Journal of Orofacial Orthopedics-Fortschritte Der Kieferorthopadie最新文献

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.

Purpose: Adverse side effects of fixed retainers in terms of unwanted tooth movements have been described for both the upper and lower jaw, but data about the extent and movement patterns for the maxilla are scarce. The purpose of the present retrospective case-control study was to analyze the amount and direction of unwanted tooth movements despite upper bonded retainers as well as to analyze possible predisposing pretreatment- and treatment-related factors.

Methods: Plaster casts of 1026 patients who completed orthodontic treatment and a subsequent retention phase of 2 years were screened for unintentional tooth movements. The study group comprised 57 patients with visually obvious tooth movements in the upper jaw, while 57 randomly selected patients without visible tooth movements served as control group. For all patients, plaster casts after debonding of multibracket appliance (T1) and after supervised retention (T2) were digitized, and superimposed digitally using a stable palatal reference area. Thereafter, translational and rotational movements were measured in all three planes of space. Pretreatment- and treatment-related factors of the study and control groups were compared by χ² test, exact Fisher test, Mann-Whitney U test, and the T‑test for independent samples.

Results: The mean translational movements ranged between 0 and 0.6 mm and the average rotational movements between 0 and 1.3°. Large individual movements up to 2.7 mm translation and 15.9° rotation were seen. A movement pattern around the Y‑ and Z‑axis with an opposite rotational peak at the canines ("upper twist effect") was identified. Compared to the control group, patients of the study group showed a significantly smaller intercanine width pretreatment. Also, study group patients presented a larger intercanine expansion and a slightly larger overjet reduction during treatment, and were more often affected by retainer bonding site detachments and wire fractures, but without reaching statistically significance.

Conclusion: Upper bonded retainers show a similar unwanted movement pattern ("twist effect") like the one described for mandibular retainers.

Purpose: The aim of this study was to examine the effect of methylphenidate, prescribed for individuals with attention deficit hyperactivity disorder (ADHD), on orthodontic tooth movement (OTM) and root resorption.

Methods: In all, 30 rats were divided into (1) control (C), (2) constant (MCD), and (3) increasing dose of methylphenidate (MID) groups and 2 subgroups for each of them (nonorthodontic (30 days)/orthodontic (44 days)). After receiving saline or methylphenidate for 30 days, rats in the nonorthodontic groups were euthanized (n = 5/group). Subsequently, 50 g of orthodontic force was applied to the remaining rats' first molars for 14 days (orthodontic groups). Quantitative micro-computed tomography (micro-CT) and immunohistochemical analyses were conducted. For statistical analyses Kruskal-Wallis and Dunnet tests were applied with a significance set at p < 0.05.

Results: Micro-CT analysis demonstrated a statistically significant increase in tooth displacement with higher doses of methylphenidate compared to control and lower-dose groups, though no significant difference was detected between MID-44 and MCD-44 groups. Orthodontic force led to a significant increase in root resorption, peaking in the coronal region and diminishing toward the apex. The highest amount of resorption was observed in the MID groups, with a significant difference between nonorthodontic MID-30 and C‑30 groups. No significant changes in bone parameters were noted in the tension zone, but numerical reductions in trabecular thickness (Tb.Th), bone volume fraction (BV/TV), and bone mineral density (BMD) were observed. In nonorthodontic cohorts, VEGF and RANK levels were significantly elevated in the MID-30 group, along with increased TRAP expression, indicating bone resorption. Orthodontic cohorts exhibited a significant increase in RANK- and TRAP-positive cells with methylphenidate administration. Reductions in OPG and elevations in RANK, RANKL, VEGF, and TRAP were noted, primarily between orthodontic and nonorthodontic groups.

Conclusion: The present rat model suggests a weak potential for methylphenidate to increase root resorption. However, increased doses of methylphenidate accelerated OTM.

Background and aim: Patients with statutory health insurance (SHI) in Germany must undergo an assessment of orthodontic treatment need using the "Kieferorthopädische Indikationsgruppen" (KIG; orthodontic indication groups) classification system since 2002. A treatment need only exists if anomalies of a certain degree of severity are present. The aim of this study was to evaluate the age-dependent prevalence and percentage distribution of KIG grades requiring treatment in patients with SHI before the age of 18 over a 10-year period.

Patients and methods: Between 2012 and 2021, treatment indication existed for 1951 (1025 female, 926 male) out of 2288 patients with SHI in the cohort of this study before the age of 18 according to current SHI guidelines. The KIG classification was based on the highest existing KIG grade. There were no multiple classifications. The patient cohort was divided into three patient groups (PG) according to chronological age for analysis: PG 1 < 10 years of age (early treatment), PG 2 10 to < 13 years of age (main treatment) and PG 3 13 to < 18 years of age (late treatment).

Results: In PG 1 (454 patients), the KIG classifications D (26.5%), K (25.5%), M (19.4%), and P (18.0%) dominated. In PG 2 (998 patients), classifications D (33.2%), predominated, whereas K (7.5%) and M (5.9%) rarely occurred. The classifications E (12.6%) and P (13.3%) appeared quite frequently. Transverse deviations occurred only about half as often in PG 2 as in PG 1 and PG 3. In PG 3 (499 patients), the classification E (17.6%) was particularly common, while P (2.6%) was rare. The proportion of KIG grades 5 decreased depending on age: 19% in PG 1, 13.5% in PG 2, 10.4% in PG 3. The prevalence of sagittal classifications was highest in all age groups (45.9% in PG 1, 39.1% in PG 2, 31.5% in PG 3).

Conclusions: The distribution of KIG classifications requiring treatment was not homogeneous, but age dependent. The differences were particularly evident in the early treatment group and may be due to the limited applicability of the KIG classification system in patients before late mixed dentition. With increasing age at initial examination, the prevalence of sagittal classifications decreased, while that of vertical classifications increased. Still, the sagittal classifications D and M occurred most frequently in all age groups. The KIG classification D was always the most common in all patients until the age of 18.

Purpose: This study aimed to compare the perception of practitioners with varying levels of expertise and laypeople regarding the orthodontic treatment need and facial harmony in patients with increased anterior overjet.

Methods: Three groups of observers (orthodontists, general dentists, and laypeople, in total n = 48) were asked to rate on images-using a 10-point visual analog scale (VAS)-the facial harmony and treatment need of a sample of 8 patients with class II division 1 malocclusion and overjets of 2, 4, 6, and 8 mm.

Results: Statistically significant differences were observed between the three groups of observers regarding patients with an overjet of 4 mm and above (p < 0.001). Treatment need was perceived at an overjet of 4 mm by orthodontists and 6 mm by general dentists, whereas laypeople did not perceive a need for treatment in any of the groups (p < 0.001). Regarding perception of facial harmony, orthodontists had the lowest threshold (4 mm overjet), while dentists followed at a greater overjet of 6 mm or more (p < 0.001). A statistically significant correlation between the noticed facial harmony and the perceived orthodontic treatment need was found in all observers (p < 0.001).

Conclusion: The perceived orthodontic treatment need for class II division 1 malocclusion increased with increasing professional expertise.

Objective: To analyze the effects of the time span between archwire changes on the amount of transverse dental arch expansion. The design was a prospective, controlled clinical trial. Randomization was performed by computer-generated allocation tables.

Methods: In all, 35 patients were evaluated in three groups treated with fixed appliances and the same four sequential leveling archwires, however, with different replacement periods: 28 days (4-week [4W] group), 56 days (8-week [8W] group), and 84 days (12-week [12W] group). Digital models were measured before the treatment (T0) and at the end of the evaluation period (T1) by a blinded operator with OrthoAnalyzer® software (3-Shape, Copenhagen, Denmark) and compared using MANOVA. A multiple linear regression was also used to evaluate the influences of age, initial dental crowding, incisor inclination, and facial pattern on the amount of expansion.

Results: Mean expansion was 2.77 ± 0.84 mm (upper arch) and 3.12 ± 0.88 mm (lower arch) in the 12W group; 1.96 ± 0.82 mm and 2.27 ± 0.96 mm in the 8W group, and 1.11 ± 0.93 mm and 1.32 ± 0.91 mm in the 4W group, respectively for the upper and lower arches. The amount of expansion varied significantly between the groups in the area of the canines, first premolars, and second premolars for both arches. Expansion was less in older patients. Initial dental crowding, incisor inclination and facial pattern had no influence on dental expansion.

Conclusion: Longer time spans between archwire changes provided greater amounts of expansion, while age is inversely related, with younger patients expressing greater amounts of expansion. The results also suggest that the expansion provided by the fixed appliances is expressed mainly in the canine and premolar areas.

Purpose: This two-arm parallel randomized controlled trial aimed to evaluate and compare periodontal changes due to rapid maxillary expansion (RME) using tooth-bone-borne and tooth-borne devices in growing patients via clinical examinations and cone-beam computed tomography (CBCT).

Materials and methods: Forty-two eligible patients (aged 11-14 years; transverse maxillary deficiency, posterior crossbite) were screened and divided into two groups based on the treatment received (randomization was performed using computer-generated numeric sequences): hybrid hyrax tooth-bone-borne group (TBB) and hyrax tooth-borne group (TB). The primary outcome was the change in cortical bone thickness (by CBCT). In addition, the clinical attachment level (CAL), gingival recession, and bleeding were assessed. Both examinations were performed before and 3 months after the activation phase. Intergroup comparisons were performed using analysis of covariance (ANCOVA; P < 0.05).

Results: Twenty-one patients (12 girls and 9 boys; mean initial age, 13.3 years) were included in the TBB group and 21 (5 girls and 16 boys; mean initial age, 13.2 years) were included in the TB group. The TB group exhibited a decrease in buccal bone thickness in the first premolars and first molars at all three evaluated levels. Specifically, tooth 14 at 3 mm from the enamel-cement junction showed a significant width reduction (0.7 mm; p < 0.001), accompanied by a notable increase in palatal cortical thickness at 6 mm of enamel-cement junction (1.13 mm; p < 0.001).

Conclusions: RME resulted in buccal bone thickness reduction at the first premolar with hyrax treatment. In the molar region, both devices resulted in cortical bone alterations that were less pronounced in the TBB group.

Purpose: Three-dimensional imaging has become an increasingly important component of orthodontics. Associated with this, however, is a higher radiation exposure for patients. New cone-beam computed tomography (CBCT) devices have been developed that can provide low-dose CBCT (LD-CBCT). We hypothesized that LD-CBCT is as precise and reproducible as standard high-dose CBCT (HD-CBCT) in segmenting roots and crowns as well as measuring tooth length.

Methods: HD-CBCT and LD-CBCT scans were taken of four human cadaveric heads. Thirty single-rooted teeth were segmented twice by one investigator. The length of each tooth was also measured. Lin's concordance correlation coefficient (CCC) was calculated to assess the agreement of HD-CBCT and LD-CBCT measurements and the intraclass correlation coefficient (ICC) was calculated to assess intrarater reliability. Analyses were supported by Bland-Altman plots.

Results: Volume measurements obtained using HD-CBCT were significantly higher than those obtained using LD-CBCT (p < 0.001). CCC was 0.975 (95% confidence interval [CI] = 0.956-0.986) indicating excellent agreement between the two modalities. Intrarater reliability between the two sets of LD-CBCT and HD-CBCT volume measurements was excellent (ICC = 0.998, 95%CI = 0.995-0.999 [HD-CBCT], ICC = 0.997, 95%CI = 0.992-0.998 [LD-CBCT]). CCC for tooth length measurements was 0.991 (95% CI = 0.983-0.995), indicating excellent agreement between HD-CBCT and LD-CBCT. Intrarater reliabilities between the two sets of tooth length measurements were also excellent for both methods (ICC = 0.998, 95%CI = 0.995-0.999 [HD-CBCT], ICC = 0.997, 95%CI = 0.992-0.998 [LD-CBCT]).

Conclusions: Within the limitations of this experimental setting, LD-CBCT is as valid as HD-CBCT for measuring tooth length. Regarding the volume differences, in vivo studies are required to determine their clinical relevance.

Purpose: To test the hypothesis that single nucleotide polymorphisms (SNPs) in the muscle-related genes actinin alpha 3 (ACTN3), creatine kinase muscle (CKM), and angiotensin I converting enzyme (ACE) are associated with sleep bruxism (SB).

Methods: This study involved 45 individuals diagnosed with SB through self-report questionnaires, clinical examination, and polysomnography. Deoxyribonucleic acid samples were collected, and three SNPs, rs1815739 in ACTN3, rs8111989 in CKM, and rs4341 in ACE, were selected for genotyping via real-time PCR. The associations between SB and SNPs were investigated with genotypic, allelic, recessive, and dominant models via the χ² test. Associations between SNPs and SB were estimated by odds ratios (ORs) with 95% confidence intervals (CIs), with significance considered when p < 0.05.

Results: Sixteen individuals, 11 males (68.7%) and 5 females (31.3%), were diagnosed with SB. Another 29 individuals (16 males and 15 females) without bruxism were included in the control group. For rs1815739, the CC genotype was associated with a high prevalence of SB (p = 0.032). In the recessive model, homozygous CC individuals presented 392% greater odds for SB than individuals with CT/TT (OR 4.92; 95%CI 1.29-18.73). No differences were observed for rs8111989 and rs4341 in the tested models (p > 0.05).

Conclusion: Polymorphism rs1815739 in ACTN3 was associated with SB.