Journal of Orofacial Orthopedics-Fortschritte Der Kieferorthopadie最新文献

Aim: To compare ibuprofen and acupressure for pain relief after insertion of elastomeric orthodontic separators.

Materials and methods: A randomized control clinical trial was conducted in an orthodontic clinic. A total of 75 orthodontic patients aged 12-16 years participating in the study were randomly allocated to receive either 400 mg of oral ibuprofen, applying acupressure therapy, or no pain-relief approach. Pain scores were recorded on visual analog scales (10 cm) over a week at different times (4, 10, 18, 24 h, and 1 week). The margin of equivalence was defined as 10 mm.

Results: For all timepoints, the control group recorded the highest pain. For the ibuprofen and acupressure group, after 4 h, 18 h, and 1 week, no significant difference was noted. However, after 10 h, no significant difference in pain between the control and acupressure groups was noted and the ibuprofen group showed significantly lower pain. In the acupressure group, the highest pain was noted at 10 h. After this timepoint, pain progressively decreased with time and the lowest pain was noted after 1 week. In the control and ibuprofen groups, the highest pain was after 4 h, and then progressively decreased with time and the lowest pain was noted after 1 week.

Conclusions: There was no significant difference in pain perception between participants using ibuprofen or acupressure and both groups recorded significantly lower pain than the control group at most of the observed timepoints. Results support the analgesic effect of the acupressure approach.

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.

Purpose: The aim of this study was to show a possible correlation between the mean wear time of Hawley retainers and long-term mandibular arch stability as assessed via wear time analysis with microsensors.

Methods: This longitudinal retrospective study comprised 47 subjects (mean age 16.30 ± 1.06 years) having been treated with a nonextraction protocol and presenting moderate crowding at pretreatment. For retention, all patients were instructed to use a mandibular Hawley retainer for 12 months, and wear time was documented every 3 months during a posttreatment period of 6 months using TheraMon software. These individuals were divided into two groups. Those who adhered to a wear time equal to or more than 12 h/day (group 1A; N = 17) and those who complied for less than 12 h/day (group 2A; N = 30) were compared with respect to changes of the mandibular arch during the first 6 months of retention. Furthermore, a subgroup of 28 patients who completed a 12-month follow-up period were again divided into two groups: the individuals in group 1B (N = 12) adhered to a wear time equal to or more than 8 h/day, while those in group 2B (N = 16) complied for less than 8 h/day. Little's Irregularity Index, intercanine and intermolar widths, arch length, overjet, and overbite were measured on mandibular models taken at pretreatment (T0) and posttreatment (T1), as well as 6 months (T2) and 12 months (T3) after debonding. Pearson correlation test, independent samples t‑test, and Mann-Whitney U test were used for statistical evaluation.

Results: From T1 to T2, group 1A and group 2A showed a significant relapse in intermolar width with a difference in the median value of 0.38 mm (p = 0.019). At the complete 12-month follow-up, the increase in Little's irregularity score was significantly greater in group 2B (2.54 ± 1.29 mm) than in group 1B (1.32 ± 1.03 mm; p = 0.012). The established wear time measurements showed significant negative correlations with the Little's irregularity score and overjet changes between T1 and T3 (p < 0.05).

Conclusions: The results emphasized that the use of a retainer should not fall below a level of at least 8 h/day.

Purpose: We aimed to investigate early effects of regulating alpha‑7 nicotinic acetylcholine receptor (α7nAChR) agonists and antagonists on maxillary expansion in mice.

Methods: We allocated 36 six-week-old male C57BL/6J mice into three group: 1) expansion alone, 2) expansion plus the α7nAChR-specific agonist 3‑(2,4-dimethoxybenzylidene)-anabaseine dihydrochloride (GTS-21), and 3) expansion plus alpha-bungarotoxin (α-BTX), a competitive antagonist of α7nAChR. The groups were daily injected with saline, GTS-21 (4 mg/kg/day) or α‑BTX (1 mg/kg/day), respectively, from days 0-7. In addition, a mouse model of maxillary expansion was established. Masson's trichrome staining was used to observe morphological changes and immunohistochemistry was performed to analyze α7nAChR, interleukin (IL)-1β, IL‑6, tumor necrosis factor (TNF)-α, runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN) expression in the midpalatal suture. Microcomputed tomography was used to measure midpalatal suture and palatal basal bone widths. We assessed the normal distribution of our data using the Kolmogorov-Smirnoff test and evaluated the homogeneity of variance by Levene's test, followed by a two-way ANOVA and Bonferroni tests at a significance level of P < 0.05.

Results: In the GTS-21+expansion group, osteogenesis was more active in the middle palatine suture. New bone was calcified and deposited in the suture and we observed decreased IL-1β, IL‑6, and TNF‑α expression (P < 0.05). In the α‑BTX+expansion group, we observed increased proinflammatory cytokine and decreased RUNX2 and OCN expression and increased midpalatal suture and palatal basal bone widths (P < 0.05).

Conclusion: Using α7nAChR agonists and antagonists to regulate the cholinergic anti-inflammatory pathway, the secretion of inflammatory factors and osteoblast markers during maxillary expansion were altered, indicating the potential for clinical modulation of maxillary palatal suture expansion.

Background and aim: Treatment effects of a combined rapid maxillary expansion (RME) and Delaire facemask (DFM) therapy have so far only been scientifically investigated through cephalometric analyses. The combination of cephalometric, dental cast and cone-beam computed tomography (CBCT) scan analysis was not yet used for investigating morphologic changes of the tooth-bearing palate. The aim of the present study was to determine whether patient age at treatment begin has an influence upon palatal length changes after RME/DFM therapy, and to what extent transverse palatal sutures contribute to these.

Patients and methods: In n = 6 patients (min 10.5 years, max 14.7 years) from a total group of n = 40, CBCT datasets showing all palatal sutures were visually assessed, and palatal morphology was compared with a dental cast analysis. In addition, lateral cephalograms and dental casts of n = 40 patients were divided into two groups (PG1: < 12 years, n = 20; PG2: ≥ 12 years, n = 20), and an analysis was performed to investigate changes in the tooth-bearing palate after RME/DFM treatment.

Results: The CBCT analysis showed that the median and transverse palatine sutures were always open. On the contrary, the pterygopalatomaxillary sutures were partially open only in the youngest patients. The transverse palatal suture showed age-dependent morphologic changes in the transverse and sagittal planes. The changes of the palatal width and length show clear differences between the two younger and the four older patients in the corresponding dental cast analysis. The cephalometric analysis showed that a significant improvement of the sagittal jaw relation due to ventral displacement of the maxilla during treatment occurred only in younger patients (< 12 years) despite similar initial findings in both patient groups. The dental cast analysis also revealed that changes are age-dependent: In PG1, the width increases posteriorly more than anteriorly; in PG2, this is reversed. The length increases are always significant in both patient groups, whereby the anterior, posterior, and total amounts are greater in PG1 than in PG2. In relative terms, the increases in both groups are greater posteriorly than anteriorly. There is a significant difference between the groups posteriorly and overall.

Conclusions: Morphological changes of the sutures appear to have a decisive influence on the success of RME/DFM therapy. The age-dependent reactions of pterygopalatomaxillary and transverse palatine sutures represent a further main therapeutic effect of DFM treatment in addition to those described by Delaire and explain the different changes in palate length before and after the age of 12. If the maximum effect of RME/DFM treatment is desired, it should be started before the age of 12. Treatment success is age-dependent.

Aim: To determine whether unilateral preferent chewing (UPC) affects the position and angulation of the permanent maxillary canine germ on the preferred side.

Materials and methods: In a retrospective cross-sectional study, medical records from children 7.91(± 0.8) years old with unilateral preferred chewing side and unilateral posterior crossbite were selected. The position of the maxillary canines was analysed by measuring the following angles and distances: the angles formed between the canine axis and the midline (PS; potential impact range > 15°), and that between the canine axis and the bicondylar line (W; potential impact range < 75°). In addition, the canine's position with respect to the lateral incisor (EK; potential impact range > II) and the distance between the canine cusp and the occlusal plane (CCOP potential impact range > 10 mm) were measured.

Results: The final sample consisted of 106 radiographs; thus, a total of 212 maxillary canines were analysed. Tooth angulation on the preferred chewing side was higher for the angle PS with an average angle of 13.88° (± 7.56) and its position was more frequently found in sector II (49.1%), according to the EK analysis, compared to its contralateral that had an average of 11.75° (± 10.13) for the PS angle and a frequency of 67% in the sector I (p < 0.05 in both analyses). The data obtained for the angle W resulted in an average of 76.12° (± 9.09), while on the contralateral side it was 77.16° (± 12.56; p = 0.012). Lastly, according to the CCOP analysis, the preferred chewing side measured on average 15.3 mm (± 2.4), while on the nonpreferred side it was 15.19 mm (± 2.43; p = 0.143).

Conclusions: Based on this research, UPC seems to have a certain unfavourable influence on canine position and angulation. Thus, this is another factor to consider in decision-making regarding early treatment of this development disorder.

Purpose: This study aimed to evaluate the effects of the use of class III elastics with fixed appliances and the Alt-RAMEC procedure on dentofacial structures in patients diagnosed with skeletal class III malocclusion.

Methods: The retrospective cohort study was performed on lateral cephalometric radiographs of 20 individuals (7 girls, 13 boys; mean chronological age 12.41 years) with skeletal class III malocclusion because of maxillary deficiency or maxillary deficiency and mandibular excess which were treated by using the Alt-RAMEC protocol and class III elastics. The patients were chosen from the archive of Gazi University Faculty of Dentistry, Department of Orthodontics. In order to distinguish between growth-related changes and the effects of treatment, results were compared with a control group consisting of 20 individuals (8 girls, 12 boys; mean chronological age 12 years) with similar skeletal characteristics.

Results: In the treatment group, there were significant increases of 2.2°, 4.2° and 1° in the SNA, ANB and SN/GoGN angles, respectively, in contrast to the control group (p < 0.001). There was also a significant decrease of 1.9° in the SNB angle within the treatment group in contrast to the control group (p < 0.001). While the U1/SN angle increased by 1.4° in the treatment group, the L1-NB distance decreased by 0.7 mm (p < 0.01).

Conclusions: The results of this study showed that application of the Alt-RAMEC protocol and class III elastics with fixed appliances showed successful results in the management of skeletal class III malocclusions, while avoiding undesirable dental effects, such as excessive lingual tipping of the lower incisors.

Purpose: Advancements in computer-aided design and manufacturing (CAD/CAM), such as intraoral scanners, digital treatment planning, and 3D printers, offer digital alternatives to conventional orthodontics. For transforming digital data into a traditional model, precise 3D printing technologies are necessary. With numerous settings available on each 3D printer, selecting the most precise one is challenging. Therefore, the impact of layer height, printing temperature, print speed, and infill density on the accuracy of dental models was analyzed in this study.

Methods: A 3D file of a right upper central incisor was designed and printed 275 times in total with different settings for temperature, layer height, print speed, and infill density by using polylactic acid (PLA) filament on an industrial 3D printer. After scanning the models, root mean square error was calculated for analysis of precision. For each group, R² value was calculated and linear regression as well as an ANOVA was performed for the factors influencing accuracy.

Results: Printing temperature as well as layer height had statistically significant impacts on printing 3D tooth models (p < 0.05). R² values of 0.43 for printing temperature as well as of 0.11 for layer height were detected. The infill density as well as the print speed had no statistically significant impacts on accuracy (p > 0.05).

Conclusion: This study confirms that choosing the correct printing temperature and layer height for printing dental models with PLA is important for obtaining good accuracy, whereas print speed and infill density have less of an impact.

Purpose: This study evaluated the effect of torque customization of lingual brackets with resin-modified bases on their shear bond strength (SBS), adhesive remnant index (ARI), and bond failure patterns (BFP).

Methods: The sample comprised 200 lingual lower incisor brackets (DTC® ORG, DTC Medical Apparatus, Hangzhou, China); 40 brackets were tested as-received and 4 groups with 40 brackets each were customized for -10, -20, +10 and +20° torque respectively with light-cured composite resin (Transbond XT™, 3M Unitek, Monrovia, CA, USA) bases. All brackets were bonded to bovine mandibular incisors. Their SBS were estimated in a universal testing machine (INSTRON®, Norwood, MA, USA) with a gingivally directed force applied at the incisal bracket-adhesive interface with 1 mm/min crosshead speed. Their ARI and BFP were evaluated under 20× magnification.

Results: The SBS was 19.9 ± 7.6 MPa for noncustomized brackets, 20.1 ± 9.0 and 18.7 ± 8.2 MPa for brackets with 10 and 20° of negative torque, and 16.6 ± 5.68 and 19.45 ± 5.84 MPa for brackets with 10 and 20° of positive torque, respectively. The differences were not statistically significant (p = 0.097). Teeth with the -20° brackets exhibited higher median ARI scores than noncustomized brackets (1.5 vs 2, p = 0.018). Adhesive-cohesive bond failure with nearly axial split was more frequent in noncustomized brackets than customized ones, the reverse being true for adhesive-cohesive failure with nearly vertical split (p < 0.05). Truly cohesive bond failures were seen only in brackets with positive torque.

Conclusions: Torque customization with a resin base is an acceptable strategy for metal orthodontic brackets as it does not affect their SBS. However, their BFP differed from noncustomized brackets, depending on the type of torque introduced.

Objective: In vitro evaluation of the morphology of the enamel surface before bonding metal tubes and after debonding using spectral domain optical coherence tomography (SD-OCT) and light microscopy.

Methods: In all, 40 extracted caries-free human molars without defects were selected and cleaned. The tooth surfaces were imaged by light microscopy and SD-OCT prior to the placement of metal tubes (Titanium Orthos; Ormco, Brea, CA, USA). The metal tubes were bonded to the teeth using four adhesive systems: group 1) BrackFix Primer SE with BrackFix adhesive, group 2) BrackFix Primer with BrackFix adhesive (VOCO, Cuxhaven, Germany), group 3) Transbond Plus SE Primer with Transbond XT adhesive, group 4) Transbond XT Primer with Transbond XT adhesive (reference, 3M Deutschland, Neuss, Germany). After tube removal, the bonded areas were imaged by light microscopy and/or OCT and evaluated according to the following four criteria: (1) depth of cohesive enamel defect, (2) enamel cracks, (3) adhesive residue after tube removal, and (4) adhesive residues after polishing.

Results: None of the groups had enamel defects or enamel cracks. Group 1 showed significantly less adhesive residue after tube removal than the other groups (p_i ≤ 0.014). There were no significant differences between the groups for adhesive residues after polishing (p_i ≥ 0.628). Adhesive residues, if present, were only detectable by OCT and covered less than 1% of the enamel surfaces evaluated.

Conclusion: Tube removal did not cause clinically relevant enamel damage such as chipping or cracking.