Long-term effects of lateral nasal wall anchored facemasks compared with tooth-borne facemasks.

INTRODUCTION: This study investigated the long-term effect and stability of skeletally anchored facemasks (SAFMs) with lateral nasal wall anchorage compared with conventional tooth-borne facemasks (TBFMs) in growing patients with a Class III relationship. METHODS: A total of 180 subjects treated with SAFMs (n = 66) and TBFMs (n = 114) were screened. Thirty-four subjects were qualified and grouped into the SAFM group (n = 17) and TBFM group (n = 17). Lateral cephalograms were taken at the initial observation, after the protraction, and at the final observation. RESULTS: Greater advancement of the maxilla was attained with SAFM than with TBFM after protraction (initial observation - after the protraction) (P <0.05). In particular, advancement of the midfacial area (SN-Or) was prominent and maintained after the postpubertal stage (P <0.05). The intermaxillary relationship was also improved (ANB, AB-MP) (P <0.05), and greater counterclockwise rotation of the palatal plane (FH-PP) was observed in the SAFM group compared with the TBFM group (P <0.05). CONCLUSIONS: Compared with TBFM, the orthopedic effects of SAFM were greater in the midfacial area. The palatal plane had a greater counterclockwise rotation in the SAFM group than in the TBFM group. Maxilla (SN-Or), intermaxillary relationship (APDI), and palatal plane angle (FH-PP) demonstrated a significant difference between the 2 groups after the postpubertal stage.

A comparative evaluation of midfacial soft tissue and nasal bone changes with two maxillary protraction protocols: Tooth-borne vs skeletal-anchored facemasks.

OBJECTIVES: Greater advancement of the maxilla can be achieved with skeletal-anchored facemasks (SAFM) using miniplates than with conventional tooth-borne facemasks (TBFM). The purpose of this study was to compare the effects of TBFM and SAFM on midfacial soft tissue and nasal bone up to two years after treatment. SETTINGS AND SAMPLE POPULATION: Sixty-seven growing patients with Class III malocclusions were treated with facemasks. They were divided into a SAFM group with 31 subjects (average age 11.1 years) and a TBFM group with 36 subjects (average age 11.0 years). MATERIALS AND METHODS: Cephalometric analysis was conducted using linear and angular midfacial measurements. Lateral cephalograms were taken initially (T0), after treatment (T1) and at two years post-treatment (T2). Significance was assessed between the two groups. RESULTS: Comparing changes in the midfacial area between the SAFM and TBFM groups during the traction period (T0-T1), angular measurements such as SNOr (1.34°), nasolabial angle (4.20°), nasal angles 1 and 2 (1.23°, 2.14°) and linear measurements such as Prn, Sn, A' distance (approximately 2 mm) increased significantly more in the SAFM group. Over the entire treatment period (T0-T2), the changes in SNOr (1.33°), nasolabial angle (6.54°), nasal angles 1 and 2 (1.45°, 2.99°) and Prn, Sn, A' distance (approximately 2 mm) remained significant (P < .05). CONCLUSIONS: In the treatment of growing patients with Class III malocclusions with maxillary deficiency, it was possible to achieve significantly greater advancement in the midfacial area with SAFM treatment than with TBFM treatment. This significant difference was well maintained at two years post-treatment.

Comparison of skeletal anchorage and tooth-borne maxillary protraction followed by fixed appliance in Class III malocclusion.

OBJECTIVES: The purpose of this study was to compare the results of skeletal anchorage (SAMP) and tooth- borne (TBMP) maxillary protraction followed by fixed appliance in growing skeletal Class III patients. MATERIALS AND METHODS: Patients treated with maxillary protraction were selected and classified into two groups (SAMP: n = 19, mean age = 11.19 years; TBMP: n = 27, mean age = 11.21 years). Lateral cephalograms taken before treatment (T0), after the maxillary protraction (T1), and after the fixed appliance treatment (T2) were analysed and all variables were statistically tested to find difference between the two groups. RESULTS: Compared to the TBMP, the SAMP showed significant forward growth of maxilla (Co-A point and SN-Orbitale) and improvement in intermaxillary relationship (ANB, AB to mandible plane, and APDI) after the overall treatment (T0-T2), with no significant sagittal changes in maxilla or mandible throughout the fixed appliance treatment (T1-T2). LIMITATIONS: In maxillary protraction, effects of skeletal anchorage were retrospectively compared with those of dental anchorage, not with Class I or III control. CONCLUSIONS AND IMPLICATIONS: After maxillary protraction, skeletal and tooth-borne anchorage did not cause significant differences in the residual growth of maxilla throughout the phase II treatment. Orthopaedic effects with skeletal anchorage showed appropriate stability in maxilla and intermaxillary relationship even after fixed appliance treatment.

Reliability and validity of mandibular posterior vertical asymmetry index in panoramic radiography compared with cone-beam computed tomography.

INTRODUCTION: The purposes of this study were to compare the asymmetry index using panoramic radiography and cone-beam computed tomography for detecting mandibular posterior asymmetry and to evaluate the diagnostic value of the asymmetry index on panoramic radiography. METHODS: A total of 43 patients were included in this study. Ten mandibular posterior distances were measured using panoramic radiography and cone-beam computed tomography, and 10 asymmetry index values were calculated. The reliability of each asymmetry index was assessed. For evaluating validity of each asymmetry index using panoramic radiography, the paired t test and the Bland-Altman analysis were used. The accuracy of the asymmetry index and the area under the curve of receiver operator characteristic were calculated. RESULTS: The asymmetry index of total ramal height showed good reliability (ICC, >0.888). In condylar height 1, specificity and negative predictive value were low (0.08 and 0.17, respectively), 95% limits of agreement were ±17.9%, and area under the curve was 0.484. In total, ramal height accuracy was 0.86, and areas under the curve were 0.926 to 0.957. CONCLUSIONS: For detecting asymmetry of the condyle region, the asymmetry index using panoramic radiography had little diagnostic value, and we recommend using cone-beam computed tomography images. However, the asymmetry index for total ramal height showed good reliability and relatively higher validity, and its diagnostic value was excellent.

Cervical vertebrae maturation, dentoalveolar, head postural and respiratory parameters in predicting the stable outcome of face-mask treatment.

BACKGROUND/OBJECTIVES: To select predictors related to cervical vertebrae maturation (CVM), dentoalveolar adaptation, head posture, and respiration on outcome of face-mask treatment. MATERIALS/METHODS: Forty-six patients (24 boys and 22 girls) with skeletal Class III pattern whose CVM stages ranged from I to IV at pretreatment were selected. The observation period was 2.87 ± 1.77 years from the end of treatment. Negative overjet and overbite was regarded as unstable. CVM, 10 skeletal variables, 6 dental adaptation variables, 4 alveolar housing variables, an airway variable, and 2 head posture variables were chosen for discriminant analysis of initial characteristics between stable and unstable groups. RESULTS: Measurements exhibiting strong correlations were distance from lower incisor to Nasion, B point (NB), Frankfort horizontal plane to Mandibular incisor Angle (FMIA), incisor overbite, body to anterior cranial base. LIMITATIONS: We missed muscle-related variables, which cannot be identified in a cephalogram. CONCLUSIONS/IMPLICATIONS: Presence of non-skeletal cephalometric factors more closely associated with stability of face-mask treatment rather than skeletal cephalometric factors at the initial stage are confirmed.

Skeletal and dentoalveolar effects of different types of microimplant-assisted rapid palatal expansion.

Objective: To evaluate the following null hypothesis: the skeletal and dentoalveolar expansion patterns in the coronal and axial planes are not different with two different types of microimplant-assisted rapid palatal expansion (MARPE) systems. Methods: Pretreatment (T0) and post-MARPE (T1) cone-beam computed tomography (CBCT) images of 32 patients (14 males and 18 females; mean age, 19.37) were analyzed. We compared two different MARPE systems. One MARPE system included the maxillary first premolars, maxillary first molars, and four microimplants as anchors (U46 type, n = 16), while the other included only the maxillary first molars and microimplants as anchors (U6 type, n = 16). Results: In the molar region of the U6 and U46 groups, the transverse expansion at the midnasal, basal, alveolar, and dental levels was 2.64, 3.52, 4.46, and 6.32 mm and 2.17, 2.56, 2.73, and 5.71 mm, respectively. A significant difference was observed in the posterior alveolar-level expansion (p = 0.036) and posterior basal-bone-level expansion (p = 0.043) between the groups, with greater posterior skeletal and alveolar expansion in the U6 group. Conclusions: Compared with the U46 group, the U6 group showed greater posterior expansion at the alveolar and basal-bone levels, with an almost parallel split. Both groups showed a pyramidal expansion pattern in the coronal view.

Variation in adhesion of Streptococcus mutans and Porphyromonas gingivalis in saliva-derived biofilms on raw materials of orthodontic brackets.

Objective: To evaluate differences in the adhesion levels of the most common oral pathogens, Streptococcus mutans and Porphyromonas gingivalis , in human saliva-derived microcosm biofilms with respect to time and raw materials of orthodontic brackets. Methods: The samples were classified into three groups of bracket materials: 1) monocrystalline alumina ceramic (CR), 2) stainless steel metal (SS), and 3) polycarbonate plastic (PL), and a hydroxyapatite (HA) group was used to mimic the enamel surface. Saliva was collected from a healthy donor, and saliva-derived biofilms were grown on each sample. A real-time polymerase chain reaction was performed to quantitatively evaluate differences in the attachment levels of total bacteria, S. mutans and P. gingivalis at days 1 and 4. Results: Adhesion of S. mutans and P. gingivalis to CR and HA was higher than the other bracket materials (SS = PL < CR = HA). Total bacteria demonstrated higher adhesion to HA than to bracket materials, but no significant differences in adhesion were observed among the bracket materials (CR = SS = PL < HA). From days 1 to 4, the adhesion of P. gingivalis decreased, while that of S. mutans and total bacteria increased, regardless of material type. Conclusions: The higher adhesion of oral pathogens, such as S. mutans and P. gingivalis to CR suggests that the use of CR brackets possibly facilitates gingival inflammation and enamel decalcification during orthodontic treatment.

Elastic anisotropy and off-axis ultrasonic velocity distribution in human cortical bone.

Elastic structure in cortical bone is usually simplified as orthotropic or transversely isotropic, which allows estimates of three-dimensional technical constants from ultrasonic and density measurements. These elastic property estimates can then be used to study phenotypic changes in cortical bone structure and function, and to create finite element models of skeletal structures for studies of organismal variation and functional adaptation. This study examines assumptions of orthotropic or transversely isotropic material structure in cortical bone through the investigation of off-axis ultrasonic velocities in the cortical plane in 10 samples each from a human femur, mandible and cranium. Longitudinal ultrasonic velocities were measured twice through each bone sample by rotating the perimeter of each sample in 1 ° angular intervals between two ultrasonic transducers. The data were fit to sine curves f(x)=(A × sin(x + B) + C) and the goodness of fit was examined. All the data from the femur fit closely with the ideal sine curve model, and all three coefficients were similar among specimens, indicating similar elastic properties, anisotropies and orientations of the axes of maximum stiffness. Off-axis ultrasonic velocities in the mandible largely fit the sine curve model, although there were regional variations in the coefficients. Off-axis ultrasonic velocities from the cranial vault conformed to the sine curve model in some regions but not in others, which shows an irregular and complex pattern. We hypothesize that these variations in ultrasonic velocities reflect variations in the underlying bulk microstructure of the cortical bone, especially in the three-dimensional patterns of osteonal orientation and structure. Elastic property estimates made with ultrasonic techniques are likely valid in the femur and mandible; errors in estimates from cranial bone need to be evaluated regionally. Approximate orthotropic structure in bulk cortical bone specimens should be assessed if ultrasound is used to estimate three-dimensional elastic properties.

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.

Assessing soft-tissue characteristics of facial asymmetry with photographs.

INTRODUCTION: Precise diagnosis and treatment of facial asymmetry are important in orthodontics. The aims of this study were to determine the soft-tissue characteristics of patients perceived to have severe asymmetry requiring treatment and the soft-tissue factors affecting the subjective assessment of facial asymmetry. METHODS: In the first part of this study, 5 observers examined 1000 photographs of patients receiving orthodontic treatment and selected 100 for further assessment. These photographs showed 50 patients who were considered to have little or moderate asymmetry and 50 who were considered to have severe asymmetry. A pilot study was performed to select the reference photographs representing the most symmetric (score of 0) and the most asymmetric (score of 100). A panel of 9 orthodontists then rated the facial asymmetry of the 100 patients on a 100-mm visual analog scale. The scale was divided into 3 equal regions. Region 1 included patients with the least facial asymmetry; according to the orthodontists, these patients did not require treatment. Region 2 included patients with moderate facial asymmetry who did not require treatment. Region 3 included patients with the most facial asymmetry who did require treatment. RESULTS: One-way analysis of variance showed that lip canting, chin deviation, body inclination difference, and gonial angle difference had significant differences between the groups. Chin deviation and gonial angle difference were significant factors affecting the assessment of facial asymmetry, according to stepwise linear regression analysis. CONCLUSIONS: These results will help in the diagnosis and treatment planning for patients with asymmetry.

Comparison of skeletal anchored facemask and tooth-borne facemask according to vertical skeletal pattern and growth stage.

OBJECTIVE: To compare the treatment effects between skeletal anchored facemask (SAFM) and tooth-borne facemask (TBFM) on different maturation stages and vertical skeletal patterns. MATERIALS AND METHODS: In this retrospective study, 28 patients who were treated with TBFM treatment and 19 patients who were treated with SAFM were reviewed. Cephalograms at the beginning and end of facemask application were obtained and assessed. Each treatment group was divided according to skeletal maturity and facial angle type. Nonparametric Mann-Whitney U-test was used for comparisons of maturity stage and vertical skeletal type between the treatment groups. RESULTS: SAFM produced a significant increase in the anterior-posterior position of orbitale (SNOr) and A point (N. per. to A). The high mandibular plane angle group of SAFM revealed greater anterior movement than that of TBFM without opening of the mandibular plane. In the SAFM group, the angulation of the maxillary incisors was retroclined at CVM3 compared to CVM4. In the younger group (CVM3), SAFM showed greater changes in the variables of orbitale (2.909°) and maxillary length (5.818 mm), compared to TBFM. CONCLUSIONS: Compared with the TBFM group, the findings suggest significant advantages for the SAFM group for relative skeletal maturity and vertical skeletal pattern.

Three-dimensional assessment of upper lip positional changes according to simulated maxillary anterior tooth movements by white light scanning.

OBJECTIVE: Esthetic improvements during orthodontic treatment are achieved by changes in positions of the lips and surrounding soft tissues. Facial soft-tissue movement has already been two-dimensionally evaluated by cephalometry. In this study, we aimed to three-dimensionally assess positional changes of the adult upper lip according to simulated maxillary anterior tooth movements by white light scanning. METHODS: We measured changes in three-dimensional coordinates of labial landmarks in relation to maxillary incisor movements of normal adults simulated with films of varying thickness by using a white light scanner. RESULTS: With increasing protraction, the upper lip moved forward and significantly upward. Labial movement was limited by the surrounding soft tissues. The extent of movement above the vermilion border was slightly less than half that of the teeth, showing strong correlation. Most changes were concentrated in the depression above the upper vermilion border. Labial movement toward the nose was reduced significantly. CONCLUSIONS: After adequately controlling several variables and using white light scanning with high reproducibility and accuracy, the coefficient of determination showed moderate values (0.40-0.77) and significant changes could be determined. This method would be useful to predict soft-tissue positional changes according to tooth movements.