Influence of heritability on occlusal traits: a systematic review of studies in twins

Comparison of the Effects of Ketorolac and Acetaminophen on RANK-L Levels in the Gingival Crevicular Fluid during Orthodontic Tooth Movement: A Pilot Study

Background: Patients usually present pain due to the release of different inflammatory mediators such as prostaglandin E2 and RANK-L. Analgesics such as acetaminophen and ketorolac can inhibit RANK-L expression and this can affect orthodontic treatment by decreasing bone remodeling and slowing orthodontic dental movement. Several studies have reported a decrease in dental movement after administering some non-steroidal anti-inflammatory drugs. Proposal: The objective was to evaluate the RANK-L levels and a possible modulation by administering acetaminophen and ketorolac in patients starting orthodontic treatment. Methodology: A double-blind, randomized clinical trial was carried out with 24 subjects divided into three study groups: calcined magnesia as a placebo, acetaminophen, and ketorolac. Gingival crevicular fluid was obtained at four time points: before pharmacological intervention, at 24 h, at 48 h, and on the 5th day. RANK-L concentrations were evaluated through ELISA analysis. Also, interproximal space generated by the elastic separator at the end of the study was recorded in the different study groups using the visual analog scale. Results: An increase in RANK-L at 24 h was observed in the placebo group compared to the ketorolac and acetaminophen groups. However, no significant differences were observed in the interproximal space at day 5 in the three study groups. Conclusion: Patients who do not take analgesics at the start of orthodontic treatment have higher levels of RANK-L. Therefore, the use of ketorolac or acetaminophen could decrease bone remodeling and interfere with orthodontic dental movement.

Heritability of dental arches and occlusal characteristics: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The genetic basis of dentoalveolar characteristics has been investigated by several studies, however, the findings are equivocal. The objective of this systematic review and meta-analysis was to evaluate the heritability of dental arches and occlusal parameters in different stages of human dentition.

SEARCH METHODS

Electronic databases PubMed, Embase, Scopus, Web of Science, and Dentistry and Oral Science Source were searched up to August 2023 without the restriction of language or publication date.

SELECTION CRITERIA

Empirical studies investigating the heritability of dentoalveolar parameters among twins and siblings were included in the review.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, and risk of bias assessment were performed independently and in duplicate by two authors and a third author resolved conflicts if needed. Joanna Briggs Institute's critical appraisal tool was used to evaluate the risk of bias among studies and the certainty of evidence was assessed using the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

Twenty-eight studies were included in the systematic review, of which 15 studies reporting heritability coefficients in the permanent dentition stages were deemed suitable for the meta-analysis. Random-effects meta-analyses showed high heritability estimates for maxillary intermolar width (0.52), maxillary intercanine width (0.54), mandibular intermolar width (0.55), mandibular intercanine width (0.55), maxillary arch length (0.76), mandibular arch length (0.57), and palatal depth (0.56). The heritability estimates for the occlusal parameters varied considerably, with relatively moderate values for crossbite (0.46) and overbite (0.44) and low values for buccal segment relationship (0.32), overjet (0.22), and rotation and displacement of teeth (0.16). However, the certainty of evidence for most of the outcomes was low according to the GRADE criteria.

CONCLUSIONS

Based on the available evidence, it can be concluded that the dental arch dimensions have a high heritability while the occlusal parameters demonstrate a moderate to low heritability.

REGISTRATION

PROSPERO (CRD42022358442).

The contribution of genetics to dental caries, oral habits and occlusal traits in Turkish twins: A comparative study

OBJECTIVE

The aims of this study were to investigate and compare the prevalence of dental caries and the frequency of oral habits, molar relationships and occlusal traits between children of multiple births, and singletons, and to determine the relative contributions of genetics and environmental factors to these parameters by using twin study design.

METHODS

The study group consisted of 345 multiple births (34 monozygotic and 122 dizygotic twin pairs, 11 sets of triplets) and 345 singletons between the ages of 2 and 17. The prevalence of dental caries, and the frequency of tooth brushing, the children's oral habits, molar relationships, and occlusal traits were recorded.

RESULTS

The percentage of children who brushed their teeth more than twice daily was statistically significantly higher in multiple births than in singletons. Higher correlation coefficients were found in dental caries index, except for decayed, filled (df) (2-5 age group) and filled (f) (6-11 age group), in the monozygotic twin pairs compared to those in the dizygotic twin pairs. In children between the ages of 6 and 11 years, mouth breathing, bruxism, lip biting, and pencil biting were higher in singletons than in children of multiple births. There were statistically significant differences between children of multiple births and singletons, with increased overjet in the 2-5 year age group being observed.

CONCLUSION

When analyzing these parameters, environmental factors must also be investigated. Due to the low incidence of twin births, longitudinal follow-up studies with more twin pairs are necessary to determine whether these results are generalizable.

Breastfeeding Protects from Overjet in Adolescence by Reducing Pacifier Use: A Birth Cohort Study

Increased dental overjet in adolescence is a clinically relevant outcome associated with the complexity and high cost of treatment, indicating the need for prevention strategies. We investigated the long-term impact of breastfeeding and pacifier use on increased overjet (IOVJ) in permanent dentition. A prospective cohort nested in a randomized controlled trial was conducted from birth to 12 years of age (n = 214). Breastfeeding and pacifier use were recorded monthly until 12 months. Overjet was assessed at age 12 years. We employed a causal mediation analysis using parametric regression models assuming no interaction between breastfeeding and pacifier usage. We found a total protective effect of breastfeeding on IOVJ (OR 0.49; 95% CI 0.28-0.96), where 63.1% were mediated by pacifier use (OR 0.61; 95% CI 0.44-0.87). Breastfeeding directly decreased the odds of IOVJ by 20%; however, the confidence interval included the null estimate (OR 0.81; 95% CI 0.41-1.60). In conclusion, breastfeeding protects by half of the IOVJ in adolescence through reducing pacifier use. Oral and general health professionals should collaborate to support WHO breastfeeding guidelines during individual patient counseling. Guidelines for practice, policy or public information require messages that include a common risk approach to oral and general health.

Strategies to improve genomic predictions for 35 duck carcass traits in an F2 population

BACKGROUND

Carcass traits are crucial for broiler ducks, but carcass traits can only be measured postmortem. Genomic selection (GS) is an effective approach in animal breeding to improve selection and reduce costs. However, the performance of genomic prediction in duck carcass traits remains largely unknown.

RESULTS

In this study, we estimated the genetic parameters, performed GS using different models and marker densities, and compared the estimation performance between GS and conventional BLUP on 35 carcass traits in an F₂ population of ducks. Most of the cut weight traits and intestine length traits were estimated to be high and moderate heritabilities, respectively, while the heritabilities of percentage slaughter traits were dynamic. The reliability of genome prediction using GBLUP increased by an average of 0.06 compared to the conventional BLUP method. The Permutation studies revealed that 50K markers had achieved ideal prediction reliability, while 3K markers still achieved 90.7% predictive capability would further reduce the cost for duck carcass traits. The genomic relationship matrix normalized by our true variance method instead of the widely used [Formula: see text] could achieve an increase in prediction reliability in most traits. We detected most of the bayesian models had a better performance, especially for BayesN. Compared to GBLUP, BayesN can further improve the predictive reliability with an average of 0.06 for duck carcass traits.

CONCLUSION

This study demonstrates genomic selection for duck carcass traits is promising. The genomic prediction can be further improved by modifying the genomic relationship matrix using our proposed true variance method and several Bayesian models. Permutation study provides a theoretical basis for the fact that low-density arrays can be used to reduce genotype costs in duck genome selection.

Prevalence and Associated Factors of Malocclusion among Preschool Children in Huizhou, China: A Cross-Sectional Study

This survey examined the prevalence of malocclusion and its associated factors in 3- to 5-year-old children in Huizhou, China. Children were recruited from 21 kindergartens using a multistage sampling method. Two examiners performed oral examinations on the children, assessing occlusal traits, including primary molar and canine relationship, overjet, crossbite, overbite, anterior open bite, scissor bite, midline deviation, crowding, and spacing. Caries experience was recorded. Self-administered questionnaires were distributed to collect background information and oral health-related habits. Chi-square test, Mann-Whitney U test, and binary logistic regression were conducted. The study invited 1485 children and eventually recruited 1454 (52.9% boys; response rate: 97.9%). The prevalence of malocclusion was 68.3%, and deep overbite was found in 48.6% of the children. Children who had lip-biting habits had a higher prevalence of deep overbite than those who did not (OR = 2.36, p < 0.05). Children who had digit-sucking habits and dental caries in anterior maxillary teeth had a lower prevalence of deep overbite than those who did not (OR = 0.73 and 0.70, respectively, p < 0.05). In conclusion, over half of the children in Huizhou who participated in the study had malocclusion. Dental caries in anterior maxillary teeth, digit-sucking, and lip-biting were the associated factors of deep overbite.

Spontaneous correction and new development of posterior crossbite from the deciduous to the mixed dentition

AIM

To determine (a) the prevalence of spontaneous correction of posterior crossbites from the deciduous to the mixed dentition and (b) the development of new posterior crossbite cases during the eruption of the first permanent molars, in orthodontically untreated children.

MATERIALS AND METHODS

A cohort of pupils aged 4-12 years participated in annual dental screenings, from 2001 to 2019. Data were collected prospectively but examined retrospectively. Children were selected who had been initially screened in their deciduous dentition and on at least one consecutive year, presenting with a posterior crossbite in the deciduous or mixed dentition. Those with a posterior crossbite in the deciduous dentition were evaluated to see whether the crossbite persisted in the mixed dentition, and vice versa.

RESULTS

Of the 2571 children participating in the annual dental screenings, 1076 children were in the deciduous dentition at their first screening appointment, with 693 having attended at least two screening appointments. Of these 693 children, 70 had a posterior crossbite in the deciduous dentition (10.1%). The crossbite persisted in the mixed dentition in only 16 out of these 70 children. Twenty-six out of the 623 children who did not have a posterior crossbite in the deciduous dentition developed one in the mixed dentition.

LIMITATIONS

The retrospective data collection, multiple examiners carrying out the dental screenings, and the absence of data on para-functions and oral habits were some of the limitations of the present study.

CONCLUSIONS

In the present sample, 1 in 10 children have a posterior crossbite in the deciduous dentition, which is however autocorrected in about three-quarters of cases. On the other hand, 4% of children developed a new crossbite in the mixed dentition. It may thus be reasonable in cases with posterior crossbite in the deciduous dentition to wait for the first permanent molars to erupt before initiating treatment.

Orofacial dysfunction, nonnutritive sucking habits, and dental caries influence malocclusion in children aged 8-10 years

INTRODUCTION

Malocclusion is one of the most prevalent oral health problems and can affect self-esteem, social relations, and oral health-related quality of life. The present study aimed to evaluate associations between malocclusion and orofacial dysfunction, nonnutritive sucking habits, cavitated carious lesions, and anxiety in Brazilian children.

METHODS

An analytical cross-sectional study was conducted with a representative sample of 739 children aged 8-10 years. Parents or guardians provided sociodemographic data and information on the nonnutritive sucking habits of the children. The children answered the Revised Children's Manifest Anxiety Scale. Four trained examiners examined the children for the diagnosis of malocclusion (dental aesthetic index), dental caries (International Caries Detection and Assessment System), and orofacial dysfunction (Nordic Orofacial Test-Screening). The control variables were selected using a directed acyclic graph. Descriptive statistics were performed, followed by unadjusted and adjusted robust logistic regression analysis (P <0.05).

RESULTS

The following variables remained associated with the occurrence of malocclusion in the final model: nonnutritive sucking habits (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.25-4.08), orofacial dysfunction (OR, 1.56; 95% CI, 1.13-2.17), and cavitated carious lesion (OR, 1.39; 95% CI, 1.03-1.89).

CONCLUSIONS

Nonnutritive sucking habits, orofacial dysfunction, and cavitated carious lesions were associated with the presence of malocclusion in children aged 8-10 years.

The Association of CYP17A1, CYP19A1, and SHBG Gene Polymorphisms in Polycystic Ovary Syndrome Susceptibility: A Systematic Review and Meta-Analysis

Objective: To elucidate the relationship between CYP17A1/CYP19A1/SHBG gene polymorphisms and PCOS susceptibility.

Methods: We searched multiple databases from inception to December 2020 and meta analysis was conducted to elucidate the relationship between gene polymorphisms and PCOS risk.

Results: 26 studies were included, comprising 4860 PCOS and 4043 controls. CYP17A1 rs743572 polymorphisms were found to be negatively associated with PCOS risk under dominant model (p = 0.017, OR = 0.83, 95%CI 0.72–0.97, I² = 74.80%, P_{heterogeneity} = 0.000) in the general population while neither CYP19A1 rs2414096 polymorphisms (p = 0.578, OR = 0.87, 95%CI 0.54–1.41, I² = 95.90%, P_{heterogeneity} = 0.000) nor SHBG rs6529 polymorphisms (p = 0.752, OR = 0.99, 95%CI 0.94–1.05, I² = 60.90%, P_{heterogeneity} = 0.012) was associated with PCOS susceptibility under dominant model in the general population.

Conclusion: CYP17A1 rs7435721 polymorphisms might be protective factors against PCOS in general populations.

Systematic Review Registration: https://www.crd.york.ac.uk/prospero/#myprospero, identifier CRD4202122640.

Heritability of facial soft tissue growth in mono- and dizygotic twins at 12 and 17 years of age: A retrospective cohort study

OBJECTIVE

The purpose of this investigation of untreated monozygotic and dizygotic twins was to identify the genetic and environmental components to the facial soft tissue growth.

SETTINGS AND SAMPLE POPULATION

The sample consisted of 52 untreated monozygotic twins (36 male and 16 female) and 46 untreated dizygotic twins (23 male and 23 female) from the Forsyth Moorrees Twin Study (1959-1975).

MATERIALS AND METHODS

Lateral cephalograms were taken at 12 and 17 years of age and traced to analyse facial convexity, nasolabial angle, upper and lower lip thickness, upper and lower lip profile and nose prominence. The genetic and environmental components of variance were analysed with structural equation modelling for multilevel mixed-effects model.

RESULTS

At 12 years of age, strong additive genetic influence was seen for facial convexity (70%), upper lip profile (66%) and nose prominence (65%), whereas strong dominant genetic components were found for upper lip thickness (56%). Nevertheless, under unique environment influence were nasolabial angle (58%), lower lip profile (51%) and lower lip thickness (64%). At 17 years of age, only upper lip thickness (55%) and nose prominence (84%) were under strong additive genetic control, while the rest of the variables were under strong dominant genetic control. The only exception was lower lip thickness (61%), which is still influenced by the unique environment.

CONCLUSION

Although monozygotic/dizygotic twins share at least part of their genome, at both times either additive, dominant or environmental components were found. Nevertheless, at 17 years of age most of the variables are either under additive or dominant genetic influence.

Association between arch perimeter management and the occurrence of mandibular second molar eruption disturbances

OBJECTIVES

To investigate the association between the management of mandibular arch perimeter during development of the dentition and its effects on second permanent molar (M2) eruption.

MATERIALS AND METHODS

Seven electronic databases were searched without restrictions up to June 2020. Assessment was performed using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool for non-randomized clinical trials (non-RCT). Odds ratio (OR) with 95% confidence intervals was calculated from random-effects meta-analyses. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool was used to assess the certainty of the evidence.

RESULTS

Five non-RCTs, with serious to moderate risk of bias, were included. A low certainty of evidence indicated that individuals undergoing mandibular arch perimeter management by controlling the position of the first molar had a high prevalence of M2 eruption difficulties. The odds of eruption disorders was 7.5 times higher (OR: 7.57, [3.72, 15.41], P < .001) in treated individuals. Subgroup analysis revealed that appliances that increased the arch perimeter lead to a greater chance of eruption disorders compared to appliances that only maintained the perimeter. The predictive factors for the M2 eruption difficulty were its previous mesioangulation in relation to the first molar (>24°) and the treatment time (>2 years).

CONCLUSIONS

Mandibular arch perimeter management during development of the dentition leads to an increase in the occurrence of M2 eruption difficulties. The identification of possible risk factors as well as the choice of the appropriate appliance type and the monitoring of these individuals seems to be essential to avoid undesirable effects with this therapy.