Celebrity smile esthetics assessment: Smile angulation.

STATEMENT OF PROBLEM: Whether deviations in the angulation discrepancy between the intercanine and interpupillary line significantly affect attractiveness is unknown. PURPOSE: The purpose of this prospective study was to quantify dental and facial esthetics to determine whether smile angulation discrepancies in individuals identified as having attractive smiles are smaller than those in the average population. MATERIAL AND METHODS: An Internet search for "best smile" and "celebrity" identified 108 celebrities (Test group). Photographs showing smiles within 10 degrees of a frontal view were gathered. In mannequin testing, small head rotation (<10 degrees) was found not to affect the measurements. Photographs of dental students were used for the control group. The angulation discrepancy between the intercanine and interpupillary line was measured using computer software. Groups were compared using the Mann-Whitney U test (α=.05). RESULTS: Usable photographs were obtained for 94 celebrities (62 women, 32 men) and were compared with photographs of 97 dental students (54 women, 43 men). Significant (P<.01) differences in angulation discrepancy were found, with celebrities having smaller mean angulation discrepancies (0.97 degrees) than dental students (1.33 degrees). The differences between men and women were not statistically significant (P>.05). CONCLUSIONS: Celebrities identified as having "best smile" had significantly smaller mean angulation discrepancies than the control group.

Split-Mouth Comparison of Splinted and Nonsplinted Prostheses on Short Implants: 3-Year Results.

PURPOSE: To compare splinted and individual restorations supported by short implants featuring an internal connection utilizing a split-mouth design. MATERIALS AND METHODS: Splinted and nonsplinted implant crowns were prospectively compared in 18 patients. After verifying the need for at least two consecutive implants bilaterally, computed tomography scans were made, virtual planning was done, and qualifying patients were enrolled. Implants were placed using a two-stage surgical approach. After 3 to 5 months, patients were randomly restored with splinted prostheses on their left or right side. Nonsplinted restorations were made for contralateral sides. Radiographs were taken at prostheses seating and yearly exams. Radiographic bone levels were analyzed and compared (SAS 9.4) to determine differences between splinted and nonsplinted implants. Complications such as screw loosening, screw breakage, or porcelain fracture were assessed at recalls. RESULTS: Eighteen patients (9 men and 9 women) with an age range from 49 to 76 years (mean = 56 years), received ≥ 4 implants in symmetrical posterior locations. Implants (n = 82) ranged in length from 6 to 11 mm with 70 implants ≤ 9 mm and 38 implants = 6 mm. At the time of this report, 3-year examinations and bone level comparisons were completed on 15 patients. One patient was lost to follow-up, one deviated from study protocol by smoking, and one was splinted on both sides due to repeated screw breakage. Screw loosening occurred in five patients on their nonsplinted side. These were 6-mm implants except for one patient. Porcelain chipping occurred for one patient on the splinted side. One 6-mm-length nonsplinted implant was lost after loading; this implant was successfully replaced after grafting. This patient had a total of six implants placed; ongoing bone level measurements included two pairs of implants only. For all implants combined, there was no significant difference (P > .05) at 1, 2, or 3 years for mean bone change around splinted and nonsplinted implants. However, length was identified as a significant factor (P = .0039). Further analysis revealed statistically significant differences between splinted and nonsplinted for 6-mm length implants at 24 (P = .0061) and 36 (P = .0144) months. A gain in mean bone level of 0.41 and 0.37 mm was observed for nonsplinted implants at 24 and 36 months compared with baseline. Bone levels for the splinted 6-mm implants were not statistically different from baseline measurements (P > .05). CONCLUSION: Results of this prospective 3-year study of splinted ipsilateral and nonsplinted contralateral implants in 15 patients show: (1) peri-implant bone levels around splinted and nonsplinted implants were not statistically different for implants greater than 6 mm in length; (2) nonsplinted 6-mm implants revealed a gain in bone at 24 and 36 months compared with baseline; (3) all screw loosening only occurred on the nonsplinted side for 5 of 15 patients; and (4) implant loss after loading occurred for one 6-mm nonsplinted implant.

Advocacy practices among U. S. pediatric dentists.

PURPOSE: Advocacy is the primary mission of the American Academy of Pediatric Dentistry (AAPD), but members' participation in advocacy is not well known. The purpose of this study was to examine advocacy by AAPD members and their attitudes toward various advocacy-related activities. METHODS: An Internet-based questionnaire, e-mailed to 4,328 AAPD members via Survey Monkey, consisted of 19 questions on: demography; advocacy training; attitudes toward advocacy; and past, recent, and current advocacy practices. RESULTS: A total of 1,046 respondents provided a 25% response rate. Ninety percent supported advocacy as a role for pediatric dentists. Two-thirds felt prepared for advocacy, but only 22% had training in residency. Participation in clinical advocacy was the most common activity, but most respondents reported local oral health promotion and promotion of oral health with other professionals. Approximately half or fewer reported participation in political action or lobbying. Pediatric dentists out of training longer were more likely to participate in advocacy as were male pediatric dentists. CONCLUSIONS: American Academy of Pediatric Dentistry members support the advocacy role of pediatric dentists and participate in a wide range of advocacy activities.

Influence of dowel type on push-out bond strength to regional root canal dentin.

PURPOSE: To compare the laboratory bond strengths of three different types of fiber-reinforced composite dowel systems in three different locations of prepared root canal dentin. METHODS: 60 human extracted intact upper central incisors were selected. The coronal aspect of each tooth was removed, and the remaining root received endodontic therapy. The roots were divided into three experimental groups (n = 20). Roots were restored with one of the following dowel systems according to the manufacturers' instructions: carbon fiber (C-Posts), quartz (Aestheti-Plus), glass fiber (FibreKor). A single bond adhesive (OptiBond Solo Plus) was applied to the walls of the dowel spaces, excess carefully removed with paper points, and then light cured for 10 seconds. A dual-polymerizing resin luting agent (Variolink II) was mixed and then placed in the dowel spaces using a lentulo spiral instrument. The roots were placed in light-protected cylinders; then the light source was placed directly on the flat cervical tooth surfaces and the cement was polymerized. Specimens were stored in light-proof boxes for 24 hours. Each root was cut horizontally, and three 1 mm-thick root segments (one apical, one middle, and one cervical) were prepared. Using a push-out test, the bond strength between dowel and dentin was measured using a universal testing machine. The data were analyzed with 2-way analysis of variance and Tukey's Honestly Significant Difference (HSD) test (alpha = 0.05). RESULTS: Dowel type and regional root canal dentin resulted in significant differences for push-out bond strength (P < 0.001). Glass fiber dowels (FibreKor) had significantly higher mean bond strength values (SD) for all dowel space regions: coronal (13.6 [1.5] MPa), middle (10.8 [1.8] MPa), and apical (8.9 [1.1] MPa). The carbon fiber dowels (C-Posts) had significantly lower bond strength values in all dowel space regions: coronal [8.6 (1.1) MPa], middle (4.7 [1.0] MPa), and apical (4.1 [1.1] MPa). Quartz dowels (Aestheti-Plus) had intermediate bond strength values: coronal (10.9 [1.1] MPa), middle (9.6 [1.1] MPa), and apical (7.7 [1.1] MPa). Also, there were differences in bond strength between regional root canal dentin, with a reduction in values from the coronal to middle and apical thirds for all experimental groups (P < 0.001).

Comparison of propofol-remifentanil versus propofol-ketamine deep sedation for third molar surgery.

This study aimed to compare continuous intravenous infusion combinations of propofol-remifentanil and propofol-ketamine for deep sedation for surgical extraction of all 4 third molars. In a prospective, randomized, double-blinded controlled study, participants received 1 of 2 sedative combinations for deep sedation for the surgery. Both groups initially received midazolam 0.03 mg/kg for baseline sedation. The control group then received a combination of propofol-remifentanil in a ratio of 10 mg propofol to 5 µg of remifentanil per milliliter, and the experimental group received a combination of propofol-ketamine in a ratio of 10 mg of propofol to 2.5 mg of ketamine per milliliter; both were given at an initial propofol infusion rate of 100 µg/kg/min. Each group received an induction loading bolus of 500 µg/kg of the assigned propofol combination along with the appropriate continuous infusion combination . Measured outcomes included emergence and recovery times, various sedation parameters, hemodynamic and respiratory stability, patient and surgeon satisfaction, postoperative course, and associated drug costs. Thirty-seven participants were enrolled in the study. Both groups demonstrated similar sedation parameters and hemodynamic and respiratory stability; however, the ketamine group had prolonged emergence (13.6 ± 6.6 versus 7.1 ± 3.7 minutes, P = .0009) and recovery (42.9 ± 18.7 versus 24.7 ± 7.6 minutes, P = .0004) times. The prolonged recovery profile of continuously infused propofol-ketamine may limit its effectiveness as an alternative to propofol-remifentanil for deep sedation for third molar extraction and perhaps other short oral surgical procedures, especially in the ambulatory dental setting.

The comparative morbidities of acute dental pain and acute asthma on quality of life in children.

PURPOSE: The purpose of this prospective cross-section survey study was to examine the comparative burden of acute exacerbations of the two most common chronic illnesses of childhood: acute dental pain and acute asthma. METHODS: All patients came from one of three distinct clinics within Nationwide Children's Hospital, Columbus, Ohio: (1) outpatient dental clinic; (2) urgent medical care unit; or (3) emergency department. Caregivers were asked information about their child's condition and the impact on their daily function. RESULTS: A total of 112 parent-child dyads were included in this study. Children were significantly more likely to be under the care of a physician for asthma than a dentist for caries (P<.001). More caregivers worried about their child's overall health due to dental caries than asthma-related symptoms (P<.001). Two thirds of children had pain due to dental caries, which kept them from sleeping; 45% were prevented from playing; 45% were prevented from going to school; and 68% from eating in the preceding week. CONCLUSION: Acute dental disease had a comparative and, in some aspects, greater impact on a child's quality of life than acute asthma.

Contribution of dentist anesthesiologists to dental anesthesiology research.

In order to determine if dentist anesthesiologists (DAs) actively contribute to research in the field of anesthesiology, and thus contribute new knowledge to the field, an extensive literature search was accomplished. DAs make up only 1.5% of dentists who actively contribute to anesthesia research but account for 10% of publications. To determine if the impact of DA research was similar to the American Dental Association (ADA) recognized specialties, h-indices of noted researchers in other specialties were compared to the h-indices of noted DA researchers. The results show that the impact of top DA researchers in dental anesthesiology is similar to the impact of top dental specialty researchers, despite lack of academic departments in dental schools where a large percentage of dental research is completed. Dentist anesthesiologists actively contribute to the research in anesthesiology for dentistry and thus, actively contribute to new knowledge in the field.

Parker flex-tip and standard-tip endotracheal tubes: a comparison during nasotracheal intubation.

The placement of endotracheal tubes in the airway, particularly through the nose, can cause trauma. Their design might be an important etiologic factor, but they have changed little since their introduction. Recently Parker Medical (Bridgewater, Conn) introduced the Parker Flex-Tip (PFT) tube, suggesting that it causes less trauma. This study aimed to compare the PFT endotracheal tube to a side-beveled, standard-tip endotracheal tube (ETT) for nasotracheal intubation (Figures 1 and 2). Forty consecutive oral surgery patients requiring nasotracheal intubation were randomized to receive either a standard ETT or the PFT tube. Intubations were recorded using a fiber-optic camera positioned proximal to the Murphy eye of the tube. This allowed visualization of the path and action of the tube tip as it traversed the nasal, pharyngeal, laryngeal, and tracheal airway regions. Video recordings made during intubation and extubation were evaluated for bleeding, trauma, and intubation time. Both bleeding and trauma were recorded using a visual analogue scale (VAS) and by 3 different evaluators. The PFT received significantly better VAS values than the standard tubes from all 3 raters (P < 0.05) in both the extent of trauma and bleeding. Since the intubations were purposefully conducted slowly for photographic reasons, neither tube displayed a time advantage. This study suggests that the PFT tube design may be safer by causing less trauma and bleeding than standard tube designs for nasotracheal intubation.

Quantification of the esthetics of dentists' before and after photographs.

PURPOSE: The purpose of this study was to measure dentists' before and after restorative treatment photographs to identify four metrics to describe the esthetic improvement: (a) central incisor width-to-height ratio; (b) central-to-lateral incisor width ratio; (c) lateral incisor-to-canine width ratio; and (d) lateral incisor percentage offset. MATERIALS AND METHODS: Internet searches for "before after" and "veneers" and "prosthodontic" were used to obtain 198 before and after photographs of patient treatments showing the restoration of the six maxillary anterior teeth with porcelain veneers, crowns or a combination. The four metrics were measured using Adobe Photoshop. Groups were compared with repeated measures ANOVA followed by a post hoc Tukey-Kramer test with the variables of "Before or After Treatment"; "Treatment Type" (veneers, crowns or a combination) and "General Dentist or Prosthodontist". RESULTS: Mean central incisor width-to-height ratio was 91.7% before treatment, 80.8% after; mean central-to-lateral incisor width ratios were 69.9% and 64.7%; mean lateral incisor-to-canine width ratios were 85.3% and 81.4% and lateral incisor percentage offsets were 9.6% and 8.7%. There were significant (p<0.05) differences for before and after treatment for all variables except central-to-lateral incisor width ratio. Differences between specialist and general dentist were not statistically significant. CONCLUSIONS: On average, esthetic prosthetic treatment resulted in reduced central incisor width-to-height ratio, increased proportional width of the mesially positioned tooth of adjacent anterior teeth and reduced lateral incisor offset. The mean values of treatments by GPs and prosthodontists were not statistically significantly different. CLINICAL IMPLICATIONS: Knowledge of dentists' optimal restorative treatments provides insight on the esthetic outcome of extensive prosthodontic therapy.

Smile arcs of Caucasian and Korean youth.

This study was designed to measure and compare the smile arcs (tooth and lip arcs) of young Caucasian and Korean subjects. Two hundred subjects (100 male and 100 female) were selected from Caucasian and Korean students. Class photographs taken with a digital camera showing the subjects with a posed smile were used for this study. Curves were rendered as semitransparent overlays, which were manipulated over the images using Adobe Photoshop to determine the best fit for tooth and lip arcs. There were statistically significant differences due to ethnicity and gender. Mean lip arcs had greater curvature than mean tooth arcs.

Impact energy absorption of three mouthguard materials in an aqueous environment.

High impact energy absorption is an essential property for mouthguard materials. The impact test performance of three popular mouthguard materials was evaluated, using the procedure in American Society for Testing and Materials (ASTM) Standard D3763. Conventional ethylene vinyl acetate (EVA; T&S Dental and Plastics, Myerstown, PA, USA) served as the control. Pro-form (Dental Resources Inc., Delano, MN, USA), another EVA material, and PolyShok (Sportsguard Laboratories, Kent, OH, USA), an EVA product containing polyurethane were also evaluated. Specimens having dimensions of 3 inch x 3 inch x 4 mm were prepared from each material. After processing that followed manufacturer recommendations, specimens were conditioned for 1 h in 37 degrees C deionized water and loaded at 20 mph by a 0.5 inch diameter indenter containing a force transducer (Dynatup Model 9250 HV; Instron Corp., Canton, MA, USA). Both large-diameter (3 inches) and small-diameter (1.5 inch) support rings were used. For comparison, two specimens of each material were tested in the dry condition. Energy absorption was determined from the area under the force-time curve at 30 ms, and results for the water-conditioned specimens were compared using anova and the Kruskal-Wallis test. For the large-diameter support ring, energy absorption (mean +/- SD in ft x lbf inch(-1)), normalized to specimen thickness, was: EVA (n = 5), 110.2 +/- 48.4; Pro-form (n = 4), 110.0 +/- 11.3; PolyShok (n = 5), 105.7 +/- 16.5. For the small-diameter support ring, energy absorption was: EVA (n = 6), 140.5 +/- 13.9; Pro-form (n = 5), 109.0 +/- 26.0; PolyShok (n = 6), 124.4 +/- 28.4 (1 ft x lbf inch(-1) = 0.534 J cm(-1)). Because of substantial variation within some specimen groups, there was no significant difference in energy absorption for the three water-conditioned mouthguard materials and the two support ring sizes. The energy absorption for each material was much greater for other specimens tested in the dry condition.

Effect of home bleaching systems on enamel nanohardness and elastic modulus.

OBJECTIVES: The purpose of this study was to evaluate the nanohardness and elastic modulus of human enamel after treatment with tray and strip bleaching systems. METHODS: Fifty-five human enamel samples were exposed to five different bleaching agents. Nanoindentations were made before and after bleaching treatments following the manufacturer's directions using a Nanoindenter XP (MTS Systems Corporation, Oak Ridge, TN, USA). Nanohardness and elastic modulus measurements were obtained and the results were statistically analyzed using a repeated measures analysis of variance with a post-hoc Tukey-Kramer multiple comparison test. RESULTS: Nanohardness and elastic modulus measurements showed decrease of mean values for each group except the control which remained the same. There were significant differences due to time (before and after treatment) and material effects in nanohardness (P<0.0001) and elastic modulus (P=0.0241). Measurements after treatment showed significant decrease in nanohardness between all groups and the control group. There was a significant difference in hardness between CP and TO after treatment. Additionally, there were significant differences in elastic modulus between the control group when compared to OB and TO after treatment. While there were significant changes in the elastic modulus due to treatment for both CP and TO, there were no significant differences between any of the groups after treatment. CONCLUSIONS: Nanohardness and elastic modulus of human enamel were significantly decreased after the application of home-bleaching systems.

Instruction in dental curricula to identify and assist domestic violence victims.

Since most domestic violence injuries occur in the head and neck areas, it is critical that dental professionals be prepared to identify, interview, and assist potential victims. The purposes of these surveys in 1996 and 2007 were to investigate U.S. and Canadian dental school curricula regarding the inclusion of domestic violence topics, determine the topics emphasized, determine beliefs of course directors about domestic violence issues, and report progress of dental curricula in preparing dental professionals regarding domestic violence over the eleven-year period. Surveys were sent to associate deans for academic affairs of dental schools in the United States and Canada in 1996 (N=64) and the United States in 2007 (N=56). Each academic dean was asked to forward the survey to the faculty member who taught this topic. Topics most frequently included and emphasized in dental school curricula were the responsibility of the health care professional (HCP) regarding domestic violence, how to identify physical and behavioral indicators, and how to refer the abused victim. The topics least frequently included and emphasized in the curricula regarded education of the abused and the impact of domestic violence on society. There were four strong beliefs reported by dental course directors: a trusting, professional rapport is essential for disclosure; the dentist or a dental team member may be the first HCP to recognize signs of abuse; the dentist has a professional responsibility to refer for assistance; and domestic violence education should be included in dental curricula. Over the eleven years, the surveys demonstrate that course directors have become more aware of the need to inform dental students about domestic violence and that more schools have increased the amount of information about domestic violence in dental courses. However, due to the complexity and sensitivity of this topic, course instructors in dental schools may consider other teaching methods to enhance learning. The authors identified the need for further course development and make recommendations to use experiential learning to enhance dental students' interpersonal and interviewing skills. These strategies may increase dentists' comfort and confidence when treating and assisting possible victims of domestic violence.

Physiologic signs during dental treatment in overweight vs normal weight children.

PURPOSE: This study compared physiologic effects of position change on overweight (OW) and normal-weight (NW) children during a preventive appointment. METHODS: A cross-sectional, case-controlled design assigned a convenience sample to either overweight (>85th percentile) or normal-weight groups (25th to 85th percentile) by body mass index (BMI). A trained examiner measured blood pressure (BP), heart rate (HR), oxygen saturation (SpO2), and 5 pulmonary functions in preoperative, upright seated, supine, and postoperative upright seated positions. Anxiety was measured using the Corah Dental Anxiety Scale. RESULTS: NW and OW groups' anxiety scores did not differ (P=.69). Mean BMIs were 20.1 and 39.7 for NW and OW subjects, respectively. Overall, BP between groups was not different (P=.051), although systolic BP for OW subjects tended to be higher. Systolic and diastolic BP dropped for both groups with supine positioning (P< or =.001). During this change, HR did not change for NW, but dropped for OW subjects (P=.001). SpO2 was significantly different between groups following position change, but not within each group. Forced vital capacity and forced expiratory volume were higher in the OW group (P< or =.01), but 2 peak expiratory measures (PEF and PEF25-75 were not (P=.05). CONCLUSION: Heart rate and oxygen saturation respond differently to positional changes in overweight patients.

Evaluation of the safety and efficacy of an automated flossing device: a randomized controlled trial.

OBJECTIVE: To evaluate the safety and efficacy of a newly developed automated flossing device (AF). METHODOLOGY: Subjects were recruited from a university campus via announcements, and were randomly assigned to a control (C), manual (M), or automated (A) group. Subjects brushed twice a day and treatment groups used their respective floss daily. The safety assessment (SA), plaque index (PI), and gingival index (GI) were measured at days one, 15, and 30. A pre- and post-intervention PI was measured at days 15 and 30. RESULTS: The majority of subjects (n=76) were students, mean age +/- SD of 23.3 +/- 5.2 years. Based on one-way analysis of covariance, C had a higher mean PI score than A at days 15 (p = 0.019) and 30 (p < 0.001), and M had a higher mean PI score than A at day 30 (p = 0.022). The C had a higher mean GI score than A at day 30 (p = 0.034). The SA included trauma associated with improper use of the AF for two subjects. CONCLUSION: At four weeks, the AF removed more interproximal plaque than M, and there was less interdental inflammation compared to brushing alone. The AF is safe and effective when used properly, and demonstrates great promise as an alternative to manual floss.

Differential scanning calorimetry (DSC) and temperature-modulated DSC study of three mouthguard materials.

OBJECTIVES: Employ differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) to investigate thermal transformations in three mouthguard materials and provide insight into their previously investigated energy absorption. METHODS: Samples (13-21mg) were obtained from (a) conventional ethylene vinyl acetate (EVA), (b) Pro-form, another EVA polymer, and (c) PolyShok, an EVA polymer containing polyurethane. Conventional DSC (n=5) was first performed from -80 to 150 degrees C at a heating rate of 10 degrees C/min to determine the temperature range for structural transformations. Subsequently, TMDSC (n=5) was performed from -20 to 150 degrees C at a heating rate of 1 degrees C/min. Onset and peak temperatures were compared using ANOVA and the Tukey-Kramer HSD test. Other samples were coated with a gold-palladium film and examined with an SEM. RESULTS: DSC and TMDSC curves were similar for both conventional EVA and Pro-form, showing two endothermic peaks suggestive of melting processes, with crystallization after the higher-temperature peak. Evidence for crystallization and the second endothermic peak were much less prominent for PolyShok, which had no peaks associated with the polyurethane constituent. The onset of the lower-temperature endothermic transformation is near body temperature. No glass transitions were observed in the materials. SEM examination revealed different surface morphology and possible cushioning effect for PolyShok, compared to Pro-form and EVA. SIGNIFICANCE: The difference in thermal behavior for PolyShok is tentatively attributed to disruption of EVA crystal formation, which may contribute to its superior impact resistance. The lower-temperature endothermic peak suggests that impact testing of these materials should be performed at 37 degrees C.

Comparison of peer assessment rating (PAR) index scores of plaster and computer-based digital models.

INTRODUCTION: The peer assessment rating (PAR) index is a valid and reliable tool for measuring malocclusion on plaster models, but it has not been shown to be valid and reliable when used to score computer-based digital models. The purpose of this study was to determine whether the PAR index is a valid and reliable measure on digital models. METHODS: The study sample consisted of 48 pairs of plaster and digital pretreatment models. One examiner, calibrated in the PAR index, scored the digital and plaster models. The overall PAR scores were examined for reliability and validity by using analysis of variance and the intraclass correlation coefficient (ICC). Reliability of the components of the PAR score was compared with values originally presented by Richmond et al (1992). RESULTS: No significant differences were found between overall PAR scores of plaster and digital models (P = .82), and scores were highly correlated (ICC = 0.95; lower confidence boundary (LCB) = 0.92; upper confidence boundary (UCB) = 0.97). Intraexaminer reliability was excellent for both plaster models (ICC = 0.98; LCB = 0.97; UCB = 0.99) and digital models (ICC = 0.96; LCB = 0.94; UCB = 0.98). Reliability of all components of the PAR score generated on digital models except for buccal occlusion was similar to those of Richmond et al. CONCLUSION: PAR scores derived from digital models are valid and reliable measures of occlusion.

Comparison of strains produced by titanium and poly D, L-lactide Acid plating systems to in vitro forces.

PURPOSE: To determine if a specific resorbable plating system provides similar fixation, in terms of strain distribution under load, to a titanium system when the Champy technique is applied for the treatment of a mandibular angle fracture. MATERIALS AND METHODS: A formalin-fixed cadaver mandible was harvested just before the study. A bicortical osteotomy was then made using a diamond disc extending in an oblique direction in the area of the angle. It was then passively fixated with a 4-hole 2.0-mm miniplate. Two stacked rosette strain gauges were bonded to the mandible on either side of the fracture. Each rosette had 3 strain gauges arranged in specific degrees relative to each other. The mandible was then placed on a dynanometer and 30 lb loads were delivered on the ipsilateral molar. Static resistance was placed in the condylar neck region to simulate the glenoid fossa. Loading was repeated 10 times with a period of 3 minutes between loads. Measurements were recorded for each strain gauge after loads were in place for 30 seconds. The same process was repeated using a 4-hole 2.1-mm resorbable miniplate. The strains were then used to calculate the maximum and minimum strains for each rosette. Hooke's law was used to calculate the principal stresses. RESULTS: Differences were observed between the strain gauges for each individual plating system. There was variability within the resorbable plate measurements as shown by the standard deviation. Using the REML ANOVA test, a significant difference was found between the 2 materials. CONCLUSION: In this in vitro study, there were significant biomechanical differences observed between a 2.0-mm titanium miniplate and a 2.1-mm resorbable miniplate when used to treat a mandibular angle fracture following Champy's principles. Based on our finding, both systems cannot be used interchangeably for the treatment of mandibular angle fractures under the same clinical conditions.

The accuracy and reliability of measurements made on computer-based digital models.

For reasons of convenience and economy, orthodontists who routinely use and maintain pre- and posttreatment plaster casts are beginning to use computer-based digital models. The purpose of this study was to determine the accuracy (validity), reproducibility (reliability), efficacy, and effectiveness of measurements made on computer-based models. A plastic model occlusion ie, dentoform, served as a gold standard to evaluate the systematic errors associated with producing either plaster or computer-based models. Accuracy, reproducibility, efficacy, and effectiveness were tested by comparing the measurements of the computer-based models with the measurements of the plaster models--(1) accuracy: one examiner measuring 10 models made from a dentoform, twice; (2) reproducibility and efficacy: two examiners measuring 50 models made from patients, twice; and (3) effectiveness: 10 examiners measuring 10 models made from patients, twice. Reproducibility (reliability) was tested by using the intraclass correlation coefficient. Repeated measures of analysis of variance for multiple repeated measurements and Student's t-test were used to test for validity. Only measurements of maxillary and mandibular space available made on computer-based models differed from the measurements made on the dentoform gold standard. There was significantly greater variance for measurements made from computer-based models. Reproducibility was high for measurements made on both computer-based and plaster models. In conclusion, measurements made from computer-based models appear to be generally as accurate and reliable as measurements made from plaster models. Efficacy and effectiveness were similar to those of plaster models. Therefore, computer-based models appear to be a clinically acceptable alternative to conventional plaster models.

Dentists' molar restoration choices and longevity: a web-based survey.

STATEMENT OF PROBLEM: The increasing trend toward esthetics has led to controversy as to the longevity of esthetic restorations and the wisdom of having traditional restorations replaced for esthetic reasons. With the assumption that the way dentists treat their own teeth may be a good indication of the accumulated wisdom of the profession, knowledge of dentists' own restorative choices may provide guidance in selecting the most appropriate restorations. PURPOSE: The purpose of this article was to determine restorative choices of dentists for personal molars and estimate restoration longevity. MATERIAL AND METHODS: Information about dentists' molars was obtained from a Web-based survey designed to receive dentists' demographic data and charting of 8 molar teeth with estimated longevity. Approximately 12,000 e-mails asking to access the website were sent to dentists' addresses randomly selected from a commercial database. Nonrespondents received 1 reminder. The responses were statistically analyzed with a chi-square analysis (alpha=.05). RESULTS: Seven hundred fifty-seven valid replies provided information for 6,034 teeth (22% unrestored, 75% restored, 2% missing). Restorations reported included amalgam (36%), gold inlay/onlay (13%), complete veneer crown (CVC) (10%), metal-ceramic crown (MCC) (8%), and composite (7%). Other esthetic options accounted for less than 3%. Restorations with more than 20 years longevity included amalgam restorations (58%), gold inlays/onlays (48%) and crowns (23%). Fifty-six percent of esthetic restorations and 5% of amalgams were placed in the last 5 years. The following restorations were placed in the last year (n=186): 38% esthetic, 29% crowns (18% MCC; 11% CVC), and 17% gold inlay/onlay or amalgam. Significant differences (P<.001) were identified for dentist's gender, year of graduation and practice location. CONCLUSIONS: Most dentists have not replaced traditional metallic restorations with esthetic alternatives. Dentists still choose nonesthetic options for significant numbers of their own restorations.