Dental anomalies associated with genetic factors

The article reviews the association between dental anomalies and genetic diseases. Knowledge of these hereditary diseases will enable the dentist to make a more extensive analysis of the families in which such diseases occur, and above all to evaluate more precisely the dental aspects that such conditions favour. This will lead to better management of diseases linked to malocclusion, congenital absence of teeth and anomalous development of dental tissues. Hereditary diseases are caused either by a single mutant gene, inherited from 1 parent and acting as dominant gene, or from a pair of mutant genes, inherited from both parents and acting recessively. Autosomal-dominant and autosomal-recessive inherited diseases are described, together with hereditary sex-linked conditions and those of multi-factorial origin. The purpose is to review such diseases so that the dentist can make an early diagnosis in clinical practice, check the predisposition toward such diseases and put in place preventive measures.     

Dental anomalies associated with incontinentia pigmenti or Bloch-Sulzberger syndrome

We report dental anomalies related to the Bloch- Sulzberger Syndrome better known as Incontinentia Pigmenti (IP). IP is an X related hereditary disease that occurs for about 95% of all patients in females and is lethal for the male foetus. Because of severe skin lesions in the neonatal period the disease is more known by dermatologists than dentists. Beside the skin lesions other associated deficiencies can be present like: ocular injuries, anomalies of hair and nails, defects of the central nervous system, malformations of the extremities and anomalies of the teeth. We report 8 female patients of different ages, out of 5 families. All were diagnosed with IP after DNA examination. Dental manifestations related to IP are: delayed eruption, oligodontia, agenesis, peg-shaped or malformed teeth, supernumerary teeth and supplementary cusps. IP is under diagnosed if the symptoms are limited to agenesis of only a few teeth and inconspicuous skin lesions. Dentists are ideally placed to identify individuals with IP and should refer patients with a presumption of IP to proper medical specialists.     

Physiological resorption of connective tissue associated with tooth eruption

The ultrastructural changes occurring during physiological resorption of connective tissue associated with erupting teeth of monkeys is described. Significant differences occur before and after the tooth emerges into the oral cavity. Before the tooth erupts connective tissue resorption over the tooth shows a cellular response involving cells of the fibrocytic and monocytic series. The cells of the fibrocytic series show changes from the resting fibrocyte which involve dilation of the cisternae of the rough endoplasmic reticulum, hypertrophy of the Golgi appearatus, the apparance of agranular vesicles, loss of the spiral configuration of polysomes and the development of numerous coated vesicles close to the cell surface. Ultimate breakup of the fibrocyte occurs. Monocytic cells become macrophagic. No breakup of macrophages occurs. In the extracellular compartment the collagen fibrils show a breakup into smaller units and eventual loss. The dental epithelium associated with this disorganized connective tissue is characterized by the development of numerous coated vesicles and a highly vesicular cytoplasm. The connective tissue and dental epithelium lateral to the crown of the tooth showed a similar ultrastructural picture which alters significantly as the tooth emerges into the oral cavity and the epithelial attachment develops. An acute inflammatory response occurs and the connective tissue supporting the forming attachment shows areas of breakdown and synthesis occurring simultaneously. These findings are discussed in terms of the mechanism of connective tissue breakdown and the fibrocyte implicated as playing an important role in this mechanism. It is suggested therefore, that the fibrocyte is capable of modulation to become either synthetic, maintaining or degradative.     

Dental anomalies associated with amelogenesis imperfecta: a radiographic assessment.

Amelogenesis imperfecta, a group of hereditary conditions primarily affecting the enamel, has been associated with dental anomalies, including taurodontism, congenitally missing teeth, delayed eruption, crown resorption, and abnormal enamel density. The purpose of this study was to assess the prevalence of these anomalies in an amelogenesis imperfecta population. The study group consisted of members of 9 unrelated families--22 family members with amelogenesis imperfecta and 13 unaffected family members. Panoramic radiographs were evaluated for taurodontism, congenitally missing teeth, delayed tooth eruption, pathologic dental resorption, pulp calcification, and radiographic enamel density. The prevalence of taurodontism was similar in people with amelogenesis imperfecta and normal people; all of the remaining parameters were more commonly observed in people with amelogenesis imperfecta. The radiographic enamel density was quantitatively reduced in teeth affected by amelogenesis imperfecta in comparison with teeth with normal enamel. These findings suggest that some of the features associated with amelogenesis imperfecta result from abnormal enamel formation (eg, decreased enamel density, crown resorption) whereas others may occur as a result of expression of the genetic mutation in cells other than ameloblasts (eg, abnormal eruption, pulp calcification).     

Recession defects associated with scraped roots treated with subepithelial connective tissue graft

The objective of the current study was to assess histomorphometrically the healing process of recession defects associated with scraped roots treated with subepithelial connective tissue graft (SCTG). Six dogs were used. Bone dehiscence defects (6 × 8 mm) and root planing were carried out on maxillary canine teeth. Following a split-mouth model, according to the treatment, left canines (control) were covered with coronally positioned flap (CPF). Right canines were submitted to treatments with SCTG. After a 3-month postoperative period, the animals were killed, and the blocks processed for the histomorphometric assessment. Data assessment demonstrated that the CPF group showed parameters of a new connective tissue attachment, length of new cement (NC), length of new bone (mean ± SD: 0.95 ± 0.53, 2.44 ± 1.97, and 1.96 ± 2.29 mm, respectively), which were higher than those of SCTG group (mean ± SD: 0.71 ± 0.36, 2.21 ± 1.28, and 1.52 ± 1.31 mm, respectively), although not significantly (P > 0.05). The length of both epithelial tissue and connective tissue apposition in the SCTG group (mean ± SD: 1.70 ± 0.53 and 2.62 ± 1.52 mm, respectively) were higher than those of the CPF group (mean ± SD: 1.18 ± 0.49 and 2.03 ± 1.03 mm, respectively), although showing no significant differences (P > 0.05). Within the limits of the current study, it was possible to conclude that there were no significant differences between the groups according to the histologic parameters assessed.     

Factors associated with occurrence and reversibility of connective tissue attachment loss

Marginal periodontitis appears to be site-specific, demonstrates rapid bursts of connective tissue attachment destruction, and may, at times, repair spontaneously. The present study was undertaken to investigate associations between bacterial populations and periodontal destruction parameters within the first 14 days after induction of experimental periodontitis in animals receiving metronidazole. Metronidazole was administered orally to four squirrel monkeys for 17 days at a daily dose of 100 mg/kg body weight. After three days (baseline), marginal periodontitis was induced by tying silk ligatures at the gingival margins of maxillary and mandibular bicuspids and molars. Subgingival bacterial samples were taken and periodontal destruction evaluated at baseline, and 3, 7 and 14 days after ligature placement. Dark-field microscopy was used to quantitate motile forms, spirochetes, straight and curved rods, filaments, cocci and fusiforms. Levels of connective tissue attachment, crestal alveolar bone and the volume of bone were assessed histometrically. Bacterial and histometric parameters were analyzed using analysis of variance. The results indicated that subgingival plaque, prior to induction of periodontitis, consisted primarily of cocci. At three days after ligature placement, cocci were significantly decreased, while straight rods became the predominant bacterial group for the remainder of the study. Spirochetes and motile forms were virtually absent at all time points. Histometric analyses showed significant loss of connective tissue attachment at three and seven days, which was reversed and repaired at 14 days. Factors relating to initiation, potentiation, and reversibility of connective tissue attachment loss are discussed.     

Dental anomalies in patients with Down syndrome

The purpose of the present study was to evaluate the incidence of dental anomalies in Brazilian patients with Down syndrome. A sample with 49 panoramic x-rays of syndromic patients aged 3 to 33 years (22 male and 27 female) was used. The characteristics of dental anomalies were observed in the panoramic radiographs in both the primary and permanent dentition, according to the ICD (International Classification of Diseases). The corresponding tables and percentile analysis were elaborated. There was a high incidence of syndromic patients with different types of anomalies, such as taurodontism (50%), proven anodontia (20.2%), suspected anodontia (10.7%), conic teeth (8.3%) and impacted teeth (5.9%). In conclusion, patients with Down syndrome presented a high incidence of dental anomalies and, in most cases, the same individual presented more than one dental anomaly.     

Dental anomalies in fucosidosis

Dental anomalies have not previously been recorded in patients with fucosidosis. A new case of this rare disorder is reported, in which a number of variations in both number and morphology of the primary and secondary dentition occur.     

Dental anomalies in a child with craniometaphysial dysplasia

Craniometaphysial dysplasia (CMD) is a rare disorder that mainly affects craniofacial bones. It is caused by mutations within a region of human homolog (Ankh) of the mouse progressive ankylosis (Ank) gene. ANK, together with other factors, regulates intracellular and extracellular levels of pyrophosphate/inorganic phosphate critical for maintaining mineral homeostasis. The systemic manifestations noted in CMD patients have been reported previously. The dental anomalies in CMD patients, however, have been minimally described in the dental literature. The purpose of this case report was to describe both systemic and dental manifestations of a 3 1/2-year-old child with craniometaphysial dysplasia. At the gross level, enamel discoloration and tooth malformations were observed in multiple primary teeth without obvious defects in the roots. Radiographic evidence of excess mineralization was noted on the primary maxillary second molars, limited to the mesial region of the crowns. The genetic and molecular effects of Ank/Ankh mutations are also discussed.     

Dental anomalies in Axenfeld-Rieger syndrome

The authors describe the case of a 10-year-old girl presenting with Axenfeld-Rieger syndrome (ARS), a rare autosomal dominant condition. The patient showed severe hypodontia, microdontia and short roots. Early diagnosis of the syndrome from its dento-facial and systemic features is important so that subsequent ocular complications may be prevented.     

Dental anomalies and associated factors in 2- to 5-year-old Brazilian children

Background. Dental anomalies in primary teeth may lead to functional and aesthetic disorders, and their recognition contributes to early diagnosis and long-term treatment planning. Objective. This study investigated the prevalence of dental anomalies in primary dentition and associated factors in Brazilian preschoolers. Methods. The study population of this cross-sectional study comprised 1260 2- to 5-year-old children from public nurseries in Canoas, southern Brazil. Dental anomalies were recorded by five trained examiners according to Kreiborg criteria; classification included double teeth, hypodontia, supernumerary, and microdontia. Results. Dental anomalies as a group were found in 2.5% of children, although no significant difference occurred between genders and races. All the anomalies were observed in the anterior region, with no significant differences between the arches. However, supernumerary teeth were significantly more frequent among the non-white racial group (Fisher; P = 0.025) and double teeth on the lower arch (McNemar; P = 0.020). Individual anomaly frequencies were: double teeth, 1.3%; hypodontia, 0.6%; supernumerary, 0.3%; and microdontia, 0.3%. Conclusions. The frequency of primary dentition anomalies as a group was greater than that reported in other populations; the findings of this study provide a clear vision of the distribution of this oral condition and may well contribute to early detection and treatment planning.     

Isolated soft tissue cleft lip: epidemiology and associated dental anomalies

Oral Diseases (2011) 17 , 221–231 Objectives: The aim of this investigation was to study the epidemiology of the isolated soft tissue cleft lip (ICL) population and to evaluate the dental anomalies associated with permanent dentition. Methods: The study included 19 children aged 9–13 years presenting ICL selected from 657 cleft lip‐affected patients treated during the last 10 years in two craniofacial centers. Only 17 patients could be included for dental anomaly evaluation: Hyperdontia, Hypodontia, Gemination, Talon tooth, Microdontia, and Macrodontia. These were compared with cleft lip and palate (CLP) and cleft lip and alveolus (CLA)‐affected populations and with normal populations. Results: The prevalence of ICL was 2.8%. All types of tooth abnormalities were found to be higher and mainly significant for the cleft side of ICL compared with the normal population. On the side opposite the cleft, the prevalence of dental anomalies reduced toward the normal individuals and was not significantly different. The significant differences found between CLP, CLA, and ICL‐affected populations were mostly depicted by lateral incisors and second pre‐molar hypodontia. Conclusions: Isolated cleft lip is a rare phenomenon among the spectrum of the cleft‐affected population. The prevalence of the dental anomalies in ICL maintains the proportional trend according to clefting severity.     

Periodontal connective tissue.

Connective tissues of the periodontium are composed of cells and their related extracellular matrix components. For these tissues to respond appropriately during development and regeneration as well as in health, a precise regulation of cell-cell interactions and cell-substrata interactions must occur. Thus, in order to achieve more predictable clinical results, it is critical that the mechanisms and proteins and factors guiding tissue development, maintenance, and regeneration be understood at the cellular and molecular level. This has resulted in an increased emphasis on identifying components of the periodontium and subsequently determining how these proteins and factors regulate cell behavior. This review summarizes our current knowledge of the proteins and factors considered important to development, maintenance, and regeneration of periodontal tissues.