after graduation. To ensure the quality of the undergraduate clinical training program, the Division of Pediatric Dentistry at the University of Manitoba changed from a comprehensive-based clinic to a block system in 1998-99. Specific communities with limited access to dental care (neighboring core area schools and Hutterite colonies) were specifically targeted as potential sources for child patients. This format increased the exposure of students to patient management as well as to complex pediatric dentistry procedures. To assess the learning experiences before and after the changes to the clinical pediatric dentistry program, sixty general dentists who had graduated from the University of Manitoba were randomly selected using the Manitoba Dental Association Directory. Surveys were sent to twenty general dentists who graduated in each of the following years: 1993, 2000, and 2002. Forty-five dentists responded, fifteen from each of the three surveyed classes. Dentists who graduated after the changes to the program (2000, 2002) reported that they performed a greater number of complex pediatric dentistry procedures and treated more toddler and preschool children than the group that graduated before the changes (1993). Referrals to pediatric dentistry specialists were higher in the 1993 group than in the 2000 and 2002 groups. In conclusion, an adequate pool of pediatric patients is critical to provide dental students with sufficient learning experiences. The dentists who graduated from the program after the changes were implemented are providing more comprehensive treatment to younger children.

Performance measures to improve the quality of orthodontic services and control expenditures

One of the most critical and contentious issues for specialist and nonspecialist professionals in the coming decades will be to evaluate the outcomes of health care services. Performance measures are imperative for elective orthodontics, because of the relatively weak evidence that they lead to significant improvements in dental and oral health, occlusal function, and psychological well-being of patients. Such measures are particularly crucial for orthodontic treatment eligible for benefit payments, because they will assure third-party dental insurers that the annual premiums levied from governments (taxes), employers (in lieu of salary increments), and individuals (in lieu of other discretionary expenditures) are well spent (ie, not wasted). Performance measures will also improve the "standards of orthodontic practice," so the continued integrity of the profession is contingent on their development.

Long-term in vitro fluoride release and rerelease from orthodontic bonding materials containing fluoride

The purpose of this study was to compare in vitro long-term (30 month) fluoride release and rerelease rates (after fluoride exposure) from 3 orthodontic bonding materials containing fluoride and 1 without fluoride. Ten samples of each material (Python, TP Orthodontics, LaPorte, Ind; Assure, Reliance Orthodontic Products, Itasca, Ill; Fuji Ortho LC, GC America, Alsip, Ill; and Transbond XT, 3M Unitek, Monrovia, Calif) were fabricated and stored in deionized distilled water at 37 degrees C. Five samples had fluoride-release rates measured at days 546, 637, 730, 821, and 913 after initial fabrication, and 5 samples were exposed to fluoride (Nupro 2% NaF gel, Dentsply Canada, Woodbridge, Ontario, Canada) for 4 minutes at day 535 and had measurements taken on days 546, 548, 552, 575, 637, 730, 821, and 913. To prevent cumulative measurements, the storage solutions were changed 24 hours before measurement. Statistically significant differences were found in fluoride-release rates (P <.0001), with Fuji Ortho LC releasing the most fluoride, followed by Python and Assure at all time points in the nonfluoride exposed group. In the fluoride-exposed group, there were significant differences in fluoride release (P <.0001), with Fuji Ortho LC releasing the most fluoride. A "burst-effect" pattern of fluoride release was seen after fluoride exposure for all materials. It was concluded that Fuji Ortho LC, Assure, and Python might have sufficient long-term fluoride-release rates to reduce white spot formation, and all are recommended as suitable fluoride-releasing orthodontic bonding materials.

Rapid palatal expansion in the young adult: time for a paradigm shift?

A 19-year-old man presented for correction of a malocclusion that included a transverse maxillary deficiency. The patient was informed that he required orthognathic surgery to expand his upper jaw and correct his malocclusion, but he refused surgical expansion. Recent evidence indicates that rapid palatal expansion can be used without surgery in young adults; the decision was therefore made to treat the patient nonsurgically. Rapid palatal expansion of the maxillary arch was accomplished by means of a Hyrax appliance, with post-treatment radiographs revealing an opening of the midpalatal suture. The belief still persists among some clinicians that young adult patients require orthognathic surgery for palatal expansion, despite recent evidence supporting a nonsurgical approach after closure of the midpalatal suture.

Controlling third-party expenditures and improving quality assurances: a plea for change

Growing demands to contain health care's inflationary expenditures have particular relevance for elective (eg, orthodontic) services, because their progressively increasing provision will ultimately jeopardize the resources for others (eg, restorative dentistry). Some form of rationalization is therefore inevitable, especially in services eligible for payments from third-party benefits. These are central concerns of the ongoing debate on whether rationalization should be driven by service efficiency and cost efficiency and who should make such decisions. The adaptation of contemporary computer-based technology could resolve this dilemma, especially if real-time comprehensive assessments of 3-dimensional craniofacial forms before and after treatment are incorporated into local and national databases. Such a facility would then help to develop clinical guidelines to optimize the provision of specific orthodontic services for particular malocclusions. Referring individual cases to these databases would subsequently help to control service expenditures and maintain or even improve their outcomes to the ultimate benefit of both the profession and the public.

Treatment and long-term follow-up of a patient with hereditary gingival fibromatosis: a case report

This report addresses the complex nature of oral diagnosis, treatment and long-term case management in the hereditary form of recurrent gingival fibromatosis. Case management is discussed in relation to a 13-year-old girl who presented with recurrent, progressive gingival enlargement requiring consecutive periodontal and orthodontic treatment. The initial course of treatment included 4-quadrant gingivectomy with reverse bevel incisions, followed by orthodontics. Microscopic examination of the gingivectomy specimens supported the clinical diagnosis. Three years later, recurrence of the condition was observed in all quadrants. To facilitate orthodontic tooth movement and to achieve optimal esthetics, another full-mouth gingivectomy was performed. There was no recurrence of the condition a year later. It is recommended that patients with this condition be monitored closely after gingivectomy, so that the treatment requirements of localized areas can be addressed as needed.

Fluoride release from new light-cured orthodontic bonding agents

The purpose of this study was to compare the rates of fluoride release with time from 1 nonfluoridated and 3 fluoride-containing orthodontic bonding materials in distilled water and artificial saliva. Materials tested were Assure (Reliance Orthodontic Products, Itasca, Ill), Fuji Ortho LC (GC, Tokyo, Japan), Python (TP Orthodontics, LaPorte, Ind), and Transbond XT (3M Dental Products, Monrovia, Calif). Ten specimens of each material type were stored in distilled water, and 10 of each type were stored in artificial saliva at 37 degrees C. Fluoride release was measured with an ion-specific electrode. Readings were taken periodically for a total time period of 6 months. At day 1, Assure released the most fluoride into distilled water (66.2 microg/cm(2)) and into artificial saliva (65.8 microg/cm(2)), followed by Fuji Ortho LC (25.9 microg/cm(2); 18.8 microg/cm(2)), Python (6.3 microg/cm(2); 4.2 microg/cm(2)), and Transbond (0.1 microg/cm(2); 0.1 microg/cm(2)). The fluoride release rates were highest during the first days of testing, declining to lower but more stable levels. At the end of 6 months, Fuji Ortho LC released the most fluoride (3.8 microg/cm(2); 3.5 microg/cm(2)) followed by Assure (3.1 microg/cm(2); 2.8 microg/cm(2)), Python (2.6 microg/cm(2); 1.7 microg/cm(2)), and Transbond (0.1 microg/cm(2); 0.1 microg/cm(2)). The type of storage medium did not dramatically affect fluoride release. The second part of the study, undertaken after a year of sample storage, tested the 20 samples of Assure for a further 2-week period, after exposure to running and still distilled water. Although fluoride release rates declined with time, they were still higher than the 1.5 microg/cm(2) level that is referenced as inhibiting decalcification of enamel in a clinical environment. Release rates were similar in running and still water at all time points. Throughout the 6-month period, all 3 fluoride-containing materials had rates of fluoride release that could theoretically inhibit decalcification of enamel.

Occlusal and oral health status of a group of 3-8-year-old South African black children

This study determined the oral health status of a group of 3-8-year-old South African black children, comprising a total of 214 children from the townships of Garankuwa, Shosanguwe, Mabopane, Hebron and Erasmus who attended a school in Akasia, Greater Pretoria Metropolitan Substructure. The decayed, missing and filled teeth (dmft), oral hygiene status, dental IQ and malocclusion status were determined. The study found that the children's oral health status and occlusal status were unacceptable. The level of their dental IQ scores was low, their oral hygiene poor, and they were in urgent need of primary and secondary dental care. In addition they were in need of both preventive and interceptive orthodontic care. A national strategy to address primary dental health care is recommended.

In vitro and in vivo fluoride release from orthodontic elastomeric ligature ties

Clinically, demineralization of enamel around orthodontic attachments can occur after only 1 month. Fluoride incorporation into elastomeric ligature ties may provide additional protection against decalcification through fluoride release. This study compared the fluoride release of fluoride-impregnated and nonfluoride elastomeric ligature ties (Ortho Arch Company) both in vitro and in vivo. A total of 260 fluoride-impregnated and 260 nonfluoride elastomerics were evaluated in this study, 400 in vitro and 120 in vivo. For the in vivo part of the study, six patients had fluoride and nonfluoride elastomerics placed in cross-quadrant fashion in their mouths; these were removed and tested for residual fluoride release after 1 month. With the use of the potentiometric analytical method, the fluoride release of the elastomerics was determined in distilled water as the 24-hour residual release, to compare the in vitro and in vivo fluoride leached into solution. The data was analyzed with the Wilcoxon matched-pairs signed ranks test. The distilled water control yielded an F- reading of 0.03 +/- 0.01 microgram/F/mL. In the in vitro part of the study, an average of 0. 38 microgram/F/mL/elastomeric was released over the 1 month period by the fluoride-impregnated elastomerics; this decreased significantly (P <. 05) to a 24-hour residual value at 1 month of 0.02 microgram/F/mL/elastomeric ligature, which is in the same order of magnitude as the distilled water control solution. The nonfluoride ties produced a calculated 24 hour residual fluoride release of 0. 003 microgram/F/mL/elastomeric after 1 month; this is much less than the distilled water control and would not be possible to measure accurately. After 1 month in vivo, significantly greater (P >.05) amounts of 24-hour residual fluoride were apparent: F- elastomerics = 1.43 microgram/F/mL/elastomeric and nonfluoride elastomerics = 0.44 microgram/F/mL/elastomeric. Fluoride ties gained weight intra-orally. Residual, leachable fluoride was present in fluoride-impregnated and nonfluoride elastomeric ligature ties after 1 month of intraoral use, due to imbibition. The clinical efficacy of fluoride-impregnated elastomeric ligature ties to prevent decalcification in the presence of plaque needs to be investigated.