Journal of Orofacial Orthopedics-Fortschritte Der Kieferorthopadie最新文献

Purpose: To evaluate soft tissue changes following maxillary protraction with different expansion protocols using three-dimensional (3D) stereophotogrammetry.

Methods: Pretreatment (T0) and postprotraction (T1) stereophotogrammetry and lateral cephalometric images of skeletal class III patients were included in this retrospective study. In all, 32 patients were treated either with a combination of rapid palatal expansion and facemask (RPE/FM; n = 16; mean age: 9.94 ± 0.68 years) or with alternate rapid maxillary expansion and constriction together with a facemask (Alt-RAMEC/FM; n = 16; mean age: 9.74 ± 1.35 years). As a control group 16 untreated patients were recruited (mean age: 9.46 ± 0.8 years). For superimpositioning of the 3D images taken at T0 and T1, the face was divided into defined regions and 3D and differences between the groups were evaluated using 3‑matic software (Materialise Europe, Leuven, Belgium). Cephalometric analyses were also performed.

Results: While the increases in the cephalometric parameters SNA and ANB were significantly greater in the treatment groups, the value for SNB also increased in the control group (p < 0.05). The results of the stereophotogrammetry analyses demonstrated that the mean changes in the RPE/FM and in the Alt-RAMEC/FM groups were significantly different for the midface compared to the control group (0.33 ± 0.26 mm, 0.3 ± 0.31 mm, 0.1 ± 0.18 mm). The maximum positive, negative, and mean changes were also significantly different between the treatment and control groups for the upper lip (p < 0.05). For the lower lip and the chin significant backward movements in the RPE/FM as well as in the Alt-RAMEC/FM group (-1.06 ± 1.26 mm, -0.68 ± 0.45 mm) were observed, while the control group (0.09 ± 0.53 mm) presented changes in the opposite direction. Regarding soft tissue changes, no significant differences were found between the RPE/FM and Alt-RAMEC/FM groups.

Conclusion: Both treatment protocols improved the soft tissue profile due to a forward movement of the midface and the upper lip, and a backward movement of the lower lip and chin, compared to the control group.

Objectives: This study aimed to evaluate the prevalence of multiheaded condyles (MHC) in a group of Turkish subjects using cone-beam computed tomography (CBCT).

Methods: In this retrospective study, CBCT scans of 975 patients (546 female, 429 male; age 15-89 years, mean age 42.46 years) who were referred to Istanbul University Faculty of Dentistry, Department of Dentomaxillofacial Radiology between 2015 and 2021 were evaluated. Bifid and trifid mandibular condyle cases were analyzed according to the patients' age, gender, and laterality, and their frequencies were determined statistically.

Results: A multiheaded mandibular condyle (MHC) was detected in 57 of the 975 patients (546 female, 429 male). MHC was diagnosed unilaterally in 49 patients; in 8 patients, it was observed bilaterally. A bifid mandibular condyle (BMC) was detected in 54 patients. A trifid mandibular condyle (TMC) was found in 2 women, and one tetrafid mandibular condyle was seen in 1 woman.

Conclusions: The prevalence of MHC was 5.84% in our proband, which is higher than in previous studies. There was no statistically significant difference between the prevalence of MHC in males or females.

Purpose: The aim of this study was to evaluate the effect of light-emitting photobiomodulation therapy (LPT) on the rate of canine distalization.

Methods: This study was performed on 60 extraction spaces formed by extraction of the upper first premolars of 30 patients (15 in the LPT group and 15 in the control group). Paul Gjessing (PG)-segmented canine retraction springs were used for canine distalization. In the LPT group, the Biolux OrthoPulse™ (Biolux Research Ltd, Vancouver, Canada) intraoral device (wavelength 850 nm LED light and an energy density of 63 mW/cm² [±13 mW/cm²]) was used for 5 min per day over a period of 84 days. For each patient, the diagnosis was based on standard orthodontic documentation with photographs, digital model casts, and cephalometric and panoramic radiographs. The anchorage loss, canine rotations, canine inclinations, and molar inclinations were also evaluated on plaster models obtained on days 0, 21, 42, 63, and 84. The models were measured by using 3Shape OrthoAnalyzer software (3Shape, Copenhagen, Denmark). Measurements were made by a researcher and a blinded clinician. For statistical comparison, a paired-samples t‑test and one-way analysis of variance (ANOVA) were used at the p < 0.05 level.

Results: The mean canine distalization rates were 1.36 mm/21 days and 1.02 mm/21 days in the LPT and control groups, respectively, and were statistically greater in the LPT group (p < 0.001). The amount of anchorage loss, canine rotations, canine inclinations and molar inclinations were not significantly different between the LPT and control groups at any of the timepoints.

Conclusion: LPT has the potential to accelerate orthodontic tooth movement by 33%.

Purpose: To assess changes in pharyngeal airway dimensions, head posture and hyoid position after maxillary expansion and face mask (FM) treatment compared to untreated class III patients.

Methods: This study examined 24 class III patients (10 girls, 14 boys, mean age: 10.97 ± 0.88 years) treated with expansion and a petit-type FM appliance and 24 untreated class III patients (16 girls, 8 boys, mean age: 10.50 ± 1.06 years). Pre- and posttreatment cephalometric radiographs were digitally analysed. Parametric data were analysed with paired and independent-samples t‑tests, nonparametric data were analysed with Wilcoxon signed-rank and Mann-Whitney U tests. Spearman's correlation analysis was used to examine the relationship between dental/skeletal treatment changes and those of craniocervical postural position, pharyngeal airway dimension and hyoid position.

Results: With respect to the hypopharyngeal airway dimension, the hypopharyngeal sagittal length (CV3'-LPW), velar angle (HRL/U-PNS) and velar length (U-PNS) significantly increased in the treatment group. All the parameters describing head posture and those describing the distances of the hyoid bone to the HRL changed significantly after treatment, but these changes were not significantly different from the control group. In the treatment group, there also occurred a significant increase in the sagittal growth of the maxilla (SNA, Co‑A, Na-Perp A, Wits), vertical growth of the maxillomandibular complex (SN-GoGN, N‑ANS, N‑Me), counterclockwise rotation of the maxilla (SN-PP) and overjet, while a clockwise rotation (y-axis) and a nonsignificant inhibition of the sagittal growth (Co-Gn) of the mandible were observed. The treatment induced increases of hypopharyngeal sagittal length (CV3'-LPW), soft palate thickness and anteroposterior movement of hyoid bone (H-CV3) demonstrated a positive correlation with changes of craniocervical angles (NSL/OPT, NSL/CVT) and a negative correlation with craniohorizontal angles (OPT/HOR, CVT/HOR). The change of the anteroposterior movement of hyoid bone (H-CV3) was also positively correlated with oropharyngeal sagittal length (CV2'-MPW), the hypopharyngeal sagittal length (CV3'-LPW) and the minimal dimension of the pharyngeal airway space (PASmin).

Conclusion: While expansion and FM treatment did not affect the head posture and hyoid bone position, positive effects were observed in the hypopharyngeal airway region.

Purpose: The aim of this retrospective study was to evaluate the effects of functional orthopedic treatment on mandibular bone structure using fractal dimension (FD) analysis of panoramic radiographs.

Methods: The study material consisted of the pre- and posttreatment digital panoramic radiographs of 80 patients (mean age 10.1 ± 2.01 years; 45 girls, 35 boys) with class II malocclusion who were treated with the monoblock or twin block appliances. The following regions of interest (ROI) were selected: ROI1, condylar process; ROI2, angulus mandibulae; ROI3, corpus mandibulae; and ROI4, mental foramen. Pre- and posttreatment FD values were compared for each ROI.

Results: FD values of the mandibular condyle did not change with the functional orthodontic treatment. FD values of the mandibular corpus region had the highest pretreatment values and significantly decreased with treatment (p < 0.05).

Conclusion: Functional orthopedic treatment altered the trabeculation of the mandibular bone, but it is speculated that the changes in the occlusal forces seemed to be of primary significance for this effect.

Purpose: Fixed orthodontic appliances induce biofilm deposition, which harbors a microbial population harmful to the periodontal health of the individual. The present study evaluated the changes in thickness, live/dead bacterial ratio, and mineral content in dental biofilm over 6 months in patients with either stainless steel or ceramic orthodontic attachments.

Methods: Eighty patients who require fixed orthodontic appliance treatment with first premolar extraction for correcting their malocclusion were selected and bonded with either stainless steel or ceramic orthodontic attachments on the buccal side. The attached buttons were retrieved at different periods-1 week, 1 month, 3 months, and 6 months. They were stained and visualized through confocal microscopy to detect biofilm thickness and the ratio of live/dead bacteria. X‑ray diffraction was used to identify the presence of calcium and phosphorous.

Results: Ceramic attachments showed a greater increase in biofilm thickness in comparison to stainless steel attachments except in the initial 1‑week evaluation. A higher live/dead bacterial ratio was observed in stainless steel attachments than in their ceramic counterparts at all four evaluation periods. Both stainless steel and ceramic surfaces exhibited the presence of mineral deposition (calcium and phosphorous) at all periods.

Conclusions: More biofilm adhesion was observed over ceramic surfaces than over stainless steel orthodontic attachments. Stainless steel attachments exhibited biofilm with a higher live/dead bacterial ratio than their ceramic counterparts at all evaluation periods. The presence of calcium and phosphorous in the adhered biofilm, pointing toward its calcification process, was identified.

Purpose: The purpose of this study was to compare the color changes of two different nanocomposites used for two different designs of clear aligner attachments.

Methods: In all, 120 human premolars were embedded in 12 upper dental models with 10 premolars in each model. Models were scanned and attachments were digitally designed. Conventional attachments (CA) were prepared for the first six models and optimized multiplane attachments (OA) were prepared for the other six models with packable composite (PC) on the right quadrant and flowable composite (FC) on the left quadrant of each model. The models were subjected to 2000 thermal cycles at 5 °C/55 °C and then consecutively immersed in the five different staining solutions each for 48 h to simulate external discoloration. Color measurements were taken with a spectrophotometer. Color changes (∆E*ab) of the attachments before and after immersion were compared with the Commission Internationale de l'Éclairage L*a*b* (CIELAB) color space approach.

Results: When ∆E*ab values were examined, no significant difference was observed between the groups according to the attachment type (P > 0.05). After the coloration process, the flowable composite group showed less coloration than the packable composite group for both attachment designs (P < 0.05). Color difference values after the staining procedure were significantly higher in the CA-PC and OA-PC groups compared to the CA-FC and OA-FC groups (P < 0.05).

Conclusion: Color change of the packable nanocomposite was more pronounced than that of the flowable nanocomposite for both attachment designs. Therefore, clear aligner attachments created using flowable nanocomposite can be recommended, especially in the anterior region where esthetics are important for the patient.

Purpose: This study aimed to evaluate the effect of bonding protocols and the type of orthodontic resin on the adhesion of microorganisms, degree of conversion (DC), and shear bond strength (SBS) of metallic brackets to enamel.

Methods: A total of 60 bovine incisors were prepared and randomly divided into 6 groups (n = 10): "bonding protocol" (A: phosphoric acid; AXT: A+Transbond™ XT primer adhesive [all Transbond™ products from 3M Unitek, Monrovia, CA, USA]; and SE: Transbond™ Plus Self Etching Primer) and "orthodontic resin" (XT: Transbond™ XT adhesive paste and CC: Transbond™ Plus Color Change). After bonding, the samples were subjected to thermocycling (5000 cycles) and to the SBS test. Bond failures were classified according to the adhesive remnant index (ARI). Next, 60 enamel blocks were sterilized in ethylene oxide in order to perform the CFU (Streptococcus mutans) assay in vitro to analyze the colony forming units (CFU/mL). Then, 60 discs of each orthodontic resin were made to measure the DC. The SBS (MPa), CFU/mL, and DC (%) data were statistically analyzed by two-way analysis of variance and Tukey's test (5%) was performed for the DC.

Results: CFU and SBS revealed no significance for all factors (P > 0.05). Tukey's test showed that A_XT (acid+Transbond™ XT adhesive paste) presented the highest DC (70.38% ± 10.5), while AXT_XT (acid+Transbond™ XT primer adhesive+Transbond™ XT adhesive paste) showed the lowest (23.47% ± 10.4). An ARI score of 2 was more frequent for the CC resin and an ARI score of 4 for the XT resin.

Conclusion: The CC resin does not reduce adhesion of S. mutans around orthodontic brackets and the bonding protocol did not influence the SBS, although the SE and A_XT groups contributed to a better DC.

Objectives: To evaluate force loss due to friction (FR) with an emphasis on esthetic brackets and their design differences during simulated canine retraction.

Materials and methods: The tested brackets were round and sharp-cornered conventional-ligating brackets and round-cornered self-ligating brackets. The tested archwires were stainless steel (0.018 × 0.025″ and 0.019 × 0.025″, and 0.018″) archwires. A total of 90 bracket-archwire combinations in 9 equally-sized groups (n = 10) were analyzed. Canine retraction was experimentally simulated in a biomechanical set-up utilizing the custom-made orthodontic measurement and simulation system (OMSS) using a NiTi coil spring that delivered a constant force of 1 N. The simulated retraction path was up to 4 mm. FR was compared among groups using the Welch t‑test. Significance level (α) was set to 0.05.

Results: The round-cornered conventional-ligating bracket exhibited the least FR (28.6 ± 5.4%), while there were no significant differences in FR between the round-cornered conventional-ligating bracket and the round-cornered self-ligating bracket with 0.018″ stainless steel wires. However, the round-cornered self-ligating bracket exhibited the least FR (34.9 ± 5.1% and 39.3 ± 4.6%) with 0.018 × 0.025″ and 0.019 × 0.025″ stainless steel archwires, respectively. The sharp-cornered conventional-ligating bracket showed the highest FR of 72.4 ± 3.0% among the bracket systems tested in this study.

Conclusions: The round-cornered conventional-ligating bracket showed less FR when compared to sharp-cornered conventional-ligating bracket. Conversely, the round-cornered conventional-ligating bracket exhibited greater FR when compared to the round-cornered self-ligating bracket, with an exception with respect to the 0.018″ wire. In general, FR increased with increased wire dimension.

Purpose: This in vitro study was conducted to compare the discoloration of a flowable self-adhesive composite, a highly filled composite adhesive, and a liquid polish applied highly filled composite adhesive for bonded lingual retainers.

Methods: Thirty composite discs were fabricated and divided into three groups: group 1, flowable self-adhesive (GC Ortho Connect™ Flow [GCO], GC Orthodontics, Tokyo, Japan); group 2, highly filled composite adhesive (Transbond™ LR [TLR], 3M Unitek, Monrovia, CA, USA); and group 3, highly filled composite adhesive with liquid polish (TLR and BisCover LV™ [TLRB], BISCO Inc, Schaumburg, IL, USA). L*a*b* values were measured by spectrophotometer prior to (T0) and following (T1) immersion in coffee. T1 - T0 differences were calculated as ∆L*, ∆a*, ∆b*, and ∆E*ab values. The Shapiro-Wilk test was performed to determine whether the data were normally distributed. The values that did not fit the normal distribution were evaluated with the Kruskal-Wallis one-way analysis of variance (ANOVA), and Dunn's test was used for multiple comparisons. The level of significance was p < 0.05.

Results: The difference between the TLR and TLRB groups was statistically significant for ∆E*ab (P = 0.007). ∆E*ab value of TLR group was greater than ∆E*ab value of TLRB group. The differences between the GCO and TLR groups (p = 0.001) and the TLR and TLRB groups (p = 0.010) were statistically significant for ∆a*. ∆a* values of GCO and TLRB groups were greater than ∆a* value of TLR group. The difference between the TLR and TLRB groups was statistically significant (p = 0.003) for ∆b*. ∆b* value of TLR group was greater than ∆b* value of TLRB group.

Conclusions: Using a Transbond LR polished with BisCover LV or only GC Ortho Connect Flow for lingual retainer bonding reduces coffee-induced discoloration.