Profile changes following extraction orthodontic treatment: A comparison of first versus second premolar extraction.

OBJECTIVE: To determine the change in the soft tissue profile following extraction orthodontic treatment with either first or second premolar extractions. METHODS: This was a retrospective clinical study of 81 consecutive orthodontic patients treated with extraction of four premolars. Patients were divided into two treatment groups according to whether four first premolar teeth (PM1 treatment group, n=48) or four second premolar teeth were removed (PM2 treatment group, n=33) during treatment. Changes in the nasolabial angle and the distance of the upper and lower lips to E-plane were compared pre- and post-treatment. Age, sex, upper lip thickness, facial convexity, facial axis, upper and lower arch crowding at pre-treatment, use of molar anchorage and the amount of retrusion of the maxillary and mandibular incisor teeth during treatment were used as explanatory variables. RESULTS: When facial convexity and facial axis at pre-treatment, the use of maxillary anchorage and the amount of retrusion of the maxillary and mandibular incisor teeth achieved as a consequence of treatment were taken into account, there was less than one degree (0.67°) difference between the change in the nasolabial angle in the PM1 treatment group compared to the PM2 treatment group (P>0.05). The mean change in the upper lip position relative to E-plane and the mean change in lower lip position relative to E-plane were also similar for the two groups. CONCLUSION: The change in soft tissue profile following orthodontic treatment was similar regardless of whether first premolar or second premolar teeth were removed.

Graduating grades and National Dental Examination results of foreign-trained and domestic dental students.

In this study, a comparison was made between the 1999-2009 graduates of the two-year structured program for foreign trained dentists at the Schulich School of Dentistry, University of Western Ontario, Canada, and the school's four-year program for domestic students. Both the students' final-year course grades and their results on the National Dental Examining Board (NDEB) written examination and objective structured clinical examination (OSCE) were compared. Differences of ≥ 10 percent in mean final-year grades and ≥ 5 percent for each component of the NDEB examination were considered academically meaningful for the purpose of this analysis. Although there were no academically meaningful and statistically significant differences in the mean overall final-year course grades between the two-year and four-year classes, there were differences in individual courses in prosthodontics, oral medicine, and practice administration. There were no differences (≥ 10 percent) in mean course grades since 2007. An academically meaningful difference in performance was observed on the NDEB written examination in three of the eleven years. There were no meaningful differences (≥ 5 percent) between the two groups in any year for the NDEB OSCE. The relevance and implications of these findings to both the two-year structured program and the newly introduced alternative pathway to certification are discussed.

The effects of non-extraction orthodontic treatment on the vertical dimension: a comparison of a dolichofacial and a mesofacial group.

OBJECTIVE: The decision regarding extraction or non-extraction orthodontic treatment for patients with different skeletal facial patterns is more commonly based on traditional concepts rather than scientific facts. The present study aimed to investigate whether dolichofacial patients responded differently compared with mesofacial patients to non-extraction orthodontic treatment with respect to vertical changes in facial height. METHODS: Twenty-eight dolichofacial patients and 29 mesofacial patients who underwent non-extraction orthodontic treatment were selected. All patients commenced treatment prior to 15 years of age and had a mean age of 12.3 years for the dolichofacial group and 12.6 years for the mesofacial group. Serial lateral cephalometric radiographs were traced by hand on acetate paper and digitised using the Rocky Mountain Orthodontics JOE 32 programme. Statistical analysis examined the recorded changes in facial axis angle, facial angle, menton-to-ANS distance and facial convexity. RESULTS: An increase in menton-to-ANS distance and facial angle and a decrease in facial convexity were observed in both groups to a similar extent. Interestingly, the facial axis of both groups remained constant throughout treatment and up to two years post-treatment. Both groups showed slightly increased facial axis angle beyond the original value at two years post-treatment. No statistically significant difference between the two groups was observed in the changes of any of the variables over time. CONCLUSION: The results countered the traditional concept that dolichofacial patients would have an increased facial height after being subjected to non-extraction orthodontic mechanics. It appeared that long-term vertical height of the face was more dependent on genetics rather than environmental influences.

Foreign-trained dentists' perceived knowledge and skills after graduation from a structured two-year program.

In this survey study, graduates of the University of Western Ontario program for foreign-trained dentists from 1999 to 2009 were asked for their perceptions of their knowledge and skill in fourteen clinical topic areas before they were admitted to the program and after graduation. Their ratings were made on a ten-point visual analog scale divided into three aptitude domains: competent, proficient, and master/expert. Definitions of each domain were provided. The majority of the respondents felt that their knowledge level improved at least one aptitude level in only four of the fourteen (29 percent) topic areas but that their skill level had increased at least one aptitude level in nine (64 percent) topic areas. Of note, clinical topics with content reflective of North American dental practice such as oral medicine and treatment planning, ethics, regulated dentistry, record keeping, and informed consent were the topic areas in which most respondents reported an improvement in both their knowledge and skill. It is suggested that programs evaluating or providing gap training for internationally trained dentists consider mandatory inclusion of these topics.

Examiner training and reliability in two randomized clinical trials of adult dental caries.

OBJECTIVES: This report describes the training of dental examiners participating in two dental caries clinical trials and reports the inter- and intra-examiner reliability scores from the initial standardization sessions. METHODS: Study examiners were trained to use a modified International Caries Detection and Assessment System II system to detect the visual signs of non-cavitated and cavitated dental caries in adult subjects. Dental caries was classified as no caries (S), non-cavitated caries (D1), enamel caries (D2), and dentine caries (D3). Three standardization sessions involving 60 subjects and 3,604 tooth surface calls were used to calculate several measures of examiner reliability. RESULTS: The prevalence of dental caries observed in the standardization sessions ranged from 1.4 percent to 13.5 percent of the coronal tooth surfaces examined. Overall agreement between pairs of examiners ranged from 0.88 to 0.99. An intra-class coefficient threshold of 0.60 was surpassed for all but one examiner. Inter-examiner unweighted kappa values were low (0.23-0.35), but weighted kappas and the ratio of observed to maximum kappas were more encouraging (0.42-0.83). The highest kappa values occurred for the S/D1 versus D2/D3 two-level classification of dental caries, for which seven of the eight examiners achieved observed to maximum kappa values over 0.90. Intra-examiner reliability was notably higher than inter-examiner reliability for all measures and dental caries classifications employed. CONCLUSION: The methods and results for the initial examiner training and standardization sessions for two large clinical trials are reported. Recommendations for others planning examiner training and standardization sessions are offered.

Bond strength of 4 orthodontic adhesives used with a caries-protective resin sealant.

INTRODUCTION: The purpose of this study was to investigate the shear peel bond strength (SPBS) and resin remnant retention after removal of orthodontic brackets bonded with 1 of 4 orthodontic adhesives (Transbond XT [3M/Unitek, Monrovia, Calif], Blugloo [Ormco Corp, Glendora, Calif], Light Bond [Reliance Orthodontic Products, Itasca, Ill], and APC Plus [3M/Unitek]) applied over a filled, resin sealant (ProSeal [Reliance Orthodontic Products]). METHODS: Extracted premolars were first acid etched and then coated with the sealant used as a primer. This was followed by cementation of a stainless steel orthodontic bracket to the buccal surface with 1 of the 4 adhesive systems. Two adhesive systems (Transbond XT and Blugloo), without the filled sealant applied, were used as references. All specimens were stored in deionized water at 37 degrees C for 30 days, thermocycled for 24 hours at 30-second intervals between 10 degrees C and 50 degrees C water baths, and debonded with a universal testing machine. RESULTS AND CONCLUSIONS: The 4 adhesive-sealant combination groups had mean SPBS values slightly lower than the 2 adhesive-only reference systems, but all were greater than 10 MPa (range, 10.1-15.9 MPa), which is considered a clinically acceptable bond strength. ANOVA showed a statistically significant difference (P <0.05) in mean SPBS among the 4 adhesive-sealant combinations. The most frequent site of bond failure at debonding for the adhesive-sealant combinations was within the adhesive.

Effectiveness of phase I orthodontic treatment in an undergraduate teaching clinic.

In this retrospective study, the Peer Assessment Rating (PAR) index was used to objectively evaluate the effectiveness of Phase I (early) orthodontic treatment provided in an undergraduate teaching clinic. Pre-treatment and post-treatment casts of ninety-three patients were analyzed. All patients selected for Phase I orthodontic treatment had Class I skeletal relationships and did not require complex orthodontic treatment such as growth modification or treatment of occlusions with missing or impacted teeth. The mean age of patients who received Phase I orthodontic treatment was 9.9 years. The mean initial PAR score for the sample was 29.70 +/-9.84. The mean reduction in PAR score was 14.9 points corresponding to a 50.2 percent decrease in the PAR score following Phase I orthodontic treatment. Seventy-three percent of the patients experienced at least a 30 percent reduction in their PAR score following Phase I (early) orthodontic treatment. The mean cost of $381.00 for the Phase I orthodontic treatment was found to be influenced by the length of treatment, type of Phase I treatment provided, age at start of treatment, and percentage reduction in PAR score. The greatest success rate for the Phase I orthodontic treatment occurred with either fixed or a combination of fixed and removable appliances. Over half of the patients recommended for Phase I orthodontic treatment in the undergraduate dental clinic were successfully treated and did not require Phase II treatment. For them, there was both a treatment and a financial benefit to the Phase I orthodontic treatment.