Alveolar bone resorption following tooth extraction characteristically illustrated

Under normal physiological conditions, bone undergoes a constant, balanced and well- regulated process of renewal and remodelling. This is needed for growth, remodelling and maintenance of skeletal form, as well as for homeostasis of skeletal and plasma calcium levels. The alveolar bone grows along with tooth eruption, and thereafter its shape and volume are influenced by local mechanical as well as systemic factors. It is maintained by forces exerted on it via the periodontal ligaments, thus teeth are mandatory for its preservation and renewal. Following tooth loss, the socket becomes filled with a blood coagulum, which is later replaced by fibrous tissue. This healing process is associated with sizeable reduction in ridge height within the first two months that continues at a slower and variable rate throughout life. There are countless examples of patients who have lost teeth at an early age, presenting with severe alveolar bone loss bone in that area / jaw. The extent is even more dramatic if the edentulous space has been opposed by natural teeth. The cases illustrated in this paper serve to remind clinicians of the need to help patients maintain as many of their natural teeth as possible, while still being cognisant of their aesthetic and functional demands, and the possible health implications.http://www.sada.co.zaam2022Prosthodontic

Dentists and dental technicians - a united team or uncomfortable alliance?

The effective practising of dentistry requires that dentists and dental technicians work hand in hand, having mutual respect for each other, while maintaining the highest standards in each of their respective disciplines. From a limited survey of dentists and dental technicians it seems that a small portion of our profession have misinterpreted the concept of “hand in hand” to be one of gross perverse incentives, corruption, collusion and dishonesty. This article may come as a shock to some and a revelation of what is known to be true to others. The issues discussed have generally been kept as “Dental family secrets”, however, the authors believe that these practices need to be uncovered if we want to put an end to this behaviour.https://www.sada.co.za/the-sadjam2022Oral Pathology and Oral BiologyProsthodontic

Ethical dilemmas when dealing with doctor Google and the importance of patient education

A 55 year old female patient presented for dental treatment. Her attending clinician immediately noted that since her first visit some days previously she had shaved her head, revealing a severe rash on her right forehead and scalphttp://www.sada.co.zaam2020Prosthodontic

Technicians and dentists : a catch 22 situation?

Dental technicians who regularly receive poor quality impressions and records are often faced with professional and ethical concerns as to how to handle the situation. They may choose to complete the task to the best of their abilities. Other options are to alter the casts to try to improve the situation and then complete the prescription, contact the dentist and discuss the issue, contact the patient, contact the medical aid, report the practitioner to the HPCSA, or refuse to do the work. Their latter actions have potentially negative implications for them, and will certainly sour working relationships. At worst, they may lose the dentist’s support. This paper explores ways in which dentists and techniciains can foster collegial and mutually beneficial relationships from early on in their careers. This will not only promote better communication, and improve the quality of work produced by them, but it will also serve the best interests of their patients and the profession as a whole.https://www.sada.co.za/the-sadjam2022Prosthodontic

Is “failure to treat” a treatment failure?

Over-servicing in dentistry has been widely reported on and censured due to the potential physical, social and financial harms it can cause a patient. In contrast, under-treatment is less often noticed or raised as a concern as it seldom presents with overt signs of carelessness or disregard. In addition, it is usually not accompanied by any time or financial burdens, thus patients rarely complain about it. While some practitioners may argue that failure to treat is a form of negligence, this paper will explore if, and when it could be justified. While practitioners may never reach a consensus agreement, the ultimate message is that all treatment should be patient centred and should only commence following their educated, considered, autonomous, and voluntary consent.https://www.sada.co.za/the-sadjam2022Prosthodontic

From Disease Association to Risk Assessment: An Optimistic View from Genome-Wide Association Studies on Type 1 Diabetes

Genome-wide association studies (GWAS) have been fruitful in identifying disease susceptibility loci for common and complex diseases. A remaining question is whether we can quantify individual disease risk based on genotype data, in order to facilitate personalized prevention and treatment for complex diseases. Previous studies have typically failed to achieve satisfactory performance, primarily due to the use of only a limited number of confirmed susceptibility loci. Here we propose that sophisticated machine-learning approaches with a large ensemble of markers may improve the performance of disease risk assessment. We applied a Support Vector Machine (SVM) algorithm on a GWAS dataset generated on the Affymetrix genotyping platform for type 1 diabetes (T1D) and optimized a risk assessment model with hundreds of markers. We subsequently tested this model on an independent Illumina-genotyped dataset with imputed genotypes (1,008 cases and 1,000 controls), as well as a separate Affymetrix-genotyped dataset (1,529 cases and 1,458 controls), resulting in area under ROC curve (AUC) of ∼0.84 in both datasets. In contrast, poor performance was achieved when limited to dozens of known susceptibility loci in the SVM model or logistic regression model. Our study suggests that improved disease risk assessment can be achieved by using algorithms that take into account interactions between a large ensemble of markers. We are optimistic that genotype-based disease risk assessment may be feasible for diseases where a notable proportion of the risk has already been captured by SNP arrays

GWAS on longitudinal growth traits reveals different genetic factors influencing infant, child, and adult BMI

Early childhood growth patterns are associated with adult health, yet the genetic factors and the developmental stages involved are not fully understood. Here, we combine genome-wide association studies with modeling of longitudinal growth traits to study the genetics of infant and child growth, followed by functional, pathway, genetic correlation, risk score, and colocalization analyses to determine how developmental timings, molecular pathways, and genetic determinants of these traits overlap with those of adult health. We found a robust overlap between the genetics of child and adult body mass index (BMI), with variants associated with adult BMI acting as early as 4 to 6 years old. However, we demonstrated a completely distinct genetic makeup for peak BMI during infancy, influenced by variation at the LEPR/LEPROT locus. These findings suggest that different genetic factors control infant and child BMI. In light of the obesity epidemic, these findings are important to inform the timing and targets of prevention strategies

Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium

Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P < 5×10−8: seven for BMI, and one for WHRadjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHRadjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in identifying GWAS loci including low frequency variants. Trans-ethnic meta-analyses further improved fine mapping of putative causal variants in loci shared between the African and European ancestry populations

Genetic Studies of Leptin Concentrations Implicate Leptin in the Regulation of Early Adiposity.

Leptin influences food intake by informing the brain about the status of body fat stores. Rare LEP mutations associated with congenital leptin deficiency cause severe early-onset obesity that can be mitigated by administering leptin. However, the role of genetic regulation of leptin in polygenic obesity remains poorly understood. We performed an exome-based analysis in up to 57,232 individuals of diverse ancestries to identify genetic variants that influence adiposity-adjusted leptin concentrations. We identify five novel variants, including four missense variants, in LEP, ZNF800, KLHL31, and ACTL9, and one intergenic variant near KLF14. The missense variant Val94Met (rs17151919) in LEP was common in individuals of African ancestry only, and its association with lower leptin concentrations was specific to this ancestry (P = 2 × 10-16, n = 3,901). Using in vitro analyses, we show that the Met94 allele decreases leptin secretion. We also show that the Met94 allele is associated with higher BMI in young African-ancestry children but not in adults, suggesting that leptin regulates early adiposity

Novel loci for childhood body mass index and shared heritability with adult cardiometabolic traits

The genetic background of childhood body mass index (BMI), and the extent to which the well-known associations of childhood BMI with adult diseases are explained by shared genetic factors, are largely unknown. We performed a genome-wide association study meta-analysis of BMI in 61,111 children aged between 2 and 10 years. Twenty-five independent loci reached genome-wide significance in the combined discovery and replication analyses. Two of these, located nearNEDD4LandSLC45A3, have not previously been reported in relation to either childhood or adult BMI. Positive genetic correlations of childhood BMI with birth weight and adult BMI, waist-to-hip ratio, diastolic blood pressure and type 2 diabetes were detected (R(g)ranging from 0.11 to 0.76, P-values Author summary Although twin studies have shown that body mass index (BMI) is highly heritable, many common genetic variants involved in the development of BMI have not yet been identified, especially in children. We studied associations of more than 40 million genetic variants with childhood BMI in 61,111 children aged between 2 and 10 years. We identified 25 genetic variants that were associated with childhood BMI. Two of these have not been implicated for BMI previously, located close to the genesNEDD4LandSLC45A3. We also show that the genetic background of childhood BMI overlaps with that of birth weight, adult BMI, waist-to-hip-ratio, diastolic blood pressure, type 2 diabetes, and age at menarche. Our results suggest that the biological processes underlying childhood BMI largely overlap with those underlying adult BMI. However, the overlap is not complete. Additionally, the genetic backgrounds of childhood BMI and other cardio-metabolic phenotypes are overlapping. This may mean that the associations of childhood BMI and later cardio-metabolic outcomes are partially explained by shared genetics, but it could also be explained by the strong association of childhood BMI with adult BMI.Peer reviewe