The influence of overhanging restoration margins on interproximal alveolar bone levels in general dental practice

New Technique for Wedge Selection in Direct Class II Restorations: A Pilot Study

Background: Performing an appropriate Class II direct restoration is a great challenge. The correct selection of the matrix system and the elements used for its stabilization will have a great impact on the result. The aim of this study is to show a new digital method for a predictable selection of the wedge and compare it with the conventional method. Methods: Sixty patients were randomly divided into two groups. In Group 0, the wedge was selected intraoperatively by visual examination, while in Group 1 the wedge was selected preoperatively through the measurement of the cervical embrasure on the bite-wing radiography. The number of wedges used, modifications to them, and tissue damage were registered, along with the quality of the proximal contact and the marginal adaptation. Results: Student's t-test revealed a statistical difference between the number of wedges used, which was higher in Group 0 (p < 0.05). Pearson Chi-square test showed that tissue damage was statistically higher in Group 0 (p < 0.05), while there was no statistically significant difference between groups in wedge modifications (p > 0.05). Group 1 revealed a higher frequency of satisfactory proximal contact and marginal adaptation (p < 0.05). Conclusions: This new technique reduces wedges waste and tissue damage and provides an adequate interproximal anatomy.

Class II composite restoration technique teaching: A randomised controlled crossover laboratory-based trial involving a novel ringless sectional matrix technique

INTRODUCTION

Objectives were to assess how different techniques (including a novel ringless sectional matrix approach) affect students' restorative outcomes, and their preferences for and preparedness to clinically implement new techniques with the aim of introducing appropriate techniques to the undergraduate curriculum.

MATERIALS AND METHODS

Students performed two class II composite restorations in plastic teeth using two sectional matrix techniques (separating ring vs. without [ringless]), and two composite restorative techniques (incremental vs. injection-moulded bulk-fill). Restorations were assessed on multiple parameters which were combined to rate them as "good" or not. Online surveys assessed students' preferences for and preparedness to clinically implement new techniques.

RESULTS

Contact area concavity (OR = 106, p < .001) and cervical marginal overhang (OR = 7.4, p < .001) were much more likely with the separating ring compared to the ringless sectional matrix technique. "Good" restorations were 29.5 times more likely when using ringless compared to separating ring techniques and 3.3 times more likely when using the injection-moulding bulk-fill compared to layered composite technique. A majority of students preferred the ringless to separating ring sectional matrix technique and the injection-moulding bulk-fill to layered composite technique. Large majorities felt prepared to implement the new techniques clinically with no or minimal guidance.

CONCLUSIONS

A classic sectional matrix technique with separating ring resulted in a much greater occurrence of contact area concavity and cervical marginal overhang than a novel ringless approach. When allied with student preferences and clinical preparedness, inclusion of the novel ringless approach in the undergraduate curriculum can be supported alongside bulk-fill injection-moulding techniques.

Radiological assessment of alveolar bone loss associated with overhanging restorations: A retrospective cone beam computed tomography study

Background/purpose

Studies suggested that presence and size of overhanging restoration margins play role in alveolar bone loss. The aim of this study was to determine the prevalence and distribution of overhanging approximal restorations, to evaluate the effect of presence and size of overhang on bone loss using cone beam computed tomography (CBCT) reformatted panoramic images, and to encourage the use of CBCT in retrospective studies on restorative dentistry.

Materials and methods

CBCT images of 382 patients with approximal restorations were included in the study. On CBCT images, alveolar bone loss adjacent to each restored surface was determined and compared to the control tooth. The overhang size was measured and categorized as small, medium, or large. Data obtained were evaluated statistically using Kruskal Wallis, Mann Whitney U, chi-square, and one-sample chi-square tests with a significance level set at P < 0.05.

Results

A total of 216 (32.4%) surfaces with overhanging restorations were detected in CBCT images. The number of overhanging surfaces with alveolar bone loss (71.3%) was higher than the control surfaces with bone loss (49.1%) (P < 0.05). The amount of bone loss adjacent to overhanging surfaces (2.28 ± 1.69 mm) was significantly higher compared to control surfaces (1.53 ± 1.73 mm) (P < 0.05). However, the same trend applied to the surfaces without overhang and their controls. The amount of bone loss was not correlated with the overhang size (P > 0.05).

Conclusion

Approximal restorations with and without overhanging margins may often result in alveolar bone loss, the amount of which is not always correlated with the overhang size.

Assessment of the readiness of restorations manufactured by CAD/CAM in terms of marginal fit (Part I)

Background

The master cast is the gold standard for the control and eventual adjustment of restorations produced by conventional procedures. Some digital workflow bypasses the master cast and relies completely on the precision of the CAD/CAM restoration.

Aim

To examine the reproducibility of the margins of CAD/CAM restorations generated from a single digital scan. Also, to check the readiness of these restorations for delivery directly after fabrication without adjustment on a master cast and thereby eliminate the need for the master cast.

Methods

A total of 18 metal substructures made from cobalt chrome alloy were fabricated utilizing a single STL file. The circumference was divided into eight zones. The vertical marginal discrepancy (VMD) was measured at each zone of each metal substructure, with optical microscopy at ×200 magnification.

Results

Measurements of vertical marginal discrepancy were in a range of (-94: 300) with a mean of 62 ± 60 μm. A one-way ANOVA test revealed that the mean VMD is significantly different among the 18 substructures (F17, 1,134 = 63.948, p < 0.001).

Conclusion

Although all the received substructures were fabricated from the same scan file, they were not identical and varied widely, and they were going outside the acceptable range in some zones. Within the limitations of this study, the marginal fit can be improved by extraoral adjustments on the master cast. Thus, skipping the master cast deprives the dentist of delivering a restoration of higher quality.

Sectional matrix solutions: the distorted truth

Sectional matrix techniques offer more predictable solutions to achieving contact areas when placing direct interproximal posterior composites than circumferential matrix techniques, resulting in reduced reported complaints of food packing from patients. Despite this, a large majority of UK dentists and therapists don't currently use them. Sectional matrix systems are technique-sensitive to use, which can be a barrier to implementation for inexperienced users. The matrices can easily distort during their placement and stabilisation and when placing the restorative material. This can result in unwanted, clinically relevant problems in the resulting restorations, some of which may not be discernible once they have occurred. This paper explores the advantages and disadvantages of sectional matrices and the processes and techniques involved in their use, before discussing the potential for distortion at each step. It offers solutions to some of the commonly seen problems which will provide more predictable outcomes for those already using these techniques and encourage non-users to add them to their armamentarium.

Occlusal trauma is associated with periodontitis: A retrospective case-control study

BACKGROUND

Excessive occlusal forces and occlusal trauma have been implicated as co-destructive factors for periodontitis in animal models. The objective of this study was to assess the association between occlusal trauma and periodontitis.

METHODS

A total of 167 cases and 205 controls were included for analysis. Occlusal trauma was the exposures of interest and was registered for cases and controls. Additional clinical co-variables were registered as well for further analysis. The association of the exposure and periodontitis was determined by the odds ratio and logistic regression analysis adjusted for confounders.

RESULTS

Amalgam restorations, pathogenic occlusion and occlusal trauma were more frequent in cases as compared to controls (P ≤ 0.05). The distribution of pathogenic occlusion and occlusal trauma was similar according to the stage and class of periodontitis. Logistic regression analysis showed a significant association for cigarette smoking, systemic conditions, amalgam restorations, pathogenic occlusion, and occlusal trauma with periodontitis (P ≤ 0.05). After adjusting for confounding variables in the model, amalgam restorations and occlusal trauma remained strongly associated with periodontitis (P ≤ 0.05).

CONCLUSIONS

Occlusal trauma is strongly associated with periodontitis. Additional long-term prospective studies are necessary to further understand the impact of the occlusal condition and periodontitis.