Automated artificial intelligence-based three-dimensional comparison of orthodontic treatment outcomes with and without piezocision surgery

OBJECTIVE(S)

This study aims to evaluate the influence of the piezocision surgery in the orthodontic biomechanics, as well as in the magnitude and direction of tooth movement in the mandibular arch using novel artificial intelligence (AI)-automated tools.

MATERIALS AND METHODS

Nineteen patients, who had piezocision performed in the lower arch at the beginning of treatment with the goal of accelerating tooth movement, were compared to 19 patients who did not receive piezocision. Cone beam computed tomography (CBCT) and intraoral scans (IOS) were acquired before and after orthodontic treatment. AI-automated dental tools were used to segment and locate landmarks in dental crowns from IOS and root canals from CBCT scans to quantify 3D tooth movement. Differences in mesial-distal, buccolingual, intrusion and extrusion linear movements, as well as tooth long axis angulation and rotation were compared.

RESULTS

The treatment time for the control and experimental groups were 13.2 ± 5.06 and 13 ± 5.52 months respectively (P = .176). Overall, anterior and posterior tooth movement presented similar 3D linear and angular changes in the groups. The piezocision group demonstrated greater (P = .01) mesial long axis angulation of lower right first premolar (4.4 ± 6°) compared with control group (0.02 ± 4.9°), while the mesial rotation was significantly smaller (P = .008) in the experimental group (0.5 ± 7.8°) than in the control (8.5 ± 9.8°) considering the same tooth.

CONCLUSION

The open source-automated dental tools facilitated the clinicians' assessment of piezocision treatment outcomes. The piezocision surgery prior to the orthodontic treatment did not decrease the treatment time and did not influence in the orthodontic biomechanics, leading to similar tooth movements compared to conventional treatment.

Striving for Perfection: How Stable Is Orthodontic Treatment When Excellent Outcomes Are Achieved? A 9-Year Post-Treatment Retrospective Study

(1) Aims: The main objective of this retrospective study was to assess the long-term stability of difficult orthodontic treatments treated to an excellent result and to correlate stability to possible prognostic factors. Secondary objectives were to observe the changes in retention protocol over time and to assess Oral Health-related Quality of Life (OHRQoL) after a long-term post-treatment follow-up. (2) Methods: Cases presented for final examination by orthodontic postgraduate students were retrospectively screened for eligibility. Eligible patients were recalled for a post-treatment recall appointment (T2), consisting of a clinical examination and intraoral scan, and were asked to complete the Oral Health Impact Profile-14 (OHIP-14-DK). Gender, age at treatment commencement (T0), treatment modality and duration, and retention protocol were extracted from the records. At T2, the duration of the retention period was recorded, and retainers in place were clinically compared to the original retention protocol. The following variables were assessed on the sets of models at T0, T1 (end of treatment), and T2: arch length and width, overjet and overbite, Dental Aesthetic Index (DAI), Peer Assessment Rating score (PAR), and Little's Irregularity Index (LII). Multiple regression models were conducted. (3) Results: Eighty-five subjects attended T2. The mean post-treatment follow-up was 9.4 years +/- 2.4. In the upper arch, at T1, 74 patients had a combination of fixed and removable retainers, while at T2, 55 had a fixed retainer only. In the lower arch, at T1, 67 patients had a fixed retainer only, with this number increasing to 76 at T2. From T0 to T1, the PAR score improved by 96.1%, with the improvement remaining at 77.5% at T2. The stability of lower inter-canine and upper inter-premolar widths was significantly correlated with the extent of changes during treatment. The presence of a lower fixed retainer at T2 and a low LII at T1 were prognostic factors for stability. The mean weighted total OHIP-14 score at T2 was very low (1.6 ± 2.4 points). (4) Conclusions: In a sample with an initial high-severity malocclusion and treated to an excellent outcome, long-term stability was very good. Good stability can be retained when a lower fixed retainer is present at T2 and when a low LII is achieved at T1.

Oral health knowledge is associated with oral health-related quality of life: a survey of first-year undergraduate students enrolled in an American university

BACKGROUND

Oral health knowledge forms part of oral health literacy that enables individuals to inform appropriate oral health decisions and actions. Oral health-related quality of life (OHRQoL) characterizes self-perception of well-being influenced by oral health. This study aimed to examine the relationship between oral health knowledge and OHRQoL.

METHODS

A random sample of 19-to-24-year-old first-year undergraduate students (n = 372) in Minnesota, United States of America was used. Each student was assessed with an online survey using the Comprehensive Measure of Oral Health Knowledge (CMOHK) and the OHRQoL items of the World Health Organization (WHO) Oral Health Questionnaire for Adults. Relationships between OHRQoL parameters and CMOHK together with other covariates were assessed using ordinal regression models. Associations between OHRQoL parameters were examined with the Kendall's tau-b method.

RESULTS

Dry mouth (45%) was the most reported OHRQoL issue. The respondents showing good oral health knowledge were less likely to experience speech or pronunciation difficulty (β=-1.12, p = 0.0006), interrupted sleep (β=-1.43, p = 0.0040), taking days off (β=-1.71, p = 0.0054), difficulty doing usual activities (β=-2.37, p = 0.0002), or reduced participation in social activities due to dental or oral issues (β=-1.65, p = 0.0078).

CONCLUSIONS

This study suggested a protective effect of better oral health knowledge on specific OHRQoL issues. In addition to provision of affordable dental services, university-wide oral health education can be implemented to improve OHRQoL in undergraduate students.

Treatment change comparisons between skeletal Class I and II white adolescents with 3 different vertical divergencies-part 1: Frankfort-Mandibular Incisor Angle (FMIA) and soft-tissue profile

INTRODUCTION

This study investigated the interrelationship between FMIA and soft-tissue profile changes in skeletal Class I and II white adolescents with 3 different vertical skeletal patterns.

METHODS

Two hundred seventy cephalometric images were constructed from pretreatment and posttreatment cone-beam computed tomography images of 135 white adolescents (69 females and 66 males with a mean age of 12.8 ± 1.4 years pretreatment and 15.0 ± 1.4 years posttreatment). SNA, SNB, ANB, Frankfort Mandibular Angle [FMA], Incisor Mandibular Plane Angle [IMPA], Frankfort-Mandibular Incisor Angle [FMIA], and Z angle were measured. A mixed-model analysis of variance was performed for patients with an increased posttreatment Z angle to evaluate within-subject and between-subject effects of variables in relation to horizontal and vertical skeletal patterns. Post-hoc tests were conducted to identify statistical significance among the 3 different divergent subgroups.

RESULTS

Patients with a skeletal Class I relationship had straighter facial profiles and a larger FMIA than patients with a skeletal Class II relationship before and after treatment. FMA, FMIA, IMPA, and Z angle treatment changes were similar between the skeletal Class I and II groups. The final FMIA means of the 3 divergent subgroups converged at 65° in the skeletal Class I group and 60° in the skeletal Class II group. The mandibular incisors were uprighted during treatment in the hyperdivergent patients whose Z angle values increased after treatment.

CONCLUSION

Horizontal skeletal relationships seem more suitable for determining the desired FMIA in Tweed's total space analysis than vertical skeletal divergencies.

Effectiveness of Physical Therapy in Orthognathic Surgery Patients: A Systematic Review of Randomized Controlled Trials

Orthognathic surgery (OS) can present many complications that affect patients' rehabilitation. However, there have been no systematic reviews that assessed the effectiveness of physiotherapy interventions in the postsurgical rehabilitation of OS patients. The aim of this systematic review was to analyze the effectiveness of physiotherapy after OS. The inclusion criteria were randomized clinical trials (RCTs) of patients who underwent OS and who received therapeutic interventions that included any physiotherapy modality. Temporomandibular joint disorders were excluded. After the filtering process, five RCTs were selected from the 1152 initially obtained (two had acceptable methodological quality; three had insufficient methodological quality). The results obtained showed that the effects of the physiotherapy interventions studied in this systematic review on the variables of range of motion, pain, edema and masticatory muscle strength were limited. Only laser therapy and LED showed a moderate level of evidence in the postoperative neurosensory rehabilitation of the inferior alveolar nerve compared with a placebo LED intervention.

Bone Remodeling during Orthodontic Movement of Lower Incisors-Narrative Review

The tooth movement in the alveolus is possible due to bone remodeling. This process could be the risk factor for the formation of gingival recessions-the most common side effects of orthodontic therapy. Gingival recessions are found 5.8-11.5% more frequently among the orthodontically treated patients. What is more, anterior mandibular teeth are the ones most prone to gingival recession dehiscences and fenestrations. The aim of this narrative review was to evaluate, based on CBCT (Cone beam computed tomography) scans, the changes in the alveolar bone of lower incisors in adolescent and adult patients after orthodontic tooth movements. From the pool of 108 publications, a total of 15 fulfilled the criteria of this review. Both retrospective and prospective longitudinal studies-using CBCT or CT (Computed Topography) and evaluating alveolar bone changes in mandibular incisors during orthodontic treatment performed before and after teeth movement-were included. In the group of growing patients, either proclination or retroclination of mandibular incisors led to increase of the distance from CEJ (cementoenamel junction) to marginal bone crest. The difference in bone loss was greater on the lingual side of the incisors in both types of tooth movement. The results were similar for adults patients. The thickness of the alveolar bone was reduced after proclination (total bone thickness) among growing and non-growing patients and retraction (lingual and buccal) of lower anterior teeth in the group of growing patients. The only improvement was measured for buccal thickness of mandibular incisor in bimaxillary protrusion patients treated with extraction therapy. The control of retraction movement (more root than crown movement) enhanced preservation on bone height and thickness. In order to minimize possible deterioration and place teeth in the center of alveolus, CBCT monitoring and scrupulous clinical evaluation are recommended.

Three-dimensional analysis of the posttreatment displacements of mandibular anterior teeth with rigid and flexible lingual retainers

INTRODUCTION

The purpose of this study was to analyze any posttreatment changes in the positions of mandibular anterior teeth retained by 2 different fixed retention methods (rigid or flexible) and their effectiveness in minimizing postorthodontic tooth movement.

METHODS

Thirty patients were selected for inclusion in this retrospective study. Group I consisted of 15 patients with 0.032-in stainless steel rigid retainers bonded to canines only. Group II consisted of 15 patients with 0.0215-in twisted stainless steel flexible retainer bonded to all mandibular anterior teeth. Geomagic Control (3DS Systems, Rock Hill, SC) software was used to quantify the changes between selected points. Paired t test was used for intragroup comparisons in all 3 coordinates, and an independent-sample t test was used for intergroup comparison.

RESULTS

In the transverse dimension, significant intergroup differences were found in displacements of distoincisal points of the right lateral (P <0.05) and left central incisors (P <0.01). In the sagittal dimension, significant intergroup differences were found in the displacements of mesioincisal point of the right central incisor (P <0.05) and distoincisal point of the left central incisor (P <0.01). Examining total displacement, there were significant intergroup differences in mesioincisal point on the right central incisor, distoincisal point on the left lateral incisor (P <0.05).

CONCLUSIONS

Our results suggested that central incisor contacts were more likely to shift with the rigid retainers, especially in sagittal and transverse dimensions. However, no statistically or clinically significant changes were noted in the third-order or vertical positions of the teeth with either retention method.

Characterisation of anterior open bite in primary school-aged children: A preliminary study with artificial neural network analysis

BACKGROUND

Non-nutritive sucking habits, bottle feeding, and facial hyperdivergency have been suggested as the influencing factors of anterior open bite (AOB). There was inconsistent reporting of prevalence and a gap of knowledge in the literature.

AIM

The aim of this study was to investigate the prevalence of AOB in 7- to 12-year-olds, with a special interest to characterise the determinants of this malocclusion.

DESIGN

A sample of 203 children aged 7 to 12 years were selected from a primary school in regional Australia. The legal guardian of each child completed a self-administered questionnaire. Data were assessed using methods of univariate statistics and neural analysis.

RESULTS

The prevalence of AOB and thumb sucking was 24.1% and 23.2%, respectively. AOB was associated with the habit (correlation = 0.754) and duration (correlation = 0.574) of thumb sucking. Age, gender, birth order, feeding modality, sleep patterns, history of orthodontic treatment and tonsil, adenoid or grommet surgery, and parents' level of education were not related to AOB (correlation absolute value ≤ 0.474).

CONCLUSIONS

Thumb sucking, specifically for prolonged duration, increases the risk of development of AOB. Cessation of thumb sucking habits should be encouraged at an early age to avoid the development of AOB.

Incorporation of Arginine to Commercial Orthodontic Light-Cured Resin Cements-Physical, Adhesive, and Antibacterial Properties

(1) Background: The amino acid arginine is now receiving great attention due to its potential anti-caries benefits. The purpose of this in vitro study was to evaluate the shear bond strength (SBS), ultimate tensile strength (UTS), and antimicrobial potential (CFU) of two arginine-containing orthodontic resin cements. (2) Methods: Forty bovine incisors were separated into four groups (n = 10): Orthocem, Orthocem + arginine (2.5 wt%), Transbond XT, and Transbond XT + arginine (2.5 wt%). The brackets were fixed to the flat surface of the enamel, and after 24 h the SBS was evaluated using the universal testing machine (Instron). For the UTS test, hourglass samples (n = 10) were made and tested in a mini-testing machine (OM-100, Odeme). For the antibacterial test (colony forming unit-CFU), six cement discs from each group were made and exposed to Streptococcus mutans UA159 biofilm for 7 days. The microbiological experiment was performed by serial and triplicate dilutions. The data from each test were statistically analyzed using a two-way ANOVA, followed by Tukey’s test (α = 0.05). (3) Results: The enamel SBS mean values of Transbond XT were statistically higher than those of Orthocem, both with and without arginine (p = 0.02033). There was no significant difference in the SBS mean values between the orthodontic resin cements, either with or without arginine (p = 0.29869). The UTS of the Transbond XT was statistically higher than the Orthocem, but the addition of arginine at 2.5 wt% did not influence the UTS for either resin cement. The Orthocem + arginine orthodontic resin cement was able to significantly reduce S. mutans growth, but no difference was observed for the Transbond XT (p = 0.03439). (4) Conclusion: The incorporation of arginine to commercial orthodontic resin cements may be an efficient preventive strategy to reduce bacterial growth without compromising their adhesive and mechanical properties.

Orthodontic Tooth Movement Studied by Finite Element Analysis: an Update. What Can We Learn from These Simulations?

PURPOSE OF REVIEW

To produce an updated overview of the use of finite element (FE) analysis for analyzing orthodontic tooth movement (OTM). Different levels of simulation complexity, including material properties and level of morphological representation of the alveolar complex, will be presented and evaluated, and the limitations will be discussed.

RECENT FINDINGS

Complex formulations of the PDL have been proposed, which might be able to correctly predict the behavior of the PDL both when chewing forces and orthodontic forces are simulated in FE models. The recent findings do not corroborate the simplified view of the classical OTM theories. The use of complex and biologically coherent FE models can help understanding the mechanisms leading to OTM as well as predicting the risk of root resorption related to specific force systems and magnitudes.

Orthodontic Treatment of Periodontally Compromised Teeth After Laser Periodontal Therapy: A Case Report

Objective: To assess stability of laser periodontal therapy (LPT) results after orthodontic tooth movement. Background: Periodontitis and malocclusion each exhibit high global prevalence. Thus, dentists inevitably face increasing demand for orthodontic treatment in patients with reduced periodontal support. Many of these patients benefit from orthodontic treatment, provided that periodontal inflammation is controlled. Materials and methods: We present a case demonstrating successful orthodontic treatment of periodontally compromised teeth after LPT. A patient with severe attachment and alveolar bone loss received orthodontic treatment 13 months after neodymium-doped: yttrium aluminum garnet LPT (1064 nm). We utilized three laser parameter sets for various purposes during the procedure-ablation of the periodontal pocket epithelium (2.8 W, 20 Hz, 100 μs), clot stabilization (2.8 W, 20 Hz, 550 μs), and photobiomodulation (2.8 W, 20 Hz, 100 μs, noncontact). Results: Treatment resulted in improved radiographic bone levels, clinical parameters consistent with periodontal health, and favorable occlusal relationships. Conclusions: In the presented case, we successfully treated a patient presenting with malocclusion and reduced periodontal support while avoiding the risk and morbidity of conventional periodontal surgery. Controlled clinical research to establish the predictability of the described approach appears warranted.

Effect of Photobiomodulation on Relapse in an Experimental Rapid Maxillary Expansion Model in Rat

Rapid maxillary expansion (RME) is performed on transversely deficient maxilla. As all orthodontic treatments, retention is important in maintaining therapeutic outcomes. Fixed /removable retainers are used post-RME causing hygiene and compliance problems. Given photobiomodulation's positive effects on the quantity and quality of bone regeneration, its effect on post-RME relapse was studied. Thirty Sprague Dawley rats were randomly divided into group R, non-irradiated RME-treated (n = 12), group P, irradiated RME-treated (n = 12) and group C, non-RME non-irradiated (n = 6). A 1.5 mm metal ring inserted between maxillary incisors at days 0 and 15 was expanded until 1.5 mm space was obtained at day 30. In group P, Ga-Al-As diode laser (810 nm, 100 mW, 4J/cm² , 30 secs) was applied on days 0, 2, 4, 6, 8, 10, 12 and 14 as predictor variable. The relapse was measured as the space lost between incisors for 30 days after appliance removal (primary outcome variable) and compared with t-test. In week 2, space loss in group P was significantly lower (P < 0.05) than all other groups. The relapse during weeks 2 and 3 was significantly lower in group P than group R. However, no significant difference in relapse amount was found between groups during first and fourth week. There was a significant difference (P < 0.05) between groups in relapse rates (secondary outcome variable) but not in total relapse after 4 weeks. Photobiomodulation proved beneficial in resisting relapse in our study, and it is suggested to be continued until the end of expansion.

Association between Gingival Biotype and Facial Typology through Cephalometric Evaluation and Three-Dimensional Facial Scanning

In dentistry, the assessment of periodontal biotype is considered one of the most important parameters with which to plan treatment, and craniofacial morphology might affect it. The aim of this study was to investigate the association between facial typology and gingival biotype in patients by means of two-dimensional and three-dimensional evaluations of facial typology. This study included 121 participants searching for orthodontic treatment (43 M, 78 F; 20.4 ± 10.4). Gingival biotype was evaluated based on the transparency of the periodontal probe through the gingival margin of the mid-buccal sulcus for both upper (UGB) and lower (LGB) anterior teeth. SellionNasion^GonionGnation (SN^GoGn) and CondylionGonionMenton (CoGoMe^) angles were measured on two-dimensional cephalograms. Three-dimensional face scans were acquired by means of a three-dimensional facial scanner (3dMD system) and successively analyzed to assess the facial typology using the ratio between lower facial height (SNMe) and total facial height (NMe). A chi-squared test and regression analysis were used to evaluate the associations between gingival biotype and facial morphology (p < 0.05). The chi-squared test showed that there was no statistically significant association between facial typology and gingival biotype (UGB p = 0.83; LGB p = 0.75). The logistic regression showed an association between SNMe/NMe and the UGB (p = 0.036), and SNMe/NMe and LGB (p = 0.049). The decreased ratio of SNMe/NMe might be a protective factor for a thin gingival biotype.