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 16-18-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 were 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 erosive tooth wear.

Association between molar hypomineralization, genes involved in enamel development, and medication in early childhood: A preliminary study.

BACKGROUND: Molar hypomineralization (MH) is defined as a multifactorial condition, and thus, its presence may be defined by interactions between environmental and genetic factors. AIM: To evaluate the association between MH, genes involved in enamel development, and the use of medication during pregnancy in early childhood. DESIGN: One hundred and eighteen children, 54 with and 64 without MH, were studied. The data collected included demographics, socioeconomic data, and the medical history of mothers and children. Genomic DNA was collected from saliva. Genetic polymorphisms in ameloblastin (AMBN; rs4694075), enamelin (ENAM; rs3796704, rs7664896), and kallikrein (KLK4; rs2235091) were evaluated. These genes were analyzed by real-time polymerase chain reaction using TaqMan chemistry. The software PLINK was used to compare allele and genotype distributions of the groups and to assess the interaction between environmental variables and genotypes (p < .05). RESULTS: The variant allele KLK4 rs2235091 was associated with MH in some children (odds ratio [OR]: 3.75; 95% confidence interval [CI] = 1.65-7.81; p = .001). Taking medications in the first 4 years of life was also associated with MH (OR: 2.94; 95% CI = 1.02-6.04; p = .041) and specifically in association with polymorphisms in ENAM, AMBN, and KLK4 (p < .05). The use of medications during pregnancy was not associated with MH (OR: 1.37; 95% CI = 0.593-3.18; p = .458). CONCLUSION: The results of this study suggest that taking medication in the postnatal period appears to contribute to the etiology of MH in some evaluated children. There may be a possible genetic influence of polymorphisms in the KLK4 gene with this condition.

Polymorphisms associated with oral clefts as potential markers for oral pre and malignant disorders.

OBJECTIVE: To investigate whether genes in the Wnt pathway, which have been previously associated with both oral clefts and oral squamous cell carcinoma, are also associated with oral potentially malignant disorders (leukoplakia, erythroplakia and lichen planus). MATERIALS AND METHODS: Case-control study: Dataset consisted of clinical information linked to DNA samples from affected subjects diagnosed with oral potential malignant disorders and oral cancer and their matched controls. Individual samples, clinical history, and potential risk factors were obtained through the Dental Registry and DNA Repository project of the School of Dental Medicine, University of Pittsburgh. The rs1533767 (WNT11), rs9879992 (GSK3B), and rs3923087 (AXIN2) were tested. After genomic DNA had been extracted, genotyping was performed blindly to clinical diagnosis status. Representation of genotypes and alleles in affected subjects in comparison to the unaffected individuals was determined using PLINK. Additional analysis was performed to investigate associations between environmental (socioeconomic/lifestyle) risk factors and the oral pathologies studied using STATA. RESULTS: Two of the SNPs tested (rs9879992 in GSK3B and rs3923087 in AXIN2) were statistically, significantly associated with the pathologies studied (p = 0.039 and 0.038, respectively). CONCLUSION: Single-nucleotide polymorphisms in genes in the Wnt pathway were associated with oral potentially malignant disorders.

Molar-incisor hypomineralization in a cohort of individuals born with cleft lip and palate.

OBJECTIVE: This study aimed to investigate the frequency of molar-incisor hypomineralization (MIH) in individuals born with cleft lip and or cleft palate. SETTINGS AND SAMPLE: Three hundred eighty-six individuals born with cleft lip and/or palate before orthodontic treatment. METHODS: All the individuals were submitted to a clinical examination and intraoral standardized photos. The registration of MIH was taken by two orthodontists and analysed in association with the cleft type and laterality. The Kruskal-Wallis test and the regression test were used to compare the frequency of molars and incisors affected according to cleft type and laterality, sex and age. RESULTS: We found a frequency of 67.87% of MIH in the studied sample. The frequency varied from 25% (in individuals born with cleft palate) to 77% in individuals born with bilateral cleft lip and palate). The number of affected molars was statistically different depending on cleft type and laterality (P < .001- Kruskal-Wallis test). Differences were found between individuals born with unilateral cleft lip and palate and unilateral cleft lip and alveolus (P = .03), and with isolated cleft palate (P = .03), and between individuals born with bilateral cleft lip and palate and born with unilateral cleft lip and alveolus (P = .01), and cleft palate (P = .01). Sex (P = .21) and age (P = .36) had no influence on the frequency of MIH. A positive correlation was found between the number of molars affected and incisors affected (P < .001). CONCLUSION: Individuals born with cleft lip and palate have a higher frequency of MIH, and the complexity of cleft type was associated with the number of affected molars.

A randomized clinical trial of hyaluronic acid gel pulpotomy in primary molars with 1 year follow-up.

OBJECTIVE: This randomized clinical study aimed to evaluate the success of hyaluronic acid (HA) as a pulpotomy medicament of human primary molars and to compare it with formocresol (FC) and ferric sulphate (FS) pulpotomy treatments up to 12 months. MATERIALS AND METHODS: The study was conducted with 130 primary molars of 44 children. The ethical approval and registration to clinical trials (No: NCT04115358) were completed. After the removal of all the coronal pulp tissue, a 0.5% HA gel, or a FC, or a 20% FS solution were applied randomly to the radicular pulp tissues of the primary molars. Then, the pulp chambers were filled with a zinc oxide eugenol cement and restored either with a composite filling material or with a stainless-steel crown. The treatment success rates of the 3 groups were followed and compared clinically and radiographically at 1st-, 3rd-, 6th- and 12th-months. RESULTS: Primary molars treated with FC, FS and HA dressings were clinically successful 77.5%, 86.8% and 87.5% respectively after 12th-month follow-up (p > .05). Radiographic successes of FC, FS and HA groups were lower than clinical successes (57.6%, 68.8%, 57.9% respectively at the 12th-month) but the difference between the groups was not statistically significant (p > .05). Equivalence analysis assuming not more than 10% difference between the materials suggested that HA was not inferior to FC or FS. CONCLUSIONS: Within the limitations of this study, our randomized clinical trial shows that HA is a promising pulpotomy medicament in primary molars. However, further studies are justified to further improve the HA material success.

Genetic variants in tooth agenesis-related genes might be also involved in tooth size variations.

OBJECTIVE: The present study aimed to evaluate if genetic variants in PAX9, MSX1, TGFα, FGF3, FGF10, FGF13, GLI2 and GLI3 are involved in TS of permanent teeth. MATERIALS AND METHODS: Pretreatment dental records from orthodontic patients were assessed prior to recruitment. Patients with tooth agenesis and congenital anomalies (including oral cleft) and/or syndromes were excluded. Dental casts were used to measure the maximum crown dimensions of all fully erupted permanent teeth except second and third molars in mesiodistal direction. Teeth with caries, occlusal wear, mesiodistal restorations, and obvious deformities were not evaluated. Genomic DNA samples were used for genotyping. The allelic discrimination of 13 genetic variants was performed. The associations between TS and genotype were analyzed by linear regression, adjusted by gender at a significance level of p ≤ 0.05. RESULTS: Genetic polymorphisms in the tooth agenesis-related genes studied here were associated with increased and decreased TS, in both maxilla and mandible (p < 0.05). CONCLUSION: This study reported associations of novel tooth agenesis-related gene variants with permanent tooth size variations. CLINICAL RELEVANCE: The presence of some genetic variants could allow the prediction of permanent tooth size.

Whether drug detection in urine and oral fluid is similar? A systematic review.

Urine has been a biological matrix of choice for drug screening, but recent advances in technology and the introduction of commercial oral fluid assays have effectively established oral fluid as a viable alternative matrix. This systematic review aimed to evaluate the sensitivity of oral fluid in detecting some illicit drugs compared to urine, and to compare the initial and final detection times of these drugs in both fluids. The electronic search in MEDLINE, Cochrane Library, Scopus, and Web of Science was carried out covering studies published from January 2003 and June 2019, in order to find all valid studies that detected drugs in oral fluid and urine in the same patient. Studies about illicit drugs, such as tetrahydrocannabinol, cocaine, amphetamines and illicit opioids, with fluids collection at the same day, controlled drug administration during the study, reported administration interval and time of collection were favored. Out of 2598 studies identified by electronic search, 7 studies were selected for qualitative analysis. Five were clinical trials and 2 were crossover trials. In total, 74 patients aged 20-52 years underwent a diagnostic examination (4 studies with tetrahydrocannabinol, 1 with methamphetamine, and 2 with cocaine) after drug administration. Illicit drug detection in oral fluid is similar to urine but oral fluid has a strong potential for the immediate detection of recent marijuana use compared to urine. In relation to cocaine and methamphetamine, the largest drugs detection window is obtained through urine analysis. Oral fluids cannot replace urine for most of the purposes of drug testing.

Aquaporins' Influence on Different Dental Erosive Wear Phenotypes in Humans.

Dental erosive wear is a multifactorial condition of high prevalence. Nowadays, there is an emphasis on discovering individual genetic predisposition for the development of this condition. Aquaporins (AQPs) are water channel proteins expressed in salivary glands, as well as during tooth development. They are involved in salivary secretion and composition and linked to physiological protection of the oral cavity. The aim of this study was to explore the relationship between different dental erosive wear phenotypes, AQP genes, and selected environmental factors. Data from 705 dental patients were used to investigate the association between dental erosive wear phenotypes and AQPs' single-nucleotide variants. Phenotypes were further analyzed considering diet and oral hygiene data, using logistic regression analysis, as implemented in PLINK, with the assumption that dental erosive wear is a complex gene-environment model. Associations were found between severe erosive tooth wear and rs2878771 (AQP2) for the genotypic (p = 0.02) and dominant (p = 0.03) models, and rs3736309 (AQP5) for the allelic model (p = 0.02). Logistic regression analyses, after implementing the Bonferroni correction, showed that several significant associations were present when covariates were included, suggesting that a strong environmental component is present. Our results show that dental erosive wear establishes under a gene-environmental complex model.

Terminology of Erosive Tooth Wear: Consensus Report of a Workshop Organized by the ORCA and the Cariology Research Group of the IADR.

Our understanding of erosive tooth wear and its contributing factors has evolved considerably over the last decades. New terms have been continuously introduced, which frequently describe the same aspects of this condition, whereas other terms are being used inappropriately. This has led to unnecessary confusion and miscommunication between patients, professionals, and researchers. A group of 15 experts, selected by the European Organization for Caries Research (ORCA) and the Cariology Research Group of the International Association for Dental Research (IADR), participated in a 2-day workshop to define the most commonly used terms in erosive tooth wear. A modified Delphi method was utilized to reach consensus. At least 80% agreement was achieved for all terms discussed and their definitions related to clinical conditions and processes, basic concepts, diagnosis, risk, and prevention and management of erosive tooth wear. Use of the terms agreed on will provide a better understanding of erosive tooth wear and intends to enable improved communication on this topic.

On the Variable Clinical Presentation of Molar-Incisor Hypomineralization.

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Original reports on the etiology of the condition and possible risk factors were inconclusive, and we refuted the original suggestion that MIH is an idiopathic condition and suggested that MIH has complex inheritance and is due to the interaction of more than one gene and the environment. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. Later we expanded this work to include genes related to the immune response. In this report, we provide a rationale to explain the variation seen in the clinical presentation of MIH, which can affect just one molar out of the four or just a portion of a particular molar.

Genes Regulating Immune Response and Amelogenesis Interact in Increasing the Susceptibility to Molar-Incisor Hypomineralization.

Ameloblasts are sensitive cells whose metabolism and function may be affected by inflammatory stimuli. The aim of this study was to evaluate the possible association between polymorphisms in immune response-related genes and molar-incisor hypomineralization (MIH), and their interaction with polymorphisms in amelogenesis-related genes. DNA samples were obtained from 101 nuclear families that had at least 1 MIH-affected child. Eleven single-nucleotide polymorphisms (SNPs) were investigated in immune response genes using TaqMan® technology allele-specific probes. A transmission disequilibrium test was performed to verify overtransmission of alleles in all MIH families, as well as in families only with mild or severe MIH-affected children. Gene-gene interactions between the immune-related and amelogenesis-related polymorphisms were analyzed by determining whether alleles of those genes were transmitted from heterozygous parents more often in association than individually with MIH-affected children. In severe cases of MIH, significant results were observed for rs10733708 (TGFBR1, OR = 3.5, 95% CI = 1.1-10.6). Statistical evidence for gene-gene interactions between rs6654939 (AMELX) and the SNPs rs2070874 (IL4), rs2275913 (IL17A), rs1800872 (IL10), rs1800587 (IL1A), and rs3771300 (STAT1) was observed. The rs2070874 SNP (IL4) was also significantly overtransmitted from heterozygous parents with the rs7526319 (TUFT1) and the rs2355767 (BMP2) SNPs, suggesting a synergistic effect of the transmission of these alleles with susceptibility to MIH. This family-based study demonstrated an association between variation in TGFBR1 and MIH. Moreover, the polymorphisms in immune response and amelogenesis genes may have an additive effect on the risk of developing MIH.

MMP13 Contributes to Dental Caries Associated with Developmental Defects of Enamel.

The aim of this study was to investigate the association between genetic polymorphisms in MMP8, MMP13, and MMP20 with caries experience and developmental defects of enamel (DDE) in children from the Amazon region of Brazil. Den tal caries and DDE data were collected through clinical examination from 216 children. Genomic DNA was extracted from saliva, and genotyping of selected polymorphisms in MMP8 (rs17099443 and rs3765620), MMP13 (rs478927 and rs2252070), and MMP20 (rs1784418) was performed using TaqMan chemistry and endpoint analysis. χ2 or Fisher's exact tests were used to compare allele and genotype distributions between children with caries experience and caries-free children and between DDE-affected and -unaffected children with an established alpha of 5%. The polymorphism rs478927 in MMP13 was associated with caries experience and DDE (p < 0.05). The analysis performed comparing children with both conditions (caries experience plus DDE) and children with neither of the conditions (caries-free chil dren without DDE) demonstrated that children carrying the MMP13 rs478927 TT genotype were more likely to have concomitant occurrence of these two conditions (OR = 5.8, 95% CI 2.1-15.8; p = 0.0003). In conclusion, the genetic polymorphism rs478927 in MMP13 was associated with caries experience and DDE.

Effect of TiF4 varnish on microbiological changes and caries prevention: in situ and in vivo models.

OBJECTIVE: The aim of this study was to evaluate microbiological changes, oral soft tissue toxicity, and caries-preventive effect of an experimental titanium tetrafluoride (TiF4) varnish compared with a commercially available fluoride varnish (NaF), using in situ and in vivo models. MATERIALS AND METHODS: The treatment groups were the following: TiF4 varnish (experimental varnish), Duraphat® (fluoride positive control), placebo varnish (no fluoride), and no treatment (negative control). The varnishes were applied once over the enamel surface using a microbrush. For the in vivo study, 48 Wistar rats were infected with Streptococcus sobrinus 6715, received a treatment, and were submitted to a cariogenic challenge. After 4 weeks, S. sobrinus, oral soft tissue toxicity, presence, and severity of caries were evaluated. For the in situ study, 12 volunteers took part in this randomized crossover, double-blind study performed in four phases of 14 days each. They used intraoral appliances containing four enamel specimens that received the varnish according treatment group. After 24 h, the varnish was removed and plaque accumulation was allowed. A 20% sucrose solution was dripped over the enamel blocks (10×/day for 5 min each). Total streptococci, S. mutans, Lactobacillus, Candida spp. counts, and presence of white spot lesions were evaluated. Lesion depth was also quantified by micro-CT. RESULTS: For the in vivo study, the fluoride (F-varnishes) showed a statistically significant reduction in the percentage of S. sobrinus compared to the negative control (p < 0.05). Toxicological analysis revealed no abnormalities in oral tissues of rats from all groups, and both F-varnishes reduced the number and severity of caries lesions, without significant differences (p < 0.05). No statistical differences in microbiological counts were seen for the in situ experiment (p > 0.05). However, the specimens treated with TiF4 exhibited lower percentage of white spot lesions and the lesion depth was significantly reduced by F-varnishes (p < 0.05). CONCLUSIONS: F-varnishes showed reduction in the percentage of S. sobrinus in vivo, no oral soft tissue toxicity, and a caries-preventive effect in vivo and in situ. CLINICAL RELEVANCE: NaF varnish is largely used due its capacity to form CaF2-like layer on enamel. Therefore, development of studies focused on other fluoride compounds such as a TiF4 varnish, which may have greater efficacy than NaF against tooth demineralization, is important.

Polymorphisms in FGF3, FGF10, and FGF13 May Contribute to the Presence of Temporomandibular Disorders in Patients Who Required Orthognathic Surgery.

BACKGROUND: To evaluate whether genetic polymorphisms in FGF3, FGF10, and FGF13 are associated with temporomandibular disorders (TMD) in patients that presented dentofacial deformities requiring orthognathic surgery. MATERIAL AND METHODS: The sample comprised a total of 113 patients of both sexes. The diagnosis of TMD was performed before orthognathic surgery between Research Diagnostic Criteria for Temporomandibular Disorders (RDC-TMD). According to the TMD assessment, the patients were divided into 3 major groups: myofascial pain, articular disc displacements and other TMD conditions (arthralgia, arthritis, and arthrosis). Genomic DNA was collected from saliva samples and genetic polymorphisms in FGF3 (rs1893047 and rs7932320), FGF10 (rs900379) and FGF13 (rs5931572 and rs5974804) were analyzed by real-time polymerase chain reactions. The association between the TMD conditions and the genetic polymorphisms assessed were analyzed by Poisson Regression. The model was calculated on bivariate and adjusted by sex. The established alpha was 5%. Data were analyzed by using SPSS software (IBM, Armonk, NY). RESULTS: The genetic polymorphisms rs7932320 in FGF3 (P < 0.001) and rs900379 in FGF10 (P < 0.05) were associated with the presence of muscle disorder. The genetic polymorphisms rs1893047 in FGF3, rs900379 in FGF10, and rs5974804 and rs5931572 in FGF13, were associated with the presence of disk displacement (P < 0.05). The genetic polymorphisms rs1893047 and rs7932320 in FGF3, rs900379 in FGF10, and rs900379 in FGF10 were associated with other TMD conditions (P < 0.05). CONCLUSION: Genetic polymorphisms in FGF3, FGF10, and FGF13 genes were associated with temporomandibular disorders in a population with dentofacial deformities.

TMJ arthrosis: does the occlusal relationship really interfere? A comparison between cone beam computed tomography and dried skulls.

The aim of this study was to investigate the association between condylar bone morphological characteristics with occlusal conditions. Besides the study will compare the tomography images with the real condition in 122 temporomandibular joints from 61 skulls. The occlusal conditions were evaluated by number of teeth missing, measurement of overjet and overbite, in millimeters, and presence or absence of crossbite, openbite and dental rotation. The condylar bone morphological conditions were classified in five types (normal, presence of erosion, presence of osteophytes, flattening and/or deformation). This classification was used in real skulls and in Cone Beam Computed tomography (CBCT) images. The data were submitted to statistical analysis with a level of significance of 0.05. Occlusal variables have no association to morphologic data (p > 0.05). Normal condylar bone was seen in 62 CBCT versus 53 in real skulls while morphological alterations were seen in 60 CBCT versus 67-real condyles. The clinical and tomographic measurements were compared, demonstrating an important difference in the classification demonstrating poor association between detection methods (k - 0.3, p < 0.001). The occlusal conditions appear to have no correlation with the morphological condyle conditions. The CBCT is a reliable diagnostic method, although it may present divergences of findings when compared with clinical raw examination to morphologic condylar conditions.

Polymorphisms in Nonamelogenin Enamel Matrix Genes Are Associated with Dental Fluorosis.

The aim of this study was to evaluate whether genetic polymorphisms in AMELX, AMBN, ENAM, TFIP11, and TUFT1 genes are associated with dental fluorosis (DF). A total of 1,017 children from 2 Brazilian cohorts were evaluated. These populations lived in cities with fluoridation of public water supplies. DF was assessed in erupted permanent teeth using the modified Dean index. The polymorphisms rs946252, rs12640848, rs4694075, rs5997096, and rs4970957 were analyzed by real-time PCR from genomic DNA. Associations between DF, genotype, and allele distribution were evaluated using the χ2 test, with an alpha of 5%. The polymorphisms rs4694075, rs5997096, and rs4970957 in AMBN, TFIP11, and TUFT1 were associated with DF (p < 0.05). In conclusion, enamel matrix genes are associated with DF.

Genes Involved in the Enamel Development Are Associated with Calcium and Phosphorus Level in Saliva.

Saliva components play a crucial role in the integrity of the dental enamel and in caries susceptibility. The saliva characteristics are controlled by many factors, including genetic factors. Therefore, this study aimed to evaluate the association between the genetic variations in genes expressed in enamel development with calcium and phosphorus levels in saliva. We collected 276 unrelated 12-year-old children from private and public schools. Saliva was collected for DNA extraction from oral cells and for measurement of calcium and phosphorus. Inductively coupled plasma-mass spectrometry determined calcium and phosphorus levels in whole saliva. Fifteen genetic variations in 9 genes were analyzed. The genotype was determined by real-time polymerase chain reactions. Data were analyzed using Plink with an alpha of 5%. Genetic variations in AMELX, AMNB and ESRRB were associated with the calcium level in saliva (p < 0.05). A borderline association was observed in ENAM allele distribution shown with phosphate level in saliva (p = 0.049). In conclusion, our results are the first to report that genetic variations contribute to calcium and phosphorus levels in saliva.

Genetic polymorphisms underlying the skeletal Class III phenotype.

INTRODUCTION: Our goal was to verify the association between candidate polymorphisms and skeletal Class III malocclusion in a well-characterized homogeneous sample set. METHODS: Thirty-five single-nucleotide polymorphisms were studied from 10 candidate loci in 54 Class III subjects and 120 controls. Skeletal Class III characteristics included ANB angle less than 0°, SNB angle greater than 83° (mandibular prognathism), SNA angle less than 79° (maxillary deficiency), Class III molar relationship, and negative overjet. Inclusion criteria for the controls were ANB angle between 0° and 4°, Class I molar relationship, and normal overjet. Chi-square and Fisher exact tests and principal component (PC) analysis were used to determine overrepresentation of marker alleles with alpha of 0.05. Odds ratios and 95% confidence intervals were calculated. RESULTS: MYO1H (rs10850110 AG) (P = 0.001) with PC2 and between FGF10 (rs593307 A

Mesio-Distal and Buccal-Lingual Tooth Dimensions are Part of the Cleft Spectrum: A Pilot for Future Genetic Studies.

Objective : Considering that oral clefts and tooth dimensions may be part of the same phenotypic spectrum, the aim of this study was to investigate tooth dimensions in permanent dentition and dental malformations, including tooth size discrepancies, of subjects born with clefts compared with individuals without clefts. Design : Cross-sectional study. Participants : The cleft group was composed of 66 subjects, and the noncleft group consisted of 66 healthy unrelated subjects. Main Outcome Measures : The mesio-distal and buccal-lingual crown diameter of fully erupted permanent teeth outside the cleft area was measured using a digital caliber. Clinical records and radiographs were used to evaluate the type of clefts and dental anomalies. Results : The lower second premolar was significantly reduced in the CLP and CP groups. The upper lateral incisor was found to be significantly smaller in the CP group, only for mesio-distal dimensions (P < .05). Dental agenesis was found in eight (12%) cleft subjects and supernumerary teeth in two (3%). Conclusions : Subjects born with oral clefts presented size reduction in specific dental groups.

Chapter 4: Development Defects of Enamel and Dentine and Coronal Caries.

The development of the human dentition is prone to disruption due to its delicate and complex nature - including variations in tooth number and anatomical form and in the characteristics of enamel, dentine, and cementum. This chapter will focus on developmental defects of dental enamel (DDE) and dentine (DDD), which can be associated with considerable treatment burden on an individual, often related to the change in dental hard tissue characteristics in those at increased caries risk. DDE are prevalent and can be related to genetic conditions such as amelogenesis imperfecta and environmental challenges such as direct physical trauma to the developing tooth or systemic insults during the different phases of amelogenesis. Phenotypical variability can be great, making diagnosis difficult in many cases. There are two major enamel defects - the quantitative defect of hypoplasia and the qualitative defect of hypomineralization. DDDs are less prevalent than DDEs, with two major DDD types: dentinogenesis imperfecta and dentine dysplasia. The main features of the DDDs are enamel fracture exposing the dentine and subsequent wear, with enlarged pulp spaces in some variants. The appearance may be affected, with bulbous teeth and grey-blue to brown opalescent colouring. With respect to dental caries, developmental defects of the teeth, in themselves, do not cause caries risk; however, they can change the manifestation of the disease due to creating niches for biofilm accumulation and thereby increasing cleaning difficulty and changing the physical and chemical characteristics of dental hard tissues and how they react to cariogenic challenges.