Development and validation of an objective virtual reality tool for assessing technical aptitude among potential candidates for surgical training.

BACKGROUND: Good technical skills are crucial for surgeons. Yet although surgical training programs strive to assess technical aptitude when selecting surgical residents, valid assessments of such aptitude are still lacking. Surgical simulators have been proposed as a potentially effective tool for this purpose. The current study aims to develop a technical aptitude test using a virtual reality surgical simulator, and to validate its use for the selection of surgical residents. METHODS: The study had three phases. In Phase 1, we developed an initial version of the technical aptitude test using the Lap-X-VR laparoscopic simulator. In Phases 2 and 3 we refined the test and collected empirical data to evaluate four main sources of validity evidence (content, response process, internal structure, and relationships with other variables), and to evaluate the feasibility and acceptability of the test. Specifically, Phase 2 comprised a review of the test by 30 senior surgeons, and in Phase 3 a revised version of the test was administered to 152 interns to determine its psychometric properties. RESULTS: Both the surgeons and interns rated the test as highly relevant for selecting surgical residents. Analyses of the data obtained from the trial administration of the test supported the appropriateness of the score calculation process and showed good psychometric properties, including reliability (α = 0.83) and task discrimination (mean discrimination = 0.5, SD = 0.1). The correlations between test scores and background variables revealed significant correlations with gender, surgical simulator experience, and video game experience (ps < 0.001). These variables, however, explained together only 10% of the variance in test scores. CONCLUSIONS: We describe the systematic development of an innovative virtual reality test for assessing technical aptitude in candidates for surgical training, and present evidence for its validity, feasibility and acceptability. Further validation is required to support the application of the test for selection, as well as to discern the impact of gender, surgical simulator experience, and video game experience on the fairness of test results. However, the test appears to be a promising tool that may help training programs assess the suitability of candidates for surgical training.

Number of consecutive procedures after endodontic treatment to extraction: A 28-year retrospective study.

STATEMENT OF PROBLEM: After endodontic treatment, teeth may require additional treatment. Data regarding the number of treatments up to extraction after endodontic treatment are lacking. PURPOSE: The purpose of this retrospective study was to evaluate the number of consecutive restorative procedures performed on a specific tooth starting from endodontic treatment up to extraction. A comparison was made between crowned and uncrowned teeth. MATERIAL AND METHODS: A retrospective study was conducted using 28 years of data from a private clinic. The total number of patients was 18 082 and included 88 388 treated teeth. The data were collected for permanent teeth that received at least 2 consecutive retreatments. The data included tooth number, procedure type, date of procedure, total number of procedures conducted during the study period, extraction date, time from endodontic treatment to extraction, and whether the tooth had been crowned or not. Endodontically treated teeth were divided into 2 groups: extracted and nonextracted. In each group, a comparison was made between crowned and uncrowned teeth and between anterior and posterior teeth by using the Student t test (α=.05). RESULTS: In the non extracted group, teeth that were crowned required significantly (P<.05) fewer restorative treatments (mean ±standard deviation 2.9 ±2.1) than uncrowned teeth (5.01 ±2.98). For extracted teeth, the mean time from endodontic treatment until extraction was 10.39 years. Crowned teeth were extracted after a mean of 11.06 years and 3.98 treatments, while uncrowned teeth were extracted after a mean of 9.96 years and 7.22 treatments (P<.05). CONCLUSIONS: Endodontically treated teeth that were crowned required significantly fewer subsequent restorative procedures than uncrowned teeth and exhibited higher survival rates up to extraction.

Using Job Analysis for Identifying the Desired Competencies of 21st-Century Surgeons for Improving Trainees Selection.

OBJECTIVE: The current selection for surgical training is based on ineffective methods. In order to identify or to develop more valid selection tools to improve the selection, it is necessary to first define what are the competencies that are most important for success in contemporary surgery. Therefore, the current study aims to identify what competencies are required for success as a surgeon in the 21st-century and to evaluate their relative importance for selection for surgical training. METHODS: Job analysis was conducted using a mixed-methods design. First, 104 senior surgeons from all surgical fields from various hospitals in Israel were interviewed in order to query their perceptions of competencies associated with success as a surgeon. Their answers were coded and analyzed to create a list of important competencies. Next, a larger sample of 1,102 surgeons and residents from all surgical fields completed a questionnaire in which they rated the importance of each competency in the list for success as a surgeon and for selection for surgical training in the 21st-century. RESULTS: Twenty-four competencies (five technical skills, six cognitive abilities, 13 personality characteristics) were identified in the interview analysis. Analysis of the questionnaire's data revealed that all 24 competencies were perceived as important for success as a surgeon in the 21st-century as well as for selection for surgical training. The perceived importance of personality characteristics was higher than both cognitive abilities (p < 0.001) and technical skills (p < 0.001). The results did not differ between different surgical fields. CONCLUSIONS: Twenty-four competencies were identified as important for 21st-century surgeons and for selection for surgical training. Although all competencies were perceived as important, personality characteristics were perceived as more important than technical skills and cognitive abilities. This updated definition of required competencies may aid in developing more valid selection methods of candidates for surgical training.

Correlation Between the Tragus-Incisal Distance and Interocclusal Rest Distance.

PURPOSE: To evaluate correlations of arch size and sex with the interocclusal rest distance (IORD), as well as to estimate proportional variance. MATERIALS AND METHODS: A total of 106 participants were examined. The participants, 38 men and 68 women, were aged 22 to 30 years, were fully dentate, had no signs of abnormal abrasion, and had intact posterior occlusal contacts. Measurements of interocclusal rest distance and tragus-incisal distance were recorded, and the rest angle created between the tragus-incisal distance in maximum intercuspation and in resting vertical dimension were calculated according to the cosine formula. Correlation between the size of the mandible (tragus-incisal distance, mean of left and right sides) and the IORD were calculated using Pearson correlation coefficient. Correlations for sex (calculated separately for male and female) and rest angle were also assessed. RESULTS: The mean (SD) tragus-incisal distance values were 123.38 (6.77) mm for all participants, 120.01 (4.64) mm for women, and 130.72 (5.24) mm for men. The mean (SD) IORD values were 2.76 (1.3) mm for all participants, 2.13 (0.9) mm for women, and 3.87 (1.17) mm for men. The mean (SD) rest angle values were 1.26 (0.55) degrees for all participants, 1.02 (0.41) degrees for women, and 1.7 (0.49) degrees for men. Pearson correlation coefficient between IORD and tragus-incisal distance was significant (P < .05). According to t test, there was a significant difference between men and women for IORD, tragus-incisal distance, and rest angle (P < .01). CONCLUSION: A correlation exists between IORD and arch size. A statistically significant difference was found between men and women for IORD and arch size values.

Isolation and Characterization of Streptococcus mutans Phage as a Possible Treatment Agent for Caries.

Streptococcus mutans is a key bacterium in dental caries, one of the most prevalent chronic infectious diseases. Conventional treatment fails to specifically target the pathogenic bacteria, while tending to eradicate commensal bacteria. Thus, caries remains one of the most common and challenging diseases. Phage therapy, which involves the use of bacterial viruses as anti-bacterial agents, has been gaining interest worldwide. Nevertheless, to date, only a few phages have been isolated against S. mutans. In this study, we describe the isolation and characterization of a new S. mutans phage, termed SMHBZ8, from hundreds of human saliva samples that were collected, filtered, and screened. The SMHBZ8 genome was sequenced and analyzed, visualized by TEM, and its antibacterial properties were evaluated in various states. In addition, we tested the lytic efficacy of SMHBZ8 against S. mutans in a human cariogenic dentin model. The isolation and characterization of SMHBZ8 may be the first step towards developing a potential phage therapy for dental caries.

Next generation of dentists moving to amalgam-free dentistry: Survey of posterior restorations teaching in North America.

OBJECTIVES: The dental field is gradually reducing the use of amalgam and moving towards adhesive restoration. This change is in accordance with the advancement and improvement of composite resin materials and adhesion systems. Consequently, posterior cavity preparations teaching should be re-examined to determine whether dental schools are adapting their curriculum to fit the current trends in dentistry and what rationale supports their decisions. METHODS: An online questionnaire was constructed to assess the time dedicated to teaching composite materials and amalgam, in addition to the principles of posterior preparations, for composite restorations in North American dental schools. RESULTS: A total 33 schools responded to the questionnaire. A large variation was found in teaching methods and techniques of posterior restorations. The reasoning for teaching amalgam restorations was diverse as were the principles of composite resin preparation taught. CONCLUSION: No agreed principles of cavity preparation for resin composite restorations were found, as opposed to explicit agreement on amalgam cavity preparations. The results demonstrate a lack of clear guidelines for cavity preparation of resin composite restorations. Dental schools may benefit when a consensus on this topic is achieved.

Antibacterial Effect of a Temporary Cement-Dissolving Liquid.

PURPOSE: Methods for removing temporary cement with an antibacterial effect might improve prosthetic treatment prognosis. MATERIALS AND METHODS: Three removal methods were assessed: (1) immersion of an acrylic provisional restoration in a temporary cement dissolver (Temp-off); (2) mechanical removal with a dental explorer; and (3) sandblasting. Two temporary cements, one with eugenol (Temp-Bond) and one without eugenol (Temp-Bond NE) and of two thicknesses (100 µm and 250 µm), were examined. RESULTS: Immersion in Temp-off produced the most effective bacterial count decrease compared to the other methods (P < .05). No significant difference was found between the two cement types, although the decrease in count was more evident in the thicker (250 µm) cement layer. CONCLUSION: Temp-off dissolving liquid used for removal of temporary cement exhibited an antibacterial effect and nonmechanical cleaning ability.

Determining the interchangeability of KaVo PROTAR semi-adjustable articulators.

OBJECTIVE: Interchangeable articulators are crucial for a precise clinical outcome. Lack of interchangeability will affect the accuracy of the occlusion of prosthetic restorations. The objective of this study was to evaluate the interchangeability of KaVo PROTARevo articulators. METHOD AND MATERIALS: KaVo PROTARevo semi-adjustable articulators in routine use were employed. Identical casts were transferred among the articulators and the distance between casts was measured using digital photos of sagittal and frontal aspects of each articulator by two independent examiners. Interchangeability was assessed and analyzed by designated software. RESULTS: Inter-examiner reliability was found to be high. Of 231 possible pairs of articulators only 27 pairs were found to be interchangeable (less than 166 µm in all measured dimensions), and of the other 204 pairs of articulators at least one of the dimensions measured was larger than 166 µm. CONCLUSION: The majority of articulators tested did not pass the 166-µm criterion to establish them as interchangeable. Therefore, in order to maintain accuracy while producing restorations, it is advisable to use the same articulator throughout the entire process, both at the clinic and in the dental laboratory.

Antibacterial Activity of Orthodontic Cement Containing Quaternary Ammonium Polyethylenimine Nanoparticles Adjacent to Orthodontic Brackets.

Enamel demineralization is a common problem found in patients using orthodontic devices, such as orthodontic braces. It was found that Streptoccocus mutans growth increases adjacent to orthodontic devices, which may result in caries development. Incorporated antibacterial quaternary ammonium polyethylenimine (QPEI) nanoparticles were previously shown to be highly efficacious against various bacteria. Combining antibacterial materials in orthodontic cement may be advantageous to prevent bacterial outgrowth adjacent to orthodontic brackets. The aim was to evaluate the efficiency of orthodontic cement containing QPEI nanoparticles in reducing S. mutans and Lactobacillus casei outgrowth adjacent to orthodontic brackets. Orthodontic brackets were bonded to the buccal surfaces of extracted lower incisors. The antibacterial effect on S. mutans and L. casei outgrowth of Neobond bracket adhesive orthodontic cement with and without QPEI nanoparticles was compared. The antibacterial effect was evaluated using crystal violet staining and bacterial count (CFU/mL). The teeth in the experimental group, with the QPEI nanoparticles cement, showed significantly lower optical density (OD) values and CFU counts of S. mutans and L. casei than the teeth in the control group (p < 0.05). Based on the results, it can be concluded that orthodontic cement containing QPEI nanoparticles significantly inhibits S. mutans and L. casei growth around orthodontic brackets.

Testing Motor Learning Curves Among Dental Students.

Motor learning up to reaching proficiency can be registered and displayed as a learning curve. Understanding the nature of the motor learning curves will allow proper planning of teaching. The aim of this study was to measure the rate of motor learning of novice dental students in preparing dental cavities. A total of 66 first-year students (21 males and 45 females) at a dental school in Israel participated in this 12-week study. In the first and last weeks, the students prepared 12 cavities in 45 minutes in a composite material plate, using a dental high-speed burr. In the ten weeks between tests, manual performance was measured by drilling two cavities, limited to 3.5 minutes per cavity. The results showed that improvement was significant (p<0.05) at two-week intervals in all cases except for the sixth and seventh weeks, when a significant increase was observed only after three weeks. The performance of the lowest performing students (those with grades in the lowest third of the class) remained low throughout the entire course. Further subdivision of the class into two groups showed that the upper half reached the minimum required performance in week 9, whereas the lower half achieved it only three weeks later. The authors concluded that the 12-week study was not sufficiently long for the learning curve to reach a plateau. Dental students present a variety of motor learning curves and different rates of proficiency acquisition, so understanding the nature of these curves, and the differences among students, may be useful in lesson planning to support the process of motor learning.

Antibacterial Effect of Provisional Cements with Incorporated Polyethyleneimine Nanoparticles: An In Vivo Study.

PURPOSE: Provisional restorations exhibit various degrees of microleakage when cemented. Incorporation of quaternized polyethyleneimine nanoparticles (QPEI) into provisional cements may be effective against bacteria in vivo. MATERIALS AND METHODS: Nine polymethylmethacrylate provisional restorations in human volunteers were evaluated after cementation with and without QPEI nanoparticles. Bacterial load in the provisional cement was assessed after 1 week of cementation. RESULTS: The number of colony-forming units in the cement with QPEI was significantly lower (P < .05) than in the control cement. CONCLUSION: The results of this in vivo study clearly indicate that provisional cement incorporating QPEI nanoparticles significantly reduces viable bacterial counts in the provisional cement in all patients.

Teaching New Materials and Techniques for Fixed Dental Prostheses in Dental Schools in the United States and Canada: A Survey.

PURPOSE: Tooth-supported fixed dental prostheses (FDPs) remain an extensive therapeutic option, with new materials and a digital fabrication process gradually replacing traditional methods. The variety of advances calls for dental schools to expand the teaching of this field. Our aim was to examine the nature and the amount of theoretical and practical training in clinical FDP courses, and the extent to which new methods and innovations in the field are being integrated. MATERIALS AND METHODS: Data were collected using an online questionnaire including theoretical and practical teaching regarding clinical courses, restorative materials, and new fabrication methods, which was sent to 58 dental schools in North America. RESULTS: A total of 36 schools responded to the survey for a response rate of 62.1%. All the schools teach theoretical and practical porcelain-fused-to-metal (PFM) restorations, and almost all the schools teach full-metal FDPs. In more than half (57.1%) of the schools, zirconia-based FDPs are placed by students. Students place partial veneer FDPs in less than one-fifth (17.9%) of the schools. The average number of restorations required for completion of the clinical course is 7.3 FDP units. The respondents assessed that of the total FDPs placed by students in the clinical course, tooth-color coping (zirconia/alumina/porcelain) FDPs constituted 16.2%. None of the schools produce computer-assisted design/computer-assisted manufacturing copings or crowns within the school. CONCLUSIONS: All North American dental schools include teaching and placement of PFM restorations in their curriculum, but only one-third teach ceramic-based crowns. The low average number of required crowns may lead to graduates not being exposed to and trained in up-to-date dental restorative materials and techniques.

Prosthetic rehabilitation of congenitally missing canines: a case series.

Hypodontia is a relatively common finding, although rarely are the canines the missing teeth. Congenitally missing canines are challenging to treat because of their unique role in the masticatory system and the fact that they are in the esthetic zone. This article discusses two patients with missing permanent canines, various treatment planning considerations, and the provided prosthetic solutions.

Existing concepts and a search for evidence: a review on implant occlusion.

The prevalence of dental implant treatment raises the question: What factors may challenge osseointegration? The dental literature presents two main approaches, which are well-documented: loss of bone around the implant due to infection and a presumed association between implant load and bone loss. This article discusses the effect of load or overload on the bone loss around dental implants. The dental literature is reviewed to assess the scientific evidence related to the effect of occlusal load on osseointegration. Recommendations found in the literature for occlusal schemes for implant-supported prostheses are examined and discussed, and statements regarding implant occlusion are assessed for their validity today, after more than four decades of implants service in prosthetic dentistry.

Trends in material choice for posterior restorations in an Israeli dental school: composite resin versus amalgam.

According to a recent American Dental Association survey, posterior composite resin restorations now outnumber amalgam restorations in the United States. Dental schools around the world vary considerably in the extent to which they teach the use of composite resins. We aimed to determine if there has been an increase in the placement of posterior composite restorations in an Israeli dental school and if faculty experience affects the type of posterior restoration placed. In this retrospective study, we recorded and analyzed all the restorations performed by undergraduate students in the last five academic years at the Hebrew University Hadassah School of Dental Medicine in Jerusalem. All clinical records of student treatments between 2004 and 2009 were screened, and direct restorations were registered. Out of 6,094 posterior restorations performed during the study period, 42.3 percent were made of composite resin, increasing from 36.8 percent in 2004-05 to 48.5 percent in 2008-09, an increase of 11.7 percent. When clinical instructors were asked to state their preference if they themselves were to undergo posterior restoration, similar results were obtained. Instructors with less than ten years' experience preferred posterior composite resin restorations in 54.8 percent of the hypothetical situations, compared with 37.2 percent preferred by instructors with ten years of experience or more. It appears that the use of composite resin was influenced mainly by the prevailing trend and was not based on scientific evidence. Dental faculties should define criteria, based on up-to-date clinical studies, for using new materials, taking into consideration differences among instructors regarding treatment concept.