Evaluation of split-cast techniques for remounting casts on a dental articulator: A survey and an in vitro study.

INTRODUCTION: This study aimed to investigate the difference between senior dental students and prosthodontic faculty members regarding their opinions, attitudes and adoption of six split-cast techniques for remounting complete dentures. The accuracy of each technique for measurements of the vertical and the anteroposterior dimensions was assessed. MATERIALS AND METHODS: Six split-cast techniques to remove the casts were compared. A total of 115 participants removed a set of casts on six different articulators, and a questionnaire survey was administered. A digital Vernier caliper was used to measure the linear dimensional changes between the laterally pindexed references on each cast. The data were statistically analysed at α = 0.05. RESULTS: There were significant differences between senior dental students and prosthodontic faculty members in their responses regarding adoption of daily practice and techniques requiring more skill (p = .001). To adopt a specific technique in daily practice, most students and faculty members chose long round die pins (36.4%) and central groove indexing (CGI; 40.7%), respectively. For techniques requiring more skills, most students and faculty members chose long rectangular die pins (30.7%) and short round dowel pins (33.3%), respectively. CONCLUSION: Dental students preferred ShRP, whilst faculty members preferred LReP. All participants considered CGI to be the easiest amongst the techniques. For comparison with baseline measurements, both senior dental students and prosthodontic faculty members considered side notch indexing and double dowel pins to be the most accurate techniques for vertical measurements, and CGI for anteroposterior measurements.

Evaluation of Cast Re-Orientation on a Dental Surveyor Using Three Tripod Techniques: A Survey and In Vitro Study.

PURPOSE: To survey different educational levels (i.e., students, interns, technicians, and prosthodontic faculty) with regard to their opinions, attitudes, and adoption of three selected tripod techniques. The study will also investigate the accuracy of these techniques to reposition casts on the dental surveyor in anterio-posterior (AP) and lateral directions at both technique and educational levels. MATERIALS AND METHODS: Tripod points, scored lines, and cemented post tripod techniques were used in this study. Three Kennedy class II modification I stone casts, duplicated from a standard cast, were assigned to each of the tripod techniques. The tilt angles of all casts were set on the dental surveyor to 10° (control angle) in AP and lateral directions using a digital angle gauge with an accuracy of 0.2°. The casts were tripoded accordingly. A total of 243 participants were involved in this study. Participants were first asked to remount the three casts on three different dental surveyors using the tripod technique noted on each cast. Questionnaires were then given to each participant in an individual interview setting; this assured a 100% response rate. The angle differences were calculated. All data were coded and entered into an Excel Spreadsheet file. Statistical analyses were performed using a paired Chi-square, Wilcoxon Matched-pairs, ANOVA, and Tukey post hoc tests at 5% level of significance. RESULTS: No significant difference was found between the educational levels relative to the responses to technique demands, sensitivity, and time required for reorientation (p = 0.08202, 0.8108, 0.6874, respectively); however, the majority of respondents reported low technique demands, low sensitivity, and time saving for technique C in comparison to techniques A and B. Significant differences were noted among the educational levels in response to preference and adoption questions (p = 0.0035 and 0.0015, respectively). The highest percentage of faculty chose technique A for inclusion into the academic curriculum. Wilcoxon Matched-pairs test revealed that technique C was the least difficult and most practical (p = 0.0001, 0.0427, respectively). One-way ANOVA revealed significance in angle differences from the set position for technique A in lateral tilt and techniques A and B in AP tilt (p = 0.0466, 0.0194, 0.0424, respectively). A comparison of positivity (overtilt) and negativity (undertilt) between the three techniques in lateral and AP tilts using Chi-square test resulted in significant differences in both directions of tilt (p < 0.0001). Technique C resulted in remounting the casts at the control position in 15.64% in both directions; this was a higher percentage than the other two techniques (A and B). Wilcoxon Matched-pairs test was used to compare between the techniques relative to angle differences from the standard position. No differences were found between technique A and B in lateral tilt position (p = 0.9271), while significance was detected in AP tilt (p < 0.0001). Significant differences were detected between technique C in comparison to A (p < 0.0001, p = 0.0303) and B (p < 0.0001) in lateral and AP tilt directions. CONCLUSIONS: Within the limitations of this study, it can be concluded that technique C (cemented post technique) was more favored among the respondents across all educational levels. This technique presented high potential in accurately reorienting casts on the dental surveyor in comparison to the tripod points and scoring techniques (p < 0.0001).