Runx2 heterozygosity alters homeostasis of the periodontal complex.

BACKGROUND AND OBJECTIVE: Haploinsufficiency of Runx2 (Runx2+/- ) causes dental anomalies. However, little is known about the involvement of Runx2 in the maintenance of dentin, cementum, and the periodontal ligament (PDL) during adulthood. This study aimed to observe the effects of Runx2+/- on homeostasis of the periodontal complex. MATERIALS AND METHODS: A total of 14 three-month-old Runx2+/- mice and their wild-type littermates were examined using micro-computed tomography, histology, and immunohistochemistry. Phenotypic alterations in the dentin, cementum, and PDL were characterized and quantified. RESULTS: Haploinsufficiency of Runx2 caused cellular changes in the PDL space including reduction of cell proliferation and apoptosis, and irregular attachment of the collagen fibers in the PDL space into the cementum. Absence of continuous thickness of cementum was also observed in Runx2+/- mice. CONCLUSION: Runx2 is critical for cementum integrity and attachment of periodontal fibers. Because of its importance to cementum homeostasis, Runx2 is essential for homeostasis of periodontal complex.

Classification of Skeletal Phenotypes of Preadolescent Patients With Isolated Cleft Palate Using Principal Component Analysis and Cluster Analysis.

This study aimed to classify the skeletal phenotypes of preadolescent patients with isolated cleft palate using principal component analysis and cluster analysis. Sixty-four preadolescent female patients with isolated cleft palate (incomplete hard palate and complete soft palate cleft group, n=51; complete cleft of the hard and soft palate group, n=13; the mean age when lateral cephalograms were taken, 7.08±0.76 y) were included. Ten angular and 2 ratio cephalometric variables were measured on a lateral cephalogram. Cluster analysis was performed using 3 representative variables obtained from principal component analysis (SN-GoMe, SNA, and SNB). The differences in the variables among the clusters were characterized using the Kruskal-Wallis test. As a result of the analysis, 6 clusters were obtained from 3 groups: the retrusive maxilla and mandible group: cluster 3 (14.1%, moderately hyperdivergent pattern), cluster 5 (17.2%, severely hyperdivergent pattern); the normal maxilla and mandible group: cluster 1 (23.4%, normodivergent pattern), cluster 4 (12.5%, moderately hyperdivergent pattern), cluster 6 (20.3%, severely hyperdivergent pattern); the normal maxilla and protrusive mandible group: cluster 2 (12.5%, normodivergent pattern). The distribution of isolated cleft palate types did not differ among the 6 clusters ( P >0.05). Two thirds of the patients (68.7%, clusters 1, 2, 4, and 6) had a normal anteroposterior position of the maxilla, while one third of the patients (31.3%, clusters 3 and 5) showed a retrusive mandible. These results indicate that isolated cleft palate patients have diverse maxillo-mandibular growth patterns compared with patients with cleft lip and palate.

Association between Condylar Bone Density and Disk Displacement in the Temporomandibular Joint.

Measuring bone density (BD) is a common method of determining bone quality; however, the relationship between condylar BD and the occurrence of temporomandibular joint (TMJ) disorders has not been investigated. To address this knowledge gap, we aimed to investigate condylar BD in terms of TMJ disk displacement (TMJ DD) using computed tomography (CT) and magnetic resonance imaging (MRI). We classified TMJ MRI results according to the position of the disk: normal disk position (Normal), anterior disk displacement with reduction (ADDR), and anterior disk displacement without reduction (ADDNR). After retrospectively evaluating 86 female condyles, we determined the total, cortical, and trabecular BD in the upper-joint portion of the condyle and the whole condyle using CT data. To standardize condylar BD, we calculated the BD ratios by dividing the condylar BD by the cervical axis BD. The Kruskal-Wallis test analyzed the differences in BD measurements in the TMJ DD patient groups and showed significant between-group differences in condylar BD. The total and trabecular BD was significantly higher in ADDNR condyles than in Normal or ADDR condyles (Normal = ADDR < ADDNR). However, there was no significant difference in the cortical BD among the three TMJ DD groups. The BD ratios showed a similar tendency with condylar BD. These results suggest that increased condylar BD - specifically total and trabecular BD - may be significantly associated with ADDNR condyles. Our findings will help clinicians determine the course of treatment for patients with disk-related TMJ disorders.

Poorer sleep quality in patients with chronic temporomandibular disorders compared to healthy controls.

OBJECTIVES: This study aimed to investigate and compare sleep quality between patients with chronic temporomandibular disorder and healthy controls, and to analyze the association of sleep quality with disease characteristics, obstructive sleep apnea risk factors, and excessive daytime sleepiness. METHODS: Chronic temporomandibular disorder patients (n = 503, mean age: 33.10 ± 13.26 years, 333 females) and 180 age- and sex-matched healthy controls (mean age: 32.77 ± 12.95 years, 116 females) were included, who completed well-organized clinical report and answered questions on sleep quality (Pittsburgh Sleep Quality Index), sleep apnea risk factors (STOP-Bang questionnaire), and excessive daytime sleepiness (Epworth sleepiness scale). RESULTS: Mean global Pittsburgh Sleep Quality Index scores were significantly higher in the patients (6.25 ± 2.77) than in healthy controls (3.84 ± 2.29) (p <  0.001). Poor sleep was significantly more prevalent in the patient group (56.9%) than in healthy controls (22.2%) (p <  0.001). Compared with healthy controls, chronic temporomandibular disorder patients had a higher likelihood of obstructive sleep apnea (STOP-Bang total score ≥ 3; 7.2% vs. 16.1%; p <  0.01) and higher excessive daytime sleepiness (Epworth sleepiness scale score ≥ 10; 12.8% vs. 19.7%; p <  0.05). Age (odds ratio = 2.551; p <  0.001), female sex (odds ratio = 1.885; p = 0.007), total Epworth sleepiness scale score (odds ratio = 1.839; p = 0.014), and headache attributed to temporomandibular disorder (odds ratio = 1.519; p = 0.049) were the most powerful predictors of poor sleep (global Pittsburgh Sleep Quality Index score ≥ 5) in chronic temporomandibular disorder patients. CONCLUSION: Chronic temporomandibular disorder patients had markedly impaired sleep quality than healthy controls. Poorer sleep in patients with chronic temporomandibular disorder was associated with a variety of clinical factors, including a higher likelihood of excessive daytime sleepiness, older age, female gender, higher Epworth sleepiness scale scores, and the presence of headache attributed to temporomandibular disorder.

Predictors of Red Blood Cell Transfusion in Bimaxillary Orthognathic Surgery: A Retrospective Study.

Background: Orthognathic surgery requires red blood cell (RBC) transfusions more frequently than other oral and maxillofacial surgeries. The purpose of this study was to identify reliable predictors for RBC transfusion during bimaxillary orthognathic surgery (BOS). Methods: This retrospective study reviewed 1,616 electronic medical records of patients who underwent BOS during a 5-year period at Seoul National University Dental Hospital. The perioperative variable data were collected from electronic medical records and analyzed by dividing patients into the two groups (non-transfusion and transfusion group). Results: Of the 1,616 patients, 1,311 patients were excluded. The remaining 305 patients were divided into non-transfusion (NTF, n = 256) and transfusion (TF, n = 49) groups. Univariate logistic regression analysis revealed that age, body mass index, the presence of several adjunctive surgeries (including genioplasty, extraction, and mandibular angle reduction), preoperative hemoglobin (Hb) and prothrombin time, surgical time, amount of fluid infusion and blood loss, and mean pulse rate during surgery were significant factors predicting RBC transfusion. Multivariate logistic regression analysis revealed that preoperative Hb and blood loss amount during surgery were significantly related to RBC transfusion in BOS patients. Conclusion: Since blood loss amounts could not be measured preoperatively, we found that the independent predictor associated with RBC transfusion during BOS was a low preoperative Hb level.

Comparison of dentoskeletal and soft tissue changes between tooth-borne and tooth-bone-borne hybrid nonsurgical rapid maxillary expansions in adults: a retrospective observational study.

BACKGROUND: Despite the gradual increase in the use of rapid maxillary expansion (RME), specifically RME with the aid of skeletal anchorage in adults, there have been no reports comparing dentoskeletal and soft tissue changes between nonsurgical tooth-borne and tooth-bone-borne RMEs in adults. This study aimed to analyse differences in dentoskeletal and soft tissue changes between tooth-borne and tooth-bone-borne RMEs using a similar appliance design and the same expansion protocol in adult patients. METHODS: Twenty-one patients with tooth-borne expansion (a conventional expansion screw with two premolars and two molar bands for dental anchorage [T-RME]) and the same number of patients with tooth-bone-borne hybrid expansion (a conventional expansion screw with two premolar and two molar bands for dental anchorage and four mini-implants in the palate for skeletal anchorage [H-RME]) were included. Dentoskeletal and soft tissue variables at pretreatment (T1) and after expansion (T2) were measured using posteroanterior and lateral cephalograms and frontal photographs. The sex distribution of the two groups was analysed using the chi-square test, and the change after RME in each group was evaluated using the Wilcoxon signed-rank test. Differences in pretreatment age, expansion duration, post-expansion duration, and dentoskeletal and soft tissue changes after RME between the two groups were determined using the Mann-Whitney U test. RESULTS: There were no significant differences in the expansion protocol, pretreatment conditions, and sex distribution between the two groups. Despite similar degrees of dental expansion at the crown level between the two groups, H-RME induced increased skeletal and parallel expansion of the maxilla compared to T-RME. After expansion, H-RME demonstrated increased forward displacement of the maxilla without significant changes in the vertical dimension, while T-RME exhibited increased backward displacement of the mandible, increased vertical dimension, and decreased overbite. Both groups showed significant retroclination and extrusion of the maxillary incisors without significant intergroup differences. There were no significant soft tissue changes between the two groups. CONCLUSION: This study suggests that using skeletal anchorage in RME may induce increased skeletal and parallel expansion of the maxilla without significant effects on the vertical dimension.

Sex differences in the hypothalamic-pituitary-adrenal axis in patients with burning mouth syndrome.

OBJECTIVE: To investigate the sex differences in clinical features, including salivary flow rate, psychological distress and hypothalamic-pituitary-adrenal axis response and their inter-relationships in patients with burning mouth syndrome. SUBJECTS AND METHODS: Eighteen men and 37 postmenopausal women with burning mouth syndrome underwent a comprehensive questionnaire evaluation, psychological evaluation and salivary flow rate measurement. Laboratory tests were performed to investigate the function and integrity of the hypothalamic-pituitary-adrenal axis. RESULTS: Both unstimulated and stimulated salivary flow rates were higher in men than in women (unstimulated: 0.58 ± 0.32 vs. 0.37 ± 0.15 ml/min, p < .01; stimulated: 1.83 ± 0.63 vs. 1.22 ± 0.31, p < .001). Symptom severity scored on a visual analogue scale negatively correlated with anti-diuretic hormone levels in both sexes. The visual analogue scale scores negatively correlated with unstimulated (r = -.652, p < .01) and stimulated (r = -.376, p < .05) salivary flow rates in men and women, respectively. Unstimulated salivary flow rates positively correlated with anti-diuretic hormone (r = .453, p < .05) and progesterone (r = .402, p < .05) levels only in women. CONCLUSIONS: Our results suggest that clinicians should consider hypothalamic-pituitary-adrenal axis response, as well as sex and salivary flow rates, when identifying the aetiology of patients with burning mouth syndrome, as it may enable more accurate and effective treatment.

Effect of Bisphenol A Glycol Methacrylate on Virulent Properties of Streptococcus mutans UA159.

Bisphenol A glycidyl methacrylate (bis-GMA), which is released into the oral environment by dental composites through incomplete polymerization, hydrolysis, and mechanical degradation, can significantly influence oral ecology around resin-based materials. The purpose of this study was to investigate how bis-GMA changes the virulence properties of Streptococcus mutans, a major cariogenic bacterium in humans. The results show that bis-GMA not only inhibited the planktonic growth of cells in medium containing glucose, fructose, or mannose, but also reduced the viability of S. mutans. However, the presence of bis-GMA increased sugar transport and intracellular polysaccharide accumulation in S. mutans, thereby increasing the potential of cell persistence. In addition, bis-GMA could enhance S. mutans's adhesion to hard surfaces and glucan synthesis, which could contribute to biofilm formation. Although free bis-GMA made cells vulnerable to acidic stress, it also provided increased resistance to hydrogen peroxide, which might confer an advantage in competition with other oral microorganisms during the early stage of biofilm development. Interestingly, the presence of bis-GMA did not change the ability of S. mutans to interact with saliva. The results suggest that leachable bis-GMA could contribute to biofilm-related secondary dental caries at the marginal interface between resin-based materials and teeth by altering the virulent properties of S. mutans, although bis-GMA reduced the planktonic growth and viability of S. mutans.

Microbial changes in biofilms on composite resins with different surface roughness: An in vitro study with a multispecies biofilm model.

STATEMENT OF PROBLEM: The single-species biofilm method cannot represent the interaction and complex functions of microorganisms associated with oral biofilms. PURPOSE: The purpose of this in vitro study was to investigate microbial changes in biofilms on composite resins of varying surface roughness by using a multispecies biofilm model with early-colonizing streptococci, middle colonizer, and late-colonizing gram-negative anaerobes. MATERIAL AND METHODS: Composite resin disks were prepared with different roughness: SR180, SR400, SR1500, and SRGlass roughened with 180-, 400-, and 1500-grit silicon carbide paper and glass (control surface without surface roughening). Surface roughness was analyzed by confocal laser scanning and scanning electron microscopy. After multispecies biofilms had been grown on the composite resin surfaces, the adhesion of Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and of total bacteria was determined after 1 (T1) and 4 (T2) days. Differences in surface roughness among the 4 groups were tested with 1-way ANOVA. Multifactorial analysis of variance was used to determine the time-related differences in the bacterial composition with respect to surface roughness (α=.05). RESULTS: The order of SR, from highest to lowest, was SR180 (1.45 ±0.11 µm), SR400 (0.62 ±0.05 µm), SR1500 (0.35 ±0.02 µm), and SRGlass (0.15 ±0.01 µm) (SR180>SR400>SR1500>SRGlass, P<.001). Increased surface roughness was not proportional to bacterial adhesion. Significant differences in the adhesion of total bacteria was only found between SRGlass and SR180 (SR180>SRGlass, P=.029). The adhesion of S. mutans and S. sobrinus to SR180 and SR400 was higher than that to SRGlass (SR180=SR400>SRGlass; S. mutans, P=.003; S. sobrinus, P=.002). However, the adhesion of A. actinomycetemcomitans and P. gingivalis to composite resin was not significantly influenced by surface roughness. Adhesion of total bacteria, S. mutans, and S. sobrinus increased from T1 to T2 (T1T2; A. actinomycetemcomitans, P<.001; P. gingivalis, P=.013). CONCLUSIONS: Decreased adhesion of cariogenic streptococci and total bacteria was observed at surface roughness values of around 0.15 µm. Periodic finishing of surface roughness should be considered to minimize the adhesion of cariogenic streptococci to composite resin surfaces.

Compositional differences in multi-species biofilms formed on various orthodontic adhesives.

OBJECTIVES: To investigate the aspects of multi-species biofilm formation on various orthodontic adhesives with different surface characteristics. METHODS: Multi-species biofilms using 13 bacterial species were grown on the surfaces of composite, compomer, and resin-modified glass-ionomer cement (RMGI). The changes in Streptococcus mutans (Sm), Streptococcus sobrinus (Ss), Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and total bacteria were determined at day 1 (T1) and day 4 (T2) using real-time polymerase chain reaction. Surface roughness (SR), surface free energy (SFE), and surface texture were analyzed to explain the differences in bacterial compositions among the adhesives. Repeated measures analysis of variance was used to determine time-related changes in bacterial compositions with respect to adhesive type. The Kruskal-Wallis test was used to determine differences in SR and SFE among the adhesives. RESULTS: There were no significant differences in the adhesion of total bacteria among the adhesives; however, the adhesion of Sm, Ss, and Pg was higher to RMGI than the other adhesives. The amount of Sm, Ss, and total bacteria increased from T1 to T2, while Pg and Aa decreased from T1 to T2. RMGI showed a rougher surface relative to composite or compomer due to the presence of micro-pores and/or flaws. Compomer had the greatest SFE followed by RMGI and composite. Interestingly, SR differences were about 10 times greater than SFE differences among the adhesives. CONCLUSIONS: Considering the greater differences in SR than SFE among the adhesives, the rougher surface of RMGI may cause greater adhesion of Sm, Ss, and Pg.

Influence of temporomandibular joint disc displacement on craniocervical posture and hyoid bone position.

INTRODUCTION: The purpose of this study was to evaluate craniocervical posture and hyoid bone position in orthodontic patients with temporomandibular joint (TMJ) disc displacement. METHODS: The subjects consisted of 170 female orthodontic patients who consented to bilateral magnetic resonance imaging of their TMJs. They were divided into 3 groups based on the results of magnetic resonance imaging of their TMJs: bilateral normal disc position, bilateral disc displacement with reduction, and bilateral disc displacement without reduction. Twenty-five variables from lateral cephalograms were analyzed with 1-way analysis of variance to investigate differences in craniocervical posture and hyoid bone position with respect to TMJ disc displacement status. Pearson correlation coefficients were calculated to analyze the relationships between craniofacial morphology and craniocervical posture or hyoid bone position. RESULTS: Subjects with TMJ disc displacement were more likely to have an extended craniocervical posture with Class II hyperdivergent patterns. The most significant differences were found between patients with bilateral normal disc position and bilateral disc displacement without reduction. However, hyoid bone position in relation to craniofacial references was not significantly different among the TMJ disc displacement groups, except for variables related to the mandible. Pearson correlation coefficients indicated that extended craniocervical posture was significantly correlated with backward positioning and clockwise rotation of the mandible. CONCLUSIONS: This suggests that craniocervical posture is significantly influenced by TMJ disc displacement, which may be associated with hyperdivergent skeletal patterns with a retrognathic mandible.

Comparison of safety of general anesthesia and intravenous sedation during third-molar extraction surgery.

This study compared the safety of general anesthesia (GA) and intravenous sedation (IVS) in patients who underwent extraction of one or more third molars. Data from 1260 patients (GA group, n = 1043; IVS group, n = 217) were retrospectively analyzed, including demographics, preoperative data, intraoperative hemodynamic parameters (blood pressure, heart rate, and oxygen saturation level), and medications administered intraoperatively and postoperatively. The incidence of intraoperative circulatory variations, surgery and anesthesia durations, postoperative complications, and medication use were assessed and compared. The GA group had longer anesthesia and surgery durations, a higher incidence of hypotension, and a higher frequency of postoperative analgesic use than the IVS group. Dexmedetomidine was the most frequently used sedative agent. The IVS group had a lower incidence of intraoperative hypotension but they had a higher need for vasopressors in the recovery room. Both anesthesia methods maintained satisfactory oxygen saturation levels and sufficient anesthesia throughout the procedure, but they showed different characteristics regarding the duration of surgery and anesthesia duration, hemodynamic stability, and postoperative analgesic needs. IVS may be preferable for patients at risk of cardiovascular complications such as hypotension or tachycardia during surgery.

The influence of a continuous increase in thickness of opaque-shade composite resin on masking ability and translucency.

OBJECTIVES: This study was conducted to determine the minimum thickness of opaque-shade composite resin required to mask discolored tooth structures or darkness of the oral cavity and to determine the effect of the brand and shade of composite resins on masking ability and translucency. MATERIALS AND METHODS: Discs and beveled specimens were manufactured using six opaque-shade light-curing composite resins (Charisma, Heraeus Kulzer; Estelite Sigma Quick, Tokuyama; Gradia Direct Anterior, GC). The discolored tooth structures and darkness of the oral cavity were reproduced using background tiles. The disc specimen colors were measured using a spectroradiometer by increasing the thickness of the beveled specimens on the backing by 0.05 mm in series, and color difference (ΔE*(ab)) and translucency parameter (TP) were calculated. RESULTS: The thicknesses of opaque-shade composite resins that masked the C4 shade and black backings were 0.80-1.45 and 1.85-2.00 mm, respectively. Overall, the ΔE*(ab) and TP values decreased as the thickness of the opaque-shade composite resins increased. When the shades of the composite resins were identical, the TP decreased in the order of Charisma, Estelite Sigma Quick and Gradia Direct Anterior. When the brand was fixed, the TP was higher in the OA3 shade than in the OA2 shade. A significant correlation was seen between ΔE*(ab) and TP (p < 0.05). CONCLUSIONS: The brands and shades of the composite resins were shown to have a clear effect on TP, but an inconsistent tendency for ΔE*(ab).

Managing oral biofilms to avoid enamel demineralization during fixed orthodontic treatment.

Enamel demineralization represents the most prevalent complication arising from fixed orthodontic treatment. Its main etiology is the development of cariogenic biofilms formed around orthodontic appliances. Ordinarily, oral biofilms exist in a dynamic equilibrium with the host's defense mechanisms. However, the equilibrium can be disrupted by environmental changes, such as the introduction of a fixed orthodontic appliance, resulting in a shift in the biofilm's microbial composition from non-pathogenic to pathogenic. This alteration leads to an increased prevalence of cariogenic bacteria, notably mutans streptococci, within the biofilm. This article examines the relationships between oral biofilms and orthodontic appliances, with a particular focus on strategies for effectively managing oral biofilms to mitigate enamel demineralization around orthodontic appliances.

Effect of a multichannel oral irrigator on periodontal health and the oral microbiome.

Oral biofilms or dental plaques are one of the major etiological factors for diverse oral diseases. We aimed to evaluate the effect of a multichannel oral irrigator (MCOI) on periodontal health in 29 participants randomly divided into two groups: the MCOI group and the control group. To evaluate the effect of the MCOI on periodontal health, the modified Quigley Hein Plaque Index (PI), Mühlemann-Son Sulcus Bleeding Index (SBI), bleeding on probing (BOP), and swelling were evaluated and compared before and after MCOI use for 3 days. Although PI and SBI showed statistically significant increases in the control group, the MCOI group showed no significant changes in either parameter. Moreover, the percentage of BOP was significantly lower in the MCOI group. Saliva samples were analyzed by 16s rRNA amplicon sequencing to investigate changes in the oral microbiome. Sequencing results showed that Porphyromonas spp. were significantly increased in the control group, whereas no significant change was detected in the MCOI group. Using the MCOI, enriched populations and functional pathways were detected in pioneer species comprising non-mutans streptococci. These findings provide evidence of the effectiveness of the MCOI in maintaining periodontal health and a healthy microbial ecology in the oral cavity.

Differences in dentoskeletal and soft tissue changes due to rapid maxillary expansion using a tooth-borne expander between adolescents and adults: A retrospective observational study.

Objective: The purpose of this study was to compare the differences in dentoskeletal and soft tissue changes following conventional tooth-borne rapid maxillary expansion (RME) between adolescents and adults. Methods: Dentoskeletal and soft tissue variables of 17 adolescents and 17 adults were analyzed on posteroanterior and lateral cephalograms and frontal photographs at pretreatment (T1) and after conventional RME using tooth-borne expanders (T2). Changes in variables within each group between T1 and T2 were analyzed using Wilcoxon signed-rank test. Mann-Whitney U test was used to determine the differences in the pretreatment age, expansion and post-expansion durations, and dentoskeletal and soft tissue changes after RME between the groups. Spearman's correlation between pretreatment age and transverse dentoskeletal changes in the adolescent group was calculated. Results: Despite similar amounts of expansion at the crown level in both groups, the adult group underwent less skeletal expansion with less intermolar root expansion after RME than the adolescent group. The skeletal vertical dimension increased significantly in both groups without significant intergroup difference. The anteroposterior position of the maxilla was maintained in both groups, while a greater backward displacement of the mandible was evident in the adult group than that in the adolescent group after RME. The soft tissue alar width increased in both groups without a significant intergroup difference. In the adolescent group, pretreatment age was not significantly correlated with transverse dentoskeletal changes. Conclusions: Conventional RME may induce similar soft tissue changes but different dentoskeletal changes between adolescents and adults.

Relationship between rotational disc displacement of the temporomandibular joint and the dentoskeletal morphology.

OBJECTIVE: The purpose of this study was to evaluate the relationship between rotational disk displacement (DD) of the temporomandibular joint (TMJ) and the dentoskeletal morphology. METHODS: Women aged > 17 years were included in this study. Each subject had a primary complaint of malocclusion and underwent routine cephalometric examinations. They were divided into five groups according to the findings on sagittal and coronal magnetic resonance images of their TMJs: bilateral normal disk position, bilateral anterior DD with reduction (ADDR), bilateral rotational DD with reduction (RDDR), bilateral anterior DD without reduction (ADDNR), and bilateral rotational DD without reduction (RDDNR). Twenty-three cephalometric variables were analyzed, and the Kruskal-Wallis test was used to evaluate differences in the dentoskeletal morphology among the five groups. RESULTS: Patients with TMJ DD exhibited a hyperdivergent pattern with a retrognathic mandible, unlike those with a normal disk position. These specific skeletal characteristics were more severe in patients exhibiting DD without reduction than in those with reduction, regardless of the presence of rotational DD. Rotational DD significantly influenced horizontal and vertical skeletal patterns only in the stage of DD with reduction, and the mandible exhibited a more backward position and rotation in patients with RDDR than in those with ADDR. However, there were no significant dentoskeletal differences between ADDNR and RDDNR. CONCLUSIONS: The results of this study suggest that rotational DD of TMJ plays an important role in the dentoskeletal morphology, particularly in patients showing DD with reduction.

Effects of Presurgical Mandibular Incisor Decompensation on Long-Term Outcomes of Class III Surgical Orthodontic Treatment.

This research aimed to evaluate the effects of presurgical mandibular incisor decompensation on long-term outcomes of Class III surgical orthodontic treatment. Thirty-five patients with skeletal Class III malocclusion who received conventional surgical orthodontic treatment were included. Mandibular incisor brackets with -6° of inclination were placed normally in 18 patients (NB group) and inversely in 17 patients (RB group). Between-group differences and relationships between incisal and skeletal variables were analyzed based on lateral cephalograms at pretreatment, presurgery, postsurgery, posttreatment, and retention. Mandibular incisors were more labially inclined in the RB group than in the NB group from presurgery to retention. No significant between-group differences were observed in presurgical and postsurgical skeletal relationships. The NB group exhibited a larger overjet with deficient interincisal contact at postsurgery than the RB group. Skeletal Class III relationship was also more severe in the NB group at retention. More lingually inclined mandibular incisors at presurgery and larger overjet at postsurgery were correlated with a more severe skeletal Class III relationship at retention. Thus, establishing appropriate postsurgical overjet by sufficient presurgical mandibular incisor decompensation may play a significant role in postsurgical stability of Class III surgical orthodontic treatment.

Relationship of computed tomography-verified degenerative condylar morphology with temporomandibular joint disk displacement and sex.

OBJECTIVE: This study investigated the association of computed tomography (CT)-verified degenerative condylar changes with disk displacement (DD) and sex. STUDY DESIGN: Multidetector CT and cone beam CT scans of 165 condyles were evaluated for erosion, osteophyte formation, flattening, subcortical sclerosis, generalized sclerosis, subcortical defects, and loose joint bodies. Disk position was determined using magnetic resonance imaging. The association of degenerative alterations with disk position and sex was analyzed. RESULTS: The risks of erosion, osteophyte formation, and flattening were significantly increased by 3.72, 9.00, and 6.35 times, respectively, in the joints with DD without reduction (DDNR); however, the risks of these changes did not increase significantly in joints with DD with reduction. The risks of extensive erosion and slight and moderate osteophyte formation significantly increased only in the joints with DDNR. The degenerative changes were more likely to exist together in the joints with DDNR than in those with a normal disk position. The association of DD and most degenerative morphologies was not significantly influenced by sex. CONCLUSIONS: Erosion, osteophyte formation, and flattening were significantly associated with DDNR, regardless of sex.