Studies of dental anomalies in a large group of school children

Association between craniofacial patterns and third molar agenesis in orthodontic patients

PURPOSE

Third molar agenesis (TMA) is the most common craniofacial anomaly and has been associated with craniofacial patterns in different populations. Therefore, the aim of this retrospective cross-sectional study was to assess a possible association between craniofacial patterns and TMA in German orthodontic patients.

METHODS

Patients undergoing orthodontic treatment with dental records including anamnesis, pretreatment lateral cephalograms and orthopantomograms were evaluated. Cephalometric analyses were conducted digitally and lines, angles and proportions were measured to investigate craniofacial morphology. Skeletal classes were determined by the individualised Wits appraisal and ANB angle. The TMA was identified with the help of orthopantomograms. Patients showing agenesis of at least one third molar were included in the TMA group. Statistical analysis was performed to assess the association between TMA and craniofacial patterns (α of p ≤ 0.05).

RESULTS

A total of 148 patients were included, 40 (27.0%) presented at least one missing tooth (TMA group) and 108 (73.0%) showed full dentition (control group). Skeletal class determined by the individualised Wits appraisal revealed statistical significance between the TMA and control groups (p = 0.022), in which TMA patients were 11 times more likely to present with an individualised skeletal class III (odds ratio 11.3, 95% confidence interval 1.7-139.5). Skeletal cephalometric analysis revealed no statistical differences between TMA and control groups for any further angular, linear and proportional parameters.

CONCLUSION

Third molar agenesis was associated with skeletal class III determined by the individualised Wits appraisal.

Frequency and variability of nonmetric dental crown traits of primary and permanent molars in a group of orthodontic patients

BACKGROUND

The present study aimed to assess the frequency and variation of 13 nonmetric dental crown traits (NDCT) in permanent and primary molars in German orthodontic patients.

METHODS

Dental records from orthodontic patients were screened and evaluated. First and second permanent and primary upper and lower molars (from left and right sides) were assessed. Teeth with cavitated dental caries, occlusal wear, restorations and obvious dental deformities were not evaluated. The NDCT for permanent molars were identified and scored according to the odontoscopic system developed by Arizona State University Dental Anthropology System (ASUDAS). The NDCT for primary molars were identified and scored according to ASUDAS, Hanihara's method and Sciulli's method. The χ2 test was used to investigate side preference and sexual dimorphism at a significance level of p ≤ 0.050.

RESULTS

A total of 163 orthodontic patients (82 males and 81 females) aged 8-14 years were included. A sexual dimorphism was observed for the hypocone in first upper permanent molar (p = 0.041). The protostylid was observed in lower permanent molars (range 2.1-10%). Males presented more hypoconulid than females (p = 0.019). Only females presented the distal trigonid crest in lower first permanent molars (p = 0.002). The most common groove pattern in primary molars was Y; male presented more Y grade than females in the lower second primary molar (p = 0.039). Asymmetry was observed in some traits, ranging from 0 to 100%.

CONCLUSION

The present study showed the frequency of NDCT of molars in German orthodontic patients and demonstrated that some traits present sexual dimorphism.

Exploring the sex-associated differences in molars fused roots

BACKGROUND

Human sexual dimorphism is associated with many biological characteristics, including dental variables.

OBJECTIVES

To investigate if molars fused roots present sex-associated differences.

METHODS

Panoramic radiographs were used to investigate the frequency and distribution of permanent molars fused roots. Only patients with all first and second permanent molars were included. Third molars were not investigated. Any molar with roots fused apical to the usual furcal position were considered molar fused roots. Comparisons between males and females were performed using chi-square or Fisher's and Mann-Whitney tests and the established alpha was 5% (p<0.05). Sex-differential liability models were also proposed.

RESULTS

A total of 84 males and 86 females were included and 1360 molars were analyzed. Among them, 46 (26.06%) present at least one molar with fused root. Second maxillary molars were the most affected teeth. There was an association between sex and molars with fused roots. Females had a 3.4 higher chance to present fused roots than males (OR=3.4, CI 95% 1.6-6.8; p=0.0008). The female: male ratio of molars with fused roots was 2.5:1. The number of molars with fused roots ranged from 1 to 6 per patient, and the mean number of Females presented more molars with fused roots (mean = 1.01; standard deviation = 1.52) than males (mean = 0.31; standard deviation = 0.85) (p<0.05).

CONCLUSIONS

Molar fused root of permanent teeth presents sex-associated differences, in which females are more affected than males. Our results support sex-differential liability models for molars fused roots.

Potential Association of Molar-Incisor Hypomineralization (MIH) with Dental Agenesis and Infraoccluded Deciduous Molars: Is MIH Related to Dental Anomaly Pattern (DAP)? An Observational Cross-Sectional Study

Background: Dental Anomaly Pattern (DAP) is a collection of morphologic, numeric, and eruptive anomalies of teeth that are often observed together, suggesting a potential genetic relationship. Our objective was to assess the potential associations of Molar-Incisor Hypomineralization (MIH), a common developmental defect of enamel mineralization with a controversial etiology, with two specific components of DAP: (1) agenesis (AG) and (2) infraoccluded deciduous molars (IODM). Establishing such an association between MIH and one or both anomalies would provide evidence supporting a genetic link between MIH and DAP. Methods: We examined pretreatment intraoral standardized photographies and panoramic radiographs from 574 children aged 8-14 years, 287 having MIH and 287 without MIH, comparing the frequencies of AG and IODM in both groups. The subject samples were sourced from the databases of the orthodontic department at a university hospital. Results: The frequencies of AG in the MIH and non-MIH groups were 7% and 8%, respectively (p = 0.751). The corresponding frequencies of IODM were 27% and 19.2%, respectively (p = 0.082). That is, children with MIH did not exhibit an increased frequency of AG or IODM compared to those without MIH. Conclusions: These findings do not support the inclusion of MIH in DAP. Nevertheless, further analysis of possible associations is necessary to definitively validate or invalidate this hypothesis.

Exploring the association between PITX2, third molars agenesis and sella turcica morphology : PITX2, third molars agenesis and sella turcica morphology

OBJECTIVES

PITX2 is required for mammalian development and single nucleotide polymorphisms (SNPs) in this gene could be involved in dental agenesis and sella turcica patterns. Thus, the present study evaluated the association between SNPs in PITX2, third molars agenesis and sella turcica phenotypes.

MATERIALS AND METHODS

The sample consisted of healthy orthodontic German patients with lateral cephalometric radiographs with clearly visualization of the sella turcica, and dental orthopantomograms. The morphological variations of the sella turcica were evaluated using the lateral cephalograms, while third molar agenesis was evaluated using orthopantomograms. DNA isolated from buccal cells was used for genotyping three SNPs in PITX2 (rs3796902, rs1947187, and rs2595110). The analyzes were performed using a significance of 5%. There was no association between third molar agenesis and sella turcica phenotypes (p > 0.05). SNPs in PITX2 were also not associated with third molars agenesis (p > 0.05).

RESULTS

SNPs in PITX2 were associated with sella turcica phenotypes. The rs3796902 was associated with hypertrophic posterior clinoid process (p = 0.013). The rs1947187 and rs2595110 were associated with sella turcica bridge type A (p = 0.013 and p = 0.011, respectively for genotype distribution). Patients that carry the genotypes GG-CC-AG (rs3796902- rs1947187- rs2595110) had 7.2 higher chance to present sella turcica bridge type A (p = 0.002; Odds ratio = 7.2, Confidence interval 95% 2.04-27.04).

CONCLUSIONS

Third molar agenesis was not associated with SNPs in PITX2 and sella turcica phenotypes. SNPs in PITX2 may have an important role in sella turcica pattern.

The cantilever contact-point resin bonded bridge; adhesion 2.0

AIM

When young patients are congenitally missing anterior teeth, different treatment modalities can be used to complement the dental arch. This article proposes a new treatment modality for the replacement of anterior teeth, the cantilever contact-point resin bonded bridge (CCP-RBB).

MATERIALS AND METHODS

In this proof of principle study, CCP-RBB's delivered by one operator were clinically assessed. Patients who were missing maxillary incisors and had suitable intra-oral conditions for a contact-point cantilever RBB were included. Three cases are presented to describe all adhesive steps. This proof of principle clinical study is presented with up to 60 months follow-up of the cantilever contact resin bonded bridges.

RESULTS

A total of 19 CCP-RBB's were evaluated after a mean period of 29.8 months. None of the restorations exhibited failure, carious lesions or fractures during the follow-up periods, demonstrating an absence of restoration debonding or the need for repair.

CONCLUSION

The new cantilever contact-point resin bonded bridge exhibited an excellent treatment modality without failure or debonding up to 5 years. More and extended duration in vivo studies are needed to evaluate this new treatment modality.

CLINICAL SIGNIFICANCE

In this proof of principle the new cantilever contact-point resin bonded bridge obtained excellent results up to 5 years of clinical follow-up.

Is there an association between molar incisor hypomineralization and developmental dental anomalies? A case-control study

BACKGROUND

The aim of this study was to determine whether there is any association between molar incisor hypomineralization and developmental dental anomalies.

METHODS

Two pediatric dentists evaluated panoramic radiographs of 429 children aged 8-14 years with molar incisor hypomineralization (study group) and 437 children without molar incisor hypomineralization (control group) in terms of developmental dental anomalies. Twelve different developmental dental anomalies were categorized into four types: size (microdontia, macrodontia); position (ectopic eruption of maxillary permanent first molars, infraocclusion of primary molars); shape (fusion, gemination, dilaceration, taurodontism, peg-shaped maxillary lateral incisors); and number (hypodontia, oligodontia, hyperdontia) anomalies.

RESULTS

No significant difference was observed in the frequencies of developmental dental anomalies between the study and control groups in total, females, and males (p > 0.05). A statistically significant difference was found between the distribution of developmental size, position, shape, and number anomalies between the study and control groups (p = 0.024). The most common anomaly in both groups was hypodontia (6.3% and 5.9%, respectively). There was a significant difference between the study and control groups in terms of subtypes of shape anomaly in all children and females (p = 0.045 and p = 0.05, respectively).

CONCLUSIONS

While a significant difference was observed between the distributions of types of developmental dental anomalies between individuals with and without molar incisor hypomineralization, there was no difference in terms of the frequency of developmental dental anomalies.

Five-Year Follow-Up of a Child with Non-Syndromic Oligodontia from before the Primary Dentition Stage: A Case Report

BACKGROUND

Congenital absence of teeth is a major dental abnormality in pediatric dentistry and the absence of six or more teeth is defined as oligodontia. Few reports of patients with non-syndromic oligodontia without systemic disease have continued dental follow-up from an early age.

METHODS

We performed the five-year follow-up from before the eruption of the primary dentition of a Japanese child with non-syndromic oligodontia and analyzed changes in dental arch growth.

RESULTS

At the oral examination at the age of 1 year and 2 months, eight primary incisors were congenitally absent. Therefore, we made dentures for the patient at the age of 3 years and 4 months. From the age of 5 years and 1 month, the child received articulation training for dysarthria from a speech therapist to improve the function and appearance of the oral cavity. Measurement of the patient's dental models revealed a particularly narrow dental arch, especially between the primary canines.

CONCLUSIONS

Our findings highlight the importance of treatment for patients with non-syndromic oligodontia from an early age by multiple medical professionals, recognizing that the missing teeth affect the growth of the maxillofacial region.

Association between Hypodontia and Angle’s Malocclusions among Orthodontic Patients in Kathmandu, Nepal

Background. Disturbances during the early tooth development stages may result in the congenital absence of teeth. The purpose of this study was to assess the relationship between hypodontia and Angle’s malocclusions. Materials and Methods. The sample comprised 601 orthodontic patients’ pretreatment records (242 men and 259 women), selected from the achieved orthodontic records. Developmental anomalies of teeth affecting the number were examined on dental panoramic radiographs. Based on Angle’s classification, pretreatment dental casts were assessed and classified into different classes of malocclusion. The relationship between hypodontia and different classes of malocclusion was evaluated using the chi-square test. Results. The prevalence of tooth agenesis was 7.48%, that is, 45 out of 601 samples. There were a total of 72 (0.42%) missing teeth, excluding the third molars. The most frequent missing tooth was the maxillary lateral incisor (35, 48.61%), followed by the mandibular lateral incisor (14, 19.44%), the mandibular central incisor (6, 8.33%), the mandibular second premolar (5, 6.294%), and the maxillary second premolar (4, 5.55%). Hypodontia was more common in the upper jaw. Although hypodontia was mostly seen in Class I malocclusion patients (7.87%), followed by Class II malocclusion patients (6.99%) and least in Class III malocclusion patients. However, there was no significant difference in hypodontia among different classes of malocclusions (p = 0.352). Conclusion. The most frequently missing tooth was the maxillary lateral incisor, followed by lateral and central mandibular incisors and mandibular second premolars, while excluding the third molars. The present study did not find any association between various types of malocclusions and hypodontia.

Association of third molar agenesis and microdontia with genetic polymorphisms in vitamin-D-related genes

The present study aimed to evaluate if functional genetic polymorphisms in vitamin-D-related genes are associated with third molar agenesis and third molar microdontia in German orthodontic patients. Pre-orthodontic and follow-up treatment records were evaluated for phenotype definition. Saliva samples were collected for DNA extraction. Eight potential functional genetic polymorphisms in VDR [rs731236 (TaqI), rs7975232 (ApaI), rs2228570 (FokI), and rs1544410 (BsmI)], CYP27B1 (rs4646536), CYP24A1 (rs927650), GC (rs4588), and SEC23A (rs8018720) were evaluated using real-time PCR. Comparison among the groups were performed (third molar anomaly vs. control; third molar agenesis vs. control; and third molar microdontia vs. control) with an alpha of 5%. A total of 164 patients were analyzed. Forty-nine (29.9%) patients had at least one third molar anomaly. In the haplotype analysis, genetic polymorphisms in VDR and CYP27B1 were associated with third molar anomalies (p<0.05). The G allele in rs8018720 (SEC23A) was more frequent in microdontia cases. In the genotype distribution analysis, rs8018720 in SEC23A was associated with third molar microdontia in the co-dominant (p=0.034; Prevalence Ratio [PR]=5.91, 95% Confidence Interval [CI]= 1.14-30.66) and in the recessive (p=0.038; PR=5.29; 95% CI= 1.09-25.65) models. In conclusion, vitamin D-related genes could be involved in third molar anomalies.

Congenitally missing second permanent molars in non‑syndromic patients (Review)

Hypodontia (tooth agenesis) is regarded as the most common congenital dental anomaly. The present review discusses the epidemiological characteristics of congenitally missing second permanent molars (CMSPMs) within a systematic review of the literature. The review was based on Pubmed library associated with the search of various scientific databases or academic resources, improved by hand search of reference lists. The terms ‘hypodontia’ or ‘anodontia’ in combination with ‘prevalence’ or ‘epidemiology’ were searched in the data sources for studies published between January 2001 and December 2020. Abstracts of non-English papers were also analyzed. The inclusion criteria were as follows: i) Study provided precise data about CMSPMs, even if no second permanent molar was reportedly missing; ii) the number of CMSPMs distributed by jaw was provided and iii) studies on subjects >3 years were used. The exclusion criteria were as follows: i) Studies on patients with history of trauma of the maxilla or the mandible, any type of syndrome affecting bone metabolism, metabolic disorders, previous extraction or tooth loss due to dental caries, cleft lip and palate; ii) studies performed on cohorts of patients with hypodontia and iii) studies reporting data including third molars, except for those that presented sufficient data to perform correct calculations. A total of 79 studies were selected, accumulating a population of 281,968 people, with an average sample size of 3,524.60±11,255.25. The prevalence of CMSPMs (IpHSPM) was 2.79±3.16% among all missing teeth (1.03±1.59% for upper CMSPMs and 1.76±2.32% for lower CMSPMs; P=0.011). There were no significant differences (P=0.250) in IpHSPM between men (1.59±1.52%) and women (2.13±1.67%). However, significant differences were recorded between continents. Furthermore, lower CMSPMs were found more frequently in orthodontic samples (P=0.033). The prevalence of CMSPMs is low compared with the overall prevalence of CM teeth. Despite the rarity of these anomalies, early detection is important to enable practitioners to plan and start treatment at the best time for optimal results.

Exploring the Association Between Genetic Polymorphisms in Genes Involved in Craniofacial Development and Isolated Tooth Agenesis

Tooth agenesis is a common congenital anomaly in humans and is more common in oral cleft patients than in the general population. Many previous studies suggested that oral cleft and tooth agenesis share a similar genetic background. Therefore, this study explored the association between isolated tooth agenesis and genetic polymorphisms in genes that are crucial for craniofacial and tooth development. Panoramic radiographs, anamnesis, and genomic DNA from 273 patients were included. Patients were classified as tooth agenesis present, when at least one permanent tooth was congenitally missing. Patients with syndromes and oral cleft were excluded. Only unrelated patients were included. The genetic polymorphisms in BMP2 (rs235768 and rs1005464), BMP4 (rs17563), RUNX2 (rs59983488 and rs1200425), and SMAD6 (rs3934908 and rs2119261) were genotyped by real-time polymerase chain reaction. Genotype and allele distributions were compared between the tooth agenesis phenotypes and controls by Chi-square test. Haplotype and diplotype analysis were also performed, in addition to multivariate analysis (alpha of 0.05). A total of 86 tooth agenesis cases and 187 controls were evaluated. For the rs235768 in BMP2, patients carrying TT genotype have higher chance to present tooth agenesis [p < 0.001; prevalence ratio (PR) = 8.29; 95% confidence interval (CI) = 4.26–16.10]. The TT genotype in rs3934908 (SMAD6) was associated with higher chance to present third molar agenesis (p = 0.023; PR = 3.25; 95% CI = 1.17–8.99). BMP2 was also associated in haplotype and diplotype analysis with tooth agenesis. In conclusion, genetic polymorphisms in BMP2 and SMAD6 were associated with isolated tooth agenesis.

The global distribution of permanent canine hypodontia: A systematic review

Objective

To systematically review studies on canine agenesis prevalence in different populations and continents, based on the jaw, sex, location, and associated dental anomalies.

Methods

Electronic and hand searches of English literature in PubMed, Web of Science, Scopus, OpenGrey, and Science Direct were conducted, and the authors were contacted when necessary. Observational studies (population-based, hospital/clinic-based, and cross-sectional) were included. For study appraisal and synthesis, duplicate selection was performed independently by two reviewers. Study quality was assessed using a modified Strengthening the Reporting of Observational Studies in Epidemiology checklist, with main outcome of prevalence of canine agenesis.

Results

The global population prevalence of canine agenesis was 0.30% (0.0-4.7%), highest in Asia (0.54%), followed by Africa (0.33%), and the least in Europe and South America (0.19% in both continents). Canine agenesis was more common in the maxilla (88.57%), followed by both maxilla and mandible (8.57%), and the least common was mandible-only presentation (2.86%). The condition was more common in females (female:male ratio = 1.23), except in Asia (female:male ratio = 0.88) and Africa (female:male ratio = 1). In Asia, unilateral agenesis was almost twice as prevalent as bilateral, but in Europe, the bilateral form was more common.

Conclusions

The overall prevalence of canine agenesis is 0.30%, with the highest prevalence in Asia, followed by Africa, Europe, and South America. The condition is more common in the maxilla than the mandible, and in females than males (except in Asia and Africa), with unilateral agenesis being more common in Asia and the bilateral form showing a greater prevalence in Europe.

Sexual dimorphism of tooth agenesis patterns in non-syndromic oligodontia in Japanese patients

OBJECTIVE

Wide individual variation observed in tooth agenesis patterns in patients with non-syndromic oligodontia could be affected by sexual dimorphism. Therefore, the present study investigated sex-associated differences in tooth agenesis patterns in patients with non-syndromic oligodontia.

DESIGN

Subjects were 108 male (ages 7-46 years) and 184 female (ages 7-43 years) orthodontic patients missing ≥6 permanent teeth, excluding third molars. The number of agenetic teeth per patient, excluding third molars, and the prevalence of agenesis of each tooth type were evaluated using panoramic radiographic images. Rankings of the most common tooth agenesis patterns in the maxillary and mandibular arches were calculated. The number of agenetic teeth per patient was compared between sexes using the Mann-Whitney test. The prevalence of tooth agenesis for each tooth type was compared between sexes using the χ² and Fisher's exact tests with Bonferroni correction.

RESULTS

No significant sex difference in the distribution of the number of agenetic teeth was observed. The prevalence of agenesis of the maxillary second premolars was significantly higher in females (P < 0.007) and the prevalence of agenesis of the mandibular central incisors was significantly higher in males (P < 0.007). Sexual dimorphism was observed in the highly ranked tooth agenesis patterns.

CONCLUSIONS

No significant difference in the severity of tooth agenesis was observed between sexes; however, sexual dimorphism was observed in the tooth agenesis patterns of patients with non-syndromic oligodontia. Although various tooth agenesis patterns were identified, sex-specific tendencies suggest that categories can be utilized in future epidemiologic research and planning.

IRF6, MSX1, TGFA, dental anomalies, and skeletal malocclusion

OBJECTIVE

Verify the presence of association between four variables-transforming growth factor α (TGFA; C/T rs1523305), interferon regulatory factor 6 (IRF6; A/C rs2013162), muscle segment homeobox 1 (MSX1; A/G rs12532), and dental anomalies-with skeletal malocclusion by comparing these four variables with Angle Classes I, II, and III, and normal, hyperdivergent, and hypodivergent growth patterns.

METHODS

A total of 505 orthodontic records of patients older than 8 years were evaluated. The sample consisted of 285 (56.4 per cent) females, 220 (43.6 per cent) males, 304 (60.2 per cent) Whites (the rest were mixed Blacks with Whites), with a mean age of 20.28 (±10.35) years (ranging from 8 to 25 years). Eight cephalometric points, which served as the anatomical framework for obtaining angles and cephalometric measurements, were used for skeletal characterization using the Dolphin Software. Samples of saliva were collected and the DNA was extracted, diluted and quantified. Markers in TGFA, IRF6, and MSX1 were used and genotypes were obtained using TaqMan chemistry. Odds ratio (OR) and 95 per cent confidence interval (CI) calculations, chi-square, Fisher's Exact, Mann-Whitney, and correlation coefficient tests (significance level: 95 per cent) were performed. Bonferroni correction was applied and an alpha of 0.0006 was considered statistically significant.

RESULTS

There was no statistically significant associations between markers in TGFA or IRF6 with skeletal malocclusions. Tooth agenesis was associated with facial convexity (P < 0.001). MSX1 was associated with Class II skeletal malocclusion (P = 0.0001, OR = 0.6, CI = 0.46-0.78).

CONCLUSION

Individuals with tooth agenesis were more likely to have a convex face. MSX1 was associated with Class II skeletal malocclusion.

Is dental agenesis associated with craniofacial morphology pattern? A systematic review and meta-analysis

BACKGROUND/OBJECTIVE

Craniofacial discrepancies have been associated with congenital dental anomalies. The aim of this study was to determine if there is any scientific evidence in the literature regarding the association between dental agenesis and craniofacial morphology.

MATERIALS AND METHODS

A systematic review and meta-analysis following the PRISMA Statement were conducted and registered in PROSPERO database. A broad search was conducted on databases (PubMed, Virtual Health Library, Web of Science, and Scopus) and grey literature. Articles that were selected based on predetermined eligibility criteria were assessed for quality and risk of bias according to the guidelines described by Folkes and Fulton. Those articles with similarities were submitted to meta-analysis using the RevMan 5.3 program. The certainty of the evidence was tested using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation).

RESULTS

An electronic search of 975 articles resulted in 12 articles. These and four articles identified through manual search were eligible to be assessed for methodological quality and the risk of bias. Eleven articles presented moderate to high methodological quality. The included articles observed a reduced mandibular plane, a smaller maxilla and more differences with the increase in the severity of dental agenesis. Seven articles were included in the meta-analyses. Dental agenesis presented smaller SNA angle (P < 0.0001/CI -1.74 [-2.55, -0.92]) with moderate certainty of the evidence; and smaller ANB angle (P = 0.01/CI -0.80 [-1.44, -0.17]), with low certainty of the evidence.

CONCLUSIONS

This systematic review and meta-analysis demonstrated that dental agenesis may be associated with specific craniofacial morphology. Further studies are necessary due to the variation of the certainty of the evidence.

CONFLICT OF INTEREST

none declared.

REGISTRATION

PROSPERO (CRD42017055882).

Association of tooth agenesis with dental anomalies in young subjects

AIM

The aim of the current study is to correlate the presence of tooth agenesis with other dental anomalies in 7- to 15-year-old patients.

MATERIALS AND METHODS

After evaluating 4000 panoramic radiographs of young subjects, 430 revealed the presence of tooth agenesis, except for the third molar, and are retrospectively observed and compared with a non-agenesis control group of 500 subjects, in order to investigate the existence of other associated dental anomalies in both groups.

RESULTS

The prevalence of tooth agenesis was approximately 9.30% (430/4000); no significant gender differences were found. A significantly higher prevalence of microdontia of the maxillary lateral incisors (p < 0.001) and delayed tooth development (p = 0.0001) was observed in the agenesis group (group A), while delayed development of permanent teeth (p < 0.0001) and hypo-occlusion of the primary molars (p = 0.0130) were found in the control group (group B).

CONCLUSIONS

Agenesis patients presented a significantly higher prevalence of microdontia of the maxillary lateral incisors. Instead, non-agenesis patients presented a high prevalence of delayed permanent tooth development and hypo-occlusion of the primary molars. Moreover, further researches are needed to elucidate the role of genetics and environmental factors in the current sample group.

Fracture strength of lithium disilicate cantilever resin bonded fixed dental prosthesis

OBJECTIVES

Metal and Zirconia cantilever resin bonded fixed dental prosthesis (RBFDPs) are extensively used when missing anterior teeth. Lithium disilicate is not used a lot as it is not indicated by the manufacturers. The aim of this in vitro study was to investigate the fracture strength of lithium disilicate cantilever RBFDPs with different configurations and compare them to metal and zirconium RBFDPs.

METHODS

Sound extracted human canines (N = 60) were divided into six groups, to be restored with a cantilever RBFDP. Specimen were randomly divided over 6 groups (n = 10): Full crown of lithium disilicate (FCL); Veneer wing of lithium disilicate (VL); Connector of lithium disilicate (CL); Palatal wing of lithium disilicate (PL); Palatal wing of zirconia (PZ) and Palatal wing of metal ceramic (PM). All bridges were bonded with an adhesive system. After thermalcyclic ageing (20 × 10³x, 5-55 °C) all samples were loaded until fracture occurred. Failure types were classified and representative SEM done.

RESULTS

The mean fracture strength results per group were: 588N (FCL) 588N (PM), 550N (CL), 534N (PL), 465N (VL), 38N (PZ). A significant (p = 0.001) difference was found between the groups, all groups had a higher fracture strength than the zirconia RBFDPs. Failure type analysis showed some trends among the groups. Irrepairable fractures of the root were only seen in samples restored with lithium disilicate. Metal and zirconia RBFDPs predominantly failed on the adhesive interface, where 60% of the zirconia samples had pretest debondings.

SIGNIFICANCE

No differences in fracture strength were found between cantilever RBFDPs made from metal or lithium disilicate. Metal (0% pre-test failures) and zirconium (60% pretest failures) RBFDPs failed predominantly on the adhesive interface whereas the lithium disilicate (0% pre-test failures) samples showed fractures in the contact area. The least invasive connector (CL) and Metal (PM) RBFDP obtained a high fracture strength and optimal fracture pattern.

Assessment of oral health-related quality of life in adolescents, young adults, and adults with dental agenesis: A comparative study

AIM

To detect the impact on oral health-related quality of life (OHRQoL) in adolescents, young adults, and adults with dental agenesis (DA).

METHODS

A comparative study (1:2) matched for age and sex was designed. Data of participants, aged 14-55 years (group with DA: G1; group without DA: G2), and who answered the Brazilian version of the Oral Health Impact Profile-14 questionnaire, were collected. One-way analysis of variance and Student's t-test were applied, considering p <.05 to be significant.

RESULTS

The final sample consisted of 90 participants (G1 = 30; G2 = 60), with a mean age of 28.76 (±10.87) years. The mean scores in the G1 and G2 groups were 5.30 ± 5.35 and 2.45 ± 3.95, respectively. Comparing the means of both groups, in terms of the total score (p = .01), psychological discomfort (p = .04), psychological disability (p = .01), and social disability (p = .04) showed statistical differences. Evaluating G1, the age did not influence the negative impact on OHRQoL. The variables, years of study (≥9), DA severity, and location of DA in the anterior and posterior regions negatively influenced OHRQoL in different domains (p <.05).

CONCLUSION

Despite low OHRQoL, DA generated negative impact on OHRQoL in adolescents/young adults, and adults.

Tooth agenesis-related GLI2 and GLI3 genes may contribute to craniofacial skeletal morphology in humans

OBJECTIVE

The present cross-sectional, multi-centre, genetic study aimed to determine, whether single nucleotide polymorphisms (SNPs) in tooth agenesis (TA)-associated GLI2 and GLI3 genes contribute to the development of craniofacial skeletal morphology in humans.

DESIGN

Orthodontic patients from an ethnically heterogeneous population were selected for the present study (n = 594). The presence or absence of TA was determined by analysis of panoramic radiography and dental records. The subjects were classified according to their skeletal malocclusion and facial growth pattern by means of digital cephalometric analysis. Genomic DNA was extracted from squamous epithelial cells of the buccal mucosa and SNPs in GLI2 (rs3738880, rs2278741) and GLI3 (rs929387, rs846266) were analysed by polymerase chain reaction using TaqMan chemistry and end-point analysis.

RESULTS

Class II skeletal malocclusion presented a significantly lower frequency of TA (P < 0.05). Subjects without TA showed significantly higher ANB angles (P < 0.05). Genotype and/or allele distributions of the SNPs in GLI2 (rs3738880, rs2278741) and GLI3 (rs846266) were associated with the presence of TA (P < 0.05). The SNPs rs3738880, rs2278741 and rs929387 were also associated with some type of skeletal malocclusion (P < 0.05), but not with the facial growth pattern (P > 0.05). The G allele for TA-related GLI2 rs3738880 was strongly linked to the presence of Class III skeletal malocclusion (OR = 2.03; 95% CI = 1.37-3.03; P<3125 × 10^-6). GLI2 rs2278741 C allele was overrepresented in individuals without TA, suggesting it as a protective factor for this dental phenotype (OR = 0.43; 95% CI = 0.24-0.78; P<625 × 10^-5).

CONCLUSION

The present study suggests that SNPs in TA-associated GLI2 and GLI3 genes may also play a role in the development of skeletal malocclusions. rs3738880 and rs2278741 in GLI2 seems to contribute to the genetic background for skeletal Class III and TA, respectively. TA could be an additional predictor of craniofacial morphology in some cases. Further research replicating the reported associations should be performed.

Symmetry of dental agenesis in Down Syndrome children

Background/purpose

Down syndrome (DS) may affect the mouth, influencing its function, feeding and hence overall health status. We aim at investigating the frequency and type of dental agenesis in a school-age DS sample, evaluating gender, laterality, upper or lower side, and mono- or bi-laterality.

Materials and methods

Oral clinical and radiological exams were performed. Forty-six (20 female and 26 male) panoramic radiographs, done when DS patients were 8-12 years old, were examined, from patients between 3 and 25 years old at the first visit.

Results

The percentage of missing teeth was compared with chi-squared test: 65% of patients presented agenesis of one or more teeth. The most frequently missing teeth were the upper left lateral incisor, the lower second premolars and the upper right lateral incisor. Usually, the absence was bilateral. There was no difference between sexes, between mandible and maxilla, either in the left or in the right side.

Conclusion

A high occurrence of dental agenesis was observed in DS patients: some teeth were mostly affected and bilateral agenesis was frequent. Due to the high prevalence of teeth agenesis in DS patients, special care is devised for correct development of oral functions and for avoidance of oral pathologies.

Non-syndromic tooth agenesis patterns and their association with other dental anomalies: A retrospective study

OBJECTIVE

This study aimed to investigate the prevalence and the factors associated with non-syndromic tooth agenesis, besides identifying its pattern of occurrence.

STUDY DESIGN

Pre-orthodontic exams of 3400 subjects, aged 8-30 years, were selected from a radiographic center in Brazil. Panoramic and periapical radiographs were analyzed to verify the presence of tooth agenesis and other six dental anomalies. Descriptive statistics were calculated using the Tooth Agenesis Code tool and, to evaluate significant associations, a negative binomial regression model was constructed. Besides, unadjusted and adjusted prevalence ratios (PR) were calculated for the bivariate and the multivariate analysis.

RESULTS

Prevalence of tooth agenesis was 3.0% (n = 68) and 41 different phenotypic patterns were observed. Teeth most often symmetrically missing were maxillary lateral incisors (13.2%) and mandibular second premolars (8.8%). Females (PR = 3.49, CI 95% = 1.96-6.19) presented more tooth agenesis. Other dental anomalies, such as palatal displacement of maxillary canine and infraocclusion of primary molar were significantly more frequent (p < 0.001) in subjects with agenesis.

CONCLUSION

There was a strong relationship between tooth agenesis and gender and the association with other dental anomalies was significant, with the exception of the supernumerary teeth, which seems to be independent.

Agenesis of the upper lateral incisors: Study of an orthodontic population and clinical illustration

In his daily practice, the orthodontist is regularly asked to treat patients with one or more missing teeth. Considering their functional and esthetic specificities, and the relatively high frequency of agenesia, our interest was to focus on the permanent lateral upper incisors. Our study, based on an orthodontic population including 1000 patients, shows that about 7.8% of these patients present agenesis of at least one permanent tooth (out of which 3.6% are agenesis of the upper lateral incisor). Treatment options for these cases are multiple with several decisional factors to consider: the solutions often lead to compromises, and require a multidisciplinary coordination. Therefore, the purpose of this article, was to describe the prevalence of these agenesia based on a retrospective study, and to present two clinical cases: the first case is a bilateral agenesis of the maxillary lateral incisors treated with space opening in order to place two implant-supported restorations. The second case is an agenesis of tooth 12 treated with space reopening and the placement of a cantilever bridge. These clinical cases are presented to illustrate the multidisciplinary approach involving orthodontics, prosthodontics, and periodontology, in order to achieve the most esthetic and functional results possible.

Dental anomalies in different growth and skeletal malocclusion patterns

OBJECTIVES

To evaluate prevalence, distribution, and sexual dimorphism of dental anomalies (DA) among different skeletal malocclusions (SM) and growth patterns (GP) under the hypothesis that specific clinical patterns exist and may indicate common etiological roots.

MATERIALS AND METHODS

A total of 1047 orthodontic records of patients older than 8 years were evaluated. The SN-GoGn angle was used to classify GP (hypodivergent, normal, and hyperdivergent), and the ANB angle was used to verify SM (Angle Classes I, II, and III). These assessments were done from lateral cephalometric radiographs. DA were diagnosed using panoramic radiographs by one calibrated investigator. Odds ratios, chi-square, and Student's t-tests were used.

RESULTS

Of the subjects, 56.7% were female, with mean age of 16.41 (±10.61) years. The prevalence of DA was 15.7%. Impaction and tooth agenesis were the most prevalent DA, with relative frequencies of 14.4% and 9.7%, respectively. DA were most prevalent in Class III SM (80.8%) and in hypodivergent GP (82.5%), although this was not statistically significant. Tooth agenesis ( P < .01) and microdontia ( P = .025) were significantly more common among hypodivergent GP and Class III SM, respectively.

CONCLUSIONS

The results of this study support the idea that DA are preferentially associated with certain patterns of malocclusion.

Association between Tooth Agenesis and Skeletal Malocclusions

Objectives

The aim of this study was to evaluate the association between tooth agenesis and skeletal malocclusions in Brazilian non-syndromic orthodontic patients.

Material and Methods

Pretreatment orthodontic records of 348 patients of both genders and with various skeletal malocclusions were examined. Tooth agenesis was evaluated in panoramic radiographs. Angular measurements were taken from lateral cephalometric radiographs to classify the patient’s malocclusion as skeletal Class I, Class II and Class III. Subjects were divided into 2 groups, “with tooth agenesis” and “without tooth agenesis”. Chi-square or Fisher exact test was used to compare categorical data. ANOVA with Tukey’s post-test was used for means comparisons. An alpha of 5% was established.

Results

From 348 analysed patients, 28 presented tooth agenesis. There was no difference between genders (P = 0.27) nor mean age (P = 0.16). The most prevalent skeletal malocclusion was Class I (63.11%), followed by Class II (25.94%), and Class III (10.95%). The mean of congenitally missing teeth was 1.3 (SD 0.13). Thirteen subjects had premolar agenesis, 13 upper lateral incisor agenesis, 4 lower incisor agenesis and 2 molars agenesis. The group with tooth agenesis presented A point-nasion-B point (ANB) angle smaller (1.66 [SD 2.52]) than the group without tooth agenesis (2.86 [SD 2.49]) (P = 0.01). ANB angle had a negative correlation with the number of congenitally missing teeth (P = 0.039; r = -0.39).

Conclusions

Tooth agenesis is associated with a smaller A point-nasion-B point angle and is negatively correlated with the number of congenitally missing teeth.

Dental Anomalies in a Brazilian Cleft Population

Objective

The aim of this study was to radiographically investigate the prevalence of dental anomalies outside the cleft area in a group of Brazilian patients with nonsyndromic cleft lip and/or palate (NSCL/P).

Design, Participants, and Setting

A retrospective analysis of 207 panoramic radiographs of patients with NSCL/P aged 12 to 45 years without history of tooth extraction and orthodontic treatment was performed.

Results

Dental anomalies were found in 75.4% of the patients, and tooth agenesis (29.2%) and supernumerary tooth (2.6%) were the most common anomalies. The risk of agenesis was higher among the individuals with cleft palate (CP) compared with individuals with cleft lip (CL) and cleft lip and palate (CLP) (agenesis: CP versus CL: odds ratio 6.27, 95% confidence interval 2.21-17.8, P = .0003; CP versus CLP: odds ratio 2.94; 95% confidence interval 1.27-6.81, P = .01). The frequency of dental agenesis was higher in patients with unilateral complete CLP (agenesis: P < .0001), incomplete bilateral CLP (agenesis: P = .0013), complete CP (agenesis: P < .0001), and incomplete CP (agenesis: P < .0001). The frequency of supernumerary teeth was higher in patients with bilateral complete CLP ( P < .0001). The frequency of dental agenesis ( P < .0001) and ectopic tooth ( P = .009) was higher than the frequency estimated for general population.

Conclusions

The prevalence of dental anomalies in patients with NSCL/P was higher than that reported in overall population. This study found preferential associations between dental anomalies and specific extensions of NSCL/P, suggesting that dental agenesis and ectopic tooth may be part of oral cleft subphenotypes.

Tooth Size in Patients with Mild, Moderate and Severe Hypodontia and a Control Group

Objectives:

To compare tooth size between subjects with mild, moderate and severe hypodontia and a control group.

Material and Methods:

The study comprised 120 patients with hypodontia divided into three groups of 40 mild (≤2 teeth congenitally missing), 40 moderate (3-5 teeth congenitally missing) and 40 severe (≥6 teeth congenitally missing) hypodontia; and 40 age and sex matched controls. Tooth size was recorded by measuring the mesiodistal and buccolingual dimensions of all fully erupted teeth on study models using digital callipers and compared between all hypodontia and control groups using Two-way ANOVA and Post Hoc Tests of subgroup comparison.

Results:

Two-way ANOVA revealed patients with hypodontia had significantly smaller mesiodistal and buccolingual tooth dimensions compared with controls (p<0.05). Furthermore patients with more severe hypodontia demonstrated significantly smaller tooth dimensions than those in the mild and moderate hypodontia subgroups (p<0.05). The most affected tooth in terms of tooth size reduction was the maxillary lateral incisor and the least affected tooth was the mandibular first molar.

Conclusion:

Patients with hypodontia have smaller tooth dimensions than control. Tooth size appears to be affected by the degree of hypodontia, with severe hypodontia having a greater effect on tooth size reduction. The findings of this study may contribute to understanding the aetiology of hypodontia and aid the multidisciplinary management of this complex condition.

Systematic review and meta-analysis of congenitally missing permanent dentition: Sex dimorphism, occurrence patterns, associated factors and biasing factors

PURPOSE

We aimed to summarize/analyze, comprehensively and for the first time, the literature on the prevalence of congenitally missing teeth (CMT) in males and females and the CMT pattern, taking various associated and biasing factors into account.

METHODS

A search was performed independently by two authors during September 2012 till June 2013 to find all the available literature regarding CMT-associated factors and patterns comprising sex dimorphism, arches, anterior/posterior regions, unilateral/bilateral patterns, and involved teeth. The data were statistically analyzed.

RESULTS

Seventy-four studies were included. The mean CMT prevalence was 6.42±2.76% in males and 7.55±2.67% in females. Overall, CMT is more prevalent in females but only in epidemiological samples, and not in orthodontic or dental patients. Enrolling orthodontic/dental patients might increase the observed CMT in boys and/or reduce it in girls. Gender dimorphism was not affected by any of the factors: time, regions, or the biasing factors. There is not a significant predominance of maxillary or mandibular involvement, although the anterior segment is more likely to be affected.

CONCLUSIONS

CMT is more common in girls and in the anterior segment, regardless of the date of publication. Contrary to the commonly held belief regarding more CMT prevalence in female orthodontic patients, it was shown that in dental/orthodontic patients, CMT prevalence is higher in boys.

Prevalence of hypodontia and associated factors: a systematic review and meta-analysis

OBJECTIVES

To determine the prevalence and factors associated with hypotonia.

DESIGN

Systematic review and meta-analysis.

DATA SOURCE

A search strategy was developed along with inclusion criteria and run in MEDLINE and EMBASE (published from 2002 to August 2012) databases to reveal all studies on the prevalence of hypodontia or associated factors. A hand search of reference lists and a Google search aimed to improve the sensitivity of the literature search.

SELECTION CRITERIA

All studies on the prevalence of hypodontia or associated factors published from 2002 onwards were included. Abstracts of non-English papers were also analyzed.

DATA SELECTION AND EXTRACTION

All potential articles were checked against the inclusion criteria independently, and in duplicate by two investigators. A checklist was used to assess the quality of selected studies.

MAIN OUTCOME

Prevalence of hypodontia, excluding third molars.

RESULTS

The overall prevalence of hypodontia was found to be 6.4% (95% CI: 5.7, 7.2). There was a statistically significant difference in the prevalence of hypodontia by continent (Q = 34.18, P<0.001). Prevalence of hypodontia was the highest in Africa: 13.4% (95% CI: 9.7, 18.0), followed by Europe (7% CI: 6.0-8.0%), Asia (6.3% CI: 4.4, 9.1) and Australia (6.3% CI: 5.3, 7.4) with a lower prevalence in North America (5.0% CI: 4.1-5.9) and Latin America and Caribbean (4.4% CI: 3.2-6.1). Females were found to have a higher prevalence than males (combined OR 1.22; 95% CI: 1.14, 1.30). The most commonly affected teeth were mandibular second premolars followed by maxillary lateral incisors and maxillary second premolars. The prevalence of mild, moderate and severe hypodontia was found to be 81.6, 14.3 and 3.1% respectively.

CONCLUSIONS

There was a high variation in the prevalence of hypodontia between the studies. African populations were found to have a higher risk for tooth agenesis and there was an increased risk for females to have hypodontia than males.

The prevalence of dental anomalies in a turkish population

Purpose:

The aim of the present study was to investigate the prevalence of dental anomalies in a Turkish population according to the gender and age.

Materials and Methods:

A retrospective study was performed using panoramic radiographs of 2025 patients (885 males and 1140 females) ranging in age from 9 to 35 (mean age 25.61±10.04) years attending Department of Oral Radiology, University of Istanbul, Faculty of Dentistry. These patients were examined to determine the presence of developmental dental anomalies involving hypodontia, hyperdontia, microdontia, taurodontism and other root anomalies. The incidence of these anomalies were assessed according to the gender and age.

Results:

Among the 2025 subjects, a total of 96 individuals (42 males and 54 females) showed at least one of the selected dental anomalies (4.74%). Tooth agenesis was the most common dental abnormality (1.77%) followed by taurodontism (1.18%), hyperdontia (0.79%), microdontia (0.54%) and root anomalies (0.44%), respectively.

Conclusion:

Tooth agenesis is the most common developmental dental anomaly in the studied Turkish population followed by taurodontism.

Genetic variations in MMP9 and MMP13 contribute to tooth agenesis in a Brazilian population

We investigated the association between polymorphisms in the MMP2 (rs243865), MMP9 (rs17576), and MMP13 (rs2252070) genes with tooth agenesis in humans. Two hundred eighty-five unrelated individuals (202 controls without tooth agenesis and 83 cases with tooth agenesis) were evaluated in a cross-sectional single-center study. The study participants were recruited through the Pediatric Dental Clinics of the Federal University of Rio de Janeiro, Brazil. Genotyping of the selected polymorphisms for MMPs was carried out by real-time PCR using the Taqman assay method from genomic DNA isolated from buccal epithelial cells of all the studied individuals. There was no significant association of MMP2 genotype or allele distribution with tooth agenesis or its absence. For MMP9, a significant difference in allele frequency was evident between the two groups (P = 0.05). With regard to the affected side, there was a significant difference between unilateral tooth agenesis and the control group in the distribution of MMP9 (P = 0.05). Also, there was a significant difference in MMP9 distribution between tooth agenesis in the maxilla and control individuals (P = 0.03). The genotype distribution of MMP13 differed significantly between the group with unilateral tooth agenesis and the controls (P = 0.01). Our findings provide evidence that MMP9 and MMP13 may be involved in tooth agenesis.

Meta-analysis of congenitally missing teeth in the permanent dentition: Prevalence, variations across ethnicities, regions and time

BACKGROUND

Congenitally missing teeth (CMT) are of concern to many fields of dentistry. Only a few reviews have been published in this regard.

AIM

The aim was to analyze the literature on CMT in the permanent dentition, excluding the third molars, and to identify potential links with ethnicity, geographical regions, and time.

METHODS

A total of 118 reports on CMT were collected by two authors by interrogating databases. Sample homogeneity, publication bias, publication year (in Caucasian and Mongoloid samples, and in general), ethnicities, and geography of CMT prevalence were statistically analyzed using a Q-test, Egger regression, linear regression, a Spearman coefficient, Kruskal-Wallis, a Dunn post-hoc (α = 0.05), and a Mann-Whitney U test (α = 0.0125, α = 0.0071).

RESULTS

The mean CMT prevalence was 6.53% ± 3.33%. There were significant geographic differences in CMT rates (P = 0.0001, Kruskal-Wallis) and between ethnicities (P = 0.0002, Kruskal-Wallis). According to the Mann-Whitney U test (α = 0.0071), eastern Asians (P = 0.0008) and Europeans (marginally significant, P = 0.0128) showed an elevated prevalence, while Western Asians (P = 0.0001) and Americans (marginally significant, P = 0.0292) had lower prevalence rates. Compared with other ethnicities, Mongoloids showed higher prevalence (P = 0.0009) while Asian Caucasians showed lower rates (P = 0.0005, Mann-Whitney U, α = 0.0125). The year of publication was not significantly correlated with any of the subsamples studied (P > 0.3, linear regression).

CONCLUSIONS

Clinicians should be vigilant in the assessment of CMT in Mongoloids. No increase of this condition was detected during the last century.

Meta-analysis and systematic review of the number of non-syndromic congenitally missing permanent teeth per affected individual and its influencing factors

BACKGROUND AND PURPOSE

Dental aplasia (or hypodontia) is a frequent and challenging anomaly and thus of interest to many dental fields. Although the number of missing teeth (NMT) in each person is a major clinical determinant of treatment need, there is no meta-analysis on this subject. Therefore, we aimed to investigate the relevant literature, including epidemiological studies and research on dental/orthodontic patients.

METHODS

Among 50 reports, the effects of ethnicities, regions, sample sizes/types, subjects' minimum ages, journals' scientific credit, publication year, and gender composition of samples on the number of missing permanent teeth (except the third molars) per person were statistically analysed (α = 0.05, 0.025, 0.01).

LIMITATIONS

The inclusion of small studies and second-hand information might reduce the reliability. Nevertheless, these strategies increased the meta-sample size and favoured the generalisability. Moreover, data weighting was carried out to account for the effect of study sizes/precisions.

RESULTS

The NMT per affected person was 1.675 [95% confidence interval (CI) = 1.621-1.728], 1.987 (95% CI = 1.949-2.024), and 1.893 (95% CI = 1.864-1.923), in randomly selected subjects, dental/orthodontic patients, and both groups combined, respectively. The effects of ethnicities (P > 0.9), continents (P > 0.3), and time (adjusting for the population type, P = 0.7) were not significant. Dental/orthodontic patients exhibited a significantly greater NMT compared to randomly selected subjects (P < 0.012). Larger samples (P = 0.000) and enrolling younger individuals (P = 0.000) might inflate the observed NMT per person.

CONCLUSIONS

Time, ethnic backgrounds, and continents seem unlikely influencing factors. Subjects younger than 13 years should be excluded. Larger samples should be investigated by more observers.

Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment

Congenitally missing teeth (CMT), or as usually called hypodontia, is a highly prevalent and costly dental anomaly. Besides an unfavorable appearance, patients with missing teeth may suffer from malocclusion, periodontal damage, insufficient alveolar bone growth, reduced chewing ability, inarticulate pronunciation and other problems. Treatment might be usually expensive and multidisciplinary. This highly frequent and yet expensive anomaly is of interest to numerous clinical, basic science and public health fields such as orthodontics, pediatric dentistry, prosthodontics, periodontics, maxillofacial surgery, anatomy, anthropology and even the insurance industry. This essay reviews the findings on the etiology, prevalence, risk factors, occurrence patterns, skeletal changes and treatments of congenitally missing teeth. It seems that CMT usually appears in females and in the permanent dentition. It is not conclusive whether it tends to occur more in the maxilla or mandible and also in the anterior versus posterior segments. It can accompany various complications and should be attended by expert teams as soon as possible.

Assessing the association of taurodontism with numeric dentition anomalies in an adult central Indian population

AIM

To study the association between taurodontism and numeric anomalies in adult population.

MATERIALS AND METHODS

Out of 1,012; 946 panoramic radiographs and dental records were retrospectively assessed to determine the presence of dental agenesis and supernumerary and taurodont teeth.

RESULTS

Taurodontism of one or more teeth was observed in 164 cases (97 females and 67 males). Hypodontia was observed in 148 patients (84 females and 64 males) with 62 patients having associated taurodontism (38 females, 24 males), oligodontia in 12 patients (five females and seven males) of whom nine patients also had taurodontism of one or more teeth (five females and four males). Forty-five patients (32 females and 13 males) presented with 57 supernumerary teeth (ST) with 12 patients having simultaneous presence of taurodontic tooth (seven females and five males).

CONCLUSION

Our study suggests a preferential association between tooth agenesis and taurodontism; however, such association was not observed in individuals with hyperdontia. Understanding the nature of this preferential association may be of importance in determining the etiology of both conditions. This association may also define a subphenotype for future genetic studies on dental development. Further molecular studies are necessary to verify the etiology and mechanism of taurodontism associated with tooth agenesis.

Meta-analysis and systematic review of factors biasing the observed prevalence of congenitally missing teeth in permanent dentition excluding third molars

No meta-analyses or systematic reviews have been conducted to evaluate numerous potential biasing factors contributing to the controversial results on congenitally missing teeth (CMT). We aimed to perform a rather comprehensive meta-analysis and systematic review on this subject. A thorough search was performed during September 2012 until April 2013 to find the available literature regarding CMT prevalence. Besides qualitatively discussing the literature, the meta-sample homogeneity, publication bias, and the effects of sample type, sample size, minimum and maximum ages of included subjects, gender imbalances, and scientific credit of the publishing journals on the reported CMT prevalence were statistically analyzed using Q-test, Egger regression, Spearman coefficient, Kruskal-Wallis, Welch t test (α=0.05), and Mann-Whitney U test (α=0.016, α=0.007). A total of 111 reports were collected. Metadata were heterogeneous (P=0.000). There was not a significant publication bias (Egger Regression P=0.073). Prevalence rates differed in different types of populations (Kruskal-Wallis P=0.001). Studies on orthodontic patients might report slightly (about 1%) higher prevalence (P=0.009, corrected α=0.016). Non-orthodontic dental patients showed a significant 2% decline [P=0.007 (Mann-Whitney U)]. Enrolling more males in researches might significantly reduce the observed prevalence (Spearman ρ=-0.407, P=0.001). Studies with higher minimums of subjects' age showed always slightly less CMT prevalence. This reached about -1.6% around the ages 10 to 13 and was significant for ages 10 to 12 (Welch t test P<0.05). There seems to be no limit over the maximum age (Welch t test P>0.2). Studies' sample sizes were correlated negatively with CMT prevalence (ρ=-0.250, P=0.009). It was not verified whether higher CMT rates have better chances of being published (ρ=0.132, P=0.177). CMT definition should be unified. Samples should be sex-balanced. Enrolling both orthodontic and dental patients in similar proportions might be preferable over sampling from each of those groups. Sampling from children over 12 years seems advantageous. Two or more observers should examine larger samples to reduce the false negative error tied with such samples.

Prevalence of Dental Anomalies in Patients with Nonsyndromic Cleft Lip and/or Palate in a Brazilian Population

Objective

Many studies have demonstrated a high frequency of dental anomalies in patients with cleft lip and/or palate. Because dental anomalies may complicate dental treatment, we investigated the prevalence of dental anomalies in a group of Brazilian patients with nonsyndromic cleft lip and/or palate.

Design, Participants, Setting

Retrospective analysis was performed using clinical records of 296 patients aged between 12 and 30 years with repaired nonsyndromic cleft lip and/or palate without history of tooth extraction and orthodontic treatment. Associations between oral clefts and presence of dental anomalies outside the cleft area were investigated.

Results

Dental anomalies were identified in 39.9% of the nonsyndromic cleft lip and/or palate patients, and tooth agenesis (47.5%), impacted tooth (13.1%), and microdontia (12.7%) were the most common anomalies. Cleft lip patients were less affected by dental anomalies compared with cleft palate or cleft lip and palate patients ( p = .057). Specifically, patients with unilateral cleft lip and palate were significantly more affected by dental anomalies than those with bilateral cleft lip and palate ( p = .00002), and individuals with unilateral complete cleft lip and palate ( p = .002) and complete cleft palate ( p = .01) were significantly more affected by tooth agenesis than other cleft types. Agenesis of the premolars ( p = .043) and maxillary lateral incisors ( p = .03) were significantly more frequent in patients with unilateral complete cleft lip and palate.

Conclusions

The present study revealed a high frequency of dental anomalies in nonsyndromic cleft lip and/or palate patients and further demonstrated that patients with unilateral cleft lip and palate were frequently more affected by dental anomalies than those with bilateral cleft lip and palate. Moreover, our results demonstrate that dental anomalies should be considered during dental treatment planning for individuals affected by nonsyndromic cleft lip and/or palate.

Gender differences in the growing, abnormal, and aging jaw

Despite wide variations in the size and shape of the human face, head, and body, there is remarkable consistency for quantifiable gender-specific facial traits. The relationships between the growing jaws and tooth eruption are complex, but they show gender-specific trajectories in children and adolescents. Disturbances in genetic, endocrine, and nutritional regulatory controls result in gender-specific and nonspecific disorders. Gender-specific differences are also apparent in the aging jaw, with the acceleration of jawbone atrophy upon loss of teeth, especially in women.

Dental anomalies in a Portuguese population

OBJECTIVE

The aim of this study was to evaluate the prevalence and pattern of agenesis, supernumerary teeth, impacted teeth and transpositions, as well as the relation between them, in a Portuguese sample.

MATERIAL AND METHODS

The study sample consisted of 2888 patients, observed between 2005 and 2009 at the Dentistry Clinic of the Instituto Superior de Ciências da Saúde-Norte (ISCSN, Portugal). The study included evaluation of the following parameters: agenesis of all teeth, supernumerary teeth, impacted permanent teeth and tooth transposition. The age range varied from 7 to 21 years. In order to study the absence of the third molar, subjects aged below 14 years were excluded. Statistical analysis was performed using SPSS(®).

RESULTS

Excluding third molars, the prevalence of tooth agenesis, supernumerary teeth, impacted teeth and transpositions was 6.1%, 0.8%, 1.8% and 0.2%, respectively, for this Portuguese population. There was a significantly higher prevalence of supernumerary teeth in males than in females (P < 0.05). The mesiodens was the most frequent supernumerary tooth, the upper canine was the most frequent impacted tooth, and the upper canine and upper lateral were the two most frequently transposed teeth. There was a significantly higher prevalence of missing third molars in the impacted canine group than in the non-impacted canine group (P < 0.05).

CONCLUSIONS

Agenesis is the most frequent dental anomaly. There are no differences between genders, except for supernumerary teeth, which are found more frequently in men. A relation between third molar agenesis and impacted canines was found.

Dental findings and oral health status in patients with mucopolysaccharidosis: a case series

OBJECTIVE

To present a mucopolysaccharidosis (MPS) case series evaluating oral manifestations (clinical and radiographic), oral health status and discussing its implications.

PATIENTS AND METHODS

All patients with MPS attending the Genetics clinic/Brazil were evaluated by means of anamnesis, clinical and radiographic examinations.

RESULTS

The final sample consisted of 12 subjects (nine males and three females), with ages ranging from 3-31 years old. Concerning oral health, it was observed high levels of caries and periodontal problems. About oral manifestations, this study clinically observed more cases of delayed tooth eruption, thickness of alveolar process and thick lips. Radiographically, it was observed alterations on condyle, mandibular ramus and joint fossa.

CONCLUSION

The dental changes in MPS population are high and consequently it is important to know them for differential diagnoses, early treatment intervention, prevention and education of both patients and parents/caregivers about oral health.

Tooth Agenesis Association with Self-reported Family History of Cancer

It has been proposed that tooth agenesis and cancer development share common molecular pathways. We performed a cross-sectional study to investigate the epidemiological and molecular association between tooth agenesis and self-reported family history of cancer. Eighty-two individuals with tooth agenesis and 328 individuals with no birth defect were recruited from the same institution. Tooth agenesis was assessed in permanent teeth and was defined based on the age of the participants and when initial tooth formation should be radiographically visible. We also investigated the role of genes involved in dental development that have been implicated in tumorigenesis, and 14 markers in AXIN2, FGF3, FGF10, and FGFR2 were genotyped. Individuals with tooth agenesis had an increased risk of having a family history of cancer ( p = 0.00006; OR = 2.7; 95% C.I., 1.6-4.4). There were associations between AXIN2, FGF3, FGF10, and FGFR2 with tooth agenesis [ i.e., individuals who carried the polymorphic allele of FGFR2 (rs1219648) presented higher risk for having premolar agenesis ( p = 0.02; OR = 1.8; 95% C.I., 1.1-3.0)]. In conclusion, tooth agenesis was associated with positive self-reported family history of cancer and with variants in AXIN2, FGF3, FGF10, and FGFR2. Prospective studies are needed to confirm if tooth agenesis can be used as a risk marker for cancer.