Journal of Orofacial Orthopedics-Fortschritte Der Kieferorthopadie最新文献

Purpose: For the fabrication of an orthodontic mini-implant (OMI)-borne appliance, the position of the inserted OMI can be detected by a silicone impression or an intraoral scan (IOS). In case of digital planning, it can be taken over from the planning and the appliance can be produced in advance. This study aimed to evaluate the accuracy of these three techniques and whether there is an association with the insertion angle.

Methods: Two OMIs were digitally planned and placed in the anterior palate of 11 human cadavers with different insertion angles. Subsequently, the position of each OMI was detected by an IOS, a silicone impression, and a cone-beam computed tomography (CBCT) scan, whereby the CBCT scan was set as "real position". The measurements of accuracy were performed between the CBCT data as a reference and the preoperative digital planning, the IOS and the plaster model manufactured from the silicone impression.

Results: The IOS was the most accurate in detecting the Top (mean deviation 0.14 mm) and the Apex (mean deviation 0.36 mm) of the OMIs. Significant linear deviations between the three modalities were registered for both Top (p < 0.001) and Apex (p = 0.010). The digital planning procedure achieved the lowest mean angular deviation of 3.7° and was significantly more accurate in this respect than the IOS (p < 0.001).

Conclusion: All methods were subject to small, but clinically irrelevant deviations. Within the limitations of a cadaver study, all methods appear to be suitable for clinical use. However, the digital workflow could be advantageous, requiring only a single visit for OMI placement and simultaneous appliance fitting.

Objectives: This study aimed to assess the efficacy of a mobile phone application (app) to improve oral hygiene of patients undergoing fixed orthodontic treatment.

Materials and methods: This randomized controlled clinical trial was conducted with a total of 60 patients undergoing fixed orthodontic treatment in two groups: intervention and control (n = 30 each). A previously designed mobile app (Labkhand) was used by patients in the intervention group. Orthodontic plaque index (OPI) and modified gingival index (MGI) were recorded in the two groups at baseline (first session or T0), and after 1 (T1) and 3 (T2) months. The number of debonded/broken brackets was also recorded, and pain score of the patients was assessed at nine time points. Data were analyzed using the χ² test, paired t‑test, and repeated measures analysis of variance (ANOVA; α = 0.05).

Results: The two groups demonstrated no significant difference in OPI and MGI at T0 (P > 0.05). OPI and MGI at T1 and T2 were significantly lower in the intervention group than in the control group (P < 0.05). The number of patients with broken brackets in the intervention group was significantly lower than that in the control group (P = 0.017). The two groups reported no significant difference in pain score (P > 0.05).

Conclusion: The Labkhand mobile app successfully improved oral hygiene indices of patients undergoing fixed orthodontic treatment, and decreased the frequency of broken brackets after 1 and 3 months of use.

Purpose: To compare failure rates and maximum load capacity (F_max) of six different computer-aided design/computer-aided manufacturing (CAD/CAM) retainers with those of the hand-bent five-stranded stainless steel twistflex retainer.

Materials and methods: Six groups (n = 8 per group) of commercially available CAD/CAM retainers (cobalt-chromium [CoCr], titanium grade 5 [Ti5], nickel-titanium [NiTi], zirconia [ZrO₂], polyetheretherketone [PEEK], and gold) and twistflex retainers were tested for long-term sufficiency and for F_max using a self-developed in vitro model. All retainer models underwent a simulated ageing process of about 15 years (1,200,000 chewing cycles with a force magnitude of 65 N at 45° followed by storage in water at 37 °C for 30 days). If retainers did not debond or break during ageing, their F_max was determined in a universal testing machine. Data were statistically analysed using Kruskal-Wallis and Mann-Whitney U‑tests.

Results: Twistflex retainers did not fail (0/8) during ageing and had the highest F_max (445 N ± 51 N). Ti5 retainers were the only CAD/CAM retainers that also did not fail (0/8) and had similar F_max values (374 N ± 62 N). All other CAD/CAM retainers had higher failure rates during ageing and significantly lower F_max values (p < 0.01; ZrO₂: 1/8, 168 N ± 52 N; gold: 3/8, 130 N ± 52 N; NiTi: 5/8, 162 N ± 132 N; CoCr: 6/8, 122 N ± 100 N; PEEK: 8/8, 65 ± 0 N). Failure was due to breakage in the NiTi retainers and debonding in all other retainers.

Conclusion: Twistflex retainers remain the gold standard regarding biomechanical properties and long-term sufficiency. Of the CAD/CAM retainers tested, Ti5 retainers seem to be the most suitable alternative. In contrast, all other CAD/CAM retainers investigated in this study showed high failure rates and had significantly lower F_max values.

Purpose: The purpose of this ex vivo study was to compare the cleaning performance of three commercially available orthodontic cleaners on polymethyl methacrylate (PMMA) test specimens covered with biofilm.

Methods: Twenty subjects wore an individually manufactured vacuum-formed maxillary splint with four integrated PMMA test specimens for 7 days. The four test specimens were located on the buccal surfaces of the maxillary molars. After a 7-day wearing period, the PMMA test specimens colonized by biofilm were divided into two halves. One half was placed in 150 ml of tap water or in 150 ml of cleaning solution of the cleaners Retainer Brite® (Dentsply International Raintree Essix, Sarasota, FL, USA), Kukis® Xpress (Reckitt Benckiser, Heidelberg, Germany) or Dontodent (Propack, Heidelberg, Germany) while the other half remained uncleaned. The modified o‑phthaldialdehyde (OPA) method was used to determine the amount of protein on both halves of the test specimens. The difference was tested for significance as a measure of the cleaning effect using a paired sample t‑test.

Results: The cleaning performance of the three orthodontic cleaners was higher than the cleaning performance of tap water (mean 25.9 ± 6.5%). While Retainer Brite® (mean 54.5 ± 7.1%) removed significantly more biofilm than Dontodent (mean 41.5 ± 9.2%, p < 0.001) and Kukis® Xpress (mean 39.9 ± 11.5%, p < 0.001), there was no significant difference in the cleaning performance between Kukis® Xpress and Dontodent (p = 1).

Conclusion: Seven-day-old biofilm is only removed partially by the investigated orthodontic cleaners, so that they are not suitable as the only measure for removing established biofilms.

Purpose: Aim of the present study was to assess the relative distribution of occlusal forces after orthodontic treatment and during the first 3 months of the retention phase using a computerized occlusal analysis system (T-Scan, Tekscan Inc., Norwood, MA, USA).

Materials and methods: A total of 52 patients were included in this prospective cohort study and underwent analysis of occlusal forces on the level of tooth, jaw-half, and -quadrant during a 3-month period. Furthermore, differences between three retention protocols (group I: removable appliances in both jaws; group II: fixed 3-3 lingual retainers in both jaws; group III: removable appliance in the maxilla and fixed 3-3 lingual retainer in mandible) were assessed with Wilcoxon signed-rank tests at 5%.

Results: Directly after debonding, measured forces distribution were similar to published references for untreated samples. In the following, no significant difference was found between retention protocols II and III with regard to the asymmetry of the anterior occlusal forces. Both groups maintained an asymmetric force distribution in the anterior segment during the study period. There was also no difference between groups II and III in the distribution of occlusal forces for the posterior segments. Both retention concepts kept the symmetrical distribution of occlusal forces stable over the observation period. The retention concept of group I demonstrated a symmetrical distribution of occlusal forces in the anterior segment after debonding and this remained stable during the 3‑month period. In the posterior segment, no improvement of the initially asymmetric masticatory force distribution could be observed.

Conclusions: All three studied retention protocols showed stability in retaining their original symmetrical or asymmetrical occlusal force distribution posteriorly/anteriorly during the 3‑month observation period. Therefore, an even distribution of occlusal forces should be the aim of the finishing phase, as no relative benefit of any single retention scheme in terms of post-debond improvement during the retention phase was seen.

Introduction: This study aimed to investigate whether the facial soft tissue changes of individuals who had undergone surgically assisted rapid maxillary expansion (SARME) would be detected by three different well-known facial biometric recognition applications.

Methods: To calculate similarity scores, the pre- and postsurgical photographs of 22 patients who had undergone SARME treatment were examined using three prominent cloud computing-based facial recognition application programming interfaces (APIs): AWS Rekognition (Amazon Web Services, Seattle, WA, USA), Microsoft Azure Cognitive (Microsoft, Redmond, WA, USA), and Face++ (Megvii, Beijing, China). The pre- and post-SARME photographs of the patients (relaxed, smiling, profile, and semiprofile) were used to calculate similarity scores using the APIs. Friedman's two-way analysis of variance and the Wilcoxon signed-rank test were used to compare the similarity scores obtained from the photographs of the different aspects of the face before and after surgery using the different programs. The relationship between measurements on lateral and posteroanterior cephalograms and the similarity scores was evaluated using the Spearman rank correlation.

Results: The similarity scores were found to be lower with the Face++ program. When looking at the photo types, it was observed that the similarity scores were higher in the smiling photos. A statistically significant difference in the similarity scores (P < 0.05) was found between the relaxed and smiling photographs using the different programs. The correlation between the cephalometric and posteroanterior measurements and the similarity scores was not significant (P > 0.05).

Conclusion: SARME treatment caused a significant change in the similarity scores calculated with the help of three different facial recognition programs. The highest similarity scores were found in the smiling photographs, whereas the lowest scores were found in the profile photographs.

Purpose: For resolving anterior dental crowding or spacing, it is of key interest in personalised orthodontic diagnostics and treatment planning to predict the extent of space gained or lost in the anterior dental arch by changing incisor inclination or position. To facilitate the determination of anterior arch length (AL) and to predict its alterations following tooth movements, a mathematical-geometrical model, based on a third-degree parabola, was established. The aim of this study was to validate this model and assess its diagnostic precision.

Methods: This retrospective diagnostic study evaluated 50 randomly chosen dental casts taken before (T0) and after (T1) orthodontic treatment with fixed appliances. Plaster models were digitally photographed, allowing two-dimensional digital measurements of arch width, depth and length. A computer programme based on the mathematical-geometrical model to be validated was created to calculate AL for any given arch width and depth. Mean differences and correlation coefficients as well as Bland-Altman plots were used to compare the measured and the calculated (predicted) AL, evaluating the precision of the model.

Results: Inter- and intrarater reliability tests showed reliable measurements of arch width, depth and length. Measured and calculated (predicted) AL revealed high concordance according to concordance correlation coefficient (CCC), intraclass correlation coefficient (ICC), and Bland-Altman analyses and negligible differences between the mean values.

Conclusions: The mathematical-geometrical model calculated anterior AL without significant difference to the measured AL, indicating its validity. The model can thus be used clinically for predicting alterations of AL following therapeutic changes of incisor inclination/position.

Objectives: Digital imaging techniques are important in dental diagnostics and therapy planning. Thus, the goal was to investigate the current state of the science regarding two- (2D) and three-dimensional (3D) imaging for clinical orthodontic issues via a systematic literature review and meta-analysis.

Materials and methods: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the search was carried out using common electronic databases with the following terms: cbct AND opt AND dentistry, cbct AND opt AND orthodontics, cbct AND opt, three-dimensional imaging AND two-dimensional imaging AND orthodontics, cbct AND lateral cephalogram. A forest plot was utilized to depict the standardized mean differences (SMD) using a random-effects model to account for study heterogeneity. Heterogeneity assessment of the various trials was conducted using the I²-value and the Q‑test.

Results: Of the 362 articles (1987-2023) identified, 41 articles met the inclusion criteria. The studies were categorized into four groups based on clinical background: mini-implant placement, root resorptions, impacted canines and cephalometric measurements. For mini-implant placement, 4 papers explored the benefits of 3D imaging. Root resorption detection was the focus of 4 studies, while 8 articles investigated 3D diagnostics for impacted canines. Overall, while 2D imaging suffices for evaluating mini-implant placement, CBCT images offer enhanced accuracy for investigating root resorptions and improved sensitivity in identifying impacted canines. Comparability of 2D and 3D imaging, with a focus on cephalometric measurements, was evaluated in 25 studies. Within this group, 10 papers were included in a meta-analysis, comparing SNA, SNB and ANB angle measurements. The random-effects model was used to compare the results of the SNA, SNB and ANB angles, which were presented in forest plots. No significant differences were found in the comparison of 2D and 3D imaging techniques for the SNA angle (p = 0.338; SMD = 0.39; 95% CI -0.40 to 1.18), the SNB angle (p = 0.650; SMD = 0.11; 95% CI -0.35 to 0.57), and the ANB angle (p = 0.666; SMD 0.89; 95% CI -0.32 to 0.50), whereby heterogeneity was high for all (I² = 90.27%, p < 0.001, I² = 76.81%, p = 0.004, and I² = 93.29%, p < 0.001, respectively).

Conclusion: Based on the findings and the additional meta-analysis, 3D imaging is either equivalent or potentially superior to conventional 2D imaging for all subgroups. Further studies are required.

Background: With the constant improvement of photopolymerizable resin, direct three-dimensional (3D) printing of retainers and aligners (R&A) has gained popularity in recent years. The primary objective of this research was to systematically evaluate the evidence regarding the accuracy of 3D-printed R&A in terms of trueness and precision (T&P).

Methods: Electronic database searches were performed on PubMed, Science Direct, Web of Science, Scopus, Ovid, and Clinicaltrial.gov through 17 November 2023. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to assess the risk of bias and applicability concerns of the methodologic quality of the articles.

Results: A total of 12 in vitro studies were selected. Five studies reported the accuracy of 3D-printed retainers and another seven reported on aligners. For the 3D-printed retainer group, only Naeem et al. [1] reported both T&P and found that stereolithography (SLA) and PolyJet photopolymer (PPP) printers demonstrated higher accuracy than digital light processing (DLP) and continuous digital light processing (cDLP) printers. For the 3D-printed aligners group, only Koenig et al. [2] reported both T&P and found that 3D-printed aligners fabricated with photopolymerizable polyurethane resin demonstrated higher trueness (0.14 ± 0.020 mm) compared to conventional thermoformed aligners (0.188 ± 0.074 and 0.209 ± 0.094).

Conclusion: The existing digital workflow involving various printing materials, angulations, printing thickness, and printing technologies is feasible for the fabrication of direct 3D printing of R&A with variable degrees of accuracy. Most techniques worked within the clinically acceptable level of accuracy of 0.25 mm.

Trial registration number: PROSPERO CRD 42022312907.

Objectives: This study aimed to evaluate the feasibility and accuracy of using magnetic resonance imaging (MRI) for the three-dimensional (3D) localization of tooth germs. A MRI 3D dataset was compared to a cone-beam computed tomography (CBCT) dataset, which is the current gold standard method in the localization of tooth germs. In this proof-of-concept study, the potential of eliminating the exposure of patients to ionizing radiation for tooth germ localization was evaluated.

Methods: A halved pig head (Sus scrofa domestica) was imaged with MRI and CBCT. The MRI data were manually segmented using InVesalius 3.1.1 (Centro de Tecnologia da Informação Renato Archer, Campinas, Brazil) to generate a 3D model, later processed in OnyxCeph3™ (Image Instruments GmbH, Chemnitz, Germany). The CBCT data were directly imported into OnyxCeph3™ for processing. Both datasets were combined with intraoral scans, and 12 raters took measurements to compare the ability to localize tooth germs with the help of the two modalities.

Results: A total of 144 measurements were obtained (2 modalities × 6 measurement sections × 12 raters). The interrater reliability was high (intraclass correlation coefficients [ICCs] ≥ 0.99 for both modalities). The average differences between CBCT and MRI measurements ranged between -0.43 mm (Bonferroni-Holm-corrected 90% confidence interval [-0.69 mm, -0.16 mm]) and 0.48 mm [0.34 mm, 0.63 mm] and were equivalent with respect to a margin of -1 mm to 1 mm in all measurement sections (Bonferroni-Holm-corrected P < 0.01 in all sections).

Conclusion: MRI demonstrates high potential as a nonionizing alternative to CBCT for 3D localization of impacted and displaced teeth, particularly in children and adolescents. The fluid-filled dental follicle provides excellent contrast in MRI, aiding precise localization. Future clinical studies with larger sample sizes are essential for validation.