Ross Bryant

Purpose: The aim of this study was to evaluate the influence of horizontal gingival displacement on the accuracy of an intraoral scanner (IOS) with 0.5 and 1mm subgingival finish lines.Materials and Methods: A 3D printed resin dental model was fabricated with a removable milled zirconia die of tooth #46 full crown preparation and 3D printed resin gingiva. A supragingival control group, and six test groups were designed and fabricated with varying horizontal gingival displacement (0.12mm, 0.25mm 0.45mm) each with subgingival finish line positions of 0.5mm (groups 1 to 3, respectively) and 1mm (groups 4 to 6, respectively). The Trios3 (3Shape) IOS was used to scan 18 samples per group and the scans were superimposed with a reference scan of the die without the gingiva. Absolute marginal discrepancies (AMD) between test and reference scans were measured at 8 fixed points around the prep, and at the largest marginal discrepancy (LMD) site. The one-way ANOVA test measured statistical differences between the groups, and the Games-Howell test compared each pair of groups.Results: The highest mean AMDs at fixed sites were on the distolingual surface for all study groups including the control group (p
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Problem: There is little understanding of patients’ experiences and perceptions with satisfaction relating to a single-tooth implant in the aesthetic zone. Objectives: The objective of this study was to better understand patients’ lived experiences with a single tooth-implant crown in the aesthetic zone, especially their perceptions of satisfaction. Methods: An interpretive phenomenological analysis approach was the adopted research design. In the maintenance phase, 13 current patients who previously had a maxillary implant placed in the aesthetic zone and restored with a single-unit prosthesis from dental specialty trainees at the participating university were invited to join the study, from which nine participants, ages ranging from 24 to 76 years, were included. Demographics, digital photographs, intraoral scans, and self-administered questionnaires were collected to assist in identifying diversity in the sample. The phenomenological data, comprised of audio-recorded semi-structured one-to-one interviews with the participants, were transcribed verbatim, coded, and analyzed thematically, aided by computer-assisted qualitative data analysis software. Results: Participants underlined that a single-tooth implant is not simply a technological solution, since they typically perceive it as recovering their normal lives. Patient satisfaction’s multidimensional nature was corroborated since the perceived reasons for satisfaction varied widely among the group of participants. It seems that negative feelings of dissatisfaction arose for some participants during the treatment process originating from adverse events, patient-clinician relationships, and/or perceptions of high expectations or uncertainty, whereas, these feelings eventually mostly diminished to the extent that participants expressed overall satisfaction with the treatment outcome. Underlying this was usually a perception of improvement in the social aspect of their lives, including in self-esteem and self-confidence, by having their appearance restored in a natural way, despite some of them recognizing that the resulting appearance was not perfectly matching their natural dentition.Conclusion: Many aspects of the treatment, especially the final outcome, influenced participant satisfaction at different stages of the process. The results should provide clinicians with an improved understanding of the basis for managing patients’ expectations with information reiteratively and efficiently. This may ultimately reduce the potential for negative feelings of patients toward the implant treatment experience.

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Crown preparation is a challenging procedure for dental students, especially in the posterior region. It has been reported that the incidence of iatrogenic damage to adjacent teeth is very high during conventional crown preparation. Objectives: To determine the effect of using a protective matrix for preventing iatrogenic damage to adjacent teeth during crown preparation on typodont teeth by undergraduate dental students.Methods: 60 undergraduate students, in their second-year, volunteered for this study as part of their formal learning to prepare the mandibular first molar for a full-metal crown restoration on a manikin-mounted typodont. The study was divided into three parts: Part I- students were randomly assigned into two groups to either undertake tooth preparation according to a traditional crown preparation protocol, or tooth preparation using a protective matrix, followed by Part II- a crossover of the groups in the subsequent session. Part III - subsequent to the initial sessions, the students undertook a usual timed crown preparation exercise, during which using the matrix was optional. Damage to the adjacent teeth was evaluated subjectively by calibrated faculty members both using a standard traditional approach and virtual-assisted using a digital system. Depth and volumetric measures of the damage were also objectively evaluated using a digital system.Results: During the practice sessions, the traditional subjective assessment found that adjacent tooth iatrogenic damage was significantly (p=.027) less frequent when the protective matrix was used, 76.9%, compared to when it was not used, 92.5%. A similar statistically significant (p=.009) pattern was found with the subjective virtual-assisted digital assessment, which showed a frequency of 82.4% when using the matrix compared to 98% when it was not used. The objective digital assessment tended to show a higher overall frequency of damage than that found with the subjective faculty-member assessments. During the two combined initial sessions the mean depth scores were 0.281±0.14mm without a protective matrix and 0.216±0.13mm with a protective matrix, which was significantly deeper iatrogenic depth damage (p = .041) without the matrix. Conclusions: The use of a protective matrix during typodont crown preparation by dental students reduced the frequency of iatrogenic damage to adjacent teeth.

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Aim: To study the effect of implant overdenture maintenance events on psychosocial outcomes using existing Visual Analogue Scale (VAS) and Oral Health Impact Profile (OHIP-49) measures, and to assess the association between VAS overall satisfaction and OHIP scores. Materials and methods:The data for this study were obtained from the charts of 86 edentulous patients who began implant overdenture treatment in a randomized clinical trial at the University of British Colombia between 2003 and 2006, and were followed for 5 years. Participants had been randomly assigned to receive either one or two implants to retain their mandibular dentures. Each participant had completed two patient-based outcome questionnaires at baseline before implant treatment, two months, one, three and five years after treatment. The questionnaires were the OHIP-49 and VAS assessing the following denture related variables for mandibular and maxillary dentures separately (pain, comfort, appearance, function, stability, speech, hygiene, and overall satisfaction). All maintenance events related to implants, attachments and overdentures bases were recorded. Results:After 5 years, completed data were available for 62 participants. No significant differences in the mean value of VAS scores for all mandibular denture outcome variables and OHIP-49 scores between participants who received one and two implants allowed for pooling of all the participant data into one group to study the effects of mandibular overdenture maintenance on patient-based outcomes without specifying the number of implants they had received. Participants were divided into three maintenance groups, low, medium and high, based on the number of maintenance events they experienced during the five years. No significant differences were found in the 5-year VAS scores or in total OHIP-49 scores between the three groups of patients (ANOVA and Kruskal Wallis, p>.05). Except for the one year time point, there was a significant association at the baseline, 2 months and 5 years between the VAS overall satisfaction and total OHIP-49 scores.Conclusions:The number of maintenance events did not tend to affect patient-based outcomes. The lack of significant correlation between VAS overall satisfaction and OHIP-49 cores at the one-year interval suggests that these two questionnaires are not necessarily measuring the same outcomes.

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