A Pragmatic Study Shows Failure of Dental Composite Fillings Is Genetically Determined: A Contribution to the Discussion on Dental Amalgams

Erosive Tooth Wear, Wine Intake, and Genetic Variation in COMT and MMP2

INTRODUCTION

Erosive tooth wear (ETW) is a multifactorial condition of increasing prevalence in the younger population. This study aimed to explore the association between different ETW phenotypes with MMP2 and COMT single-nucleotide variants and selected environmental factors.

METHODS

Saliva samples, erosive wear, and dental caries experience data and dietary/behavioral information from 16- to 18-year-old patients (n = 747) were used. Genotypes were obtained, and phenotypes were further analyzed considering diet and behavioral data, using logistic regression as implemented in PLINK, with an alpha of 0.05.

RESULTS

When comparing individuals' ETW-free with those with mild ETW, an association was found with COMT rs6269 (p = 0.02). The comparison between ETW-free individuals with individuals with severe ETW also showed an association with COMT rs6269 under the recessive model (p = 0.03). Logistic regression showed that in the presence of less common alleles of MMP2 rs9923304 and COMT rs6269, ETW was more likely to occur when individuals drank wine. The GG genotype of COMT rs6269 was associated with the presence of lower (p = 0.02) and higher (p = 0.02) caries experience when individuals with ETW only in enamel were compared with individuals with ETW involving dentin.

CONCLUSION

The results support a role of genes in ETW, with wine consumption being identified as a significant modulator, suggesting that gene-environment interactions may contribute to the development of ETW.

Augmented Reality and Virtual Reality in Dentistry: Highlights from the Current Research

Many modern advancements have taken place in dentistry that have exponentially impacted the progress and practice of dentistry. Augmented reality (AR) and virtual reality (VR) are becoming the trend in the practice of modern dentistry because of their impact on changing the patient’s experience. The use of AR and VR has been beneficial in different fields of science, but their use in dentistry is yet to be thoroughly explored, and conventional ways of dentistry are still practiced at large. Over the past few years, dental treatment has been significantly reshaped by technological advancements. In dentistry, the use of AR and VR systems has not become widespread, but their different uses should be explored. Therefore, the aim of this review was to provide an update on the contemporary knowledge, to report on the ongoing progress of AR and VR in various fields of dental medicine and education, and to identify the further research required to achieve their translation into clinical practice. A literature search was performed in PubMed, Scopus, Web of Science, and Google Scholar for articles in peer-reviewed English-language journals published in the last 10 years up to 31 March 2021, with the help of specific keywords related to AR and VR in various dental fields. Of the total of 101 articles found in the literature search, 68 abstracts were considered suitable and further evaluated, and consequently, 33 full-texts were identified. Finally, a total of 13 full-texts were excluded from further analysis, resulting in 20 articles for final inclusion. The overall number of studies included in this review was low; thus, at this point in time, scientifically-proven recommendations could not be stated. AR and VR have been found to be beneficial tools for clinical practice and for enhancing the learning experiences of students during their pre-clinical education and training sessions. Clinicians can use VR technology to show their patients the expected outcomes before the undergo dental procedures. Additionally, AR and VR can be implemented to overcome dental phobia, which is commonly experienced by pediatric patients. Future studies should focus on forming technological standards with high-quality data and developing scientifically-proven AR/VR gadgets for dental practice.

Matrix Metalloproteinase 2 Is Associated With Secondary Caries Independent From the Restorative Material

Certain patients, despite receiving proper treatment, still show higher failure rates of restorative dental treatments. The aim of this work was to test if MMP2 and MMP3 alleles are overrepresented in individuals with secondary caries. A total of 1,089 individuals from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository project were selected for this study. From this total, 341 individuals were selected for having a record of secondary caries in any type of restoration and were matched with 748 individuals by sex, age, ethnicity, and restorative work in the same teeth that did not fail. Genomic DNA extracted from saliva was used to obtain genotypes in five markers of MMP2 and MMP3 using TaqMan chemistry and end-point analysis. Chi-square was used to test if differences in allele and genotype distributions were statistically different at an alpha of 0.05. The less common allele and homozygote genotype of MMP2 rs9923304 were less commonly found among individuals with secondary caries. The less common allele of MMP2 rs2287074 was also less frequent among individuals with secondary caries. These results provide statistical evidence for the role of MMP2 in failure of restorations due to secondary caries. We can conclude that MMP2 variation impacts the risk of having secondary caries, independent of the restorative material.

Association of matrix metalloproteinase-2 gene polymorphisms with susceptibility to type 2 diabetes: A case control study

AIMS

Genetic variations mediating MMP-2 expression may result in individual differences in susceptibility to particular diseases. Our aim was to investigate the possible association of certain MMP-2 gene variants with the susceptibility of type 2 diabetes (T2D) in a Tunisian population.

SUBJECTS AND METHODS

A retrospective case-control study involving 310 normoglycemic control subjects and 791 T2D patients was conducted. Genotyping of MMP-2 variants was performed by real time PCR.

RESULTS

Minor allele frequencies (MAF) of the rs243865 and the rs243866 MMP-2, were significantly different between T2D cases and controls. Setting homozygous wild-type genotype carrier as reference, a reduced risk of T2D was seen with the rs243865 and the rs243866 genotypes. Haploview analysis revealed limited linkage disequilibrium between the tested MMP-2 and variants, with most haplotypes (99.5%) captured by 7 MMP-2 haplotypes. Taking the GCCC haplotype as reference for MMP-2 (OR = 1.00), a reduced frequency of TTCC haplotypes (P = 0.04) and the GTCC haplotype (P = 3.5 · 10^-5) was noted in T2D which indicates a protective nature of these two haplotypes for T2D development.

CONCLUSION

To the best of our knowledge, the present study is the first to demonstrate a consistent association of the rs243865 and rs243866 genotype with a protection for T2D.

Biomarkers for Lifetime Caries-Free Status

The purpose of this study was to address the hypothesis that extreme outcomes of dental caries, such as edentulism or prematurely losing permanent teeth are associated with genetic variation in enamel-formation genes. After scanning 6206 individuals, samples of 330 were selected for this study. Tested phenotypes included patients who were edentulous by age 30, patients with missing first molars by age 30, patients with missing second molars by age 30, and caries-free patients. Fourteen single nucleotide polymorphisms were genotyped by TaqMan chemistry. The analyses of each phenotype were performed using the software PLINK with an alpha of 0.05. Nominal associations were found between rs12640848 in enamelin (p = 0.05), rs1784418 in matrix metallopeptidase 20 (p = 0.02), and rs5997096 in the tuftelin interacting protein 11 and being caries-free at the age of 60. When combining patients that were missing both first mandibular molars and missing both second mandibular molars, no associations were found. Matrix metallopeptidase 20, and tuftelin interacting protein 11 also showed trends for association with being caries-free. Genetic variation in TFIP11, MMP20, and ENAM may have a protective effect increasing the chances of individuals preserving their teeth caries-free over a lifetime.

Maxillary incisor enamel defects in individuals born with cleft lip/palate

Cleft lip with or without cleft palate (CLP) is considered the most frequent congenital malformations of the head and neck, with cleft individuals exhibiting more chances of presenting abnormalities such as developmental defects of enamel (DDE). Matrix metallopeptidase 2 (MMP2) is a membrane-bound protein with collagen-degrading ability and has important roles in tooth formation and mineralization. The aim of this study was to evaluate the frequency, location, severity and extent of DDE found in the maxillary incisors for groups of individuals born with CLP, as well as understanding their relationship with the cleft side. Besides, this study addresses the hypothesis that DDE can be influenced by variation in the MMP2 genes (rs9923304). Individual samples, clinical history, intraoral photographs and panoramic radiographs were obtained from 233 patients under treatment at the Cleft Lip and Palate Service of the University Hospital Lauro Wanderley at the Federal University of Paraíba. Digital images were examined by the same evaluator using the Classification of Defects According to the Modified DDE Index, and then loaded into the Image Tool software, where two measurements were made: total area of the buccal surface (SA) and the area of the DDE (DA), obtaining the percentage of the surface area affected (%SAD) (ICC = 0.99). Genomic DNA was extracted from saliva samples from 124 participants. Genotyping was carried out using TaqMan chemistry for one marker in MMP2 (rs9923304). Statistical analyses were performed by The Jamovi Project software. The Shapiro-Wilk test was applied, followed by the Student's t-test and the Mann-Whitney test. Chi-square and Fisher's exact tests, and odds ratio (OR) with 95% confidence interval (CI) calculations were used to determine Hardy-Weinberg equilibrium and statistically significant differences with an alpha of 0.05. No significant differences in the prevalence and extent of enamel defects were found between male and female individuals born with CLP (p = 0.058256). The frequency of individuals presenting teeth with DDE, in relation to the cleft and non-cleft side, was statistically different (p <0.001; OR = 7.15, CI: 4.674> 7.151> 10.942). However, the averages of %SAD were similar (p = 0.18). The highest means of the %SAD were found in individuals with bilateral cleft lip with or without cleft palate (BCLP) when compared to individuals with unilateral cleft lip with or without cleft palate (UCLP), for the teeth inside (IA) and outside the cleft area (OA) (p <0.001). Regardless of the cleft side, individuals with BCLP were 7.85 times more likely to have more than one third of the tooth surface affected, showing more frequently defects in the three thirds (OA: p <0.001) (IA: p = 0.03), as well as a higher frequency of more than one type of defect (OA: p = 0.000358) (IA: p = 0.008016), whereas in UCLP, defects were isolated and restricted to only one third, more frequently, the incisal third (OA: p = 0.009) (IA: p = 0.001), with greater frequency of milder defects, such as demarcated (p = 0.02) and diffuse (p = 0.008) opacities. A higher frequency of the T allele, less common, was observed in the group of CLP individuals who had all the affected teeth or at least two teeth with %SAD greater than 20% (p = 0.019843). Our results suggest that MMP2 may have a role in the cases that presented DDE and genotyping rs9923304 could serve as the basis for a genomic approach to define risks for individuals born with CLP. Frequency and severity of DDE is strongly related to the CLP phenotype, since the highest values were found for BCLP. However, the extent of the DDE is independent of its relationship with the side of the cleft.

Talon Cusp Associates With MMP2 in a Cohort of Individuals Born With Oral Clefts

OBJECTIVE

The aim of this study was to use dental development as a tool to subphenotype oral clefts and investigate the association of MMP2 with dentin-pulp complex anomalies, in order to identify dental anomalies that are a part of a "cleft syndrome."

DESIGN

Two hundred and ninety individuals born with cleft lip and palate were evaluated and several clinical features, such as cleft completeness or incompleteness, laterality, and presence of dental anomalies were used to assess each individual's cleft status. We tested for overrepresentation of MMP2 single nucleotide polymorphism rs9923304 alleles depending on individuals having certain dental anomalies. Chi-square and Fisher exact tests were used in all comparisons (α = .05).

RESULTS

All individuals studied had at least one dental anomaly outside the cleft area. Significant differences between individuals born with clefts with and without talon cusp (P = .04) were observed for the frequency of the MMP2 less common allele.

CONCLUSION

All individuals born with cleft lip and palate had alterations of the dentition, and a quarter to half of the individuals had alterations of the internal anatomy of their teeth, which further indicates that dental anomalies can be considered as an extended phenotype for clefts. MMP2 was associated with talon cusp in individuals born with oral clefts.

Ageing of Dental Composites Based on Methacrylate Resins-A Critical Review of the Causes and Method of Assessment

The paper reviews the environmental factors affecting ageing processes, and the degradation of resins, filler, and the filler-matrix interface. It discusses the current methods of testing materials in vitro. A review of literature was conducted with the main sources being PubMed. ScienceDirect, Mendeley, and Google Scholar were used as other resources. Studies were selected based on relevance, with a preference given to recent research. The ageing process is an inherent element of the use of resin composites in the oral environment, which is very complex and changes dynamically. The hydrolysis of dental resins is accelerated by some substances (enzymes, acids). Bonds formed between coupling agent and inorganic filler are prone to hydrolysis. Methods for prediction of long-term behaviour are not included in composite standards. Given the very complex chemical composition of the oral environment, ageing tests based on water can only provide a limited view of the clinical performance of biomaterial. Systems that can reproduce dynamic changes in stress (thermal cycling, fatigue tests) are better able to mimic clinical conditions and could be extremely valuable in predicting dental composite clinical performance. It is essential to identify procedure to determine the ageing process of dental materials.

Phenome-Wide Scan Finds Potential Orofacial Risk Markers for Cancer

Cancer is a disease caused by a process that drives the transformation of normal cells into malignant cells. The late diagnosis of cancer has a negative impact on the health care system due to high treatment cost and decreased chances of favorable prognosis. Here, we aimed to identify orofacial conditions that can serve as potential risk markers for cancers by performing a phenome-wide scan (PheWAS). From a pool of 6,100 individuals, both genetic and epidemiological data of 1,671 individuals were selected: 350 because they were previously diagnosed with cancer and 1,321 to match to those individuals that had cancer, based on age, sex, and ethnicity serving as a comparison group. Results of this study showed that when analyzing the individuals affected by cancer separately, tooth loss/edentulism is associated with SNPs in AXIN2 (rs11867417 p = 0.02 and rs2240308 p = 0.02), and leukoplakia of oral mucosa is associated with both AXIN2 (rs2240308 p = 0.03) and RHEB (rs2374261 p = 0.03). These phenotypes did not show the same trends in patients that were not diagnosed with cancer, allowing for the conclusion that these phenotypes are unique to cases with higher cancer risk.

Aquaporin locus (12q13.12) might contribute to susceptibility of temporomandibular joint disorder associated with periodontitis

Aquaporins (AQPs) are membrane channels that provide for transport of water and other small molecules across the lipid bilayer of cells. Their function is essential for physiologic processes such as cell volume regulation, chondrocyte hypertrophy during appendicular skeletal growth, water reabsorption in the kidney tubules, and water excretion by the salivary glands. The ten AQP isoforms show tissue specificity and are involved in different pathologies and inflammatory diseases. This study addresses the hypothesis that arthritis, periodontitis, and temporomandibular joint disorders (TMDs) can be influenced by variation in the AQP genes at 12q13.12 locus. Salivary samples of 688 individuals were obtained from the Dental Registry and DNA Repository project at the University of Pittsburgh. Ten polymorphisms in four AQP genes (AQP1, 2, 5, and 6) were genotyped and correlated to disease status as reported by patients. Associations were found between the single nucleotide polymorphism (SNP) rs467323 in AQP2 and TMD in both genotypic (p = 0.03) and recessive (p = 0.02) models, and between rs1996315 in AQP6 and periodontitis (p = 0.05). Combined analysis of TMD and periodontitis showed an association with rs3741559 in AQP2 (p = 0.02). When conducting haplotype analysis of rs467323 and rs10875989 in AQP2, the haplotype CT showed an association with the TMD phenotype (p = 0.007). Our results suggest that the aquaporin locus at 12q13.12 may contribute to the pathogenesis of inflammatory conditions such as periodontitis and TMD. Thus, oral and skeletal health are correlated and potential susceptibility screening strategies may be developed.

HIV status does not worsen oral health outcomes

Last January 31st, Journal of Clinical Periodontology just made available the report titled "A Retrospective Analysis of Dental Implant Survival in HIV Patients," which concluded that "implants placed in HIV-positive patients had similar survival rates as HIV-negative patients." These data support our hypothesis that infection by HIV does not lead to worse oral health outcomes, including worse periodontitis. We looked 6,092 individuals and selected all HIV-positive subjects (N = 73) and matched them by age, sex, ethnicity, and smoking habits with 261 HIV-negative control subjects. Based on these 334 total individuals, several dental conditions, including the need for root canal treatment, gingivitis, periodontitis, hairy leukoplakia, and dental caries were compared between the two groups. Overall, there was no difference in dental disease between the HIV-positive and HIV-negative groups. In our data, it was found that the prevalence of periodontitis in HIV-positive patients was 16.4% and in HIV-negative patients 19.2%.

From Caries Progression and Restoration Failures to Periapical Lesions in the Era of Precision

KNOWLEDGE TRANSFER STATEMENT

Dental research can be thought of as a continuum of clinical observations that are dissected in the laboratory with answers that can be brought back to the clinic to change patient management. We believe this is the case for the use of adhesive systems and outcomes of dental treatment. Clinical observations related to negative outcomes have been tested in the laboratory and solutions have been proposed, with more precise implementation of these solutions possible when genomic approaches are added. Here we elaborate on this process based on the observations that lead to an attempt to inactivate metalloproteinase activity by dentin crosslinking.