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

Variation of Tooth Crown Size in Cleft Lip and Palate Patients

AIM

This study aims to compare the mesiodistal (MD) and buccolingual (BL) tooth crown size (TCS) of adult patients with cleft lip and palate (CL/P) and patients without CL/P.

MATERIALS AND METHODS

The sample of this study consisted of 146 adult patients, of both genders, of which 73 were included in the case group (with CL/P) and 73 were included in the control group (without CL/P). Data regarding gender and age and cleft type were collected. In addition, dental models were evaluated to obtain the TCS in the maximum distance of the MD and BL dimensions of all erupted permanent teeth (except third molars). The results were submitted to statistical analysis with a significance level of 0.05.

RESULTS

In the upper arch, the central incisors (CI) were smaller in the case group for the MD and BL dimensions (p < 0.05). The lateral incisors (LI) and canine (C) were smaller only in the BL width (p < 0.05) and the second molars (SM), were smaller only in the MD dimensions. In the lower arch, there were significant differences only in the BL width between groups, the CI and LI presented smaller measurements in CL/P patients, while the left first molar (FM) and right first premolar (FPM) were larger (p < 0.05) than in patients without CL/P.

CONCLUSION

Patients with CL/P have different sizes in certain teeth compared to patients without CL/P.

CLINICAL RELEVANCE

Cleft lip and palate patients usually present important dental anomalies; thereby, the knowledge about trends in tooth size variations in CL/P patients can aid in dental and orthodontic treatment planning to obtain a stable, functional, and esthetic occlusion.

Odontogenesis-related candidate genes involved in variations of permanent teeth size

OBJECTIVE

The aim of the study was to evaluate the association between genetic polymorphisms in RUNX2, BMP4, BMP2, TGFβ1, EGF, and SMAD6 and variations in permanent tooth size (TS).

MATERIALS AND METHODS

This cross-sectional study evaluated 110 individuals' dental casts to determine the maximum tooth crown size of all fully erupted permanent teeth (third molars were excluded) in the mesiodistal (MD) and buccolingual (BL) dimensions. Genomic DNA was obtained from the epithelial cells of the oral mucosa to evaluate the genetic polymorphisms in RUNX2 (rs59983488 and rs1200425), BMP4 (rs17563), BMP2 (rs235768 and rs1005464), TGFβ1 (rs1800470), EGF (rs4444903), and SMAD6 (rs2119261 and rs3934908) through real-time PCR. The data were submitted to statistical analysis with a significance level of 0.05.

RESULTS

The genetic polymorphisms rs59983488, rs1200425, rs17563, rs235768, rs1005464, rs1800470, and rs4444903 were associated with MD and BL TS of the upper and lower arches (p < 0.05). The polymorphism rs2119261 was associated with variation in TS only in the upper arch (p < 0.05). The rs3934908 was not associated with any TS measurement (p > 0.05).

CONCLUSIONS

In summary, this study reports novel associations between variation in permanent TS and genetic polymorphisms in RUNX2, BMP4, BMP2, TGFβ1, EGF, and SMAD6 indicating a possible role of these genes in dental morphology.

CLINICAL RELEVANCE

Polymorphisms in odontogenesis-related genes may be involved in dental morphology enabling a prediction of permanent TS variability. The knowledge regarding genes involved in TS might impact the personalized dental treatment, considering that patients' genetic profile would soon be introduced into clinical practice to improve patient management.

Sagittal Jaw Relationship of Different Types of Cleft and Non-cleft Individuals

To investigate whether the craniofacial sagittal jaw relationship in patients with non-syndromic cleft differed from non-cleft (NC) individuals by artificial intelligence (A.I.)-driven lateral cephalometric (Late. Ceph.) analysis. The study group comprised 123 subjects with different types of clefts including 29 = BCLP (bilateral cleft lip and palate), 41 = UCLP (unilateral cleft lip and palate), 9 = UCLA (unilateral cleft lip and alveolus), 13 = UCL (unilateral cleft lip) and NC = 31. The mean age was 14.77 years. SNA, SNB, ANB angle and Wits appraisal was measured in lateral cephalogram using a new innovative A.I driven Webceph software. Two-way ANOVA and multiple-comparison statistics tests were applied to see the differences between gender and among different types of clefts vs. NC individuals. A significant decrease (p < 0.005) in SNA, ANB, Wits appraisal was observed in different types of clefts vs. NC individuals. SNB (p > 0.005) showed insignificant variables in relation to type of clefts. No significant difference was also found in terms of gender in relation to any type of clefts and NC group. The present study advocates a decrease in sagittal development (SNA, ANB and Wits appraisal) in different types of cleft compared to NC individuals.

Human permanent tooth sizes are associated with genes encoding oestrogen receptors

OBJECTIVE

To evaluate if genetic polymorphisms in the oestrogen receptor 1 (ESR1) and oestrogen receptor 2 (ESR2) genes encoded for oestrogen receptors alpha (ERα) and beta (ERβ) are involved in permanent tooth size.

DESIGN

Cross-sectional study.

SETTING

Orthodontic Clinic at School of Dentistry of Ribeirão Preto, University of São Paulo.

PARTICIPANTS

A total of 108 orthodontic patients.

MATERIALS AND METHODS

Pre-treatment orthodontic records were evaluated. Dental casts were used to determine the maximum crown measurements of fully erupted permanent teeth in the mesiodistal dimensions. Second and third molars were not included in the analysis. Genomic DNA samples were used for the genotyping of four genetic polymorphisms: ESR1 (rs9340799 and rs2234693) and ESR2 (rs1256049 and rs4986938). The associations between tooth size and sex were evaluated using t test. The associations between tooth size and genotype were analysed with linear regression and adjusted by sex at an alpha of P⩽0.05.

RESULTS

Female patients presented smaller tooth size than male patients. A statistically significant difference was observed in almost all teeth (P<0.05). The genetic polymorphisms in rs9340799, rs2234693, rs1256049 and rs4986938 were associated with some tooth sizes in both the maxilla and mandible (P<0.05).

CONCLUSION

This study provides evidence that genetic polymorphisms in ESR1 and ESR2 could be associated with tooth size in permanent teeth.

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

OBJECTIVE

The present study aimed to evaluate if genetic variants in PAX9, MSX1, TGFα, FGF3, FGF10, FGF13, GLI2 and GLI3 are involved in TS of permanent teeth.

MATERIALS AND METHODS

Pretreatment dental records from orthodontic patients were assessed prior to recruitment. Patients with tooth agenesis and congenital anomalies (including oral cleft) and/or syndromes were excluded. Dental casts were used to measure the maximum crown dimensions of all fully erupted permanent teeth except second and third molars in mesiodistal direction. Teeth with caries, occlusal wear, mesiodistal restorations, and obvious deformities were not evaluated. Genomic DNA samples were used for genotyping. The allelic discrimination of 13 genetic variants was performed. The associations between TS and genotype were analyzed by linear regression, adjusted by gender at a significance level of p ≤ 0.05.

RESULTS

Genetic polymorphisms in the tooth agenesis-related genes studied here were associated with increased and decreased TS, in both maxilla and mandible (p < 0.05).

CONCLUSION

This study reported associations of novel tooth agenesis-related gene variants with permanent tooth size variations.

CLINICAL RELEVANCE

The presence of some genetic variants could allow the prediction of permanent tooth size.

Analysis of permanent second molar development in children born with cleft lip and palate

OBJECTIVE

The study of dental development in individuals born with cleft lip and palate (CLP) serves to determine when orthodontic intervention should start. To evaluate the permanent second molar development in children born with cleft lip and palate according to Demirjian's and Nolla's methods.

METHODOLOGY

Out of a total of 513 digital panoramic radiographs, 113 pairs of children aged 3 to 16 years were selected. The exams were from children born with or without cleft lip and palate, of the same sex, with an age difference of up to 30 days. The images were analyzed by three examiners and reliability was checked through intra-examiner agreement by the Kappa test. The data were analyzed by Wilcoxon's and Mann-Whitney tests according to each dataset.

RESULTS

The findings indicated delayed development of the permanent second molars in children with CLP (P<0.001). The development of the right permanent second molar was delayed compared to the left molar in children with CLP. Moreover, mandibular teeth showed significantly earlier development than maxillary teeth in both the case and control groups. There was no significant difference in the development of permanent second molars between sexes.

CONCLUSION

Children with CLP presented delay in the development of permanent second molars.

Delayed maturation and reduced crown width of the permanent first mandibular molar in all subgroups of cleft lip and palate

OBJECTIVES

Surgical closure of the cleft damages nerves and blood supply in the area and may possibly negatively influence dental development in children with cleft lip and palate (CLP). Previous studies of the permanent first mandibular molar (M1_inf ) in children with unilateral complete CLP found delayed maturation and decreased follicle/crown width before any surgical interventions. This study aimed to investigate if these findings are representative for the total population of individuals born with CLP.

SETTING AND SAMPLE POPULATION

A population-based consecutive longitudinal sample of 224 children with clefts: 183 with CLP (66 with complete [47 unilateral, 19 bilateral], 117 with incomplete [70 unilateral, 47 bilateral], and 41 with unilateral incomplete cleft lip (controls), was examined pre- and post-lip closure (at 2 and 22 months of age).

MATERIAL AND METHODS

In lateral cephalometric X-rays (obtained as part of a standard treatment protocol), M1_inf follicle maturation and follicle/crown width were assessed. Mantel-Haenszel test and Pearson's correlation coefficient R were used to describe relationships. Differences between group means were tested using Wilcoxon rank sum test. Significance level was set to 5%.

RESULTS

Follicle maturation was significantly delayed in all groups with CLP compared to that in controls (P < .01). Follicle and crown width were significantly reduced in all CLP groups compared with those in controls (P < .01). Sex did not influence these variables.

CONCLUSION

Delayed follicle maturation and decreased follicle/crown/tooth size were found to be part of the congenital traits characterizing individuals with all types of CLP and not a result of surgical iatrogenesis.

Early post-natal development of the mandibular permanent first molar in infants with unilateral complete cleft lip and palate

OBJECTIVES

Studies have shown that the mandibular permanent first molar (M1_inf ) in young children with isolated cleft palate is characterized by delay in maturation and has reduced crown width. Consequently, it is of interest to investigate the early maturation and width of the follicle and crown of M1_inf in children with combined cleft lip and palate.

DESIGN

Retrospective, longitudinal study. Cephalometric X-rays of 47 consecutive Danish children with UCCLP (37 males; 10 females) and 44 with unilateral incomplete cleft lip (UICL) (29 males; 15 females) examined at 2 and 22 months of age. UICL served as control group. Maturation (according to Haavikko), width of follicle (FW) and crown (CW) of M1_inf were assessed.

RESULTS

The maturation of the first mandibular molar was delayed in both genders at 2 and 22 months of age. FW and CW were smaller in children with UCCLP at both 2 and 22 months of age. There was a positive correlation between maturation and FW.

CONCLUSIONS

Maturation of the first mandibular molar is delayed in both genders, and FW and CW were reduced in UCCLP compared to controls. Maturation was correlated with FW.

On the Etiology of Molar-Incisor Hypomineralization

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Reports on the etiology of the condition and possible risk factors are inconclusive and the original suggestion that MIH is an idiopathic condition is often cited. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. In this report, we provide a rationale to explain the preferential affection of molars and incisors. We suggest that MIH is a genetic condition based on its prevalence, which varies depending on the geographic location, and the evidence that on occasion second primary molars, permanent canines, and premolars can show signs of hypomineralization of enamel when molars and incisors are affected.

Association between tooth size and interarch relationships in children with operated complete unilateral cleft lip and palate

Background

To evaluate mesiodistal tooth width of patients with UCLP comparing tooth size in different Goslon Yardstick scores and between cleft and noncleft sides.

Methods

The Department of Orthodontics at Bauru Dental School and Hospital of Rehabilitation of Craniofacial Anomalies – University of Sao Paulo. Hundred forty-four pairs of dental casts of patients with UCLP. These dental casts were divided into 3 groups: group I (patients with Goslon rating of 1 and 2), group II (Goslon rating of 3) and group III (Goslon rating of 4 and 5). The control group consisted of 40 pairs of dental casts of noncleft Class I patients at the same age range. Mesiodistal width of maxillary permanent central incisors, lateral incisors and first molars were measured using a digital caliper. Intergroup comparisons were performed using ANOVA followed by Tukey tests. T tests were used to compare tooth size between cleft and noncleft sides (p <0.05).

Results

Differences for tooth size were observed between individuals with different Goslon Yardstik scores. Mesiodistal widths of maxillary central incisors in subjects of Group III were significantly smaller compared to Group I and to the control group. The lateral incisors at the cleft side were smaller than the antimere.

Conclusions

Mesiodistal tooth size was smaller in poor Goslon yardstick scores. Cleft and noncleft sides demonstrated similar maxillary tooth size except for the lateral incisor.

Cleft Palate-Craniofacial Journal 50th anniversary editorial board commentary: anatomy, basic sciences, and genetics--then and now

To celebrate the 50th year of the Cleft Palate-Craniofacial Journal we look back to where we started in 1964 and where we are now, and we speculate about directions for the future in a "Then and Now" editorial series. This editorial examines changing trends and perspectives in anatomical, basic science, and genetic studies published in this 50-year interval. In volume 1 there were 45 total papers, seven (16%) of which were peer-reviewed basic science and genetic articles published: four in anatomy, three in craniofacial biology, and none in genetics. In contrast, in volume 50, of 113 articles there were 47 (42%) peer-reviewed basic science and genetic articles published: 30 in anatomy, five in craniofacial biology, and 12 in genetics. Topical analysis of published manuscripts then and now reveal that similar topics in anatomy and craniofacial biology are still being researched today (e.g., phenotypic variability, optimal timing of surgery, presurgical orthopedics, bone grafting); whereas, most of the more recent papers use advanced technology to address old questions. In contrast, genetic publications have clearly increased in frequency during the last 50 years, which parallels advances in the field during this time. However, all of us have noticed that the more "cutting-edge" papers in these areas are not being submitted for publication to the journal, but instead to discipline-specific journals. Concerted efforts are therefore indicated to attract and publish these cutting-edge papers in order to keep the Cleft Palate-Craniofacial Journal in the forefront of orofacial cleft and craniofacial anomaly research and to provide a valuable service to American Cleft Palate-Craniofacial Association members.