The Importance of the Occlusal Plane in Predicting Better Facial Soft Tissue in Class II Malocclusion in Ethnic Javanese

Assessing the impact of occlusal plane rotation on facial aesthetics in orthodontic treatment: a machine learning approach

BACKGROUND

Adequate occlusal plane (OP) rotation through orthodontic therapy enables satisfying profile improvements for patients who are disturbed by their maxillomandibular imbalance but reluctant to surgery. The study aims to quantify profile improvements that OP rotation could produce in orthodontic treatment and whether the efficacy differs among skeletal types via machine learning.

MATERIALS AND METHODS

Cephalometric radiographs of 903 patients were marked and analyzed by trained orthodontists with assistance of Uceph, a commercial software which use artificial intelligence to perform the cephalometrics analysis. Back-propagation artificial neural network (BP-ANN) models were then trained based on collected samples to fit the relationship among maxillomandibular structural indicators, SN-OP and P-A Face Height ratio (FHR), Facial Angle (FA). After corroborating the precision and reliability of the models by T-test and Bland-Altman analysis, simulation strategy and matrix computation were combined to predict the consequent changes of FHR, FA to OP rotation. Linear regression and statistical approaches were then applied for coefficient calculation and differences comparison.

RESULTS

The regression scores calculating the similarity between predicted and true values reached 0.916 and 0.908 in FHR, FA models respectively, and almost all pairs were in 95% CI of Bland-Altman analysis, confirming the effectiveness of our models. Matrix simulation was used to ascertain the efficacy of OP control in aesthetic improvements. Intriguingly, though FHR change rate appeared to be constant across groups, in FA models, hypodivergent group displayed more sensitive changes to SN-OP than normodivergent, hypodivergent group, and Class III group significantly showed larger changes than Class I and II.

CONCLUSIONS

Rotation of OP could yield differently to facial aesthetic improvements as more efficient in hypodivergent groups vertically and Class III groups sagittally.

Effects of Class II elastics during growth on the functional occlusal plane according to skeletal pattern and extraction vs nonextraction

OBJECTIVES

To investigate the effect of Class II intermaxillary elastics on the functional occlusal plane (FOP) of growing patients.

MATERIALS AND METHODS

A total of 50 participants aged 11 to 16 years were selected from a university clinic archive >1-year after treatment and after undergoing 6 months of Class II elastic wear, taking pretreatment (T0) and posttreatment (T1) lateral cephalometric radiographs, and consenting to participate at recall (T2). Participants were divided into 3 groups according to skeletal pattern or into 2 groups according to treatment with extraction (E) or nonextraction (NE). Angular changes of FOP relative to the Sella-Nasion (SN), mandibular plane (MP), and Frankfort horizontal (FH) were compared within and between groups.

RESULTS

A statistically significant reduction of FOP-SN/FH, but not of FOP-MP, was found from T0-T1-T2 when all patients were grouped together. FOP-SN/MP/FH was significantly the largest in the patients with a hyperdivergent skeletal pattern, but lowest in the patients with a hypodivergent skeletal pattern at T0, T1, and T2 (P < .032). FOP-MP at T0-T2 was statistically larger in group E than in group NE (P < .02). No differences were found for FOP changes (change before treatment minus after treatment and change after treatment minus 1 year after treatment) between different skeletal patterns (P > .433) and treatment groups (P > .193).

CONCLUSIONS

Use of Class II elastics during the growth period was not found to show adverse effects on FOP rotation. Neither skeletal pattern nor treatment modality differed in the response to Class II elastics with regard to FOP changes. Individual patient growth pattern must be taken into consideration when treatment planning the use of Class II elastics. Orthodontists should take into account individual skeletal and growth patterns while using Class II elastics.

Evaluation of Skeletal Changes after Mandibular Setback Surgery Using the NM-Low Z Plasty Technique in Skeletal Class III Patients

OBJECTIVE

 Bilateral sagittal split osteotomy (BSSO) is a standard mandibular setback procedure for skeletal class III patients. Our center has been using NM-Low Z plasty, a BSSO modification, since 2016. The study's objective was to evaluate skeletal changes in 38 skeletal class III patients following mandibular setback surgery using NM-Low Z plasty. With Dolphin Imaging software, three lateral cephalograms were traced and digitized: T0, T1, and T2. The distance between the B-point and the SN7 perpendicular line defined immediate changes after surgery (T1-T0) and stability after surgery (T2-T1). The reliability test included 6 cephalograms retraced after 2-week interval. At point B, the principal result was horizontal movement forward.

STATISTICAL ANALYSIS

 The analysis used paired t-tests.

RESULTS

 The mean mandibular setback was 9.78 mm, and the mean skeletal relapse was 2.61 mm, or 26.69%. Statistical analysis showed postoperative differences (p < 0.05). Vertical measurement in B-SN7 reduced immediately and postoperatively.

CONCLUSION

 Postoperatively, the mandible relapsed significantly forward and upward. Rotational relapse is a concern with NM-Low Z plasty in hypo-/: normodivergent patients.

COL1A1 and FGFR2 Single-Nucleotide Polymorphisms Found in Class II and Class III Skeletal Malocclusions in Javanese Population

OBJECTIVE

 The aim of this article is to analyze and compare the presence of single-nucleotide polymorphisms (SNPs) of COL1A1 and FGFR2 in class II and class III Javanese populations.

MATERIALS AND METHODS

 Cephalometric radiographs from total 63 patients of class II and III were analyzed. SNP analysis was performed based on both COL1A1 and FGFR2 sequences amplified from total DNA of patients' fresh blood. Principal component analysis was done to calculate the data and find the correlation of the cephalometric indicators influenced by each mutation. t-test and Mann-Whitney analysis were performed to check the significance of differences occurred in each studied parameter (p < 0.05).

RESULT

 There were three COL1A1 SNPs found in class II and only two in class III, while three FGFR2 SNPs found in both classes. Class II phenotype seemed to be strongly influenced by Y-axis and mandibular plane angle, while class III by lower gonial angle and mandibular plane angle.

CONCLUSION

 Based on this study, we suggest that rs2249492 of COL1A1 and rs2981582 of FGFR2 play important roles in class III, while rs2277632 of COL1A1 and rs2981582 of FGFR2 play important role in class II skeletal malocclusion in Javanese population.

Skeletal and Dentoalveolar Effects Induced by the Paolone- Kaitsas Appliance in the Treatment of Class II Malocclusion: A Controlled Retrospective Study on Lateral Cephalograms

The aim of this study was to assess the skeletal and dentoalveolar effects induced by the Paolone-Kaitsas functional appliance (PK appliance) in the treatment of growing patients affected by Class II malocclusion. A group of 25 Class II patients, treated with the PK appliance followed by fixed appliances, was evaluated with lateral cephalograms at the start (9.6 ± 1.6 years) and at the end of treatment (13.0 ± 1.5 years), and was compared with a matched untreated Class II control group of 23 subjects selected from the web archive of the American Association of Orthodontists Foundation Craniofacial Growth Legacy. Statistical comparisons were performed with the Student’s t-tests. The treated group showed a significant decrease in SNA (−2.2°), ANB (−2.2°), and Wits appraisal (−3.4 mm), a significant increase in the SN-palatal plane angle (1.1°), and a significant improvement in overjet (−2.9 mm), overbite (−2.5 mm), and molar relationship (3.6 mm). The PK appliance produced favorable dentoalveolar and skeletal effects: it inhibited maxillary growth without effects on the mandible and it also induced a downward inclination of the palatal plane.

Cephalometric Analysis, Severity Malocclusion, and Orthodontic Treatment Need Using IOTN in Deaf Children

Objectives  Studies associated with deaf children's malocclusion and their treatment need are still very rare. Therefore, cephalometric analysis with the ability to access the skeletal, dental, and soft tissues can be used to score the severity of malocclusion and index of orthodontic treatment need (IOTN) in deaf children. This study examined the use of cephalometric analysis, severity malocclusion, and orthodontic treatment need in deaf students at special need school type B (SLB-B) Tunarungu Karya Mulia in Surabaya using IOTN along with investigating IOTN correlation with the result of dental cephalometric analysis and dental health component (DHC) and aesthetic component (AC) in IOTN index.

Material and Methods  Sample data consisted of 33 students between the ages of 8 to 12 years old and never had any orthodontic treatment. This investigation applied the indices from IOTN, in which DHC had 10 malocclusions, and AC with the aesthetic anterior dentition comprising 10 color photographs and different dental attractiveness levels. In addition, scores were chosen from the worst feature, with the data analyzed at a significant correlation test of 0.05%.

Result  There was no skeletal abnormality in deaf children. It displayed the highest number of malocclusion severity scores, while the DHC assessment showed the moderate and severe categories. Based on AC evaluation, the highest numbers of malocclusion severity were found in good and moderate category in terms of teeth arrangement and aesthetic.

Conclusion  There was a correlation between the dental cephalometric analysis in deaf children and treatment need using IOTN with AC and DHC.

The Retromolar Space and Wisdom Teeth in Humans: Reasons for Surgical Tooth Extraction

OBJECTIVE

 This article explores the problem of developing pathologies in the retromolar region. Findings can serve a framework for disease prevention and for the improvement of the quality of life of patients. The present study aims to justify the possibility of utilizing morphometric methods to foresee problems in the eruption of third molars.

MATERIALS AND METHODS

 A comprehensive morphometric study of the lower jaw and facial skeleton involves 100 skulls of Homo sapiens to identify the anatomical causes of problems with wisdom teeth eruption. All said skulls are divided in two groups: I: skulls with intact dentition; II: skulls with impacted third molars.

RESULTS

 This work allows detecting abnormalities in the eruption of the third molar with high probability of success. The abnormalities in point are considered not only those associated with the generally accepted parameters but also those that occur in the leptoprosopic face cases.

CONCLUSIONS

 Face type and the structural features of the facial skeleton play a significant role in the abnormal eruption of the lower third molar.