Tooth agenesis and craniofacial morphology in an orthodontic population

The influence of three different primary treatment protocols on 5-year-old maxillary growth in patients with complete unilateral cleft lip and palate

The study evaluated the effects of three different primary treatment protocols on maxillary growth in patients aged 5 years with complete unilateral cleft lip and palate (UCLP). The secondary objective was to assess the influence of initial cleft severity, family history of class III, and status of permanent lateral incisor on maxillary growth. In total, 54 patients with non-syndromic complete UCLP were included and grouped as follows: group An underwent lip adhesion, cheilorhinoplasty associated with tibial periosteal graft for hard palate repair, and finally veloplasty; group B underwent lip adhesion, then cheilorhinoplasty with intravelar veloplasty, and finally a hard-palate repair; group C underwent cheilorhinoplasty with intravelar veloplasty and then a hard-palate repair. Five-year maxillary growth was assessed on dental models, both clinically and digitally. No difference was found with GOSLON-Yardstick scoring. Five-year measurements showed that group C tended to have the best maxillary arch morphology (p = 0.012). Initial cleft severity did not impact maxillary growth, but status of permanent lateral incisor and family history of class III did (p = 0.019 and p = 0.004, respectively). In patients aged 5 years, the two-stage approach appeared to be the least detrimental to growth development. Predictive factors for growth retardation included the absence of lateral incisor and a family history of class III.

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.

Multi-disciplinary orthodontic camouflage treatment of a severe skeletal class III malocclusion with 1 year follow-up - A case report

Rationale

Orthodontic camouflage serves its purpose in treating mild to moderate skeletal dysplasia and in conditions where the patient is reluctant to opt for orthognathic surgery or when it is contraindicated.

Patient Concerns

A 22-year-old male was concerned about his irregular teeth.

Diagnosis

Angle's dentoalveolar class III malocclusion on class III skeletal on an average mandibular plane angle with anterior crossbite, deep bite, crowding in maxillary and mandibular anteriors, proclined maxillary anteriors and retroclined mandibular anteriors with reverse overjet and congenitally missing 12, 22, palatally impacted 13 and retained deciduous 63 and palatally placed 23.

Treatment

Orthodontic camouflage with a multi-disciplinary approach.

Outcome

Optimal functional and dentofacial aesthetics were achieved by 22 months.

Take-Away Lesson

The limitations of camouflage must be kept in mind and explained to the patient. The biomechanics need to be customized and integrating different specialties helps maximize the treatment benefits.

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.

From Child to Adulthood, a Multidisciplinary Approach of Multiple Microdontia Associated with Hypodontia: Case Report Relating a 15 Year-Long Management and Follow-Up

Oral rehabilitation of patients presenting multiple microdontia is a real therapeutic challenge. These alterations in size, often associated with other dental anomalies, have aesthetic and functional repercussions for patients and can lead to significant psycho-social consequences. We report here the case of an 11-year-old patient with bilateral sectorial microdontia and agenesis of teeth numbers 13 and 23. She also presented staturo-ponderal delay and a history of acute coronary syndrome with a lower coronary occlusion of unknown aetiology. At first, additive coronoplasties and an orthodontically retained interim prosthesis answered the aesthetic and functional need during childhood and adolescence. Once she reached adulthood, a multidisciplinary meeting was conducted and a treatment plan was established. The decision was made to rehabilitate the upper arch with a permanent bridge and the lower arch with indirect adhesive restorations. This solution solved the problem of the bilateral lateral infraocclusions and tooth agenesis, restoring both aesthetics and function. This paper presents 15 years of management and treatment of a patient presenting multiple microdontia associated with hypodontia. Both the multidisciplinary approach and coordination between the different medical team members was essential to maintain the existing dentition while preparing, planning, and carrying out a personalized treatment plan once maxillofacial growth was complete.

Trends in orthodontic management strategies for patients with congenitally missing lateral incisors and premolars

OBJECTIVES

To identify changes in orthodontic management strategies in patients with hypodontia seen in 2000, 2010, and 2017/2018 (during a 1-year period).

MATERIALS AND METHODS

An assessment of the panoramic radiographs of 3701 patients from a Western Australian private practice identified 276 individuals demonstrating hypodontia. The location of missing teeth, age, sex, type of malocclusion, and the management strategies (space closure or opening) for each patient were noted.

RESULTS

Most hypodontia involved agenesis of three or fewer teeth (90%). Maxillary lateral incisors and mandibular second premolars were the most commonly missing teeth. Female preponderance was noted. When considering treatment, the odds ratio for orthodontic space opening and prosthetic replacement in 2000 was 3.266 (P value = 7e-04; 95% confidence interval [CI], 1.464-4.633) compared with patients seen in 2010 and 1.632 (P value = 7e-04; 95% CI, 0.811-2.434) compared with patients in 2017/2018. For patients demonstrating bilateral absence of maxillary lateral incisors, the odds ratio for orthodontic space opening was 3.185 (P value = 0.0215; 95% CI, 1.182-9.243) compared with counterparts with unilateral agenesis. None of the factors investigated were significantly associated with the types of treatment planned/provided for the patients with missing mandibular second premolars.

CONCLUSIONS

Maxillary lateral incisors and mandibular second premolars were the most commonly missing teeth. A trend away from space opening and prosthetic replacement toward orthodontic space closure was observed from 2000 to 2017/2018. This may reflect a change in attitude toward prosthetic replacement options and/or greater optimism with biomechanical strategies since the implementation of temporary anchorage devices to assist in space closure.

Prevalence of Class I, II and III skeletal relationships and its association with dental anomalies in an ethnic Chinese orthodontic population

Objectives:

To investigate the prevalence of skeletal Classes I, II and III in a Chinese orthodontic population, and determine its association with the prevalence of dental anomalies.

Methods:

This retrospective cross-sectional study was conducted on 2508 ethnic Chinese orthodontic patients aged 14 to 25 years who attended the Department of Orthodontics at the National Dental Centre Singapore. Radiographs, photographs and clinical records of the study sample were examined for the prevalence of dental anomalies in the permanent dentition, excluding third molars. The anteroposterior skeletal relationship was determined based on the A point–Nasion–B point angle measured from the lateral cephalogram, whereby Class I: A point–Nasion–B point = 3.6° ± 2.5° (1 standard deviation) that is 1.1° to 6.1°; Class II: A point–Nasion–B point greater than 6.1°; Class III: A point–Nasion–B point less than 1.1°. Logistic regression was used to determine the association between the anteroposterior skeletal relationship and the occurrence of various dental anomalies.

Results:

The prevalence of the anteroposterior skeletal relationship was: 49.5% Class I; 23.1% Class II; and 27.4% Class III. Class III patients had significantly lower odds of impacted teeth compared to Class I patients (odds ratio 0.608, 95% confidence interval 0.463–0.798; P=0.00009). There was no significant difference in the occurrence of the anomalies among the various anteroposterior skeletal types.

Conclusions:

The occurrence of impacted teeth was lower in Class III than Class I, while no significant differences were noted for hyperdontia, hypodontia, peg-shaped upper lateral incisors, transposition and double teeth. The occurrence of all investigated dental anomalies had no significant difference between Class II and Class I.

Adjunctive orthodontic therapy for prosthetic rehabilitation in a growing child with Axenfeld-Rieger syndrome: A case report

AIM

The congenital oligodontia impeding the development of the alveolar process resulting in disproportionate jaw growth has been previously reported. This case report describes the interdisciplinary management of an 11-year-old girl with Axenfeld-Rieger syndrome exhibiting oligodontia and maxillary hypoplasia.

METHODS AND RESULTS

An adjunctive orthodontic therapy was performed by taking advantage of bone-anchored maxillary protraction (BAMP) therapy using miniplates and 24-hour traction by intermaxillary Class III elastics. After 6 months of active treatment, the maxilla advanced by approximately 5 mm and upper lip relation improved by 3 mm without any significant changes in vertical relations. All the changes were maintained at 15th-month follow-up. A temporary removable prosthesis was given for immediate esthetics, and the definitive management is discussed.

CONCLUSION

The BAMP therapy can be a befitting alternative in cases exhibiting complex presentation involving skeletal and dentoalveolar components. An appreciable profile improvement without any dentoalveolar side effects can be achieved with BAMP therapy.

Morphometric evaluation of cranial base and sella turcica in patients with bilateral agenesis of maxillary lateral incisors

The aim of this paper is to evaluate the dimensions and morphology of cranial base and sella turcica in patients with bilateral agenesis of maxillary lateral incisors (BMLI). This retrospective study was conducted on lateral cephalometric radiographs of 34 female patients with BMLI (17.69 ± 2.96 years) and 34 female patients with complete dentation and skeletal Class 1 relationship serving as a control group (17.22 ± 2.2 years). Basicranial and maxillomandibular variables together with linear dimensions and morphology of sella turcica were evaluated. Differences between groups were analyzed by Student's t test for parametric variables and Mann-Whitney U test for nonparametric variables. Chi-square test followed by post hoc test with Bonferroni correction was used for categoric variables (p < 0.05). When compared to control group, N-S-Se angle was less negative, dimensions between Ba-Se, N-Ba, and N-Ar were larger, and SNA angle was smaller in BMLI group. There were no significant differences between groups regarding the linear dimensions of sella turcica. However, variations in sella turcica morphology were more frequent in BMLI group (n = 17; 50%) when compared to control group (n = 2; 5.8%). The most common morphologic variations in BMLI group were oblique anterior wall (20.6%) and irregularity (notching) in the posterior part of sella turcica (14.7%). The present study showed a statistically significant relationship between the presence of BMLI with some craniofacial parameters and morphological variations of sella turcica. This information may be useful as an additional and early diagnostic tool for BMLI and to highlight the possible links to its development.

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.

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).

Cervicovertebral anomalies and/or normal variants in patients with congenitally bilateral absent maxillary lateral incisors

OBJECTIVE

To determine whether there is a relationship between congenitally bilaterally absent maxillary lateral incisors (BAMLIs) and skeletal anomalies and/or normal variants.

MATERIALS AND METHODS

The records of 86 patients (62 girls, 24 boys; age 12-17 years) with congenitally BAMLIs and 86 patients (55 girls, 34 boys; age 13-18 years) without any dental or skeletal anomalies were collected and evaluated retrospectively. The study was based on the evaluation of lateral cephalometric and orthopantomographic radiographs. Posterior arch deficiency of the atlas bone (PADA); atlanto-occipital ligament calcification, known as "ponticulus posticus" (PP); and interclinoid ligament calcification, known as "sella turcica bridging" were recorded for each participant. Pearson χ2 and Fisher exact tests were used to evaluate and compare skeletal anomalies and/or normal variants between patients with BAMLIs and the control group.

RESULTS

The prevalence of cervicovertebral anomalies and/or normal variants seen in the lateral cephalometric radiographs was higher in patients with BAMLI than in the control group. The prevalence of PP was lower and that of PADA was higher in patients with BAMLIs than in the control group (P < .05).

CONCLUSION

The prevalence of PADA was increased and that of PP formation was decreased in patients with BAMLIs. There was a significant relationship between skeletal anomalies and/or normal variants.

Relationships between skeletal morphology and patterns of bilateral agenesis of third molars in Japanese orthodontic patients

The aim of this study was to reveal the correlations between bilateral agenesis of third molars (M3s) and skeletal morphology in Japanese male and female orthodontic patients. Sixty patients (30 males, 30 females), with bilateral agenesis of maxillary M3s and without agenesis of mandibular M3s (group U), and 60 patients (30 males, 30 females), with bilateral agenesis of mandibular M3s and without agenesis of maxillary M3s (group L), were selected as agenesis groups. Additionally, 60 patients (30 males, 30 females) with all four M3s were selected as the control group (group C). Patients in these three groups had no agenesis of teeth other than M3s. Lateral cephalograms of each patient were used to evaluate skeletal morphology of the maxilla and mandible. Two-way analysis of variance was used for statistical comparisons. Groups U and L had significantly smaller maxillary length and area than group C. Group U exhibited a significantly smaller lower facial height than group C. Males showed significantly larger maxillary length; total mandibular and mandibular body length; mandibular ramus height; SNB angle; maxillary area; and mandibular symphysis, corpus and ramus areas than females. Females had significantly larger lower facial height, gonial angle and ANB angle than males. Smaller maxillary length and area and lower facial height should be considered in planning orthodontic treatment for patients with bilateral agenesis of maxillary and mandibular M3s.

[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.

Morphometric covariation between palatal shape and skeletal pattern in children and adolescents: a cross-sectional study

Objective

To assess shape covariation of the palate and craniofacial complex (CFC) in children and adolescents.

Methods

Pre-treatment lateral cephalometric radiographs and corresponding maxillary casts of 100 children (8-10 years) and 100 adolescents (15-20 years) were digitized. Exclusion criteria were previous orthodontic treatment, craniofacial syndromes, mouth breathing, finger sucking, crossbite, tooth agenesis, and tooth impaction. Palatal shape was described with 239 surface and curve semilandmarks and craniofacial shape with 10 fixed landmarks and 117 curve semilandmarks. Procrustes superimposition and principal component analysis were applied for evaluation of shape variability. Shape covariation between palate and CFC was assessed with partial least squares analysis.

Results

The first five principal components explained 77 per cent (palate) and 60 per cent (CFC) of total shape variability. The palate varied mainly in height (adolescent group) and width-length (both groups), whereas the CFC varied mainly in the vertical dimension. Significant covariation was found between the craniofacial and palatal components (RV coefficient: 0.27, children; RV: 0.23, adolescents). Variation of the CFC in the vertical and anteroposterior direction was mainly related to variation in the height-width and the width-length ratio of the palate, respectively.

Limitations

The use of lateral cephalometric radiographs eliminated the transverse dimension from the craniofacial shape analysis. The study was cross-sectional, so the observed intergroup differences should be interpreted with caution.

Conclusions

Covariation strength and pattern were similar in children and adolescents. The closer a subject was to the high-angle end of the variability spectrum, the higher and narrower was the palate, and conversely.

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.

The Relationship between Agenesis of Third Molar and Craniofacial Morphology in Orthodontic Patients

Aims and Objectives:

The aim of this study was to evaluate the association between third molar agenesis and craniofacial morphology in a group of Iranian orthodontic patients.

Materials and Methods:

A total of 164 high-quality lateral cephalograms and panoramic radiographs were included in the study. Eighty-two radiographs with the absence of at least one-third molar were assigned to agenesis group and other 82 radiographic records were served as control group. Cephalometric analysis was performed, and the results were compared between the two groups using Independent Samples Student's t-test.

Results:

Significant differences were found in SNA, ANB, sum of posterior angles, and lower gonial angle between the study groups. All of them were smaller in the agenesis group.

Conclusion:

Third molar agenesis in this group of Iranian subjects is associated with deficient maxillary development and brachyfacial and hypodivergent skeletal pattern.

A radiographic survey of agenesis of the third molar: A panoramic study

Purpose:

It is a well-known fact that nature tries to eliminate what is not in use. Because of this, the number of certain teeth which are no longer necessary for function are either getting increasingly impacted or are not developing at all. This is especially the case where third molars are concerned. Furthermore, the presence or absence of the third molar is significant to all branches of dentistry and in particular, forensic dentistry.

Objectives:

The objectives of this study is to assess (1) The prevalence of third molar agenesis in population of age group 18–25 years. (2) The genderwise difference of third molar agenesis. (3) The difference between maxilla and mandible.

Materials and Methods:

Dental patients, who are advised or referred for orthopantomograph, visited to the Department of Oral Medicine and Radiology were included in the study. The study population comprised 300 patients.

Statistical Analysis:

The data obtained was tabulated and subjected to statistical analysis. SPSS version 17 software was used for the analysis of the data. The Chi-square test was used for the same.

Results:

The incidence of agenesis of the third molar is significantly higher for tooth number 18 (P < 0.001). Overall, it is significantly higher among females compared to the males (P < 0.001) in our study population.

Conclusion:

(1) The present study reports 46.7% agenesis of the third molar. (2) The frequency of third molar agenesis was found significantly greater in the females. (3) Third molar agenesis showed a greater predilection in maxilla compared to mandible.

Association between severity of hypodontia and cephalometric skeletal patterns: a retrospective study

Objective

To assess if severity of hypodontia is related to a specific skeletal pattern.

Study design

Lateral cephalometric radiographs and dental panoramic tomographs of 182 hypodontia patients were analysed. The severity of hypodontia was recorded and the sample was divided into groups with mild (n = 71), moderate (n = 56) and severe (n = 55) hypodontia. According to ethnicity, the sample was further subdivided into White Caucasians, African-British, and Arabian/Indian subgroups. Cephalometric measurements were used to quantify the skeletal discrepancy and vertical facial dimensions. Mean and standard deviation for each group were obtained for comparison and an analysis of variance (ANOVA) was carried out to assess the level of significance between the means of the readings in different severity groups.

Results

In the white Caucasian group, increased severity of hypodontia, was related to a retrusive maxilla with concomitant reduction of A point, Nasion, B point (ANB), reduced mandibular plane angle and anterior lower facial height (P value: 0.0935-0.9371). For the Black-British and Arabian/Indian groups' findings were inconsistent, with no specific pattern as the number of missing teeth increased.

Conclusion

The white Caucasian group followed a pattern that has previously been reported in other studies. For Black-British and Arabian/Indian groups' findings were inconsistent and no specific pattern emerged for different degrees of hypodontia.

Mesiodistal and Buccolingual Dimensions in Croatian Orthodontic Hypodontia Patients' Teeth

OBJECTIVE

This study compared mesiodistal (MD) and buccolingual (BL) tooth dimensions of hypodontia patients with a control group with complete dentition. The null hypothesis was that there was no difference in tooth sizes between hypodontia patients and the controls.

METHODS

The sample comprised 76 patients with hypodontia (50 female and 26 male) aged between 11 and 18 years. The control group comprised 50 females and 26 males with the same age range as the study group. Mesiodistal (MD) and buccolingual (BL) dimensions were measured on pretreatment dental casts with a digital caliper to the nearest 0.01 mm. The data were analyzed using Statistica 7.1 (StatSoft Inc.) statistical package (descriptive statistics, test of distribution normality, parametric statistics).

RESULTS

The most common congenitally missing teeth were the lower second premolars (left 13.45% and right 13.90%) and upper lateral incisors (both left and right 12.56%), followed by upper second premolars (right 9.4o% and left 10.31%). The greatest differences between the study and control group were found in upper lateral incisors, 8.08% in MD and 6.40% in BL dimension. The smallest difference was found in BL dimension of lower lateral incisor (2.37%), MD dimension of lower second premolars and upper first molar (2.61%) and MD dimension of lower central incisor (2.26%).

CONCLUSION

The teeth are smaller in subjects with hypodontia than those of the controls on average 4.02% in MD dimension and 3.85% in BL dimension. The tooth that showed the greatest difference in tooth dimension was maxillary lateral incisor.

Association between skeletal morphology and agenesis of all four third molars in Japanese orthodontic patients

The purpose of this study was to clarify differences in skeletal morphologies between male and female orthodontic patients with and without agenesis of all four third molars. A total of 64 patients (32 males and 32 females) with agenesis of all four third molars without agenesis of other teeth were selected as the third molars agenesis group (group 1). In addition, 64 patients (32 males and 32 females) with all these teeth were selected as controls (group 2). Lateral cephalograms taken between the ages of 14 and 30 years were used to compare skeletal morphology between groups 1 and 2 and between sexes. Maxillary length (P < 0.001), lower facial height (P < 0.05), gonial angle (P < 0.001) and mandibular plane angle (P < 0.001) were significantly smaller in group 1 than in group 2. Irrespective of the presence or absence of all four third molars, males had significantly smaller lower facial height (P < 0.01) and mandibular plane angle (P < 0.001) and significantly greater total mandibular length (P < 0.001), mandibular body length (P < 0.001) and mandibular ramus height (P < 0.001) than females. Japanese orthodontic patients with agenesis of all four third molars had significantly small maxillary length, lower facial height, gonial angle and mandibular plane angle.

From oral facial dysfunction to dysmorphism and the onset of pediatric OSA

The upper airway is a collapsible tube, and its collapsibility increases during sleep. Extrinsic factors such as atypical craniofacial features may increase the risks of airway collapse. We review early development of oral-facial structures and the anatomical variants that may be present at birth and can impact nasal breathing. After birth, there is a continuous interaction between orofacial functions and growth of anatomic features. We review the dysfunctions identified to date that may impact orofacial development leading to sleep-disordered-breathing through changes in the orofacial growth. The identification of risk-factors, ultimately leading to full-blown obstructive sleep apnea, may allow early recognition of these factors and the development of treatments to eliminate early problems or at least decrease their impact.

Sexual dimorphism, pattern of third molar and mandibular second premolar agenesis in Indian paediatric orthodontic patients

Objective

To determine and compare the prevalence and pattern of agenesis of third molar and mandibular second premolar in paediatric orthodontic patients of age group 9–15 for sexual dimorphism.

Methods

The digital orthopantograph was obtained from the archive record of patients of age group 9–15 year. Radiographs of 301 patients were evaluated after taking exclusion criteria into account and were assessed for the presence/absence of third molars and mandibular second premolar. Tooth development evaluation followed the method of Demirjian et al., based on eight stages of tooth formation. The agenesis of third molar in maxilla and mandible between age groups and gender was compared using Chi-squared test.

Results

The rate of agenesis of third molars was observed 36.8% in the present study. Twenty-four (24.3%) percentage of the study population showed agenesis of all the four third molars. The agenesis of third molars was found to be higher among males than females (p > 0.05). Prevalence of agenesis of mandibular second premolar was 4.7–5%.

Conclusions

Agenesis of third molars was more commonly seen in the maxilla, having male predilection. Maxillary right third molar was the most commonly missing tooth irrespective of gender.

Prevalence of isolated maxillary lateral incisor agenesis in Syrian adolescents

PURPOSE

This research is designed to obtain a better understanding and provide more insight of this phenomenon through evaluating the prevalence of congenital absence of maxillary lateral incisors in a Syrian population.

METHODS

The method involved clinical examination of 8000 school children with an equal number of males and females (age range 12-15 years) to identify students only affected by bilateral or unilateral congenital absence of maxillary lateral incisors. Agenesis was determined based on radiological evidence.

RESULTS

The results of this study showed that the prevalence of isolated maxillary lateral incisors agenesis was 1.15%. In the sample studied, 66.3% of the patients were female and 33.7% were male (p < 0.05). Absence was bilateral in 47.8% of patients and unilateral in 52.2%. Of the unilateral cases, 48% occurred on the right side and 52% on the left side, and the contralateral maxillary incisor was found to be microdont in 43.75%, right lateral in 47.6%, and left lateral in 52.4%.

CONCLUSION

The results of this study allow the conclusion that the prevalence of isolated maxillary lateral incisors agenesis in a Syrian population is within the average range with regard to other populations. A significant familial component to the etiology of maxillary lateral incisors agenesis was found.

Oro-dental features of Pallister-Killian syndrome: Evaluation of 21 European probands

Pallister-Killian syndrome (PKS) is a rare sporadic multi-systemic developmental disorder caused by a mosaic tetrasomy of the short arm of chromosome 12. A wide range of clinical characteristics including intellectual disability, seizures, and congenital malformations has previously been described. Individuals with PKS show a characteristic facial phenotype with frontal bossing, alopecia, sparse eyebrows, depressed nasal bridge, long philtrum, telecanthus, and posteriorly rotated ears. Oro-dental features, such as "Pallister lip," macroglossia, delayed eruption of primary teeth, high arched-palate, prognathism, and cleft palate have been occasionally reported in the medical literature. The aim of the study was to assess the oro-dental phenotype of PKS and to describe the oral health status in a cohort participating in the First European Workshop on PKS. A clinical dental examination was performed in 21 Caucasian probands and data regarding medical and dental history collected. Twelve probands (57%) showed an atypical dental pattern, with multiple missing teeth (primarily the first permanent molars) and 2 (10%) a double teeth. The severity of gingivitis and dental caries increased with age and gingival overgrowth was a common finding. A characteristic occlusive phenotype was found: a high-arched palate with mandibular prognathism associated with an anterior openbite and crossbite and with posterior crossbite (unilateral or bilateral). The prevalence of oral habits (non-nutritive sucking, mouth breathing, bruxism) was high, even in older probands. This study suggests that individuals affected by PKS should be observed closely for oro-dental diseases and a multidisciplinary approach is needed to implement the right preventive measures. © 2016 Wiley Periodicals, Inc.

Tooth agenesis and craniofacial morphology in pre-orthodontic children with and without morphological deviations in the upper cervical spine

AIM: To analyze differences in prevalence and pattern of tooth agenesis and craniofacial morphology between non syndromic children with tooth agenesis with and without upper cervical spine morphological deviations and to analyze associations between craniofacial morphology and tooth agenesis in the two groups together.

METHODS: One hundred and twenty-six pre-orthodontic children with tooth agenesis were divided into two groups with (19 children, mean age 11.9) and without (107 children, mean age 11.4) upper spine morphological deviations. Visual assessment of upper spine morphology and measurements of craniofacial morphology were performed on lateral cephalograms. Tooth agenesis was evaluated from orthopantomograms.

RESULTS: No significant differences in tooth agenesis and craniofacial morphology were found between children with and without upper spine morphological deviations (2.2 ± 1.6 vs 1.94 ± 1.2, P > 0.05) but a tendency to a different tooth agenesis pattern were seen in children with morphological deviations in the upper spine. In the total group tooth agenesis was associated with the cranial base angle (n-s-ba, r = 0.23, P < 0.01), jaw angle (ML/RLar, r = 0.19, P < 0.05), mandibular inclination (NSL/ML, r = -0.21, P < 0.05), mandibular prognathia (s-n-pg, r = 0.25, P < 0.01), sagittal jaw relationship (ss-n-pg, r = -0.23, P < 0.5), overjet (r = -0.23, P < 0.05) and overbite (r = -0.25, P < 0.01).

CONCLUSION: Etiology of tooth agenesis in children with upper spine morphological deviations was discussed. The results may be valuable for the early diagnosis and treatment planning of non syndromic children with tooth agenesis.

Association between third molar agenesis and craniofacial structure development

INTRODUCTION

The aim of this investigation was to study the relationship between third molar agenesis-including the number of ageneses-and craniofacial structure growth.

METHODS

We reviewed 305 clinical histories of patients treated at the Orthodontics Unit of the Faculty of Medicine and Dentistry at the University of Valencia in Spain. This included radiographic records of optimal quality. Of these, 40 patients who had agenesis of at least 1 third molar were included in the study group. A control group was formed with another 40 patients with all 4 third molars present. For both groups, a further criterion for inclusion was cone-beam computed tomography records. The cephalometric analysis was performed with NemoCeph 3D software (version 11.3.1.38; Nemotec, Madrid, Spain).

RESULTS

The only significant differences between the 2 groups were in the total gonial angle and the upper gonial angle (P ≤0.05), both of which were smaller in the study group.

CONCLUSIONS

Third molar agenesis is associated with a reduction in Jarabak's gonial angle and upper gonial angle, characteristic of patients with a more horizontal or brachyfacial skeletal pattern. No significant differences were found in other measurements.

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.

Missing teeth and pediatric obstructive sleep apnea

BACKGROUND

Missing teeth in early childhood can result in abnormal facial morphology with narrow upper airway. The potential association between dental agenesis or early dental extractions and the presence of obstructive sleep apnea (OSA) was investigated.

METHODS

We reviewed clinical data, results of polysomnographic sleep studies, and orthodontic imaging studies of children with dental agenesis (n = 32) or early extraction of permanent teeth (n = 11) seen during the past 5 years and compared their findings to those of age-, gender-, and body mass index-matched children with normal teeth development but tonsilloadenoid (T&A) hypertrophy and symptoms of OSA (n = 64).

RESULTS

The 31 children with dental agenesis and 11 children with early dental extractions had at least 2 permanent teeth missing. All children with missing teeth (n = 43) had clinical complaints and signs evoking OSA. There was a significant difference in mean apnea-hypopnea indices (AHI) in the three dental agenesis, dental extraction, and T&A studied groups (p < 0.001), with mean abnormal AHI lowest in the pediatric dental agenesis group. In the children with missing teeth (n = 43), aging was associated with the presence of a higher AHI (R (2) = 0.71, p < 0.0001).

CONCLUSION

Alveolar bone growth is dependent on the presence of the teeth that it supports. The dental agenesis in the studied children was not part of a syndrome and was an isolated finding. Our children with permanent teeth missing due to congenital agenesis or permanent teeth extraction had a smaller oral cavity, known to predispose to the collapse of the upper airway during sleep, and presented with OSA recognized at a later age. Due to the low-grade initial symptomatology, sleep-disordered breathing may be left untreated for a prolonged period with progressive worsening of symptoms over time.

Pediatric sleep-disordered breathing: New evidence on its development

Sleep-disordered breathing (SDB) in children could be resolved by adenotonsillectomy (T&A). However, incomplete results are often noted post-surgery. Because of this partial resolution, long-term follow-up is needed to monitor for reoccurrence of SDB, which may be diagnosed years later through reoccurrence of complaints or in some cases, through systematic investigations. Children undergoing T&A often have small upper airways. Genetics play a role in the fetal development of the skull, the skull base, and subsequently, the size of the upper airway. In non-syndromic children, specific genetic mutations are often unrecognized early in life and affect the craniofacial growth, altering functions such as suction, mastication, swallowing, and nasal breathing. These developmental and functional changes are associated with the development of SDB. Children without genetic mutations but with impairment of the above said functions also develop SDB. When applied early in life, techniques involved in the reeducation of these functions, such as myofunctional therapy, alter the craniofacial growth and the associated SDB. This occurs as a result of the continuous interaction between cartilages, bones and muscles involved in the growth of the base of the skull and the face. Recently collected data show the impact of the early changes in craniofacial growth patterns and how these changes lead to an impairment of the developmental functions and consequent persistence of SDB. The presence of nasal disuse and mouth breathing are abnormal functions that are easily amenable to treatment. Understanding the dynamics leading to the development of SDB and recognizing factors affecting the craniofacial growth and the resulting functional impairments, allows appropriate treatment planning which may or may not include T&A. Enlargement of lymphoid tissue may actually be a consequence as opposed to a cause of these initial dysfunctions.

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.

Association of gonial angle with morphology and bone mineral content of the body of the adult human mandible with complete permanent dentition

We investigated the differences between 2 gonial angle (GA) size groups with respect to the morphometry and quantitative bone mineral content (QBMC) of mandibles with all teeth erupted and normal occlusion. We used 19 dried mandibles that were obtained from an Indian population and stored in our department. These mandibles were at Hellman's developmental dental stage VA and were divided into low gonial angle (LGA) (GA ≤ 120°; 8 specimens; 16 sides) and high gonial angle (HGA) (GA ≥ 125°; 11 specimens; 22 sides) groups. After lateral radiography of the mandibles using a titanium step wedge, linear measurements and the QBMC were determined, on hard copies and digital images, respectively. The age and sex of the cadavers to which the specimens belonged were unknown. The mandibular cortical width (MCW) and the antegonial notch depth of the LGA group were significantly larger than those of the HGA group. No significant difference was found in the distribution of the 3 categories of mandibular cortical index (MCI) or in cortical and trabecular bone mineral contents (CBMC and TBMC). The GA size was negatively and moderately associated with the MCW and the mandibular cortical width on the point AG (MCWAG), but was not significantly associated with either variable for CBMC and TBMC. These results suggested that the GA size of these stage-VA mandibles influenced changes in the width of inferior cortex and morphology of antegonial notch. The GA size did not influence QBMC under the mental foramen of the mandible and had negative associations with the MCW and MCWAG.

Patient with oligodontia treated with a miniscrew for unilateral mesial movement of the maxillary molars and alignment of an impacted third molar

This report describes the treatment of a 20-year-old woman with a dental midline deviation and 7 congenitally missing premolars. She had retained a maxillary right deciduous canine and 4 deciduous second molars, and she had an impacted maxillary right third molar. The maxillary right deciduous second molar was extracted, and the space was nearly closed by mesial movement of the maxillary right molars using an edgewise appliance and a miniscrew for absolute anchorage. The miniscrew was removed, and the extraction space of the maxillary right deciduous canine was closed, correcting the dental midline deviation. After the mesial movement of the maxillary right molars, the impacted right third molar was aligned. To prevent root resorption, the retained left deciduous second molars were not aligned by the edgewise appliance. The occlusal contact area and the maximum occlusal force increased over the 2 years of retention. The miniscrew was useful for absolute anchorage for unilateral mesial movement of the maxillary molars and for the creation of eruption space and alignment of the impacted third molar in a patient with oligodontia.

Familial aggregation of maxillary lateral incisor agenesis (MLIA)

Agenesis of maxillary lateral incisors and mandibular second premolars is the most frequent form of hypodontia. Its prevalence varies across population from 0.8% to 4.5%. Genetic aberrations and environmental factors may cause agenesis of one or more teeth. The management of child having such a problem is very important since diastema in teeth especially in upper anteriors not only affects child's physical appearance but also its psychological development as the child wants to look like other children. In this article is presented a case of non-syndromic agenesis of maxillary lateral incisors (MLIA) and mandibular central incisors in a 10-year-old boy (patient) in permanent dentition with its management along with the radiographic investigations and photographic presentations of the other members of his family affected with this condition.

Evaluation of tooth size in patients with congenitally-missing teeth

Background and aims

Hypodontia is a common developmental abnormality of dentition. This study aimed to determine tooth width in patients affected with mild hypodontia and compare the results with a control group without tooth agenesis.

Materials and methods

The orthodontic records of 25 patients with congenital missing of one or two teeth (hypodontia group), and 25 subjects with full dentition (control group) were selected. The greatest mesiodistal width of each tooth was measured on the study models by a digital caliper. Tooth width measurements were compared between the groups using a student t-test at p < 0.05 of significance.

Results

Patients with hypodontia showed narrower teeth than the control subjects. The differences in tooth size between the two groups were statistically significant for the first and second premolars and first molar in the maxillary right and for the second premolar in the maxillary left quadrants (p < 0.05). In the lower arch, the first and second premolars and also first molar in both sides of hypodontia patients demonstrated significant reduction in tooth size compared to the control group (p < 0.05).

Conclusion

These findings suggest that patients with mild hypodontia have narrower teeth than normal subjects especially in posterior segments, which may have clinical implications during the orthodontic treatment process.

Effects of severity and location of nonsyndromic hypodontia on craniofacial morphology

OBJECTIVE

To evaluate the effects of severity and location of nonsyndromic hypodontia on craniofacial morphology.

MATERIALS AND METHODS

A total of 154 patients with at least two or more congenitally missing teeth were selected and divided into two groups (group I [mild]: patients with two to five missing teeth; group II [severe]: patients with six or more missing teeth). The patients with hypodontia were divided into three groups according to the location of missing teeth in the dental arches (anterior, posterior, and both anterior and posterior) and location of missing teeth between the jaws (maxilla, mandible, and both maxilla and mandible). Fifty Class I patients without any missing teeth served as the control group. Twenty-one measurements were performed on lateral cephalograms. Intergroup differences for the severity and location of hypodontia were analyzed using analysis of variance (ANOVA) and post-hoc Tukey tests.

RESULTS

Significant decreases were found in mandibular plane angles (P < .05), upper and lower incisor measurements (P < .05), anterior (P < .001) and posterior (P < .05) face heights, and ramus height (P < .01), as well as a significant increase in the soft tissue convexity angle (P < .05) among the hypodontia groups and control group. These differences were more excessive in the severe hypodontia group. Upper lip-E plane measurements were significantly longer in the mandible group than in the maxilla group (P < .01).

CONCLUSIONS

Patients with congenitally missing teeth have different craniofacial morphologies. The severity and location of missing teeth have a significant effect.

Orthodontic Considerations in Restorative Management of Hypodontia Patients With Endosseous Implants

The use of implant-supported restorations in patients with hypodontia remains challenging and requires a multistage treatment that begins in late mixed dentition and continues into late adolescence. The aim of this article is to review the role of orthodontics in endosseous implant rehabilitation of patients with hypodontia. The MEDLINE, Web of Science, Scopus, Cochrane databases, and necessary scientific textbooks were searched for relevant studies and reviews, and as far as possible, they were only included if they had been cited at least once in the literature. Dental implants are susceptible to overloading as the periodontal ligament is absent and the proprioceptive nerve endings are either lacking or very limited. Patients with hypodontia may present with skeletal features such as short and retrognathic maxilla, prognathic mandible, and shorter lower anterior facial height, and they sometimes need orthognathic correction as part of their overall treatment. Dental problems vary and include bimaxillary retroclination of incisors, spacing, centerline discrepancies, microdontia, hypoplastic enamels, ankylosis of the retained primary teeth, overeruptions, and volume deficiencies of alveolar ridges. The challenges mentioned, as well as bone volume deficiencies, compromise the successful placement of implants. Orthodontic strategies and techniques, such as uprighting mechanics, extrusion/intrusion, delayed space opening, and orthodontic implant site-switching, can be used to create, preserve, or augment the implant site. After orthodontic site development, the final planned position of the teeth should be maintained with a rigid bonded retainer; overlooking this stage may compromise the implant site and require orthodontic retreatment.

Dentistry and molecular biology: a promising field for tooth agenesis management

Tooth agenesis is the failure of tooth bud development, causing definitive absence of the tooth. It is the most common dental anomaly, affecting up to one-quarter of the general population. The main cause is related to abnormal function of specific genes which play key roles during odontogenesis, particularly MSX1 and PAX9. MSX1 is a transcription factor highly expressed in the mesenchyme of developing tooth germs, whereas PAX9 is a transcription factor that shows a direct relationship with craniofacial development, particularly the formation of the palate and teeth. Despite the high frequency of tooth agenesis, there are as yet only a restricted number of mutations in MSX1 and PAX9 that have been associated with non-syndromic tooth agenesis. Thus, a deeper analysis of the gene networks underlying this anomaly is imperative. By means of a literature review based on Medline, PubMed, Lilacs, NCBI, and STRING, performed between 1991 and 2010 and focused on etiologically associated mutations, this work aimed to assess the latest advances in the genetic etiology of tooth agenesis and to offer an insight into how they can assist dental practice in the near future. A better knowledge of the genetic networks underlying tooth agenesis will lead to better treatment options and, perhaps, a tool for early diagnosis possibly related to DNA examination based on polymorphic variants. Such a test based on DNA analysis may be available to and accessible by clinicians, resulting in a more accurate diagnosis and allowing for a better approach to this anomaly.

Factors that affect variability in impairment of maxillary growth in patients with cleft lip and palate treated using the same surgical protocol

No consensus exists about the causes of restriction of maxillary growth in patients with cleft lip and palate (CLP). The aim of this study was to try to identify causes of this impairment other than the influence of surgical technique and skill. We analysed a sample of 129 consecutively treated 5-year-old children with unilateral cleft lip and palate (UCLP), who were operated on by the same surgeon with the same protocol. Multiple cephalometric measurements of the sample showed a wide distribution of values for maxillary growth. We selected SNA as a value describing maxillary position. Variables investigated were: initial cast measurements; timing of lip and of gingivoalveoloplasty (GAP)/palatal surgery; and presence of permanent lateral incisors. The significance of differences was investigated with Pearson's correlation and analysis of variance (ANOVA). The factor most significantly linked with maxillary protrusion was the presence or absence of the permanent lateral incisor, even when peg laterals and supernumerary laterals were considered. Initial width of the palate measured on infant casts correlated with maxillary growth, but the timing of GAP did not. Although surgical skill and technique may be the most important factors responsible for impairment of maxillary growth, inherent tissue hypoplasia, possibly the lack of lateral incisors, seems to be the most important non-iatrogenic factor.