No more amalgams: Use of amalgam and amalgam alternative materials in primary dental care

Predictors of procedural errors in class II resin composite restorations using bitewing radiographs

Objective

To identify the potential factors that induce procedural errors during posterior proximal resin composite restorations placed by dental students.

Materials and Methods

This retrospective study evaluated 803 bitewing radiographs of posterior proximal resin composite restorations placed by dental students at Imam Abdulrahman bin Faisal University. Atypical radiographic signs of failure were screened, and different patient-, operator-, and clinical-related factors were recorded. Chi-square test was used to examine the relationship between procedural errors and recorded factors. Stepwise adjusted logistic regression model was performed to identify predictors of procedural errors.

Results

The most observed errors were internal gaps at the bonding interface and internal voids. Molars had 0.39 the risk of internal voids (odds ratio [OR] = 0.39; confidence interval [CI] = 0.25-0.60; P = <0.0001), 0.41 the risk of sharp angle (OR = 0.41; CI = 0.24-0.68; P = <0.001), and 0.57 the risk of open contact (OR = 0.57; CI = 0.34-0.97; P = 0.04) compared to premolars. Those who were >40 years of age had 1.79 the risk of overhang compared to younger patients (OR = 1.79; CI = 1.04-3.11; P = <0.04). First molars and premolars had 0.64 the risk of overhang compared to second molars and premolars (OR = 0.64; CI = 0.41-1.00; P = 0.04). Junior students had 1.97 the risk of internal gap compared to their senior counterparts (OR = 1.97; CI = 1.20-3.21; P = 0.008). Mesial restorations had 0.38 the risk of external gap compared to mesio-occluso-distal (MOD) restorations (OR = 0.38; CI = 0.19-0.78; P = 0.003). Restorations with a margin coronal to the cemento-enamel junction (CEJ) had 0.44 the risk of external gap compared to those restorations with a margin apical to the CEJ (OR = 0.44; CI = 0.29-0.66; P = <0.0001).

Conclusion

Our findings suggested a higher incidence of procedural errors in restoring premolars and MOD cavity preparations. Therefore, it is crucial to enhance the comprehensiveness of laboratory training and expose students to diverse clinical scenarios and various techniques.

Current trends in placing posterior composite restorations: Perspectives from Palestinian general dentists: A questionnair study

Aim

The success of composite restorations relies on material selection and practitioner-related factors that shape the overall outcome. This study explores the practices of Palestinian general dental practitioners in placing posterior composites, examining the impact of work sector, experience, and gender on their choices.

Materials and Methods

The study was conducted as an online cross-sectional questionnaire and involved 351 participants, with a response rate of 69.8%. The survey comprised 18 closed-ended questions covering demographics, material selection, and composite placement in special cases, techniques, and factors influencing the choices. Statistical analyses included descriptive statistics, chi-squared tests, and Fisher's exact tests.

Results

Composite was the predominant choice for small-size (83.7%) and large-size posterior cavities (60.4%). Practitioners commonly opted for composite restorations in cases involving occlusal parafunctional activity (60%), poor oral hygiene (78%), and subgingival cavities (72.2%). Only 19.6% and 5.3% reported occlusal and gingival beveling, respectively. Rubber dams for isolation stood at 30%, one-step self-etch adhesives at 44.9%, and the oblique layering technique at 51%. Light-emitting diode curing units were popular (97.55%), but monitoring output with a radiometer was infrequent (93.5%). Tofflemire metal matrix usage was 46.1%, whereas a sectional matrix system was employed by 29.8%. A 2 mm layer exposure to light curing for 20 s was reported by 62%, and 27.75% utilized additional light-curing postmatrix band removal.

Conclusion

The study highlights the need for Palestinian dental professionals to update their clinical approaches in placing composite restorations in posterior teeth. Gender, work sector, and experience influence practitioners' choices, emphasizing the importance of tailored continuing education programs for improving clinical practices.

Explore the most recent advancements in the domain of self-healing intelligent composites specifically designed for use in dentistry

Dental composites are commonly utilized in dental treatments because they have the ability to preserve the natural appearance of teeth, are minimally invasive and conservative, and enhance the overall physical and mechanical attributes. Dental composites can experience damage, like small cracks, due to factors like temperature changes and physical strain, which can reduce their effectiveness. Detecting these tiny cracks in dental composites can be quite challenging, and in certain situations, it may even be impossible. In addition, it is not possible to repair these damages in situ by using conventional materials and methods. Therefore, the self-healing ability in dental composites is necessary. In recent years, the spontaneous repair of damages such as micro-cracking in dental composite materials has been developed without any type of human intervention and the replacement of new components. The most widely used approach to create self-healing dental composites involves encapsulating a healing agent within polymer shells and dispersing these microcapsules within the acrylate matrix of the dental composite. To assess the self-healing abilities of these composites, researchers can examine changes in their fracture toughness before and after the healing process using a test called the Single Edge V-notch beam test. In the present article we reviewed the latest findings in the field of self-healing intelligent composites for application in dentistry, and also in the present study, the studies on self-healing smart dental composites will be reviewed.

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.

Teaching and placement of dental amalgam restorations at South African dental schools

Introduction

This paper set out to investigate the relationship between teaching and clinical practice of direct posterior restoration placement at tertiary dental institutions in South Africa.

Methods

A cross-sectional study using a mixed methods approach was conducted, and all the South African dental schools were invited to participate. The quantitative phase of the study analyzed the Conservative Dentistry department's records of direct restorations at a single dental school. The number of amalgam and tooth-colored restorations placed by students in the fourth and fifth year of the program from 2004 to 2019 were compared. During the qualitative phase, semi-structured interviews were held with staff from the four dental schools involved with the teaching of direct posterior restorations.

Results

The predominant direct posterior restoration placed in student clinics over a 15-year period at a South African dental school was tooth colored (75%). Teaching times do not correspond to a decrease in the placement of dental amalgam restorations for both one-surface and two-surface posterior restorations and a concomitant increase in the tooth-colored restorations.

Discussion

Academic staff involved in teaching identified that South Africa's ratification of the Minamata Convention has consequences for dental education and training. However, all schools reported that dental amalgam would continue to be taught in the absence of an appropriate alternative.

Developments in resin-based composites

With the phasing down of dental amalgam use in response to the Minamata Convention, it is likely that resin-based composite restoratives will be the dental material of choice for the direct restoration of compromised dentition in the UK, at least for the foreseeable future. The current materials have a finite lifespan, with failures predominately due to either secondary caries or fracture. Consequently, there is considerable in vitro research reported each year with the intention of producing improved materials. This review describes the recent research in materials designed to have low polymerisation shrinkage and increased mechanical properties. Also described is research into materials that are either antimicrobial or are designed to release ions into the surrounding oral environment, with the aim of stimulating remineralisation of the surrounding dental tissues. It is hoped that by describing this recent research, clinicians will be able to gain some understanding of the current research that will potentially lead to new products that they can use to improve patient treatment in the future.

Provides an overview of recent research developments aimed at improving the performance of resin-based composites.

Details the recent developments in monomers and fillers to produce resin-based composites that either have lower polymerisation shrinkage or better mechanical properties compared to current commercially available products.

Describes recent research on developing resin-based composites that can act as potential sources of antimicrobial or remineralising agents.

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.

Amalgam Phase-Down Part 1: UK-Based Posterior Restorative Material and Technique Use

Introduction:

A European Union amalgam phase-down has recently been implemented. Publicly funded health care predominates in the United Kingdom with the system favoring amalgam use. The current use of amalgam and its alternatives has not been fully investigated in the United Kingdom.

Objectives:

The study aimed to identify direct posterior restorative techniques, material use, and reported postoperative complication incidence experienced by primary care clinicians and differences between clinician groups.

Methods:

A cross-sectional survey was distributed to primary care clinicians through British dentist and therapist associations (11,092 invitations). The questionnaire sought information on current provision of direct posterior restorations and perceived issues with the different materials. Descriptive statistical and hypothesis testing was performed.

Results:

Dentists’ response rate was 14% and therapists’ estimated minimum response rate was 6% (total N = 1,513). The most commonly used restorative material was amalgam in molar teeth and composite in premolars. When placing a direct posterior mesio-occluso-distal restoration, clinicians booked on average 45% more time and charged 45% more when placing composite compared to amalgam (P < 0.0001). The reported incidences of food packing and sensitivity following the placement of direct restorations were much higher with composite than amalgam (P < 0.0001). Widely recommended techniques, such as sectional metal matrix use for posterior composites, were associated with reduced food packing (P < 0.0001) but increased time booked (P = 0.002).

Conclusion:

Amalgam use is currently high in the publicly funded sector of UK primary care. Composite is the most used alternative, but it takes longer to place and is more costly. Composite also has a higher reported incidence of postoperative complications than amalgam, but time-consuming techniques, such as sectional matrix use, can mitigate against food packing, but their use is low. Therefore, major changes in health service structure and funding and posterior composite education are required in the United Kingdom and other countries where amalgam use is prevalent, as the amalgam phase-down continues.

Knowledge Transfer Statement:

This study presents data on the current provision of amalgam for posterior tooth restoration and its directly placed alternatives by primary care clinicians in the United Kingdom, where publicly funded health care with copayment provision predominates. The information is important to manage and plan the UK phase-down and proposed phase-out of amalgam and will be of interest to other, primarily developing countries where amalgam provision predominates in understanding some of the challenges faced.

Amalgam Phase-Down Part 2: UK-Based Knowledge, Opinions, and Confidence in the Alternatives

Introduction:

Amalgam use has recently been phased down, and the potential for a phase-out is being investigated.

Objectives:

The study aimed to identify knowledge of the phase-down and opinions of a potential phase-out of amalgam by UK primary care clinicians and assess their confidence in using different materials in different situations.

Methods:

An anonymized, prepiloted cross-sectional e-survey was used to assess primary care clinicians’ knowledge and opinions of the amalgam phase-down and potential phase-out and their confidence in using amalgam and the alternatives in different situations. In total, 11,902 invitations were distributed through British dentist and therapist associations. Prior hypotheses were tested alongside descriptive statistics.

Results:

Response rate was 13% (n = 1,513). Knowledge of the amalgam phase-down was low, with just 3% clinicians correctly identifying all patient groups in whom amalgam use should be avoided in the United Kingdom. Postgraduate education on posterior composite placement was high (88%), but a large majority had personal and patient-centered concerns over the suitability of the alternatives and lacked confidence when placing composite in comparison to amalgam in difficult situations (P < 0.0001). Logistic regressions revealed that the best predictors of high confidence in placing mesio-occluso-distal composites and composites in difficult situations were being a private general dentist or being primarily a composite user.

Conclusion:

Primary care clinicians have major personal and patient-centered concerns regarding the amalgam phase-down (of which they have limited knowledge) and potential phase-out. Many lack confidence in using the alternative, composite, to restore posterior teeth in difficult situations, whereas confidence in using amalgam in similar situations is high. Effective education of clinicians and understanding patients’ needs, alongside policy changes, are required to enable a successful amalgam phase-down and potential phase-out.

Knowledge Transfer Statement:

This study shows that UK primary care clinicians are worried about the phase-down of amalgam for themselves and their patients. Many lack confidence in the alternative, composite, when used in difficult situations, which is in stark contrast to amalgam. Knowledge of the phase-down is limited. There is a need for more effective education of clinicians, an understanding of patients’ values, and policy changes to ensure the success of the phase-down and potential phase-out of amalgam.

Fall of amalgam restoration: a 10-year analysis of an Australian university dental clinic

BACKGROUND

The use of amalgam in Dentistry has decreased since the 1980s. This study aimed to (i) assess the time trend in the usage of amalgam and composite in posterior teeth at Griffith University Dental Clinic from 2010 to 2019; (ii) to test whether this trend varied according to the dental health provider.

METHODS

We analysed clinic records from 2010 to 2019. Prais-Winsten analyses were performed, and the average annual percentages change (AAPC) for amalgam and composite was estimated.

RESULTS

There were 397,013 procedures, including 80,995 direct posterior restorations. Amalgam use decreased from 12.9% in 2010 to 0.5% in 2019 among students, while composite use increased from 87.1% to 99.5% of posterior restorations. The annual increase of the composite was 1.4% per year for students, while amalgam decreased by 30.2% per year on average. A similar trend was noted among the dentists.

CONCLUSIONS

A significant decrease in the use of amalgam was observed over time for both students and professionals. This trend raises questions about curriculum reviews, focusing on the repair, maintenance and safe removal of amalgam while reinforcing the learning on Minimally Invasive Dentistry and composite restorations based on the patient's caries risk.

Leadership in dental education

Dental school education continues to evolve at a significant pace. The challenge for those in leadership positions in dental education is to deliver a curriculum which is contemporary, evidence-based, and at the same time meeting the expectations of regulators and the established dental workforce - the latter being professional colleagues, including employers of future graduates. An important change in recent years is the acceptance that dental education itself is no longer a 'start-stop process', beginning at entry to dental school and concluding at graduation. Rather, dental education should be viewed as a continuous and life-long continuum. Perhaps one of the greatest attributes we can develop in our students is the desire and ability to seek to update, refresh and develop their knowledge and skills in the ever-advancing world of dental practice.

An ex-vivo model to determine dental pulp responses to heat and light-curing of dental restorative materials

AIM

Based on histological studies from the 1960s, it is recommended that dental pulp temperature increases should not exceed 5.5 °C. However, no contemporary reliable models exist to explore the effects of heat on living dental pulp. The aim of this project was to develop a clinically valid model for studying temperature increases caused by three commonly-used light curing units (LCUs).

METHODS

Temperature increases caused by LCUs at varying exposure times and via various thicknesses of dentine were recorded using traditional approaches (i.e. thermocouple device on a laboratory bench) and an ex-vivo tooth slice model. Histomorphometric and immunohistochemical (IL-1β, HSP70, caspase-3) analysis was performed of the tooth slice model following varying exposure and culture times.

RESULTS

Reduced dentine thickness and increased exposure time led to increases in temperature. Whilst the majority of temperature increases recorded using the traditional approach (53 of 60) were greater than the recommended 5.5 °C, 52 of the 60 reference points recorded using the ex-vivo tooth slice model resulted in temperature increases of less than 5.5 °C. Temperature increases of 5.5 °C or more that are prolonged for 40 s caused an immediate decrease in cell number. IL-1β was not detected in any samples, while HSP70 was detectable immediately after exposure to a temperature increase of 6 °C or more. Higher levels of HSP70 were detected after 24 h culture in tooth slices that experienced a temperature increase of 7.5 °C or more. Low levels of caspase-3 were detected in tooth slices exposed to temperature increase of 7.5 °C or more.

CONCLUSION

Experimental arrangements for assessing LCU performance that measure temperature increases using a thermocouple device on a laboratory bench should no longer be used. Future studies in this area should include replication of the clinical environment using greater sophistication, such as the use of an ex-vivo tooth slice model as described here. Temperature increases of 5.5 °C or more for 40 s caused an immediate decrease in cell number, which supports previous findings. However, complex interactions at an immunohistochemical level suggest that while temperature increases of 5 °C or less are ideal, there may be some cell damage between 5-7 °C which might not result in pulpal death. Further investigations are indicated.