A cephalometric study to investigate the skeletal relationships in patients with increasing severity of hypodontia

Tooth agenesis: An overview of diagnosis, aetiology and management

Patients with one or more developmentally absent teeth are routinely encountered in dental practice. Tooth agenesis can be associated with significant functional, aesthetic and psycho-social problems. The present article provides an overview of the prevalence and aetiology of tooth agenesis, as well as the condition's clinical characteristics and management options with reference to the evidence base. A timely diagnosis can facilitate the appropriate planning and management which might not be straightforward, and patient care will likely require multi- and inter-disciplinary input. It is critical that dental care practitioners are aware of the clinical characteristics and management options for tooth agenesis.

Comparison of craniofacial morphology in individuals with and without hypodontia with a special focus on the number of congenitally missing teeth

Background

Hypodontia might negatively affect dental function and esthetics, what might affect patients' self-esteem, communication behavior, professional performance and thus quality of life. The aim of this study was to estimate the influence of number of congenital missing teeth on dentofacial features.

Methods

Lateral cephalograms of 60 individuals with hypodontia (study group) and 40 individuals without hypodontia (control group) were analyzed. Patients in the study group were divided into two subgroups according to the number of missing teeth (group A with hypodontia 1 to 4 teeth and group B with hypodontia 5 or more teeth). Cephalometric data were compared among the study and control groups and statistically analyzed.

Results

The results in the present study revealed a significantly shorter and more retrognathic maxilla, more prognathic chin position, more retruded incisors in both jaws, large interincisal angle, straighter facial convexity as well as more retruded upper and lower lips in the group B compared with the control group. In the group A only chin position was significantly more prognathic compared with the control group.

Conclusions

According to the results of present study impact of hypodontia on the craniofacial morphology and consequently on facial esthetics was found statistically significantly greater in patients with 5 or more congenitally missing teeth.

Number of Teeth Is Related to Craniofacial Morphology in Humans

Simple Summary

In modern humans, congenital absence of one or more permanent teeth has a prevalence of 22.6% when considering the third molars and of 6.4% when not. Its high prevalence, in conjunction with evolutionary findings pinpointing to a steady reduction in teeth number, raises the question whether the congenital absence of teeth in modern humans is an evolutionary trend rather than an anomaly. Previous studies have shown that modern humans with less teeth also have smaller faces; however, the association between teeth number and craniofacial morphology remains unclear. Here, we show that less teeth are associated with a flatter profile and a decreased facial height. These findings support the claim of a broader relationship between number of teeth and overall craniofacial development and have evolutionary implications, since face reduction comprises also an evolutionary trend in humans.

Abstract

One of the most common dental anomalies in humans is the congenital absence of teeth, referred to as tooth agenesis. The association of tooth agenesis to craniofacial morphology has been previously investigated but remains unclear. We investigated this association by applying geometric morphometric methods in a large sample of modern humans. In line with previous studies, we report here that a reduced teeth number is linked to a less convex profile, as well as to a shorter face. The effects were similar for males and females; they increased as the severity of the tooth agenesis increased and remained unaltered by the inclusion of third molars and of allometry in the analysis. Furthermore, in cases with tooth agenesis only in the maxilla, there was no detectable effect in mandibular shape, whereas maxillary shape was affected independently of the location of missing teeth. The robustness of the present sample along with the shape analysis and the statistical approach applied, allowed for thorough testing of various contributing factors regarding the presence but also the magnitude of effects. The present findings suggest a relationship between number of teeth and overall craniofacial development and have evolutionary implications.

Relationship between craniofacial morphology and congenitally missing mandibular incisors

Background/purpose

Treatment of incisors‘ agenesis is challenging that arouses orthodontists’ interests. The purpose of this study was to compare the craniofacial pattern of individuals with or without congenitally missing mandibular incisors.

Materials and methods

This retrospective study included patients receiving orthodontic consultation between 1999 and 2019 at the Orthodontic Division of the Dental Department of Taipei Medical University Hospital. Cephalometric measurements were obtained through manual tracing and by using computer software. A total of 31 measurements were obtained to evaluate skeletal, dental and soft tissues, and chin morphology. A multivariate analysis of covariance, analysis of covariance, and Scheffé’s post hoc tests were used to analyze the differences among a group of patients with one congenitally missing mandibular incisor (M1), a group of patients with two congenitally missing mandibular incisors (M2), and the control group. Student's t-test was used to analyze the differences between the M1 or M2 group and the control group. Significance was set at P < 0.05.

Results

Significant differences were observed between the M and control groups in terms of lower incisor angulation and facial balance. Regarding chin morphology, significant differences were noted between the M and control groups and also among the M1, M2, and control groups.

Conclusion

The lower incisors of the M group are more retroclined than those of the control group, resulting in retrusive lower lips. Facial balance varies between the M and control groups. Congenitally missing mandibular incisors affect chin morphology, making the chin button prominent.

Evaluation of the effects of hypodontia on the morphology of craniofacial structures

OBJECTIVE

The study aimed to investigate the effects of hypodontia on the sagittal and vertical dimensions of the jaws, dentition and the related soft tissue.

MATERIALS AND METHODS

The hypodontia group included 111 patients whose growth was completed with one or more congenitally missing teeth (CMT). Sixty additional patients with skeletal and dental class I relationship, without CMT, and who completed growth, were included as the control group. The hypodontia group was divided into three subgroups according to the intermaxillary (maxillary or mandibular) location, intramaxillary (anterior or posterior) location and the severity of hypodontia (mild: 1-2 CMT or moderate: 3-6 CMT). Twenty-three measurements were performed on lateral cephalograms of the patients. The one-way and Kruskal-Wallis Analysis of Variance tests were used for the statistical analysis. The false discovery-rate analysis was applied for the multiple comparison adjustment.

RESULTS

No significant difference was found in the skeletal measurements between all hypodontia subgroups and the control (P > .05). Upper incisors were found to be retroclined in the anterior hypodontia group. The upper lip was found to be protruded in the mandibulary hypodontia group compared to the control (P < .05).

CONCLUSION

The mild-to-moderate hypodontia did not produce a significant skeletal effect. However, hypodontia can affect the incisors, especially when CMT is in the anterior region. Besides, the effects of severe hypodontia could not be evaluated due to the insufficient number of oligodontia patients.

Effect of Tooth Agenesis on Mandibular Morphology and Position

Congenital missing teeth (OMIM #106600) is the most common dental abnormality. The aim of the study was to evaluate the effects of tooth agenesis on the total mandibular length, length of the mandibular body and alveolar process, and the mandibular anteroposterior position. The material was obtained from the Department of Orthodontics, Medical University of Warsaw. The study group included 116 patients aged 9–18 years with a congenital absence of at least two permanent tooth buds in the maxilla and/or mandible (mean: 6.2 teeth missing/patient). All patients were Caucasians: 68 (59%) females and 48 (41%) males. The control group included 115 patients without tooth agenesis matched with the age and gender of the study group. A cephalometric analysis was performed, and it was focused on assessing anteroposterior mandibular measurements. This assessment was based on 17 measurements (12 linear and 5 angular). Statistical analysis of the cephalometric measurements between the study group and the control group showed significant changes regarding selected mandibular measurements. Tooth agenesis does not affect the total length of the mandible and the length of the mandibular body, but it might reduce the length of the mandibular arch length and result in a more retrusive mandibular position.

Missing and unerupted teeth in osteogenesis imperfecta

INTRODUCTION

Osteogenesis imperfecta (OI) is a genetic disorder characterized by bone fragility and craniofacial and dental abnormalities such as congenitally missing teeth and teeth that failed to erupt which are believed to be doubled in OI patients than normal populations and were associated with low oral health quality of life. However, the etiology of these abnormalities remains unclear. To understand the factors influencing missing and unerupted teeth, we investigated their prevalence in a cohort of OI patients as a function of the clinical phenotype (OI type), the genetic variant type, the tooth type and the onset of bisphosphonate treatment.

METHOD

A total of 144 OI patients were recruited from The Shriners Hospital, Montreal, Canada, between 2016 and 2017. Patients were evaluated using intraoral photographs and panoramic radiographs. Missing teeth were evaluated in all patients, and unerupted teeth were assessed only in patients ≥15 years old (n = 82).

RESULTS

On average, each OI patient had 2.4 missing teeth and 0.8 unerupted teeth, and the most common missing and unerupted teeth were the premolars and the upper second molars, respectively. These phenomena were more prominent in OI type III and IV than in OI type I, and were not sex or age-related. Missing teeth were significantly more common in patients with C-propeptide variants than all other variants (p-value <0.05). Unerupted teeth were significantly more common in patients with α1 and α2 glycine variants or substitutions than in those with haploinsufficiency variants. Early-onset of bisphosphonate treatment would significantly increase the risk of unerupted teeth in patients with OI types III and IV (OR = 1.68, 95% CI (1.15-1.53)).

CONCLUSION

The prevalence of missing and unerupted teeth at the tooth type level in OI patients varies according to the nature of the collagen variants and the OI type. These findings highlight the role of collagen in tooth development and eruption.

The Relationship Between Dental Agenesis and Maxillary Hypoplasia in Patients With Cleft Lip and Palate

ABSTRACT

Both dental agenesis and maxillary growth restriction are well-recognized sequelae in patients with unilateral cleft lip and palate, but their etiology remains controversial. The aim of this study was to evaluate the relationship between hypodontia and maxillary volume. A retrospective review of patients age 6 to 9 with Veau III (unilateral) cleft palate who underwent Cone Beam Computer Tomography in preparation for alveolar bone grafting at 2 major Children's Hospitals between 2010 and 2016 was conducted and serial panoramic radiographs were reviewed. Thirty-eight patients were identified that met inclusion criteria and had adequate imaging. Group 1 ("poor growers") consisted of the bottom 50% of Sella-Nasion-A point minus Sella-Nasion-B point (ANB) angles and Group 2 ("good growers") consisted of the top 50% of ANB angles. Group 1 had a significantly higher mean number of missing teeth (1.58 ± 0.28 missing teeth) compared to Group 2 (0.74 ± 0.23 missing teeth), and significantly lower maxillary volume (12.88 ± 0.61 cm3 versus 15.24 ± 0.88 cm3, respectively). The severity of maxillary hypoplasia in cleft patients increases with increased dental agenesis. These data indicate that intrinsic factors play a significant role in maxillary growth restriction in cleft patients, independent of the sequelae of surgical intervention.

Development of dentofacial characteristics related to Incontinentia Pigmenti syndrome: A repeated cross-sectional study

INTRODUCTION

This research aimed to investigate the dentofacial characteristics of patients with Incontinentia Pigmenti (IP) (or Bloch-Sulzberger) syndrome in childhood, juvenile, and adulthood developmental stages.

METHODS

Fifteen female patients with a clinical diagnosis of IP, genetically confirmed by molecular testing, were included in this study. The records of 25 nonsyndromic females with Class I occlusion and lateral cephalograms obtained at similar developmental stages were selected from the American Association of Orthodontists Foundation Legacy Collection as a control group. Dentofacial features of subjects with IP and those in the control group were compared statistically using t test and Mann-Whitney rank-sum test (significance was defined as P <0.05).

RESULTS

In general, patients with IP had shorter maxillary and mandibular length, straight skeletal profile, hypodivergent growth pattern with a tendency to mandibular protrusion, shorter anterior facial height, Class III compensatory positioning of incisors, more retruded lips, and smaller maxillary incisor exposure. The degree of hypodontia severity had a significant impact on skeletal, dental, and soft-tissue features in patients with IP.

CONCLUSIONS

The results of this study showed that, since childhood, the dentofacial characteristics of patients with IP were progressively distancing from those of nonsyndromic patients with Class I occlusion, presenting their own orthodontic needs.

Scandcleft randomized trials of primary surgery for unilateral cleft lip and palate: impact of maxillary dental agenesis on craniofacial growth and dental arch relationship in 8 year olds

BACKGROUND

It is suggested that dental agenesis affects maxillary protrusion and dental arch relationship in children with unilateral cleft lip and palate (UCLP). In addition, an association between the need for orthognathic surgery and dental agenesis is reported.

AIM

The aim was to study the impact of maxillary dental agenesis on craniofacial growth and dental arch relationship in 8-year-old children with UCLP.

SUBJECTS AND METHODS

The sample consisted of individuals with UCLP from Scandcleft randomized trials. The participants had available data from diagnosis of maxillary dental agenesis as well as cephalometric measurements (n = 399) and GOSLON assessment (n = 408) at 8 years of age.

RESULTS

A statistically significant difference was found for ANB between individuals with agenesis of two or more maxillary teeth (mean 1.52°) in comparison with those with no or only one missing maxillary tooth (mean 3.30° and 2.70°, respectively). Mean NSL/NL was lower among individuals with agenesis of two or more maxillary teeth (mean 9.90°), in comparison with individuals with no or one missing maxillary tooth (mean 11.46° and 11.45°, respectively). The number of individuals with GOSLON score 4-5 was 47.2% in the group with two or more missing maxillary teeth and 26.1% respectively 26.3% in the groups with no or one missing maxillary tooth. No statistically significant difference was found in the comparison between individuals with no agenesis or with agenesis solely of the cleft-side lateral.

CONCLUSION

Maxillary dental agenesis impacts on craniofacial growth as well as dental arch relationship and should be considered in orthodontic treatment planning.

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).

The influence of mild versus severe hypodontia on facial soft tissues? A three-dimensional optical laser scanning-based cohort study

OBJECTIVE

To determine whether there are differences in the facial soft tissue morphology between participants with mild (up to two) or severe (six or more) hypodontia.

DESIGN AND SETTING

A prospective hospital-based cohort study.

PARTICIPANTS AND METHODS

Ninety-two participants, aged 11-16 years, with confirmed hypodontia were recruited. Participants were sub-grouped based on the severity (mild, two or less and severe, six or more) and distribution of the missing teeth and age. They underwent a three-dimensional (3D) optical surface scan of the facial soft tissues. Facial surface scans were compared quantitatively, applying landmark measurements and surface-based analysis.

RESULTS

In total, 92 participants, with an equal distribution between the mild (n=46) and severe (n=46) categories, were recruited. Patients with severe hypodontia displayed a reduced alar base, lower facial height, nasolabial angle (P = 0.02) and transgonial width (P < 0.001) compared to those with milder hypodontia. Furthermore, significant differences were observed between mild-male and severe-female groups regarding alar base, lower anterior face height and transgonial width and between mild-male and mild-female groups regarding nasolabial angle and transgonial width.

CONCLUSION

Significant reductions were seen in the 3D soft tissue morphology of participants with severe hypodontia, in terms of the nasolabial angle, lower facial height, alar base and transgonial widths, emphasising the importance of using facial scanning as a relatively simple non-invasive method of assessment.

Prevalence and Pattern of Hypodontia among Croatian Orthodontic Patients

Objective

The objective of this retrospective study was to assess the prevalence of hypodontia in the permanent dentition among Croatian orthodontic patients. The occurrence was evaluated concerning gender, specific missing teeth, the location, pattern of distribution in the maxillary and mandibular arches and sagittal and vertical skeletal pattern.

Material and Methods

The sample consisted of 194 patients (75 males and 119 females) from the Department of Orthodontics, Dental Clinic, Clinical Hospital Center Zagreb. Based on the severity of hypodontia the sample was divided into mild (1-2 missing teeth), moderate (3-5 missing teeth) and severe groups (6 or more missing teeth). The location of missing teeth was used to further divide the sample into anterior (intercanine region), posterior (premolars and molars) and anteroposterior groups. In addition, jaw localization of hypodontia was also considered.

Results

Permanent dentition hypodontia among Croatian orthodontic patients was found to be generally mild (80%), and a distribution was similar in the maxilla (39%) and the mandible (41%), as well as in the anterior and posterior segments of dental arch (44%). The number of missing teeth per person ranged from 1 to 12, with no significant difference between genders. The severity and location of hypodontia did not differ significantly between the genders, as well as in between the categories of sagittal and vertical skeletal patterns.

Conclusion

Present results suggest that the treatment plan for patients with hypodontia in permanent dentition should be individualized and adjusted for each case.

[Obstructive sleep disordered breathing and orthodontics: primum non nocere]

Obstructive sleep apnoea syndrome is a widespread and under-diagnosed condition, making it a major public health and safety issue. The objective of this article was to clarify some of the evidence-based elements of therapeutic decision-making and the information provided to the patient and family on the benefit-cost-security ratio of several of his therapeutic options. Published data on the effectiveness of oral appliances and functional orthopaedic appliances for obstructive sleep apnea (OSA) in children, the durability of their effects, the therapeutic possibilities of maxillary or bimaxillary expansion, and the interrelationships between permanent teeth extractions and obstructive sleep disordered breathing, were researched and analyzed. Based on available evidence, in growing patients with Class II malocclusion, treatment with functional orthopedic devices can increase the volume of the pharyngeal airway and thus hopefully reduce the risk of developing OSA. An improvement in the apnea-hypopnea index and lower oxygen saturation was observed in children treated with rapid maxillary expansion. Permanent teeth extractions prescribed for the treatment of teeth crowding in an orthodontic age patient do not result in any significant change in the upper airway. The role of the orthodontist in the multidisciplinary team in the screening and management of Obstructive Sleep Disordered Breathing (OSDB) is essential. By combining clinical experience with published data on various therapeutic approaches, the orthodontist helps the patient to benefit from better adapted care and a more sustainable outcome, while taking into account his or her preferences.

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.

Craniofacial shape differs in patients with tooth agenesis: geometric morphometric analysis

Aim

To evaluate the shape of the craniofacial complex in patients with tooth agenesis and compare it to matched controls.

Subjects and methods

The sample comprised 456 patients that were allocated to three groups: the agenesis group of 100 patients with at least one missing tooth, excluding third molars, the third molar agenesis group (3dMAG; one to four missing third molars) of 52 patients and the control group (CG) of 304 patients with no missing teeth. The main craniofacial structures depicted on lateral cephalograms were digitized and traced with 15 curves and 127 landmarks. These landmarks were subjected to Procrustes superimposition and principal component analysis in order to describe shape variability of the cranial base, maxilla and mandible, as well as of the whole craniofacial complex. For statistical analysis, permutation tests were used (10 000 permutations without replacement).

Results

Approximately half of the sample's variability was described by the first three principal components. Comparisons within the whole sample revealed sexual dimorphism of the craniofacial complex and its structures (P < 0.01). Differences between the agenesis group and matched controls were found in the shape of all craniofacial structures except for the cranial base (P < 0.05). Specifically, patients with agenesis presented with Class III tendency and hypodivergent skeletal pattern. However, the comparison between the 3dMAG and matched CG revealed no differences.

Conclusion

The shape of the craniofacial complex differs in patients with tooth agenesis suggesting that common factors are implicated in tooth development and craniofacial morphology.

Patterns of congenitally missing teeth of non-syndromic and syndromic patients treated at a single-center over the past thirty years

OBJECTIVES

Literature regarding congenitally-missing-teeth (CMT) is lacking especially on CMT-patterns. Thus, the aim of this study was to present an in-depth analysis of 843 patients with CMT treated at a single-center over the past thirty years.

DESIGN

Age, date-of-birth-year, gender, medical- and family-history, CMT-types, -numbers, -severity, -region, -symmetry, -patterns using the tooth agenesis code (TAC), and -growth types of all clinically and radiographically diagnosed CMT-patients were collected. Age and occurrence of syndromes were used to divide CMT-patients into non-syndromic patients older than nine years (group1) and syndromic CMT-patients (group2). Groups were compared especially regarding gender and CMT-severity.

RESULTS

The average CMT-number per patient was 5.5 (group1, n = 816, 59.9% female) and 15.1 (group2, n = 27, 29.6% female). There were significant less male (40.1% vs. 70.4%, respectively; P = 0.002) as well as significantly less male-oligodontia (44.8% vs. 73.9%, respectively; P = 0.009) in group1 than in group2. Group1 resulted in decreased prevalence of similar CMT-patterns with severity; the most prevalent CMT was the 2^nd premolar; there were no significant differences between the right and left side, whereas more CMT affected the maxilla; the majority of patients presented with bilateral-CMT (82.8%); females were more affected by CMT but more males had severer forms; certain single CMT differed by gender, and CMT was related to first-grade-relatives.

CONCLUSION

The majority of CMT-patients presented with hypodontia. Furthermore, same CMT-patterns seem more like to be present in patients with milder forms of tooth agenesis. Gender-specific association regarding CMT-number, severity groups, and single CMT were detected.

Dento-skeletal characteristics of cleft patients with missing teeth

Objective

The objective of this study was to compare the cephalometric skeletal and dental characteristics of unilateral complete cleft lip and palate (UCCLP) subjects with and without missing teeth.

Design

A retrospective records review was conducted for patients who are being treated at the cleft lip and palate (CLP) clinics in the College of Dentistry.

Methods

Ninety-six consecutive records of non-syndromic UCCLP subjects were recruited (33 subjects without missing teeth, 50 subjects with only one missing tooth, and 13 subjects with two or more missing teeth). Skeletal and dental characteristics were assessed using lateral cephalometric radiographs in UCCLP subjects with missing teeth and compared to the group with no missing teeth. A total of 25 linear and angular measurements were analyzed and compared between the sample groups.

Results

Of the dental variables tested, overjet was significantly different between the three groups. The UCCLP subjects with multiple missing teeth had the smallest overjet (–3.89±2.75 mm; P=0.015) among the three groups. None of the skeletal characteristics reached statistical significance.

Conclusion

Missing teeth influence the dental but not skeletal characteristics of UCCLP. Overjet is significantly reduced in UCCLP subjects with multiple missing teeth. Future studies with larger sample sizes are warranted.

Cephalometric Soft Tissue Characteristics of Unilateral Cleft Lip and Palate Patients in Relation to Missing Teeth

Objective

This study aimed to evaluate cephalometric soft tissue characteristics in individuals with unilateral complete cleft lip and palate (UCCLP) both with and without missing teeth.

Design

A retrospective investigation of patient records, who are being treated at the cleft lip and palate (CLP) clinics at the College of Dentistry. Ninety-six consecutive records of nonsyndromic UCCLP subjects were recruited (33 subjects without missing teeth and 63 subjects with missing teeth). Linear and angular soft tissue measurements obtained from lateral cephalometric radiographs were evaluated and compared among the studied samples.

Results

Lower lip was significantly retruded and shorter (p = 0.037), p = 0.015, respectively; in addition to the fact that shallower mentolabial sulcus (p = 0.05) was found in the subjects with missing teeth, the rest of the soft tissue was not significantly different between the two groups.

Conclusion

In subjects with a UCCLP anomaly, missing teeth have an effect on lower lip position and length, which influenced the mentolabial sulcus. Lower lip position and length differ between cleft patients who present with either multiple missing teeth or with no missing teeth, and this needs to be considered during orthodontic treatment planning and surgical management for the cleft defect.

Craniofacial characteristics of children with mild hypodontia

INTRODUCTION

The aim of our study was to evaluate the craniofacial characteristics of children with mild hypodontia using conventional and principal component (PC) analysis.

METHODS

We used radiographic images of 124 children (8-12 years old) with up to 4 missing teeth (55 boys, 69 girls) and of 676 reference children (365 boys, 311 girls) from the Rotterdam Generation R Study and the Nijmegen Growth Study in The Netherlands. Fifteen cephalometric measurements of children with hypodontia were compared with those of the reference children. Moreover, cephalometric parameters were combined into standardized PC scores using PC analysis, and the components were compared between the 2 groups.

RESULTS

PC analysis showed common dental characteristics for all types of hypodontia: a significant increase of the interincisal angle, and decreases of the maxillary and mandibular incisor angles. Other findings were consistent when both methods were applied: (1) anterior hypodontia was significantly associated with the high-angle (hyperdivergent) craniofacial pattern, (2) the tendency toward a Class III malocclusion was identified in maxillary hypodontia, and (3) we observed a significant reduction of lower posterior facial height in children with posterior and mandibular hypodontia.

CONCLUSIONS

Our findings suggest that children with mild hypodontia have distinctive skeletal and dental features.

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.

Patterns of non-syndromic permanent tooth agenesis in a large orthodontic population

OBJECTIVE

The aim of this study is to explore patterns of non-syndromic permanent tooth agenesis in a large orthodontic patient group.

DESIGN

A record review was performed in various orthodontic clinics to identify white patients with non-syndromic permanent tooth agenesis, excluding 3rd molars. Four hundred and fourteen subjects fulfilled the inclusion criteria.

RESULTS

In the 414 subjects with tooth agenesis, approximately 70% presented 1-2 missing teeth. Symmetric agenesis patterns were often observed in the sample (by jaw, by side, or crossed quadrants), with prevalence approaching 30% for cases with contralateral tooth agenesis within a jaw. In cases with 1 or 2 missing teeth, from the total number of potential tooth agenesis patterns in the sample, a certain part was evident, limiting the variation to 27.8% (44/158). In the entire sample, both in the maxilla and the mandible a certain incisor/premolar agenesis phenotype was observed in 59.0% of cases in isolated form.

CONCLUSIONS

Although there was variation in the tooth agenesis patterns, our findings suggest the involvement of particular genetic, epigenetic, and/or environmental factors in the formation of the entire dentition, which often lead to specific tooth agenesis phenotypes in cases where this process is disrupted. The present study provides a comprehensive categorization of orthodontic cases with tooth agenesis and can assist in planning future epidemiological and genetic studies.

The prevalence and distribution of hypodontia in a sample of Qatari patients

OBJECTIVE

The aims of this study were to determine the prevalence of hypodontia in the permanent dentition in a sample of Qatari patients attending a dental center and to compare the results with the reported findings of other populations.

MATERIALS AND METHODS

Orthodontic files including orthopantomographs of 1000 patients (655 females and 345 males, 11-36-year-old) were examined and inspected for evidence of hypodontia.

RESULTS

The prevalence of hypodontia in the present Qatari sample was 7.8%; 6.9% was in males and 8.2% in females. Hypodontia was found more frequently in the maxilla than in the mandible. The distribution of missing teeth was noticed in the left side more than the right side. The most frequently missing teeth were the maxillary lateral incisors followed by the mandibular second premolars, maxillary second premolars, and mandibular left lateral incisor. The majority of patients with hypodontia had one or two teeth missing, but rarely more than four teeth were missing in the same patient. Bilateral missing teeth in the current study was commonly seen in the maxillary lateral incisor (14.1%) followed by mandibular second premolar (12.8%) and maxillary second premolar (6.4%).

CONCLUSIONS

The prevalence of hypodontia in a sample of Qatari individuals was within the range reported in the literature for other populations. The incidence of hypodontia in the anterior segment requires multidisciplinary team approach (orthodontic and prosthodontic) to restore the esthetic and function and improve patient self-esteem.

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.

The prevalence and distribution pattern of hypodontia among orthodontic patients in Southern Iran

Objectives:

To evaluate the pattern and prevalence of hypodontia and its association with different malocclusions among orthodontic patients in southern Iran.

Materials and Methods:

In this study, a total of 494 records of orthodontic patients (162 males, 332 females) were evaluated. To investigate percent of hypodontia pertinent information of patients was evaluated. Chi-square and Fisher's exact tests were used for statistical analysis.

Results:

The prevalence of tooth agenesis was 7.66%. Thirty-eight patients were found to have at least one tooth missing. Number of patients having hypodontia was the most in class III patients, whereas the number of missing teeth was more in class II sample. However, it was not statistically significant (P = 0.569). Upper lateral incisor (27.95%), lower second premolar (21.51%), and upper first premolar (12.9%) were respectively the most frequently absent teeth. There was not statistically significant difference between sexes (P = 0.580). Hypodontia observed to be more bilaterally, in the upper arch and in the left side.

Conclusion:

The pattern and prevalence of hypodontia is different among races and ethnic groups. In our study population, hypodontia was found to be 7.66%. Higher prevalence of hypodontia in the maxillary arch and in class III patients may be considered as an etiologic factor.

Variability in dentofacial phenotypes in four families with WNT10A mutations

This article describes the inter- and intra-familial phenotypic variability in four families with WNT10A mutations. Clinical characteristics of the patients range from mild to severe isolated tooth agenesis, over mild symptoms of ectodermal dysplasia, to more severe syndromic forms like odonto-onycho-dermal dysplasia (OODD) and Schöpf-Schulz-Passarge syndrome (SSPS). Recurrent WNT10A mutations were identified in all affected family members and the associated symptoms are presented with emphasis on the dentofacial phenotypes obtained with inter alia three-dimensional facial stereophotogrammetry. A comprehensive overview of the literature regarding WNT10A mutations, associated conditions and developmental defects is presented. We conclude that OODD and SSPS should be considered as variable expressions of the same WNT10A genotype. In all affected individuals, a dished-in facial appearance was observed which might be helpful in the clinical setting as a clue to the underlying genetic etiology.

Prevalence and patterns of permanent tooth agenesis in Down syndrome and their association with craniofacial morphology

OBJECTIVE

To (1) document the prevalence and patterns of hypodontia (permanent tooth agenesis) in Down syndrome (DS) and (2) explore whether maxillary or mandibular hypodontia or simultaneous agenesis of all third molars was associated with differential alterations of the craniofacial morphology.

MATERIALS AND METHODS

Longitudinal panoramic radiographs of 25 white patients with DS (12 male, 13 female; mean age, 15.1 years) treated at The Hospital for Sick Children, Toronto, Ontario, Canada, were evaluated to document hypodontia. Cephalometric measurements of subjects with maxillary or mandibular hypodontia or agenesis of all third molars were compared with those of subjects without hypodontia in these regions using analysis of covariance adjusted for age, gender, and proportion of other missing teeth in the total number of missing teeth.

RESULTS

Hypodontia was seen in 92% of the sample when third molars were considered and in 56% when third molars were not considered. Hypodontia was more prevalent and severe in females. The most frequently agenetic teeth were maxillary and mandibular third molars > maxillary lateral incisors > mandibular second premolars > mandibular incisors > maxillary second premolars > maxillary second molars. Simultaneous agenesis of all third molars was seen in 52% of the sample. Maxillary hypodontia was not associated with significant regional craniofacial differences, while mandibular hypodontia was associated with decreased mandibular length and increased ramus∶body ratio. Agenesis of all third molars was not associated with significant craniofacial differences.

CONCLUSIONS

Hypodontia is widely prevalent in DS. The effect of the syndrome appears to be stronger than that of regional hypodontia in differentially altering the craniofacial morphology.