Knowledge and management of molar-incisor hypomineralisation amongst dentists in The Netherlands.

BACKGROUND: Molar-incisor hypomineralisation (MIH) is a frequently encountered dental condition in the clinical setting, and correct diagnosis can influence management outcomes. AIM: To assess the knowledge of and attitudes towards the management of MIH amongst dentists in the Netherlands. DESIGN: The study was conducted as a cross-sectional web survey. The questionnaire used included questions regarding respondent characteristics, awareness, knowledge and management of MIH and was distributed through the Royal Dutch Association for Dentistry (KNMT) to a random sample of 900 dentists. Variables were analysed using descriptive statistics, and differences between distinct groups of dentists were tested using the chi-squared test. RESULTS: Respondents consisted of 76.6% general dental practitioners, 9.1% paediatric dentists and 14.3% differentiated (specialist) dentists, with a 25.6% overall response rate. The majority knew the term MIH and its clinical characteristics, and could distinguish MIH from other enamel defects. Regarding aetiological factors, 76.6% reported a genetic component. In an asymptomatic case, 47.3% reported non-invasive treatments. In a mild symptomatic case, treatments from non-invasive to invasive were reported (p < .05). In a severe symptomatic case, the majority reported invasive treatments. Two-thirds of respondents were interested in further clinical training about MIH. CONCLUSIONS: Most respondents knew the term MIH and its clinical characteristics and would like further clinical training about MIH.

How geographical origin and dietary habits interact with the shape of cortical mandibular sections? A geometric morphometrics study in an archaeological context.

OBJECTIVE: Mandibular shape is strongly influenced by biomechanics, particularly during dietary shifts that often occurred in past populations. The relationship is considered extremely complex as development of the mandible is a multifactorial process. Since cortical bone distribution is purportedly more biomechanically sensitive than external shape, comparison of its distribution in past populations can provide new input to understand this complex relationship. The present study examined the effects of geographical origin and dietary habits on the internal anatomy of the mandibular corpus and symphysis. DESIGN: A morphometric analysis was conducted on 72 mandibles from different populations, sampled by their geographical origin and subsistence strategies. Procrustes ANOVAs were performed to test the impact of section-plane location, geographical origin, and dietary habits on the groups' shapes. RESULTS: The specimens' geographical origin and dietary habits had a significant effect on the shapes of the sections (Generalized Goodall F-test, F = 3.2745, df = 6, 304: p < 0.001 and F = 3.7007, df = 4, 306: p < 0.001). CONCLUSION: Geographical origin and dietary habits influenced the shape of the mandibular sections in our sample. These relationships become more complex when analysed in isolated sections. Indeed, this study revealed that symphysis sections could be predominantly influenced by individual variables, whereas intermediate sections of the corpus could be predominantly influenced by populational variables. Future studies could focus on specific sections to better identify the specific "rules of dependence" in each cross-section.

Patterns and sexual dimorphism of non-syndromic hypodontia among a French orthodontic population.

OBJECTIVES: This retrospective study aimed to estimate the prevalence of non-syndromic congenitally missing teeth (CMT) and to explore the frequency of CMT patterns in a French orthodontic population. In addition, the study sought to assess sex-based differences in CMT patterns. DESIGN: Panoramic radiographs of 4569 orthodontic patients between 9 and 21 years-old performed over a 16-year period (2006-2022) were examined to identify non-syndromic tooth agenesis, excluding third molars. A chi-square test or a Fisher exact test were used to determine the difference in the prevalence of tooth agenesis between sex and between arches. RESULTS: Tooth agenesis was observed in 7.3% of the sample (7.9% for females and 6.6% for males). Approximately 86% of the included subjects presented 1 or 2 missing teeth. Single tooth agenesis was significantly more frequent in females than males (p = 0.002, χ2). In total, 23 of the 67 different patterns of CMT observed, were present more than once. 75.5% of male patients and 79.5% of female patients presented one or both missing lateral incisors or second premolars, rarely affected at the same time. This study showed no sex difference in the patterns of tooth agenesis. LIMITATIONS: This study has limitations due to its retrospective nature and our findings apply solely to an orthodontic population from a white ethnic background. CONCLUSIONS: Clinicians should be aware of this particular incisor/premolar phenotype regardless of biological sex. Issues associated with congenitally missing teeth can be managed more effectively with early teenage diagnosis.

What do we currently need to know about molar incisor hypomineralisation (MIH) and hypomineralized second primary molars (HSPM)? / Que faut-il savoir, à l'heure actuelle, sur les hypominéralisations molaires incisives (MIH) et les hypominéralisations des secondes molaires temporaires (HSPM) ?

Introduction: Molar incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPM) are qualitative and asymmetric enamel defects. MIH affect at least one permanent first molar and can also be associated with permanent incisors. HSPM affect at least one primary second molar and possibly primary canines. Hypomineralized enamel is characteristic: the enamel prisms are disorganized, less distinct, the interprismatic space is more marked, the mineral density is decreased and the protein content is increased. Currently, etiologies remain unknown but the various studies tend towards a multifactorial model with several systemic, genetic and/or epigenetic factors, acting in a synergistic or additive way. Material and Method: The authors highlight the various factors involved in diagnosing MIH and HSPM. A review of the prevalence (French and worldwide) and etiologies of these pathologies is also provided, to enable practitioners to answer any questions parents may have. Conclusion: The knowledge of these different elements on diagnosis, structure, prevalence and etiologies will allow the orthodontist to better collaborate with the dentist but also with the parents in order to ensure an adequate dental and orthodontic management.

Introduction: L'hypominéralisation molaire incisive (MIH) et l'hypominéralisation des secondes molaires temporaires (HSPM) sont des défauts qualitatifs et asymétriques de l'émail. Les MIH affectent au moins une première molaire permanente et peuvent également être associées aux incisives permanentes. Les HSPM affectent au moins une deuxième molaire temporaire et éventuellement les canines temporaires. L'émail hypominéralisé est caractéristique : les prismes d'émail sont désorganisés, moins distincts, l'espace interprismatique est plus marqué, la densité minérale est diminuée et la teneur en protéines augmentée. Actuellement, les étiologies restent méconnues mais les différentes études tendent vers un modèle multifactoriel avec plusieurs facteurs systémiques, génétiques et/ou épigénétiques, agissant de manière synergique ou additive. Matériel et méthode: Les auteurs mettent en avant les différents éléments permettant le diagnostic des MIH et des HSPM. Un point sur les prévalences (française et mondiale) et sur les étiologies de ces pathologies est également proposé afin de permettre aux praticiens de répondre aux éventuelles interrogations des parents. Conclusion: La connaissance de ces différents éléments sur le diagnostic, la structure, les prévalences et les étiologies permettra à l'orthodontiste une meilleure collaboration avec le chirurgien-dentiste, mais également avec les parents afin d'assurer une prise en charge dentaire et orthodontique adéquate.

Insights into molar-incisor hypomineralisation in past populations: A call to anthropologists.

OBJECTIVE: Molar incisor hypomineralisation (MIH) is a developmental defect of enamel affecting the first permanent molars and often the incisors and affecting approximately 13% of the current population worldwide. Here, we aim to highlight potential differential diagnoses of MIH in archaeological collections (taphonomic discoloration, amelogenesis imperfecta, fluorosis, rachitic teeth, etc.). METHODS: Causative factors of dental discolourations are identified through a literature review. RESULTS: In an archaeological context, the sediments contained in the burial soil can lead to tooth discoloration. Taphonomic staining of the dentition may have a similar appearance to enamel hypomineralisation, and thus is a confounding factor that has the potential to cause miscalculation of the true prevalence of MIH within archaeological collections. Some rare medieval cases are reported in the modern literature but without microanalysis, misdiagnosis is possible. The aetiological factors of MIH are unknown but probably follow the multifactorial model involving systemic medical and genetic factors. CONCLUSIONS: Systematic detection and diagnosis of MIH during anthropological studies is therefore of great interest. SIGNIFICANCE: The hypotheses that only contemporary agents are causative factors of MIH could be refuted by the discovery of individuals living before medication or pollutants. The identification of MIH in a group of individuals also provides information regarding the health status of a population and reflects stress occurring during the period of mineralisation of the first permanent molars after secretion of the enamel matrix. LIMITATIONS: Taphonomic alterations of archaeological remains prevent MIH diagnosis. SUGGESTIONS FOR FUTURE RESEARCH: MIH diagnosis can be difficult in archaeological series and further non-destructive methods (microtomography, elemental analyses, etc.) are required.

Is the distribution of cortical bone in the mandibular corpus and symphysis linked to loading environment in modern humans? A systematic review.

OBJECTIVE: The human mandible is a unique bone with specific external and internal morphological characteristics, influenced by a complex and challenging loading environment. Mandibular cortical thickness distribution in cross-sections is reported to be related to facial divergence patterns, cultural and dietary habits and more generally, specific loading environment. This review hypothesises that a process of environmental mechanical sensitivity is involved in the distribution of cortical bone in the mandibular corpus and symphysis in modern humans, and that loading regimes can influence this distribution pattern. Based on a review of the recent literature, this study aims to answer the following question: "Is the distribution of cortical bone in the mandibular corpus and symphysis linked to the loading environment in modern humans?" DESIGN: A systematic review was undertaken using the PubMed/Medline, Scopus and Cochrane Library databases for publications from 1984 to 2022 investigating the relationship between cortical bone distribution in the mandibular corpus and the loading environment. A subgroup meta-analysis was performed to determine the overall effect of facial divergence on cortical thickness. RESULTS: From a total of 2791 studies, 20 fulfilled the inclusion criteria. The meta-analyses were performed in eight studies using a randomised model, finding a significant overall effect of facial divergence on cortical thickness in posterior areas of the mandible (p < 0.01). CONCLUSIONS: Within the limitations of this review, specific loading regimes and their consequent variables (diet, culture, facial divergence) were linked to cortical thickness distribution. Sex was found to be unrelated to cortical thickness pattern.

The prevalence and characteristics of and the association between MIH and HSPM in South-Western France.

BACKGROUND: Molar-incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPM) involve qualitative structural developmental anomalies of tooth enamel, affecting the first permanent molars (FPM) and the second primary molars, respectively. This developmental anomaly of systemic origin has important consequences for oral health. AIM: To determine the prevalence of MIH and HSPM in south-western France and explore the distribution of hypomineralised lesions on permanent and primary molars. DESIGN: Amongst 856 children (aged 7-9 years) in schools randomly selected by the Academy of Bordeaux (Ministry of Education), the FPM, permanent incisors and the second primary molars were examined by two examiners trained and calibrated for the diagnostic criteria for MIH and HSPM of the European Academy of Paediatric Dentistry. RESULTS: Molar-incisor hypomineralisation was present in 160 children (18.7%) and HSPM in 81 children (9.5%); 4.9% had both HSPM and MIH (42 of 856). Hypomineralised lesions were present in 1-4 FPM in affected individuals (mean = 2.4) and were distributed in an asymmetrical manner with widely varying severity at the tooth and individual level. A child with HSPM was more likely to have MIH than a child without HSPM (95% CI OR = 6.0 [3.7-9.7]; p < .0001). CONCLUSION: Molar-incisor hypomineralisation and HSPM have three main asymmetrical characteristics: tooth location, severity of hypomineralisation and number of teeth affected.

Infiltrant resin and enamel infractions: two case reports of a novel and minimally invasive approach.

To date, no consensus exists regarding the management of enamel infractions (cracks and craze lines), which may be associated with sensitivity. Two clinical cases are presented on the management of enamel infractions using a modified erosion-infiltration protocol for resin infiltration. Initially indicated for the treatment of early caries lesions, Icon (DMG) low-viscosity resin infiltrant has also been used to mask unesthetic developmental defects of enamel in anterior teeth. Treatment using this modified infiltration protocol immediately eliminated tooth sensitivity associated with the enamel infractions. Resin infiltration has the potential as a minimally invasive and effective treatment for the management of sensitivity associated with enamel infractions. (Quintessence Int 2023;54:180-185; doi: 10.3290/j.qi.b3631849).

Insights into the aetiologies of hypercementosis: A systematic review and a scoring system.

OBJECTIVES: This paper aims to better define hypercementosis, investigate its described potential aetiologies, and determine whether there are different patterns of cementum apposition and if they are a function of their supposed aetiology. DESIGN: A literature review was undertaken using the Medline, DOSS, Scopus and Cochrane Library electronic databases. Two co-authors selected the published works independently, extracted the data in accordance with the PRISMA statement. RESULTS: Among 546 articles, 75 articles were finally selected. Eight different supposed aetiologies were identified: (1) intensive masticatory effort, (2) systemic disease, (3) carious lesion and apical periodontitis, (4) impaction, (5) periodontal disease, (6) concrescence, (7) super-eruption, and (8) drugs. Some of these aetiologies can be combined in the same tooth. Hypercementosis manifestations are various in nature and extent with different patterns that may be aetiology-specific. To improve the description and associated consistency in the characterisation of hypercementosis, in this review but also in future studies, we propose a new qualitative scoring system to quickly characterise hypercementosis and determine its most relevant aetiology. CONCLUSIONS: This systematic review demonstrates that hypercementosis is a complex and not yet well-defined condition. Some forms of apposition are specific to a given aetiology. The hypercementosis characterisation may contribute to document the oral condition and/or the individuals masticatory activity.

Prevalence of taurodontism: meta-analysis in recent humans and evolutionary perspectives.

Taurodontism is a continuous anatomical variation of permanent and primary posterior teeth represented by an enlargement of the pulp cavity. A high prevalence of the trait is reported in Homo neanderthalensis remains. Exploring and refining epidemiology of taurodontism in actual populations could strengthen the hypothesis of a selective advantage for a high attrition diet (as heavy tooth wear in Homo sapiens evolution changed little until recently) or favour pleiotropic or genetic drift effects to explain the high frequency of the trait in Neandertal remains. Prevalence ranges between 0.1% and 48% in the literature. The aim of the present study is to assess the prevalence of taurodontism in recent populations by means of meta-analysis, that is, is the prevalence of taurodontism lower or higher in modern human living populations, where the selective advantages of high attrition diet are still expected? From 90 potentially eligible studies, 15 were included in the meta-analysis. Only cross-sectional studies were reported, and 14,771 participants were included. The meta-analyses were performed with a random model, calculating a weighted-mean prevalence of 11.8%. Gender was found to be unrelated to the prevalence of taurodontism (OR = 0.84 (95% CI 0.67-1.05), p > 0.05). Taurodontism occurs in approximately 11.8% of the living population. This result questions the status of taurodontism as a "typical trait" in Homo neanderthalensis and allows a possible common evolutionary mechanism in Homo sapiens and Homo neanderthalensis for the trait. Further studies should include more accurate and standardized methods to assess the condition.

Dentine disorders and adhesive treatments: A systematic review.

OBJECTIVES: A better understanding of the microstructure and mechanical properties of enamel and dentine may enable practitioners to apply the current adhesive dentistry protocols to clinical cases involving dentine disorders (dentinogenesis imperfecta or dentine dysplasia). DATA/SOURCES: Publications (up to June 2020) investigating the microstructure of dentine disorders were browsed in a systematic search using the PubMed/Medline, Embase and Cochrane Library electronic databases. Two authors independently selected the studies, extracted the data in accordance with the PRISMA statement, and assessed the risk of bias with the Critical Appraisal Checklist. A Mann-Whitney U test was computed to compare tissues damage related to the two dentine disorders of interest. STUDY SELECTION: From an initial total of 642 studies, only 37 (n = 164 teeth) were included in the present analysis, among which 18 investigating enamel (n = 70 teeth), 15 the dentine-enamel junction (n = 62 teeth), and 35 dentine (n = 156 teeth). Dentine is damaged in cases of dentinogenesis imperfecta and osteogenesis imperfecta (p = 2.55E-21 and p = 3.99E-21, respectively). These studies highlight a reduction in mineral density, hardness, modulus of elasticity and abnormal microstructure in dentine disorders. The majority of studies report an altered dentine-enamel junction in dentinogenesis imperfecta and in osteogenesis imperfecta (p = 6.26E-09 and p = 0.001, respectively). Interestingly, enamel is also affected in cases of dentinogenesis imperfecta (p = 0.0013), unlike to osteogenesis imperfecta (p = 0.056). CONCLUSIONS: Taking into account all these observations, only a few clinical principles may be favoured in the case of adhesive cementation: (i) to preserve the residual enamel to enhance bonding, (ii) to sandblast the tooth surfaces to increase roughness, (iii) to choose a universal adhesive and reinforce enamel and dentine by means of infiltrant resins. As these recommendations are mostly based on in vitro studies, future in vivo studies should be conducted to confirm these hypotheses.

Prevalence of talon cusp: Systematic literature review, meta-analysis and new scoring system.

OBJECTIVES: Talon cusp is a developmental anomaly consisting of a vertical ridge or cusp projecting labially or lingually from an anterior permanent or primary tooth. A range of prevalence between 0.06 % and 40.8 % has been reported in the literature. Although many epidemiological studies have been conducted, no synthesis of these data has been performed to date. The aim of this paper was to determine the prevalence of talon cusp and to investigate the link between sex and talon cusp. SOURCE: A systematic search was undertaken using the PubMed/Medline, Embase and Cochrane Library electronic databases for publications from 1981 to 2020 investigating the prevalence of talon cusp and the link between talon cusp and sex. STUDY SELECTION: Three reviewers selected the studies independently, extracted the data in accordance with the PRISMA statement, and assessed the risk of bias via the GRADE & Cochrane approaches. RESULTS: From 39 potentially eligible studies, 9 were selected for full text analysis and 8 were included in the meta-analysis, representing 35,224 participants. The meta-analyses were performed with a random model, calculating a weighted-mean prevalence (at least one talon cusp per individual) of 1.67 %. Sex and talon cusp were not statistically significantly associated in our study (OR = 1.10; 95 % CI [0.82-1.47]; p > 0.05). DISCUSSION: We report the first prevalence of talon cusp provided by meta-analysis in a non-syndromic sample. A non-statistically significant association between sex and talon cusp is relevant in terms of genetic etiology. In order to improve the homogeneity and accuracy of the results of further studies, we propose a new universal scoring system for talon cusp. CLINICAL SIGNIFICANCE: Talon cusp is a developmental anomaly with various clinical implications. Therapeutics may vary from simple monitoring to extraction of the supporting tooth. This condition occurs in approximately 1.67 % of the population.

Are hypomineralised lesions on second primary molars (HSPM) a predictive sign of molar incisor hypomineralisation (MIH)? A systematic review and a meta-analysis.

OBJECTIVES: Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) involve qualitative structural developmental anomalies of tooth enamel affecting the first permanent molars (and often incisors) and the second primary molars, respectively. A putative relationship between HSPM and MIH has been reported in the scientific literature. The aim was to determine whether children with HSPM are more likely to develop MIH. SOURCE: A systematic search using PubMed/Medline, Embase and Cochrane Library electronic databases for publications from 2001 to August 2017 investigating the link between MIH and HSPM was undertaken. STUDY SELECTION: Four reviewers selected the studies independently, extracted the data according to PRISMA statement, and assessed the bias risk with the Newcastle-Ottawa Scale (NOS) criteria. RESULTS: From 645 potentially eligible studies, 14 were selected for full text analysis and 5 were included in the meta-analysis. Cross-sectional and cohort studies were reported and 4662 participants were included. The meta-analyses were performed with a random model calculated an OR total of 4.66 (95% CI 2.11-10.26; P < 0.001). The weighted mean of the co-occurrence of HSPM and MIH prevalence was 19.94%. DISCUSSION: The high heterogeneity (I2 = 88%) can be explained by the great variation present in number of participants and variable caries risk. Despite the limitations of the study, the presence of HSPM is predictive for MIH, with greater MIH prevalence in the presence of mild HSPM. CLINICAL SIGNIFICANCE: Early detection and preventive intervention could reduce MIH complications.

Analytical evidence of enamel hypomineralisation on permanent and primary molars amongst past populations.

Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) involve prevalent qualitative structural developmental anomalies of tooth enamel affecting the first permanent molars (and often incisors) and the second primary molars, respectively. These demarcated hypomineralised lesions of enamel manifest as white-cream or yellow-brown opacities, with possible post-eruptive localised loss of enamel. Aetiological hypotheses have involved contemporary life factors (i.e. environmental pollutant exposure or early childhood medications) in contrast to factors not limited to a specific time period (i.e. hypoxia at birth or genetic predisposition). Evidence of MIH in ancient populations would reinforce aetiological factors present for many centuries. By means of microtomographic and X-ray fluorescence analyses the present study provides evidence that (i) two archaeological specimens: "S407" (Sains-en-Gohelle, France, 12th-16th centuries) and "B335" (Beauvais, France, 15th-18th centuries) were MIH-affected, and (ii) one individual "S323" was affected by HSPM and MIH (Sains-en-Gohelle, France, 7th-11th centuries).

Diagnostic guide enabling distinction between taphonomic stains and enamel hypomineralisation in an archaeological context.

OBJECTIVE: Molar Incisor Hypomineralisation (MIH) is a structural anomaly that affects the quality of tooth enamel and has important consequences for oral health. The developmentally hypomineralised enamel has normal thickness and can range in colour from white to yellow or brown with or without surface breakdown. The possibility of finding MIH in 'ancient populations' could downplay several current aetiological hypotheses (e.g., dioxin derivatives, bisphenols, antibiotics) without excluding the possible multifactorial aspect of the anomaly. In an archaeological context, chemical elements contained in the burial ground can stain teeth yellow or brown and therefore might create a taphonomic bias. The purpose of the present study is to test a proposed diagnostic guide enabling determination of the pathological or taphonomic cause of enamel discolouration and defects that resemble MIH present on 'ancient teeth'. DESIGN: Two sample groups including MIH discoloration (n=12 teeth) from living patients, taphonomic discoloration (n=9 teeth) and unknown discoloration (n=2 teeth) from medieval specimens were tested. Three non-destructive methods-Raman spectroscopy, X-ray micro-computed tomography and X-ray fluorescence were utilised. RESULTS: Hypomineralised enamel has decreased mineral density (p<0.0001) and increased phosphate/ß-carbonate ratio (p<0.01) compared to normal enamel whereas relative concentrations of manganese, copper, iron and lead are similar. In taphonomic discoloration, relative concentrations of these elements are significantly different (p<0.05) to normal enamel whereas mineral density and Raman spectra profile are comparable. CONCLUSIONS: Enamel hypomineralisation can be distinguished from taphonomic staining in archaeological teeth.

Mineral density of hypomineralised and sound enamel.

Molar Incisor Hypomineralisation (MIH) is a structural anomaly that affects the quality of tooth enamel and has important consequences for oral health. The developmentally hypomineralised enamel has normal thickness and can range in colour from white to yellow or brown. The purpose of the present study is to compare the mineral density of hypomineralised and normal enamel. The sample included eight MIH teeth from seven patients. MIH teeth were scanned using high resolution microtomography. Non-parametric statistical tests (Wilcoxon test for paired samples) were carried out. Hypomineralised enamel has decreased mineral density (mean 19%; p < 0.0001) compared to normal enamel. This weak enamel has implications in clinical management of MIH lesions.