Arch width changes from 6 weeks to 45 years of age

Palatal morphology: A systematic review of the association of palatal shape with genetic ancestry, sex and age

OBJECTIVES

This study aims to review the literature regarding palatal shape variation, and its influence on estimating genetic ancestry, sex, and age.

DESIGN

A literature search was performed using PubMed, Scopus and Embase databases, from inception up to January 2025. Original research articles in English examining variation in shape of human hard palate were included, irrespective of study type or publication year. Articles regarding craniofacial anomalies, pathologies and orthodontic treatment were excluded. The risk of bias was assessed independently by two reviewers using the Joanna Briggs Institute critical appraisal tool.

RESULTS

Twenty-two studies fulfilled the selection criteria. Dental casts (n = 13) and crania (n = 8) were predominantly utilised in the studies. Geometric morphometrics emerged as the predominant method for palatal shape analysis, followed by fourth-order polynomial curve fitting, visual assessments and ratios. Five studies examined ancestral variation in palatal shape, with four reporting differences between population groups. These studies, however, utilised fixed landmarks only, offering limited insight. Sexual dimorphism of palatal shape was extensively investigated (n = 12), with large numbers of semi-landmarks employed in two studies, but association was reported in four studies only. Palatal shape was reported to change from birth to adulthood but remained unchanged after adulthood.

CONCLUSION

This review highlights that palatal shape may aid ancestry classification but remains inconsistent to classify sex. Palatal shape changes during growth are allometric and hence need to be considered in forensic investigations. More standardised and robust methods may better evaluate the effects of ancestry, sex and age on 3D palatal variation.

Dynamic changes in dental arches during growth and development: clinical applications and implications

OBJECTIVES

This study aimed to investigate the dynamic changes in dental arch size and shape in children with normal occlusion and to evaluate and visualize the effects of early orthodontic treatment.

METHODS

A total of 274 normal occlusion subjects (4 to 12 years, mean age 7.38 years) were selected from a pool of 2,695 school-age children in Chengdu. These subjects were divided into 5 age groups according to Hellman's dental ages. The complete dental arch forms were described using polynomial fitting curves. To observe changes in arch size, the average arch width, depth, and perimeter were measured for each group. To analyze changes in arch shape, the arch forms were normalized using the max-min normalization and then divided into 6 clusters (grouping of shapes) using the k-means algorithm. The proportions of these clusters across different age groups were then determined.

RESULTS

The periods of rapid occlusal development occur between the ages of 4 to 8 years and 11 to 12 years, during which the arch width, depth, and perimeter increase rapidly. As children grow, the complete dental arch shape becomes more elongate. To assess and visualize early orthodontic treatment effects, typical normal arch shapes can be scaled to fit the size of individual cases.

CONCLUSION

The size and shape of arch form change dynamically from late primary dentition to early permanent dentition. Notably, the arch depth tends to increase more than the arch width.

CLINICAL RELEVANCE

A well-conducted early orthodontic treatment may bring the arch form closer to the typical normal one.

Genetic and environmental contributions to the development of dental arch traits: a longitudinal twin study

OBJECTIVE

This study aimed to estimate the relative contributions of genetic and environmental factors to phenotypic variations of dental arch traits from primary to permanent dentition stages.

METHODS

Digital dental models of 188 Australian twin pairs (90 monozygotic and 98 dizygotic) in the primary dentition stage, followed up through the mixed and permanent dentition stages, were included in the study. Landmarks were identified on both maxillary and mandibular dental arches in MeshLab for measuring intercanine widths, intermolar widths, arch lengths, overjet, overbite and molar relationships. Genetic structural equation modelling was performed on the quantitative twin data of dental arch traits.

RESULTS

The phenotypic variance of dental arch traits was generally best explained by a model incorporating additive genetic (A) and non-shared environmental (E) components, an AE model. However, the variance of overjet in the primary dentition was best explained by shared environmental (C) and non-shared environmental (E) components. Heritability estimates were high for intra-arch traits (0.65-0.88), but low to moderate for inter-arch traits (0.21-0.51). While heritability estimates fluctuated for most traits from primary to permanent dentition stages, the estimates for arch lengths and intermolar widths were mostly above 0.8 throughout development.

LIMITATION

Only twins of European descent were included in this study.

CONCLUSIONS

Dental arch traits were mostly influenced by additive genetic and non-shared environmental factors during development. Except for arch lengths and intermolar widths, genetic and environmental influences on dental arch traits fluctuated during development, with the genetic influence at its lowest during the mixed dentition stage.

Transverse dentoalveolar development in Chinese children and adolescents: A cross-sectional study using revised Andrews' Element III analysis

INTRODUCTION

This study investigated the prevalence of maxillary transverse deficiency (MTD) in Chinese children and adolescents using revised Andrews' Element III analysis and studied transverse developmental characteristics of the maxillomandibular complex.

METHODS

Plaster or digital casts of 794 participants aged 7-18 years were evaluated. MTD was diagnosed when the maxilla-mandible width difference, represented by the decompensated maxillary and mandibular first molars, exceeded 4 mm.

RESULTS

The average prevalence of MTD among patients aged 7-18 years was 31.1%. Patients with MTD exhibited narrower maxillary and/or wider mandibular arches. Strikingly, 32.3% of participants with posterior crossbite because of local crowding or mandibular deviation were not diagnosed with MTD. Dental compensation, such as a greater buccolingual inclination of the first molars, was common in patients with MTD. Transverse growth of the maxillomandibular complex was completed by 17 years old, with the maxilla undergoing greater transverse growth than the mandible. The physiological buccolingual inclination of first molars was observed in patients without MTD. The 95% reference value of the palatal arch width was 31.9-42.3 mm.

CONCLUSIONS

The prevalence of MTD is 31.1% among Chinese children and adolescents. However, it is often camouflaged by dental compensation and sagittal discrepancy. The etiology of MTD is uncoordinated width in the maxillomandibular complex, which is not solely attributed to a narrow maxilla but also to an excessively wide mandible. To enhance diagnostic accuracy, individualized measurements of the maxillomandibular complex and a revised dental decompensation formula, rather than posterior crossbite alone, are recommended for transverse diagnosis. A potential presence of MTD is indicated when the palatal arch width is <31.9 mm.

Evaluation of anterior fixed appliances on maxillary arch growth in preschool children

This study aimed to evaluate a new modified fixed appliance for rehabilitation of premature loss of anterior teeth in preschool children versus a modified Nance appliance on maxillary arch growth with parental satisfaction. The study was conducted as a clinical trial and it was carried out at Pediatric Dentistry Department, Faculty of Dentistry, Tanta University. Forty preschool children from both genders aged from 3-5 years were included in the study. The selected children were divided into two groups; Group I: Twenty children received a modified fixed bridge. Group II: Twenty received a modified Nance appliance. Evaluation of both appliances on maxillary growth was carried out at baseline, 6 and 12 months. Finally, parental satisfaction was also recorded. It was revealed that, there was continuous maxillary growth in both groups at different follow up periods with no sexual dimorphism, and parental satisfaction was significantly higher in group I than group II. A modified fixed bridge was better than Nance appliance regarding parental satisfaction and it doesn't interfere with maxillary growth.

Application of a 3D Fusion Model to Evaluate the Efficacy of Clear Aligner Therapy in Malocclusion Patients: Prospective Observational Study

BACKGROUND

Investigating the safe range of orthodontic tooth movement is essential for maintaining oral and maxillofacial stability posttreatment. Although clear aligners rely on pretreatment digital models, their effect on periodontal hard tissues remains uncertain. By integrating cone beam computed tomography-derived cervical and root data with crown data from digital intraoral scans, a 3D fusion model may enhance precision and safety.

OBJECTIVE

This study aims to construct a 3D fusion model based on artificial intelligence software that matches cone beam computed tomography and intraoral scanning data using the Andrews' Six Element standard. The model will be used to assess the 3D effects of clear aligners on tooth movement, to provide a reference for the design of pretreatment target positions.

METHODS

Between May 2022 and May 2024, a total of 320 patients who completed clear aligner therapy at our institution were screened; 136 patients (aged 13-35 years, fully erupted permanent dentition and periodontal pocket depth <3 mm) met the criteria. Baseline ("simulation") and posttreatment ("fusion") models were compared. Outcomes included upper core discrepancy (UCD), upper incisors anteroposterior discrepancy (UAP), lower Spee curve deep discrepancy (LSD), upper anterior teeth width discrepancy (UAW), upper canine width discrepancy (UCW), upper molar width discrepancy (UMW), and total scores. Subanalyses examined sex, age stage (adolescent vs adult), and treatment method (extraction vs nonextraction).

RESULTS

The study was funded in May 2022, with data collection beginning the same month and continuing until May 2024. Of 320 initial participants, 136 met the inclusion criteria. Data analysis is ongoing, and final results are expected by late 2024. Among the 136 participants, 90 (66%) were female, 46 (34%) were male, 64 (47%) were adolescents, 72 (53%) were adults, 38 (28%) underwent extraction, and 98 (72%) did not. Total scores did not differ significantly by sex (mean difference 0.01, 95% CI -0.13 to 0.15; P=.85), age stage (mean difference 0.03, 95% CI -0.10 to 0.17; P=.60), or treatment method (mean difference 0.07, 95% CI -0.22 to 0.07; P=.32). No significant differences were found in UCD (mean difference 0.001, 95% CI -0.02 to 0.01; P=.90) or UAP (mean difference 0.01, 95% CI -0.03 to 0.00; P=.06) by treatment method. However, adolescents exhibited smaller differences in UCD, UAW, UCW, and UMW yet larger differences in UAP and LSD (df=134; P<.001). Extraction cases showed smaller LSD, UAW, and UCW but larger UMW differences compared with nonextraction (df=134; P<.001).

CONCLUSIONS

The 3D fusion model provides a reliable clinical reference for target position design and treatment outcome evaluation in clear aligner systems. The construction and application of a 3D fusion model in clear aligner orthodontics represent a significant leap forward, offering substantial clinical benefits while establishing a new standard for precision, personalization, and evidence-based treatment planning in the field.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2400094304, https://www.chictr.org.cn/hvshowproject.html?id=266090&v=1.0.

Novel concept for posterior crossbite correction : Preliminary results

PURPOSE

The efficiency of dentoalveolar compensation involving both jaws for posterior crossbite correction using computer-aided design/computer-aided manufacturing (CAD/CAM) expansion and compression archwires was evaluated. Treatment outcome was tested against the null hypothesis that the transverse correction achieved would be significantly smaller than planned.

METHODS

This retrospective study included 64 patients (mean age 23.5 years, median 17.0, minimum/maximum: 9.0/63.0, standard deviation 13.7) with uni- or bilateral posterior crossbite. In all consecutively debonded patients, expansion and/or compression archwires were used for dentoalveolar correction involving both jaws. Plaster casts prior to (T1) and following treatment (T2) with completely customized lingual appliances (CCLA) were compared with the treatment plan represented by an individual target set-up. The statistical analysis was carried out using the Schuirmann TOST (two one-sided t‑tests) equivalence test on the basis of a one-sample t‑test with α = 0.025 to one side. The non-inferiority margin was set at δ = 0.5 mm.

RESULTS

All posterior crossbites could be corrected by dentoalveolar compensation involving both jaws. The mean total correction achieved was 6.9 mm (mean maxillary expansion: 4.3 mm/mean mandibular compression: 2.6 mm) with a maximum of 12.8 mm. The transverse corrections achieved in both arches at T2 were equivalent to the planned corrections in the set-up (p < 0.001).

CONCLUSION

The results of this study indicate that CAD/CAM expansion and compression archwires can be an efficient tool to achieve the desired correction in patients with a posterior crossbite even in more severe cases.

Current Trends in Pediatric Orthodontics: A Comprehensive Review

Pediatric orthodontics is a critical field focusing on the diagnosis, prevention, and treatment of dental and facial irregularities in children. This comprehensive review explores current trends and methodologies in pediatric orthodontics and discusses the multifactorial etiology of malocclusions, including genetic, environmental, and disease-related factors. The importance of proper diagnosis is highlighted, and the extraoral, intraoral, and functional evaluations essential for effective treatment planning are detailed. Various orthodontic conditions such as Class III and Class II malocclusions, abnormal oral habits, arch length discrepancies, anterior and posterior crossbites, open bites, and deep bites are examined in depth. The review also addresses the role of temporomandibular joint disorders (TMDs) and obstructive sleep apnea (OSA) in pediatric patients, emphasizing the need for early and accurate diagnosis to facilitate appropriate intervention. The use of clear aligners in early orthodontic intervention is evaluated given their efficacy and improved patient satisfaction compared to traditional appliances. Additionally, the article discusses the non-advisability of early interception for certain self-correcting malocclusions and the limitations of pediatric orthodontic treatment, including compliance-related issues and the unique anatomical considerations of deciduous dentition. This review aims to provide a detailed understanding of contemporary practices and challenges in pediatric orthodontics, offering insights for clinicians to enhance treatment outcomes and patient care.

Evaluation of Biomarkers of Bone Metabolism on Salivary Matrix in the Remodeling of Periodontal Tissue during Orthodontic Treatment

The aim of this study was to evaluate changes in the concentration of N-terminal type I collagen extension pro-peptide (PINP), tartrate-resistant acid phosphatase (TRAcP), and parathyroid hormone-related protein (PTHrP) in saliva during orthodontic treatment in order to evaluate whether changes in bone turnover marker (BTM) concentration can help highlight the effects of orthodontic mechanical loading in the absence of clinical evidence of tooth movement in terms of tooth movement. Saliva samples from 25 apparently healthy young subjects (10 females and 15 males) were collected using Salivette® (Sarstedt) with cotton swabs and the concentrations of PTHrP, TRAcP 5b, and PINP were analyzed at time 0 (T1), 25 days (T2), and at 45 days (T3). Differences in the median value of biomarker levels between baseline T1 and follow-up of the different groups (T2 and T3) were assessed using the non-parametric Mann-Whitney U test. Trough concentrations of P1NP, PTHrP, and TRAcP were 0.80 µg/L, 0.21 ng/mL, and 0.90 U/L above the method LOD. The non-parametric Mann-Whitney U test confirmed a statistically significant difference in T1 versus concentrations of T2 and T3. All subjects evaluated had a statistically significant difference between T1 vs. T3. when compared with the specific critical difference (RCV) for the analyte The results obtained demonstrate that the evaluation of BTM changes in saliva can help the evaluation of orthodontic procedures and the monitoring of biomechanical therapy.

Evaluation of maxillary dimensional changes in the mixed dentition: clear aligners vs acrylic expanders

OBJECTIVES

To compare changes in upper arch dimension and molar inclination between Invisalign First (IF) and removable acrylic expander (RE) treatments during the mixed dentition period.

MATERIALS AND METHODS

Seventeen patients meeting inclusion criteria underwent IF treatment and were age matched with a group that received treatment with a removable acrylic expander (RE). Intercanine width (ICW), intermolar width, arch depth, buccolingual inclination of the first molars (MI), surface area (SA) and volume (VAP) of the anterior palate, and expansion were compared before and after treatment. The predictability of expansion was calculated for the IF group. Analysis of variance and Kruskal-Wallis tests were used to assess differences.

RESULTS

The ICW increased significantly by 2.14 mm in the IF group and 3.49 mm in the RE group, with no significant intergroup difference. Both groups exhibited significant increases in intermolar width (P < .05), except for intermolar distopalatal width in the IF group (P = .246). Mesiobuccal rotation of the first molar was observed with IF treatment. Although SA and VAP increased in both groups, the changes were not significant for the IF group (P > .05). The RE group exhibited significantly higher increases (P < .05), with an SA increase of 34.32 mm2 and VAP increase of 119.15 mm3. MI changes were in the opposite directions. The prediction accuracy of expansion was 70.28% for canines and 34.12% for first molars.

CONCLUSIONS

Both appliances effectively expanded the intercanine region in growing patients. Expansion predictability was lower in first molars than in canines for the IF group. Removable acrylic expanders could be a choice of preference for expansion targeted to the molar region.

Mandibular Intercanine Width at Three Stages of Mixed Dentition in Children at Namakkal District: A Cross-sectional Study

Aim

To assess and compare the mandibular intercanine width (ICW) of children at three stages of mixed dentition in children at Namakkal district.

Materials and methods

An analytical cross-sectional study was conducted among 135 schoolchildren aged 7-11 years, with 45 children in each group. Group I included children with completely erupted permanent mandibular central incisors, group II included children with completely erupted permanent mandibular central and lateral incisors, and group III included children with completely erupted permanent mandibular central incisors, lateral incisors, and canines. Impressions were made in the mandibular anterior region, and study casts were prepared. Measurements of the mandibular ICW were taken using a digital vernier caliper.

Results

The mean mandibular ICW after the complete eruption of permanent mandibular central incisors, lateral incisors, and canines was 23.7, 25.5, and 25.7 mm, respectively. There was a statistically significant difference in the ICW between the three groups (p < 0.001). Post hoc tests showed that mandibular ICW was statistically significant between groups I and II and group III (p < 0.001). Linear regression analysis showed that age does not contribute to the changes in mandibular ICW.

Conclusion

The average mandibular ICW found can be a standard comparison for treatment planning in the western Tamil Nadu population. Mandibular ICW reaches its maximum after the eruption of permanent mandibular lateral incisors. Changes in mandibular ICW should be attributed to the eruption of permanent mandibular anterior teeth and not to the age of the child.

How to cite this article

Balaraman C, Asokan S, Pollachi Ramakrishnan GP, et al. Mandibular Intercanine Width at Three Stages of Mixed Dentition in Children at Namakkal District: A Cross-sectional Study. Int J Clin Pediatr Dent 2024;17(7):737-741.

The association between dental and dentoalveolar arch forms of children with normal occlusion and malocclusion: a cross-sectional study

BACKGROUND

Symmetrical and coordinated dental and alveolar arches are crucial for achieving proper occlusion. This study aimed to explore the association between dental and dentoalveolar arch forms in children with both normal occlusion and malocclusion.

METHODS

209 normal occlusion subjects (5-13 years, mean 8.48 years) and 199 malocclusion subjects (5-12 years, mean 8.19 years) were included. The dentoalveolar arch form was characterized by the smoothest projected curve representing the layered contour of the buccal alveolar bone, referred to as the LiLo curve. Subsequently, a polynomial function was utilized to assess dental and dentoalveolar arch forms. To facilitate separate analyses of shape (depth/width ratio) and size (depth and width), the widths of dental and dentoalveolar arch forms were normalized. The normalized dental and dentoalveolar arch forms (shapes) were further classified into 6 groups, termed dental/dentoalveolar arch clusters, using the k-means algorithm.

RESULTS

The association between dental and dentoalveolar arch clusters was found to be one-to-many rather than one-to-one. The mismatch between dental and dentoalveolar arch forms is common in malocclusion, affecting 11.4% of the maxilla and 9.2% of the mandible, respectively.

CONCLUSIONS

There are large individual variations in the association between dental and dentoalveolar arch forms. Early orthodontic treatment may play an active role in coordinating the relationship between the dental and dentoalveolar arch forms.

Variation of OXIS contact areas in primary molars among 3-6-year-old children with intraoral digital scanning

PURPOSE

To determine the variation of OXIS contact areas in primary molars using digital impressions generated from an intraoral scanner (IOS).

METHODS

A cross-sectional study was carried out on 214 caries-free posterior quadrants of 80 children (38 males and 42 females) aged 3-6 years. Calibration of taking digital impressions with the IOS procedure was performed initially through scanning of ten quadrants of children to provide a learning environment to the examiner. The digital impressions were then exported, and the type of interproximal contact areas present between the distal surface of the primary first molar and the mesial surface of the primary second molar were identified according to the OXIS classification. The prevalence of the types of OXIS contact areas was expressed in the form of numbers and percentages. The chi-square test was applied to investigate the variability among the arches and to understand the association of OXIS contact areas across age, gender, and arches.

RESULTS

The most common contact area type observed was I-type (59.8%), followed by S-type (15.4%), X-type (12.6%), and O-type (12.2%). The I-type contact area was most frequently seen in both males (51.6%) and females (65.5%), while the S-type contact area in males (14.7%) and X-type contact area in females (8.4% each) were the least frequent with no statistical significance between genders (p > 0.05). All three age groups studied showed the highest prevalence of the I-type contact area, which increased with an increase in age (p < 0.05). The inter-arch comparison showed a significant result in terms of the X-type contact area on the right side, and O-type, X-type, and I-type contact areas on the left side, while no statistical difference was seen in the intra-arch comparison for all contact types.

CONCLUSION

I-type contact areas were the most prevalent across the arches, age groups and genders.

Intraoral Scanning Evaluation of Maxillary Arch Changes after Modified Sommerlad Palatoplasty for around Three Years

BACKGROUND

The purpose of this study was to investigate dental arch changes after modified Sommerlad palatoplasty in patients with cleft palate by intraoral scanning technique in children with early deciduous dentition.

METHODS

This study included 60 patients with nonsyndromic unilateral complete cleft lip with palate or cleft palate only treated by modified Sommerlad palatoplasty without relaxed excision before 18 months of age and 95 healthy controls without cleft. Three-dimensional images of the maxillary dental arches of all participants at age 3 to 4 years were obtained by intraoral scanning technique. Seven parameters (anterior dental arch width, middle dental arch width, posterior dental arch width, anterior palatal arch width, posterior palatal arch width, anterior dental arch length, and entire dental arch length) were measured.

RESULTS

Compared with the male group, the posterior palatal arch width distance of controls in the female group decreased significantly ( P = 0.039), and the middle dental arch width, posterior dental arch width, and posterior palatal arch width distance of female patients decreased ( P = 0.013, P = 0.002, P = 0.005, respectively). The anterior dental arch length and entire dental arch length distance of children in the unilateral complete cleft lip with palate group was shorter than those of children with cleft palate only ( P < 0.0001, P < 0.0001, respectively). The patient group showed decreased distance of anterior dental arch width, anterior palatal arch width, anterior dental arch length, and entire dental arch length, and increased distance of posterior dental arch width and posterior palatal arch width compared with the control group ( P = 0.0002, P = 0.002, P < 0.0001, P < 0.0001, P = 0.007, P = 0.027, respectively).

CONCLUSION

The results indicated that the modified palatoplasty group showed no growth inhibition in the middle or posterior dental arch width, or palatal arch width, but slight but significant inhibition in the length of the anterior and entire dental arch.

CLINICAL QUESTION/LEVEL OF EVIDNCE

Therapeutic, IV.

Expert consensus on pediatric orthodontic therapies of malocclusions in children

Malocclusion, identified by the World Health Organization (WHO) as one of three major oral diseases, profoundly impacts the dental-maxillofacial functions, facial esthetics, and long-term development of ~260 million children in China. Beyond its physical manifestations, malocclusion also significantly influences the psycho-social well-being of these children. Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition, by mitigating the negative impact of abnormal environmental influences on the growth. Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development, ranging from fetal stages to the early permanent dentition phase. From an economic and societal standpoint, the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated, underlining its profound practical and social importance. This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children, emphasizing critical need for early treatment. It elaborates on corresponding core principles and fundamental approaches in early orthodontics, proposing comprehensive guidance for preventive and interceptive orthodontic treatment, serving as a reference for clinicians engaged in early orthodontic treatment.

Evaluation of Glenoid Fossa Position in Class II Malocclusion Associated with Mandibular Retrusion and Class III Malocclusion Associated with Mandibular Protrusion

Objective

This study examined the glenoid fossa in Class II and Class III malocclusions with mandibular retrusion and protrusion.

Materials and Methods

A retrospective investigation examined 60 Class II and 60 Class III cephalometric radiographs. Cephalometric landmarks and glenoid fossa measurements were taken. Statistical analysis contrasted the two malocclusion groups' glenoid fossas.

Results

Class II malocclusion had a much lower mean Sella-Nasion-Condylion (SNCd) angle (glenoid fossa sagittal position) than Class III (14.6° ± 1.9). Class II malocclusion had a lower mean Sella-Nasion-Gonion (SNGo) angle (32.5° ± 4.3) than Class III (36.2° ± 3.9). The SNCd angle and SNGo angle in both groups demonstrated a negative correlation, demonstrating a relationship between the glenoid fossa and the mandibular sagittal axis.

Conclusion

The glenoid fossa location differs significantly between Class II malocclusion with mandibular retrusion and Class III with protrusion. Class II malocclusion has a posterior glenoid fossa, while Class III has a less posterior one. Understanding these links may help patients receive more personalized treatment.

Extraction vs nonextraction orthodontic treatment: a systematic review and meta-analysis

OBJECTIVES

To compare four first premolar extraction and nonextraction treatment effects on intra-arch width, profile, treatment duration, occlusal outcomes, smile aesthetics and stability.

MATERIALS AND METHODS

An electronic search of the literature to June 2, 2023 was conducted using health science databases, with additional search of gray literature, unpublished material, and hand searching, for studies reporting nonsurgical patients with fixed appliances regarding sixteen sub-outcomes. Data extraction used customized forms, quality assessed with ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions) and Cochrane RoB 2 (risk-of-bias) tool. GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessed certainty of evidence.

RESULTS

Thirty (29 retrospective studies, 1 randomized controlled trial) studies were included. Random-effect meta-analysis (95% CI) demonstrated maxillary (MD: -2.03 mm; [-2.97, -1.09]; P < .0001) and mandibular inter-first molar width decrease (MD: -2.00 mm; [-2.71, -1.30]; P < .00001) with four first premolar extraction; mandibular intercanine width increase (MD: 0.68 mm; [0.36, 0.99]; P < .0001) and shorter treatment duration (MD: 0.36 years; [0.10, 0.62]; P = .007) in the nonextraction group. Narrative synthesis included three and five studies for upper and lower lip-E plane, respectively. For American Board of Orthodontics Objective Grading System and maxillary/mandibular anterior alignment (Little's irregularity index), each included two studies with inconclusive evidence. There were no eligible studies for UK Peer Assessment Rating (PAR) score. Class I subgroup/sensitivity analyses favored the same results. Prediction interval indicated no significant difference for all outcomes.

CONCLUSIONS

Four first premolar extraction results in maxillary and mandibular inter-first molar width decrease and retraction of upper/lower lips. Nonextraction treatment results in mandibular intercanine width increase and shorter treatment duration. There was no significant difference between the two groups regarding maxillary intercanine width, US PAR score, and posttreatment smile esthetics. Further high-quality focused research is recommended.

Long-term efficacy and stability of miniscrew-assisted rapid palatal expansion in mid to late adolescents and adults: a systematic review and meta-analysis

BACKGROUND

The purpose of this study is to investigate the long-term efficacy and stability of Miniscrew-assisted Rapid Palatal Expansion (MARPE), including its primary outcomes, namely the nasomaxillary complex transverse skeletal and dental expansion, and related secondary outcomes.

METHODS

Electronic databases and manual literature searches, up to October 31, 2022, were performed. The eligibility criteria were the following: studies on patients with transverse maxillary deficiency treated with MARPE in adults and adolescents over 13.5 years of age.

RESULTS

Ultimately, twelve articles were included in the analysis, one prospective and eleven retrospective observational studies. Five studies showed a moderate risk of bias, while the remaining seven studies were at a serious risk of bias. The GRADE quality of evidence was very low. MARPE is an effective treatment modality for transverse maxillary deficiency (mean success rate: 93.87%). Patients showed increased mean in the skeletal and dental transverse expansion. The basal bone composition, mean alveolar bone and mean dental expansion accounted for 48.85, 7.52, and 43.63% of the total expansion, respectively. There was a certain degree of skeletal and dental relapse over time. MARPE could also cause dental, alveolar, and periodontal side effects, and have an impact on other craniofacial bones, upper airway, and facial soft tissue.

CONCLUSIONS

MARPE is an effective treatment for transverse maxillary deficiency, with a high success rate and a certain degree of skeletal and dental relapse over time.

Gender and age effects on dental and palatal arch dimensions among full siblings

PURPOSE

This study was conducted to investigate the dental and palatal arch dimensions of male and female siblings in relation to gender and age, using three-dimensional (3D) digital casts.

METHODS

This study involved 54 subjects (27 pairs) of male-female siblings aged 15 to 45 years. Dental casts were digitized and analyzed for tooth size (TS), arch width (AW), arch length (AL), arch length discrepancy (ALD), and palatal arch dimensions (PAD). The data obtained were subjected to t-tests, and the palatal curvature (PC) was modeled using a fourth-order polynomial.

RESULTS

Significant differences (P < 0.05) between the sexes were found in the mesiodistal TS, particularly in all canines, as well as 16, 36, 46, and 41. Maxillary AW and AL were also significantly (P < 0.05) influenced by sexes. Most arch parameters were more prominent in male siblings, and the effect of age on PC differed between the sexes. In addition, the PC of adolescent females was mostly superimposed on adult females relative to males.

CONCLUSION

Among siblings, males were found to have significantly larger dental arch dimensions than females. Furthermore, PC showed some differences between the sexes in both the frontal and sagittal planes.

Skeletal and Dentoalveolar Changes With Mandibular Expansion in Growing Children

Introduction The primary objective of this study was to quantitatively analyze the skeletal and dentoalveolar parameters following the mandibular expansion with a banded appliance. It was also part of the study to evaluate the amount of dental expansion and assess the change in the intermolar and individual first molar angulation. The basal bone parameters were compared to assess the skeletal effect of removable mandibular expansion appliance therapy. Methods In this retrospective cone beam computed tomography (CBCT) study, a total of 80 subjects with mandibular expansion therapy were screened. After imposing inclusion/exclusion criteria, 70 patients (40 females and 30 males) with a mean age of 8.8±1.24 years and 4.79±3.59 months were included. The mean expansion period was 3.04±1.61 months. Skeletal parameters such as buccal cortical thickness, buccal bone width, and cortical density were measured at 2mm from the alveolar crest, mid-root, and apex region in the coronal slice at the level of the mesiobuccal root of the first molar. Expansion parameters such as intermolar width, intermolar angulation, and individual molar angulation were also measured in the same slice. Finally, basal bone parameters such as inter-mental foramina distance and anterior arch perimeter were recorded. Results No significant difference (p>0.05) was found for most skeletal parameters following the expansion, except for the mid-root buccal bone width (p<0.05). On average, 4.54±2.53 mm of dental expansion (p<0.05) was achieved at the first molar region. Individual molar angulation showed a statistically significant difference (right = 7.46±7.91°, left = 7.53±7.18°, p=<0.05). The basal bone parameters showed no significant difference (p>0.05). Conclusions The mandibular expansion device leads to an increase in intermolar distance. The amount of expansion achieved with such devices is due to the buccal tipping of the molars. Skeletal effects such as cortical thickness, buccal bone width, or changes in the basal bone dimensions should not be expected with mandibular expansion therapy.

Differences in the 3-dimensional aging changes of the lips among female adults with skeletal Class I, II, and III malocclusion

INTRODUCTION

The objective of this study was to evaluate and compare the 3-dimensional (3D) aging changes of the lips among adult skeletal Class I, II, and III malocclusion.

METHODS

Female adult orthodontic patients aged 20-50 years with pretreatment cone-beam computed tomography scans were retrospectively classified according to age (20s [20-29 years], 30s [30-39 years], and 40s [40-49 years]) and then subclassified by malocclusion into skeletal Class I, II, and III relationship (9 groups; n = 30 per group). Positional differences in midsagittal and parasagittal soft-tissue landmarks and 3D morphologic aging changes of the lips were evaluated using cone-beam computed tomography scans.

RESULTS

Labiale superius and cheilion for patients in their 40s indicated a significant downward and backward position compared with those in their 20s, regardless of skeletal classifications (P <0.05). Accordingly, the upper lip height decreased, and the mouth width increased significantly (P <0.05). For Class III malocclusion, the upper lip vermilion angle was greater for patients in their 40s than those in their 20s (P <0.05), whereas the lower lip vermilion angle was only lower for patients with Class II malocclusion (P <0.05).

CONCLUSIONS

Middle-aged adult females (40-49 years) had a lower upper lip height and greater mouth width than those in their 20s, regardless of skeletal malocclusion. However, prominent morphologic aging changes of the lips were noted on the upper lip for skeletal Class III malocclusion and the lower lip for skeletal Class II malocclusion, implying that the underlying skeletal features (or malocclusion) may influence 3D aging changes of the lips.

Relationship between vertical facial morphology and dental arch measurements in class II malocclusion: a retrospective study

Background

To evaluate the relationship between dental arch measurements and the vertical facial pattern determined in skeletal Class II untreated patients.

Methods

Lateral cephalograms and plaster models were obtained from 124 untreated female adults (average age: 17.6 ± 3.8 years). Class I (CI), Class II Division 1 (CII/1) and Class II Division 2 (CII/2) malocclusions were divided into three subgroups according to their vertical morphology as hypodivergent, normodivergent and hyperdivergent. The multivariate variance analysis (MANOVA) method was used in the comparison of measurement values according to vertical and sagittal morphology. The relationship between both A point-Nasion-B point (ANB) and Frankfurt-mandibular plane (FMA) angles and dental arch measurements was examined by Pearson correlation analysis. The significance level was received as p < 0.05.

Results

While vertical morphology has a statistically significant effect on mandibular arch length, sagittal morphology affects maxillary arch depth. The parameters influenced by both morphologies are maxillary and mandibular arch length, as well as maxillary intermolar width. The mandibular arch length was significantly shorter in hyperdivergent-CII-2 malocclusion (50.5 ± 7.4 mm). Larger values were obtained in both mandibular arch length and maxillary arch depth measurements in CII-1 malocclusion compared to CII-2 malocclusion. The maxillary intermolar width was significantly shorter in hypodivergent-CII-1 malocclusion (46.8 ± 3.4 mm), while it was higher in hypodivergent-CI malocclusion (51.1 ± 3.4 mm). The maxillary arch length was the lowest in hyperdivergent-CI malocclusion (63.1 ± 13.3 mm) and the highest in hypodivergent-CI malocclusion (72.8 ± 7.6 mm). Additionally, a positive but weak correlation was found between ANB and FMA angles.

Conclusion

Dental arch measurements have been found to be affected by both vertical facial morphology and skeletal sagittal relationship. A positive correlation was found between ANB and FMA angles.

Effects of two flap palatoplasty versus furlow palatoplasty with buccal myomucosal flap on maxillary arch dimensions in patients with cleft palate at the primary dentition stage: a cohort study

OBJECTIVE

The objective of this study was to evaluate the effect of two flap palatoplasty (TFP) versus Furlow palatoplasty with buccal myomucosal flap (FPBF) on maxillary arch dimensions in children at the primary dentition stage with cleft palate, in comparison to matching subjects without any craniofacial anomalies.

MATERIAL AND METHODS

This study included 28 subjects with an age range of 5-6 years; 10 non-cleft subjects were included in the control group, 9 patients treated with TFP, and 9 patients treated with FPBF. For the included patients, the maxillary models were scanned using a desktop scanner to produce virtual models, and the maxillary dimension measurements were virtually completed. The produced measurements were compared between the 3 groups. Maxillary models of the 28 participants were evaluated.

RESULTS

Statistically insignificant differences were detected between the 3 groups for arch symmetry measurements. Differences were detected in the inter-canine width between the 2 surgical groups and non-cleft group. Both arch length and posterior palatal depth significantly differ while comparing the TFP to the control group, with no differences between FPBF and the non-cleft group.

CONCLUSION

Furlow palatoplasty with buccal myomucosal flap might be considered a better surgical option than two flap palatoplasty for patients with cleft palate while evaluating maxillary arch dimensions at the primary dentition stage as a surgical outcome.

CLINICAL RELEVANCE

This study gives insight into the surgical technique that has limited effect on the maxillary growth and dental arch dimension. Therefore, it decreases the need for orthodontic treatment and orthognathic surgery.

TRIAL REGISTRATION

clinicaltrials.gov ( NCT05405738 ).

Comparative 3D study of dental arches in children with microcephaly associated with congenital Zika syndrome, orofacial cleft, and without craniofacial anomalies

INTRODUCTION

The dentist participates in the treatment protocol for craniofacial anomalies in individuals from the first months of life.

OBJECTIVE

to compare in a retrospective cohort study the morphometry of the edentulous palate of children microcephaly associated with congenital Zika syndrome (CZS), unilateral complete cleft lip and alveolus (UCL), and without craniofacial anomalies.

METHODS

Forty-five digitized dental molds composed the sample divided into three groups: CZS; UCL; and without craniofacial anomalies (control group). The following measurements were evaluated: intercanine and intertuberosity distances; dental arch length, area, volume, and mismatch superimposition. Parametric and non-parametric tests were applied (α = 5%).

RESULTS

CZS group showed the smallest means of intercanine distance and area than those of the other groups (p = .001 and p = .010, respectively). The dental arch length was greater in the CZS group than in the control group (p = .020). The evaluation of the mismatch superimposition showed that the CZS group had the lowest means of maximum distance and root mean square than that of the UCL group (p = .025 and p = .005, respectively).

CONCLUSION

CZS participants tended to palatal narrowing, while UCL individuals had parameters similar to those of the control group, despite the alveolus defect.

Treatment effects after maxillary expansion using invisalign first system vs. acrylic splint expander in mixed dentition: a prospective cohort study

BACKGROUND

Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What's more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors.

MATERIALS AND METHODS

After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons.

RESULTS

There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups.

CONCLUSIONS

Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD.

TRIAL REGISTRATION

This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

Long-term stability of mandibular incisor alignment in patients treated nonextraction with or without interproximal enamel reduction

INTRODUCTION

This study aimed to compare long-term mandibular incisor stability in nongrowing patients with moderate crowding treated nonextraction with and without interproximal enamel reduction (IPR).

METHODS

Forty-two nongrowing patients with Class I dental and skeletal malocclusion with moderate crowding were divided into 2 groups with an equal number of patients depending on whether IPR was used (IPR group) or not (non-IPR group) during treatment. All patients were treated by the same practitioner and used thermoplastic retainers full-time for 12 ± 1 months at the end of the active treatment. Changes in Peer Assessment Rating scores, Little's irregularity index (LII), intercanine width (ICW), and mandibular incisor inclination (IMPA and L1-NB°) were evaluated using pretreatment, posttreatment, and 8 ± 1 years postretention dental models and lateral cephalograms.

RESULTS

At the end of the treatment, Peer Assessment Rating scores and LII decreased, and ICW, IMPA, and L1-NB° increased significantly (P <0.001) in both groups. At the end of the postretention period, in both groups, LII increased, and ICW decreased significantly (P <0.001) compared with posttreatment values, whereas IMPA and L1-NB remained stable. When treatment changes were compared, increases in ICW, IMPA, and L1-NB were significantly (P <0.001) higher in the non-IPR group. When postretention changes were compared, the only significant difference between 2 groups was observed in ICW. The decrease in ICW was significantly higher in the non-IPR group.

CONCLUSIONS

Long-term stability of mandibular incisor alignment in Class I nongrowing patients with moderate crowding treated nonextraction with and without IPR was similar.

Non-Surgical Transversal Dentoalveolar Compensation with Completely Customized Lingual Appliances versus Surgically Assisted Rapid Palatal Expansion in Adults-Tipping or Translation in Posterior Crossbite Correction?

The aim of this study was to investigate buccolingual tooth movements (tipping/translation) in surgical and nonsurgical posterior crossbite correction. A total of 43 patients (f/m 19/24; mean age 27.6 ± 9.5 years) treated with surgically assisted rapid palatal expansion (SARPE) and 38 patients (f/m 25/13; mean age 30.4 ± 12.9 years) treated with dentoalveolar compensation using completely customized lingual appliances (DC-CCLA) were retrospectively included. Inclination was measured on digital models at canines (C), second premolars (P2), first molars (M1), and second molars (M2) before (T₀) and after (T₁) crossbite correction. There was no statistically significant difference (p > 0.05) in absolute buccolingual inclination change between both groups, except for the upper C (p < 0.05), which were more tipped in the surgical group. Translation, i.e., bodily tooth movements that cannot be explained by pure uncontrolled tipping, could be observed with SARPE in the maxilla and with DC-CCLA in both jaws. Dentoalveolar transversal compensation with completely customized lingual appliances does not cause greater buccolingual tipping compared to SARPE.

Predictability and Effectiveness of Nuvola® Aligners in Dentoalveolar Transverse Changes: A Retrospective Study

Nowadays, many people use clear aligners to address their dental issues. The efficacy of transparent dental aligners must be investigated even though they are more aesthetically pleasing, easy to use, and tidy than permanent tools. Thirty-five patients in this study's sample group who used Nuvola^® clear aligners for their orthodontic therapy were prospectively observed. Initial, simulated, and final digital scans were analysed with a digital calliper. The actual results were compared with the prescribed ending position to evaluate the efficacy of transversal dentoalveolar expansion. Aligner treatments in Groups A (12) and B (24), particularly in the dental tip measures, demonstrated high adherence to the prescription. On the other hand, the gingival measures exhibited a greater level of bias, and the differences were statistically significant. However, there was no difference in the outcomes between the two groups (12 vs. 24). Within specific parameters, the evaluated aligners were shown to be helpful in predicting movements in the transverse plane, particularly when considering movements linked to the vestibular-palatal inclination of the dental elements. This article compares the expansion effectiveness of Nuvola^® aligners compared with other work in the literature using competitor companies.

Correlation of Palatal Index With Pharyngeal Airway in Various Skeletal Patterns

Introduction This retrospective study aimed to correlate palatal index with pharyngeal airway in class I, class II and class III skeletal patterns. Materials and methods A total of 30 individuals with a mean age of 17.5 years were included in the study. The subjects were categorized on the basis of ANB (A point, nasion, B point) angle into skeletal class I, II, and III patterns (N=10). Using Korkhaus analysis, palatal height, palatal breadth, and palatal height index were calculated from the study models. From the lateral cephalogram, the dimensions of the upper and lower pharyngeal airways were measured using McNamara Airway Analysis. The results were calculated using the ANOVA test. Results A statistically significant difference was found in all three groups of class I, II, and III malocclusions for palatal index and airway dimensions. The skeletal class II malocclusion participants exhibited the highest mean values for the palatal index (P=0.03). Class I had the highest mean value for the upper airway (P=0.041), whereas class III had the highest mean value for the lower airway (P=0.026). Conclusion It was concluded that subjects with the class II skeletal pattern have a high palate and reduced upper and lower airways when compared with class I and class III skeletal patterns, which showed larger upper and lower airways, respectively.

Tridimensional Changes in Mandibular Arch after Rapid Maxillary Expansion Therapy: A Clinical Study

Aim: The upper jaw transverse deficit is certainly one of the most common clinical issues in the orthodontic field. It can be due to skeletal or dental factors, and its etiology may be both genetic and environmental. Rapid maxillary expanders (RMEs) are certainly the most effective appliance for upper transverse deficiency correction. The aim of this study was to evaluate the changes that occurred in the mandibular arch during treatment with RMEs in growing subjects by analyzing tridimensional lower digital casts. Materials and Methods: The study group (SG) consisted of 20 subjects (10 M, 10 F; mean age 9.4 ± 2.8 years old) randomly selected at the Department of Orthodontics at the University of Rome, "Tor Vergata". The inclusion criteria were negative posterior transverse interarch discrepancy ≥ 4 mm, mixed dentition phase with first permanent molars erupted, and prepubertal skeletal maturation stage (CS1-2), evaluated on a lateral radiograph through the Cervical Vertebral Maturation method. The SG was compared to an untreated control group (CG) of 20 subjects (10 M, 10 F, mean age 8.7 ± 2.3 years old) enrolled with the same inclusion criteria. The SG was treated by using RMEs. Dental casts of the lower arch were taken at two different times (T0-T1 = 6 months). All the dental casts were scanned with an OrthoXscan (Dentaurum 6mmbh E Co., Ispringen, Germany) and twenty points on the mandibular arch were digitized using Viewbox software. A Student t-test was used to compare the means of the quantitative variables associated with the effect of the device over time T0 and T1. Results: The results show a statistically significant increase (p < 0.05) in the intercanine and the intermolar diameters between the times T0 and T1 when compared to the CG. Conclusions: Rapid maxillary orthopedic expansion may achieve an increase in mandibular intercanine and intermolar diameter.

Long Term Outcome of Avulsed Immature Mandibular Incisor with Progressive External Root Resorption: 9 Years Follow-Up

Background

Avulsion of permanent teeth is the most common in young permanent dentition. Replantation of immature teeth after avulsion represents a major challenge in terms of treatment management and long-term prognosis. This case report describes 9 years of follow-up for an avulsed and replanted immature mandibular lateral incisor with progressive external root resorption.

Methods

A 7-year-old patient following an accident in which his mandibular left central incisor was avulsed and replanted within one hour after being stored in a physiological storage medium. However, radiographic examination conducted six weeks after the dental injury revealed inflammatory root resorption of the replanted tooth #31. To address root resorption, endodontic treatment was performed involving the use of calcium hydroxide as an intracanal medication for a short period of time, followed by root canal obturation with mineral trioxide aggregate placed below the crestal bone margin.

Results

Three months later the root resorption had progressed. Consequently, a decision was made to perform periodontal surgery. While the long-term follow-up revealed that the inflammatory root resorption had damaged half of the root, the tooth remained functional and aesthetically favourable.

Conclusions

Despite the challenges associated with replantation of an immature tooth following avulsion, this case demonstrated favourable outcomes. The tooth maintained its functionality, exhibited favourable aesthetic, and the dimensions of the alveolar ridge were preserved, allowing for the physiological expansion of the dental arch.

Assessment of Posterior Dentoalveolar Expansion with Invisalign in Adult Patients

PURPOSE

The primary aim was to evaluate dentoalveolar expansion with Invisalign clear aligners comparing linear measurements in ClinCheck vs. cone beam computed tomography (CBCT). This would enable an assessment of to what extent expansion gained from Invisalign clear aligners was due to buccal tipping and/or bodily translation of the posterior teeth. The study also evaluated the predictive value of Invisalign ClinCheck^® (Align Technology, San Jose, CA, USA) to final outcomes.

METHODS

The orthodontic records of thirty-two (32) subjects comprised the sample to conduct this study. Linear values of the upper arch width were measured for premolars and molars at two different points (occlusal and gingival) utilized for ClinCheck^® measurements and three different points for CBCT measurements before (T₀ and after treatment (T₁). Paired T-tests at a significance level of 0.05 were used for analyses.

RESULTS

Expansion was found to be possible with Invisalign clear aligners. However, more expansion was measured at the cusp tips compared to gingival margins (p < 0.0001), indicating more tipping was occurring than bodily translation. ClinCheck^® also showed a significant overestimation of the amount of expansion capable, with nearly 70% expression in the first premolar area, and the expression decreased as one moved posteriorly with only 35% expressed at the first molar area (p < 0.0001).

CONCLUSIONS

Dentoalveolar expansion with Invisalign is achieved through buccal tipping of posterior teeth and bodily translation; and there is a significant overestimation of the amount of expansion achieved between ClinCheck^® and clinical results.

Palatal surface development from 6 years of age to early adulthood: data modelling using 3D geometric morphometrics

OBJECTIVES

The study followed the modelling of postnatal growth of a healthy palate of the Central European (Czech) population sample based on transverse data on sex and age from 6 to 19 years.

MATERIALS AND METHODS

Digitised 3D models of 212 healthy palatal surfaces were evaluated using 3D geometric morphometrics and superimpositions. The individuals were grouped based on age (preschool, younger and older school age, younger and older adolescents, young adults) and sex (♂ n = 101, ♀ n = 111).

RESULTS

Female palatal development was non-linear and was interrupted between the 10-12 years and then proceeded intensively until the age of 15 when it ceased. In contrast, male-modelled growth was consistent throughout the follow-up and continued linearly until at least 19 years of age. The palate did not widen further with increasing age, and primarily palatal vaulting and heightening were found. The characteristics and distribution of areas with extensive modelled growth changes were comparable in females and males, as confirmed by the location of principal components (PC1 and PC2) within modal space and growth trajectories. The extent of sexual dimorphism increased from 15 years of age due to pubertal spurt combined with earlier completion of palatal development in females.

CONCLUSIONS

The study showed modelled healthy palatal development from 6 years of age to early adulthood, which might be utilised as reference standards for the Central European population sample.

CLINICAL RELEVANCE

The comparison of normal reference subjects with patients with cranio-maxillo-facial dysmorphologies represents the first step in diagnosing and establishing effective therapy.

Upper arch dimensional changes with clear aligners in the early mixed dentition : A prospective study

BACKGROUND

One goal of orthodontic treatment in mixed dentition is to expand the maxillary arch to allow proper tooth alignment and a correction of sagittal and vertical malocclusions. However, for most treatment protocols, expected outcome is not really clear to allow for a standardization of phase I orthodontic treatments. This lack of information makes it difficult for clinicians to predict tooth movements, including transverse expansion efficacy with Invisalign® (Align Technology, Santa Clara, CA, USA) in children. Therefore, the aim of the present study was to evaluate the transverse maxillary arch development with the Invisalign First System® in growing subjects.

METHODS

The study group included 23 subjects (9 females, 14 males, mean age 9.4 ± 1.2 years). Patients were treated nonextraction with Invisalign First System® clear aligners with no auxiliaries other than Invisalign® attachments. Transverse interdental widths were measured only in the upper arch on each model at the start (T1) and at the end (T2) of treatment. A paired t‑test was chosen to compare T2-T1 changes. The level of significance was set at 5%.

RESULTS

The greatest increase of maxillary width was detected at the level of the upper first deciduous molars (+3.7 ± 1.4 mm; P < 0.001), followed by the level of the second deciduous molars (+3.4 ± 1.6 mm; P < 0.001) and by the deciduous canine (+2.6 ± 2.0 mm; P < 0.001). Upper first molars showed a greater expansion in the intermolar mesial width (+3.2 ± 1.2 mm; P < 0.001) than in the intermolar distal (+1.7 ± 1.2 mm; P < 0.001) and transpalatal width (+1.2 ± 1.2 mm; P < 0.01).

CONCLUSIONS

The Invisalign First System® can be considered effective in growing patients who require maxillary arch development. The greatest net increase was detected at the level of upper first deciduous molars, whereas the upper first molars showed a greater expansion in the intermolar mesial width due to a rotation that occurs around its palatal root.

Arch Expansion Efficiency of Clear Aligner on Patients with Mixed Dentition Using 3ship Digital Oral Scanner

The aim of this study to evaluate the maxillary and mandibular arch expansion efficiency of clear aligner. A total of 15 patients aged between 8–11 who were admitted from January 2020 to December 2021. The 3ship digital oral scanner was used to establish a digital oral model for the patients before and after the correction. The three-dimensional model before and after correction was established by ClinCheck software to measure and record the width of each tooth position and evaluate the efficiency of arch expansion. The dental arch width was greater after correction of the width between the maxillary and maxillary canines, the width between the first premolars, the width between the second premolars, and the width between the first molars, showing statistically significant differences (P <0.05). The arch expansion efficiency in the maxillary canine area > the maxillary first premolar efficiency > the maxillary second premolar efficiency > the maxillary first molar efficiency. Through the linear regression equation, the preset expansion amount of each tooth position was reasonably predicted.Taken together our data suggested that the clear aligner efficiency can be improved by adding accessories and torque in the base bone range when necessary.

Non-Surgical Transversal Dentoalveolar Compensation with Completely Customized Lingual Appliances versus Surgically Assisted Rapid Palatal Expansion in Adults-The Amount of Posterior Crossbite Correction

The aim of this study was to compare the crossbite correction of a group (n = 43; f/m 19/24; mean age 27.6 ± 9.5 years) with surgically assisted rapid palatal expansion (SARPE) versus a non-surgical transversal dentoalveolar compensation (DC) group (n = 38; f/m 25/13; mean age 30.4 ± 12.9 years) with completely customized lingual appliances (CCLA). Arch width was measured on digital models at the canines (C), second premolars (P2), first molars (M1) and second molars (M2). Measurements were obtained before treatment (T0) and at the end of lingual treatment (T1) or after orthodontic alignment prior to a second surgical intervention for three-dimensional bite correction. There was no statistically significant difference (p > 0.05) in the amount of total crossbite correction between the SARPE and DC-CCLA group at C, P2, M1 and M2. Maxillary expansion was greater in the SARPE group and mandibular compression was greater in the DC-CCLA group. Crossbite correction in the DC-CCLA group was mainly a combination of maxillary expansion and mandibular compression. Dentoalveolar compensation with CCLAs as a combination of maxillary expansion and mandibular compression seems to be a clinically effective procedure to correct a transverse maxillo-mandibular discrepancy without the need for surgical assistance.

Longitudinal changes in the dental arch width and symmetry in identical and fraternal twins

INTRODUCTION

This study aimed to assess growth-related dental and symmetry changes in the dental arch within and between identical and fraternal twins in mixed and permanent dentition.

METHODS

Three-dimensional scanned dental models of eligible subjects were selected from the Forsyth-Moorrees Twin Study sample. This retrospective cohort study was carried out on 36 identical (18 pairs) and 28 fraternal (14 pairs) twins in mixed dentition and 36 identical (18 pairs) and 38 fraternal (19 pairs) twins in permanent dentition stages on the basis of the availability of the dental casts scanned each year from each group (Table I). Linear measurements from dental casts were performed in patients aged 8-16 years. Student t test and Pearson's correlation were used to compare the symmetry between and within the identical and fraternal twins. The resemblance and heritability patterns were retrospectively obtained from the Pearson correlation coefficient and Falconer's heritability test (H2 = 2 × b). Adjusted mixed-effects estimates and 95% confidence intervals were calculated to test the association between age and dental parameters for both mixed and permanent dentition groups.

RESULTS

Intercanine and intermolar widths significantly increased (P <0.05) during the mixed dentition but became stable after 13 years old. No statistically significant differences were found in arch symmetry between the 2 groups (ie, identical and fraternal) in any of the included measurements. Evaluation of the resemblance and heritability pattern showed nonsignificant results for all variables measured (H2 range, -0.67 to 0.56).

CONCLUSIONS

The dental arch becomes wider at a higher rate in the canine region than the molar region in both the mixed and early permanent dentition. The dental arches of twins develop symmetrically, and their growth is not mainly affected by genetics. Asymmetrical teeth will maintain their relative position to reference planes throughout growth.

What are the intra-arch risk factors for palatally displaced maxillary canine? - Results of a case-control study

INTRODUCTION

This study aimed to identify the intra-arch risk factors for palatally displaced canine by comparing the maxillary transverse dimensions, palatal depth (PD), and arch length (AL) of the subjects with and without impacted canine using cone-beam computed tomography (CBCT).

METHODS

In this prospective case-control study, 79 CBCT images of gender- and skeletal feature-matched subjects (25 cases and 54 controls) were compared. Based on the CBCT images, maxillary transverse widths at four levels (molar basal, molar alveolar, premolar basal, and premolar alveolar), maxillary PD, and maxillary AL were measured. Group comparisons were assessed using analysis of variance (ANOVA), followed by post-hoc Scheffe's test, and risk factors were identified using univariate and multivariate logistic regression.

RESULTS

The impacted canine group showed significantly smaller molar alveolar width, premolar alveolar width, PD, and greater AL compared to the control group (P = 0.046, P < 0.001, P = 0.003, and P = 0.001, respectively). No significant difference was observed in the molar and premolar basal width measurements between the two groups. Multivariate analysis showed that impacted maxillary canine was influenced by premolar alveolar width (odds ratio (OR): 0.669), PD (OR: 0.532), and AL (OR: 1.739).

CONCLUSION

Intra-arch risk factors, such as reduced maxillary premolar transverse alveolar width, PD, and greater AL, are associated with palatally displaced canine.

Scoping Review of Oral Health-Related Birth Cohort Studies: Toward a Global Consortium

The multidisciplinary nature and long duration of birth cohort studies allow investigation of the relationship between general and oral health and indicate the most appropriate stages in life to intervene. To date, the worldwide distribution of oral health-related birth cohort studies (OHRBCSs) has not been mapped, and a synthesis of information on methodological characteristics and outcomes is not available. We mapped published literature on OHRBCSs, describing their oral health-related data and methodological aspects. A 3-step search strategy was adopted to identify published studies using PubMed, Embase, Web of Science, and OVID databases. Studies with baseline data collection during pregnancy or within the first year of life or linked future oral health data to exposures during either of these 2 life stages were included. Studies examining only mothers' oral health and specific populations were excluded. In total, 1,721 articles were suitable for initial screening of titles and abstracts, and 528 articles were included in the review, identifying 120 unique OHRBCSs from 34 countries in all continents. The review comprised literature from the mid-1940s to the 21st century. Fifty-four percent of the OHRBCSs started from 2000 onward, and 75% of the cohorts were from high-income and only 2 from low-income countries. The participation rate between the baseline and the last oral health follow-up varied between 7% and 93%. Ten cohorts that included interventions were mostly from 2000 and with fewer than 1,000 participants. Seven data-linkage cohorts focused mostly on upstream characteristics and biological aspects. The most frequent clinical assessment was dental caries, widely presented as decayed, missing, and filled teeth (DMFT/dmft). Periodontal conditions were primarily applied as isolated outcomes or as part of a classification system. Socioeconomic classification, ethnicity, and country- or language-specific assessment tools varied across countries. Harmonizing definitions will allow combining data from different studies, adding considerable strength to data analyses; this will be facilitated by forming a global consortium.

Safety and efficacy of maxillary labial frenectomy in children: A retrospective comparative cohort study

BACKGROUND

Maxillary frenectomy in children is a common procedure, but concerns about scar tissue affecting diastema closure prevent many clinicians from treating prior to orthodontics.

OBJECTIVES

To determine if maxillary frenectomy is safe and if diastema size is affected by early treatment.

MATERIALS AND METHODS

Paediatric patients with hypertrophic maxillary frena were treated under local anaesthesia with diode laser and CO₂ laser. Diastema width was compared by calibrating and digitally measuring initial and postoperative intraoral photographs.

RESULTS

In total, 109 patients were included: 95 patients with primary dentition (39% male; mean age 1.9 years±1.5 years) and 14 with mixed dentition (43% male; mean age 8.1±1.3 years) with a mean follow-up of 18.0±13.2 months. No adverse outcomes were noted other than minor pain and swelling. In the primary dentition, a decrease in diastema width was observed in 94.7% with a mean closure of -1.4±1.0mm (range +0.7 to -5.1mm). In the mixed dentition, a decrease in diastema width was observed in 92.9% with a mean closure of -1.8±0.8mm (range 0 to -3.5mm). 74.5% of patients in the primary dentition and 75% of patients in the mixed dentition with preoperative diastema>2mm improved to<2mm width postoperatively.

CONCLUSIONS

Frenectomy is associated with cosmetic and oral hygiene benefits and when performed properly, does not impede diastema closure and may aid closure. Technique and case selection are critical to successful outcomes. IRB ethics approval was obtained from Solutions IRB protocol #2018/12/8, and this investigation was self-funded.

Ideal transverse position of mandibular first molars based on CBCT-derived alveolar bone coverage

BACKGROUND

In orthodontic treatment, transverse arch width often needs to be adjusted to correct anomalies such as posterior crossbite. Ideal transverse arch width at the first molars enabling long-term stability and periodontal health, however, requires sufficient posttreatment bony coverage buccally and orally of the tooth roots. Thus, the aim of this retrospective study was to determine the physiological alveolar bone thickness at the buccal and oral roots of the first mandibular molars in the general population using human CBCT scans assessing local and gender-specific differences.

METHODS

CBCTs of 124 random 11- to 55-year old patients (46 female, 78 male) were analysed retrospectively. Alveolar bone thickness was measured digitally at mesial and distal tooth roots of the first mandibular molars buccally and orally at different vertical positions (4 and 8mm apically of the cement-enamel-junction CEJ). For each patient, the mean of corresponding measurements from left and right molars was used for analysis.

RESULTS

All measurements were reliable, as proven by interrater- and interrater-reliability-testing. On average, bone thickness increased from the mesial to the distal tooth root, as well as in apical and oral direction. These local differences in alveolar bone thickness were all highly significant at p < 0.0001. Women showed thicker bone buccally at the distal tooth root at 8mm apically of the CEJ, as well as orally at both mesial and distal tooth roots 4mm apically of the CEJ.

CONCLUSIONS

The results of this study suggest that especially in buccal, mesial and gingival direction alveolar bone around mandibular first molars becomes thinner and hence the scope for orthodontic tooth movements is limited. Our results should aid assessing ideal transverse molar position based on alveolar bone coverage, although variations due to age may occur.

Comparative assessment of various cephalometric facial planes with intercanine width in orthodontic patients

OBJECTIVE:

The study was conducted to evaluate the relationship of various cephalometric skeletal patterns in the vertical and anteroposterior planes with intercanine width in untreated orthodontic patients.

METHOD AND MATERIAL:

This study included dental cast and cephalometric radiographs of 100 patients (69 females and 31 males) of the age range 13 to 33 years. Skeletal parameters including SNA, SNB, SNMP angles were found from lateral cephalometric radiographs. Intercanine widths including upper intercanine widths (UICW) and lower intercanine widths (LICW) were measured by a digital caliper.

RESULTS:

The correlation of intercanine width with SNA, SNB, and SNMP angles was analyzed by applying Pearson correlation coefficient. According to statistical analysis, the only insignificant correlation was analyzed between UICW with SNB and LICW with SN-MP.

CONCLUSIONS:

The overall result showed statistically significant relationship of various cephalometric skeletal patterns in the sagittal and vertical planes with intercanine width.

Associations of sagittal malocclusions with dental arch characteristics and crowding in Northern Finland Birth Cohort 1966

OBJECTIVE

To analyse the associations between the widths and forms of dental arches, malocclusions and crowding in middle-aged adult population.

MATERIALS AND METHODS

The study material is part of the Northern Finland Birth Cohort 1966 (NFBC1966); the subjects were examined at the age of 46 years. A total of 781 adults with full dentition and no orthodontic treatment history were included. Overjet, overbite, cross-bite and scissor bite were examined during clinical examination. The widths and forms of dental arches, molar relationships and crowding were measured using three-dimensional (3D) dental models.

RESULTS

Dental arches were significantly larger in males than in females. Class II (CII) occlusion and increased overjet (≥6 mm) were associated with narrow maxilla (P < .001, P < .05 respectively). Subjects with lateral cross-bite had significantly narrower maxilla and wider mandible (P < .05) than subjects with normal lateral occlusion. In subjects with CII occlusion, square or tapered maxilla and tapered or ovoid mandible were significantly more frequent compared to subjects with Class I (CI) occlusion (P < .05). CII occlusion was significantly associated with crowding in the maxilla (P < .01).

CONCLUSION

Narrow and tapered-shaped maxilla was related to CII occlusion, which was associated with dental crowding in the maxilla. Malocclusions were more likely to be found together with other malocclusions than alone.

Early Maxillary Dentoalveolar Changes in Children with Unilateral Cleft Lip and Palate After Palatal Repair: A Pilot Study

OBJECTIVE

To assess early maxillary dentoalveolar changes in children with unilateral cleft lip and palate (UCLP) up to 6 months after palatoplasty.

DESIGN

Pilot study.

PATIENTS AND PARTICIPANTS

Eight children with UCLP at the age of 18 to 30 months, who were awaiting palatal repair, were included.

INTERVENTIONS

All participants with repaired lip were scheduled for palatal repair between 18 and 24 months by Bardach's technique.

MAIN OUTCOME MEASURE(S)

Arch widths, arch depths, and arch perimeter was measured on 32 dental casts of 8 participants at 4 time points: just prior to palatal repair (T1), 1 month (T2), 3 months (T3), and 6 months (T4) after palatal repair. Manual method using digital vernier caliper (Zhart, India) was used for model analysis. Intraexaminer reliability was also assessed.

RESULTS

Only one examiner assessed all the dental casts after blinding. There was a significant decrease in the intercanine width (29.75 ± 1.98 mm at T1 to 26.42 ± 1.67 mm at T4; P < .001) and anterior arch depth (9.86 ± 1.07 mm at T1 to 8.29 ± 1.51 mm at T4; P < .001). Growth occurred in intertuberosity width (38.18 ± 1.40 mm at T1 to 39.76 ± 1.09 mm at T4; P < .001) and total arch depth (24.36 ± 1.21 mm at T1 to 26.79 ± 1.04 mm; P < .001) over 6 months post-surgery.

CONCLUSIONS

There was growth restriction in the anterior part of the palate, whereas the posterior region continued to grow after palatal repair. These changes were observable even in the early months after palatoplasty.

Effect of different arch widths on the accuracy of three intraoral scanners

PURPOSE

The purpose of this study was to compare the accuracy of three intraoral scanner (IOS) systems with three different dental arch widths.

MATERIALS AND METHODS

Three dental models with different intermolar widths (small, medium, and large) were attached to metal bars of different lengths (30, 40, and 50 mm). The bars were measured with a coordinate measuring machine and used as references. Three IOSs were compared: TRIOS 3 (TRI), True Definition (TD), and Dental Wings (DW). The relative length and angular deviation of both ends of the metal bars from the scan data set (n = 15) were calculated and analyzed.

RESULTS

Comparing among scanners in terms of trueness, the relative length deviation of DW in the small (1.28%) and medium (1.08%) arches were significantly higher than TRI (0.46% and 0.48%) and TD (0.33% and 0.18%). The angular deviation of DW in the small (1.75°) and medium (1.83°) arches were also significantly greater than TRI (0.63° and 0.40°) and TD (0.55° and 0.89°). Comparing within scanner, the large arch of DW showed better accuracy than other arch sizes (P < .05). On the other hand, the larger arch of TD presented a greater tendency of angular deviation in terms of trueness. No significant differences were found in terms of trueness between the arch widths of TRI group.

CONCLUSION

The different widths of the dental arches can affect the accuracy of some intraoral scanners in full arch scan.

Occlusal changes in orthodontically treated subjects 40 years after treatment and comparison with untreated control subjects

INTRODUCTION

The objective of this study was to compare the aging changes of the dental arches in orthodontically treated and untreated subjects after a 4-decade follow-up period.

METHODS

This retrospective study analyzed 2 groups. The treated group comprised 29 patients (11 male, 18 female) presenting with Class I or Class II malocclusions orthodontically treated with extractions of 4 first premolars. Dental models taken at pretreatment (12.84 years), posttreatment (14.95 years), and long-term posttreatment (51.37 years) were evaluated. The untreated (control) group consisted of 22 untreated patients with dental models taken at 13.32, 17.82, and 60.95 years of age. The dental models were digitized, and the following variables were evaluated: Little irregularity index, intercanine, interpremolar and intermolar widths, arch length, arch perimeter, overjet, and overbite. Interphase comparison of the treated group was performed with repeated measures analysis of variance and Tukey tests. Intergroup comparisons were performed using t tests (P <0.05).

RESULTS

Crowding was corrected with treatment but relapsed significantly in the long term. Intercanine width increased with treatment and decreased in the long term. Interpremolar and intermolar widths, arch perimeter, and length decreased with treatment and continued to decrease long-term posttreatment. Overjet and overbite were corrected with treatment and remained stable in the long term. From posttreatment to long-term posttreatment, a greater crowding increase was observed in the treated group than in the untreated group. The treated group demonstrated a greater decrease in mandibular intercanine and maxillary and mandibular interpremolar widths than the untreated sample. Overbite increased in the treated group and decreased in the untreated group. The multiple regression analysis showed that previous 4-premolar extractions orthodontic treatment is significantly associated with anterior crowding in the long term.

CONCLUSIONS

In the long-term, the treated patients showed relapse of crowding and a decrease in arch form. Long-term changes of treated patients were different from untreated subjects. Relapse might have contributed to greater changes in incisor crowding and arch widths observed in the treated patients.

Dental changes in humans with untreated normal occlusion throughout lifetime: A systematic scoping review

INTRODUCTION

Understanding age-related changes in normal dental occlusion is crucial for orthodontic treatment, planning, and retention, especially considering the increasing demand from adult patients. This review aimed to systematically perform a scoping literature review regarding age-related dental changes in untreated normal occlusion subjects.

METHODS

An electronic search was performed until May 2020 using the following terms: "Dental Occlusion," "Dentition," "Ageing," and "Age groups." Articles studying changes in dental occlusal traits in orthodontically untreated subjects with neutroclusion and comparing them between various age groups were included. Studies focusing on a single age group or written in languages other than English were excluded. The risk of bias of the studies was assessed with both the methodological index for nonrandomized studies and the risk of bias in nonrandomized studies of intervention tools.

RESULTS

From the initial 7681 articles, 40 were included. High methodologic heterogeneity was found among studies. Intercanine width was found to increase until 8.0 years and 15.0 years in the mandible and maxilla, respectively, whereas intermolar width increases in both arches until 26.0 years. After that, both parameters decrease into late adulthood. Crowding increases from mixed dentition until 60.0 years of age, especially in the mandible and females. Maxillary incisors procline with age while mandibular incisors retroclined.

CONCLUSIONS

The age-related evolution of occlusal traits, together with skeletal and soft tissue changes, should be considered during orthodontic planning. Well-designed prospective cohort studies are necessary for confirmatory evidence. Expectations for treatment stability should consider muscular balance and inform patients that crowding is a sign of aging that should not always be seen as a failure of orthodontic therapy. Protocol registration number: PROSPERO CRD42020138846.

Machine learning and orthodontics, current trends and the future opportunities: A scoping review

INTRODUCTION

In recent years, artificial intelligence (AI) has been applied in various ways in medicine and dentistry. Advancements in AI technology show promising results in the practice of orthodontics. This scoping review aimed to investigate the effectiveness of AI-based models employed in orthodontic landmark detection, diagnosis, and treatment planning.

METHODS

A precise search of electronic databases was conducted, including PubMed, Google Scholar, Scopus, and Embase (English publications from January 2010 to July 2020). Quality Assessment and Diagnostic Accuracy Tool 2 (QUADAS-2) was used to assess the quality of the articles included in this review.

RESULTS

After applying inclusion and exclusion criteria, 49 articles were included in the final review. AI technology has achieved state-of-the-art results in various orthodontic applications, including automated landmark detection on lateral cephalograms and photography images, cervical vertebra maturation degree determination, skeletal classification, orthodontic tooth extraction decisions, predicting the need for orthodontic treatment or orthognathic surgery, and facial attractiveness. Most of the AI models used in these applications are based on artificial neural networks.

CONCLUSIONS

AI can help orthodontists save time and provide accuracy comparable to the trained dentists in diagnostic assessments and prognostic predictions. These systems aim to boost performance and enhance the quality of care in orthodontics. However, based on current studies, the most promising application was cephalometry landmark detection, skeletal classification, and decision making on tooth extractions.

Changes in the Transverse Dimension of the Maxillary Arch of 5-Year-Olds Born With UCLP Since the Introduction of Nationwide Guidance

Objective:

To determine whether the transverse dimensions of the maxillary arch of 5-year-old children with unilateral cleft lip and palate (UCLP) have changed following centralization of cleft services in the United Kingdom.

Design:

Retrospective cross-sectional study.

Setting:

Digital analysis of UCLP maxillary dental casts.

Participants:

All available maxillary dental casts from 5-year-old participants of the Clinical Standards Advisory Group (CSAG, N = 114) and Cleft Care UK (CCUK, N = 175) studies.

Interventions:

Quantitative measurements of the intercanine width (ICW), intermolar width (IMW), and the distance from the midline to the greater and lesser side canine (GC/LC) and greater side and lesser side second primary molar (GE/LE). Degree measurements of the greater and lesser arch form angles, arch length, anterior palatal depth (APD), and posterior palatal depth were also measured.

Main outcome:

Differences between the transverse dimensions of the maxillary arch for the CSAG and CCUK cohorts.

Results:

In 5 (ICW, IMW, LC, LE, and APD) of the 11 measurements, there was a statistically significant difference between the CSAG and CCUK cohorts. In all of these, the CCUK values were greater than CSAG.

Conclusions:

There have been small but positive improvements for the transverse maxillary dimensions since centralization of the UK cleft service.