Comparison of posttreatment stability after total mandibular arch distalization with mini-implants and mandibular setback surgery.

OBJECTIVES: To compare posttreatment stability in skeletal Class III patients between those treated by total mandibular arch distalization (TMAD) with buccal mini-implants and those by mandibular setback surgery (MSS). MATERIALS AND METHODS: The samples included 40 Class III adults, 20 treated by TMAD using buccal interradicular mini-implants and 20 treated with MSS. Lateral cephalograms were taken at pretreatment, posttreatment, and at least 1-year follow-up, and 24 variables were compared using statistical analysis. RESULTS: Mandibular first molars moved distally 1.9 mm with intrusion of 1.1 mm after treatment in the TMAD group. The mandibular incisors moved distally by 2.3 mm. The MSS group exhibited a significant skeletal change of the mandible, whereas the TMAD group did not. During retention, there were no skeletal or dental changes other than 0.6 mm labial movement of the mandibular incisors (P < .05) in the MSS group. There was 1.4° of mesial tipping (P < .01) and 0.4 mm of mesial movement of the mandibular molars and 1.9° of labial tipping (P < .001) and 0.8 mm of mesial movement of the mandibular incisors in the TMAD group. These dental changes were not significantly different between the two groups. CONCLUSIONS: The TMAD group showed a slightly decreased overjet with labial tipping of the mandibular incisors and mesial tipping of the first molars during retention. Posttreatment stability of the mandibular dentition was not significantly different between the groups. It can be useful to plan camouflage treatment by TMAD with mini-implants in mild-to-moderate Class III patients.

Dental developmental complications in pediatric hematopoietic stem cell transplantation patients: A study using CMC clinical data warehouse.

OBJECTIVE: This study aimed to investigate the prevalence and extent of dental developmental complications in patients who have undergone pediatric hematopoietic stem cell transplantation (SCT) and identify the risk factors. MATERIALS AND METHODS: We retrospectively investigated the clinical data warehouse of the Catholic Medical Center information system for identifying patients who: 1) visited the Department of Pediatrics between 2009 and 2019, 2) underwent SCT under the age of 10, and 3) had panoramic radiographs. Thus 153 patients were included in this study. The prevalence and extent of tooth agenesis, microdontia, and root malformation were assessed using panoramic radiographs obtained after SCT, and the risk factors were analyzed using regression analysis. RESULTS: All 153 patients had at least one dental anomaly. When grouped according to the age at initial chemotherapy (≤ 2.5; 2.6-5.0; 5.1-7.5; > 7.5 years), the prevalence of agenesis showed statistically significant differences among the different age groups (P < 0.001). The prevalence of agenesis was highest in the youngest age group. As the initial age at chemotherapy increased, the number of affected teeth per patient decreased for all three anomalies. The location of the affected tooth was also influenced by the age at initial chemotherapy. Regression analysis demonstrated that young age at initial chemotherapy was a risk-increasing factor for tooth agenesis and microdontia. CONCLUSIONS: The age at initial chemotherapy may be a critical factor in determining the type, extent, and location of dental complications after SCT. These results suggest that careful dental follow-up and timely treatment are recommended for pediatric patients undergoing SCT.

Effects of alveolar bone displacement with segmental osteotomy: micro-CT and histomorphometric analysis in rats.

The purpose of this study was to evaluate the effects of segmental osteotomy on the blood vessels and osteoclasts in rats using micro-computed tomography (micro-CT) and histomorphometric analysis. After segmental osteotomy was performed around the maxillary first molars of 36 male Sprague-Dawley rats (n = 72), the samples were divided into a control group (no displacement), 0.5 D group (0.5 mm buccal displacement) and 1.0 D group (1.0 mm buccal displacement) (n = 24/group). At 1, 2, 4 and 8 weeks after surgery, changes in the blood vessel volume were investigated using micro-CT with perfusion of radiopaque silicone rubber. Tartrate-resistant acid phosphatase (TRAP) staining was used for histomorphometric analysis. Two-way repeated measures analysis of variance (rmANOVA) was performed to compare the volume of blood vessels and number of TRAP-positive osteoclasts among the groups. Regarding blood vessel volume, the displacement groups had no significant effects, while the time points had significant effects (p = 0.014). The blood vessel volume at 1 week was significantly smaller than that at 2, 4, and 8 weeks (p = 0.004, p = 0.026, and p = 0.005, respectively). Regarding TRAP cell count, the displacement groups had no significant effects, while the time points had significant effects (p < 0.001). The number of TRAP-positive osteoclasts at 8 weeks was significantly smaller than that at 1, 2, and 4 weeks (p < 0.001, p < 0.001, and p = 0.002, respectively), and the count at 4 weeks was smaller than that at 1 week (p = 0.011). Therefore, a regional osteoclast-related acceleratory phenomenon was maintained until 4 weeks after surgery.

Treatment effects of mandibular total arch distalization using a ramal plate.

OBJECTIVE: The purpose of this study was to evaluate treatment effects after distalization of the mandibular dentition using ramal plates through lateral cephalograms. METHODS: Pre- and post-treatment lateral cephalograms and dental casts of 22 adult patients (11 males and 11 females; mean age, 23.9 ± 5.52 years) who received ramal plates for mandibular molar distalization were analyzed. The treatment effects and amount of distalization of the mandibular molars were calculated and tested for statistical significance. The significance level was set at p < 0.001. RESULTS: The mandibular first molar distalization at the crown and root were 2.10 mm (p < 0.001) and 0.81 mm (p = 0.011), respectively. In the evaluation of skeletal variables, there was a significant increase in the Wits appraisal (p < 0.001). In the evaluation of the soft tissue, there was no significant effect on upper lip position, but the lower lips showed a significant retraction of 2.2 mm (p < 0.001). CONCLUSIONS: The mandibular molars showed a significant amount of distalization accompanied by limited extrusion and mesiobuccal rotation of the crowns. A ramal plate may be a viable device for mandibular total arch distalization in Class III patients who are reluctant to undergo orthognathic surgery.

Effects of alveolar bone displacement with segmental osteotomy: micro-CT and histomorphometric analysis in rats

Abstract The purpose of this study was to evaluate the effects of segmental osteotomy on the blood vessels and osteoclasts in rats using micro-computed tomography (micro-CT) and histomorphometric analysis. After segmental osteotomy was performed around the maxillary first molars of 36 male Sprague-Dawley rats (n = 72), the samples were divided into a control group (no displacement), 0.5 D group (0.5 mm buccal displacement) and 1.0 D group (1.0 mm buccal displacement) (n = 24/group). At 1, 2, 4 and 8 weeks after surgery, changes in the blood vessel volume were investigated using micro-CT with perfusion of radiopaque silicone rubber. Tartrate-resistant acid phosphatase (TRAP) staining was used for histomorphometric analysis. Two-way repeated measures analysis of variance (rmANOVA) was performed to compare the volume of blood vessels and number of TRAP-positive osteoclasts among the groups. Regarding blood vessel volume, the displacement groups had no significant effects, while the time points had significant effects (p = 0.014). The blood vessel volume at 1 week was significantly smaller than that at 2, 4, and 8 weeks (p = 0.004, p = 0.026, and p = 0.005, respectively). Regarding TRAP cell count, the displacement groups had no significant effects, while the time points had significant effects (p < 0.001). The number of TRAP-positive osteoclasts at 8 weeks was significantly smaller than that at 1, 2, and 4 weeks (p < 0.001, p < 0.001, and p = 0.002, respectively), and the count at 4 weeks was smaller than that at 1 week (p = 0.011). Therefore, a regional osteoclast-related acceleratory phenomenon was maintained until 4 weeks after surgery.

Correction of severe bimaxillary protrusion with first premolar extractions and total arch distalization with palatal anchorage plates.

Correction of a severe protrusive soft tissue profile without orthognathic surgery can be challenging. This case report describes the treatment of a young woman with a severe bimaxillary protrusion. Orthodontic treatment included extraction of her 4 first premolars and total arch distalization of both arches using a palatal plate appliance. The total treatment time was 24 months. Her occlusion and facial appearance were significantly improved.

En-masse retraction with a preformed nickel-titanium and stainless steel archwire assembly and temporary skeletal anchorage devices without posterior bonding.

OBJECTIVE: To evaluate the therapeutic effects of a preformed assembly of nickel-titanium (NiTi) and stainless steel (SS) archwires (preformed C-wire) combined with temporary skeletal anchorage devices (TSADs) as the sole source of anchorage and to compare these effects with those of a SS version of C-wire (conventional C-wire) for en-masse retraction. METHODS: Thirty-one adult female patients with skeletal Class I or II dentoalveolar protrusion, mild-to-moderate anterior crowding (3.0-6.0 mm), and stable Class I posterior occlusion were divided into conventional (n = 15) and preformed (n = 16) C-wire groups. All subjects underwent first premolar extractions and en-masse retraction with pre-adjusted edgewise anterior brackets, the assigned C-wire, and maxillary C-tubes or C-implants; bonded mesh-tube appliances were used in the mandibular dentition. Differences in pretreatment and post-retraction measurements of skeletal, dental, and soft-tissue cephalometric variables were statistically analyzed. RESULTS: Both groups showed full retraction of the maxillary anterior teeth by controlled tipping and space closure without altered posterior occlusion. However, the preformed C-wire group had a shorter retraction period (by 3.2 months). Furthermore, the maxillary molars in this group showed no significant mesialization, mesial tipping, or extrusion; some mesialization and mesial tipping occurred in the conventional C-wire group. CONCLUSIONS: Preformed C-wires combined with maxillary TSADs enable simultaneous leveling and space closure from the beginning of the treatment without maxillary posterior bonding. This allows for faster treatment of dentoalveolar protrusion without unwanted side effects, when compared with conventional C-wire, evidencing its clinical expediency.

Effect of frequent application of low-level laser therapy on corticotomized tooth movement in dogs: a pilot study.

PURPOSE: The purposes of the present study were to evaluate the effects of frequent applications of low-level laser therapy (LLLT) on corticotomy-assisted tooth movement in a beagle dog model and to compare the effects in the mandible and maxilla. MATERIALS AND METHODS: In 4 male beagles, the maxillary and mandibular second premolars were extracted. The third premolars were corticotomized and then protracted from the canines with a continuous force of 200 g. Daily LLLT (using an aluminum gallium indium phosphide [AlGaInP] diode) was applied at the buccal mucosa of the corticotomized premolars on 1 side only. The tooth movement was measured for 8 weeks. Fluorochromes were injected intravenously at the start of the experiment (T0) and after 2 (T2), 4 (T4), and 8 (T8) weeks to evaluate new bone formation on the tension sides. Histomorphometric and immunohistologic evaluations were performed. RESULTS: In the mandible, the movement of the corticotomized premolars in the LLLT plus corticotomy group was less than that in the corticotomy-only group, although the difference was not statistically significant. In the maxilla, no significant differences between the 2 groups were found. Osteoclastic and proliferating cell activities and the amount of new bone formation were greater in the mandibular LLLT plus corticotomy group than in the corticotomy-only group. CONCLUSIONS: The frequent application of LLLT showed no significant effect on the corticotomized tooth movement.

The thickness of alveolar bone at the mandibular canine and premolar teeth in normal occlusion.

PURPOSE: The purpose of this study was to investigate the alveolar bone thickness on the buccal and lingual aspects of mandibular canines and premolars using cone-beam computed tomography (CBCT). The differences between the left side and the right side and that in male and female measurements were reviewed. PATIENTS AND METHODS: Three-dimensional CBCT of 20 subjects with normal occlusion (9 males and 11 females; mean [SD] age, 21.9 [3.0] y) were used. The thickness of the buccal and lingual bone walls, perpendicular to the long axis of the root, was evaluated at 3 and 5 mm apical to the cementoenamel junction (CEJ) and at the root apex. RESULTS: The mean buccal bone thickness measured at 3 and 5 mm apical to the CEJ was less than 2 mm on the canines and the premolars. The buccal bone thickness of the second premolar at 3 and 5 mm from the CEJ was significantly greater than that of the canine and the first premolar. There were no significant differences between the left and right sides, and the overall measurements of the alveolar bone thickness did not show significant male/female differences. CONCLUSIONS: This study presented the thickness of the buccal and lingual bone in different locations apical to the CEJ in subjects with normal occlusion and the frequency distribution of thick buccal bone wall (≥ 2 mm). The second premolar had the highest frequency distribution of thick buccal bone (≥ 2 mm) when compared with canine and the first premolar. The teeth with thin buccal bone (< 2 mm) should be treated with care for the implant because a thin buccal bone may be damaged more easily and buccal bone resorption may occur. This study may provide estimated value for patients with normal occlusion during tooth extraction and implant installation in the canine and premolar area of the mandible. Preoperative radiographic analysis, with care in using CBCT, may be applied for tooth extraction and implant therapy.

The effect of western adaptation of Hispanic-Americans on their assessment of Korean facial profiles.

OBJECTIVE: To determine Korean facial profile preferences based on lip position as assessed by Hispanic-Americans of varying western adaptation levels and to determine whether the age and sex of the rater had any influence. METHODS: For this study, 132 Hispanic-Americans and 68 Caucasians of varying age, sex and western adaptation levels volunteered to rate their preference of Korean male and female facial silhouettes having lips ranging from retruding to protruding. The Hispanic-Americans were also asked to complete a Bidimensional Acculturation Scale questionnaire to determine their western adaptation status: low-acculturated Hispanics (LAH; lesser western-adapted Hispanic participants) or high-acculturated Hispanics (HAH; higher western-adapted Hispanic participants). RESULTS: The LAHs preferred significantly more retruded lip positions (p < 0.05) while HAHs showed some similarities with Caucasian participants in the results for the Korean male profile, even though HAHs preferred more retruded lip positions for the Korean female profile than Caucasians did (p < 0.05). The age and sex of raters did not influence the preference of facial profiles (p > 0.05). CONCLUSIONS: The results of this study suggest that Hispanic-Americans prefer a flatter Korean lip profile. It would be prudent for orthodontists to offer patients the option of altering lip profile through orthodontic and/or orthognathic surgery treatments.

Self-perception of the facial profile: an aid in treatment planning for orthognathic surgery.

PURPOSE: To investigate the difference between the self-perception of the facial profile and analogous measurements of profile photographs in 2 age groups, adolescents and young adults, and adults. PATIENTS AND METHODS: A prototypical Caucasian profile was constructed for each gender by averaging the profiles of 28 subjects with normal occlusion. Each prototypical profile was manipulated by protruding and retruding the lips in 1-mm increments to construct a series of 13 silhouettes. Next, 85 laypeople were divided into 2 groups: adolescents and young adults (age, 15 to 25 years) and adults (age, 26 to 55 years). They were asked to complete a questionnaire that included choosing the facial profile in the constructed series they thought most resembled their own profile photograph. For each group, the difference between the chosen and actual profile was compared using a 1-sample t test. The differences between the 2 groups in identifying their own profile were compared using a 2-sample t test. RESULTS: The 2 groups were different in their ability to recognize their own profile (P = .040 for the upper lip and P = .006 for the lower lip). The adolescent and young adult group was most accurate, showing no significant difference from 0 for the chosen and actual profiles. However, the adult group was significantly different for both the upper (P = .040) and lower (P = .003) lips. CONCLUSIONS: From our study results, most laypeople aged 15 to 25 years could accurately evaluate the fullness of their own facial profile, although adults aged 26 to 55 years had more difficulty in this evaluation and tended to overestimate the protrusion of their lips.

Evaluation of minimal versus conventional presurgical orthodontics in skeletal class III patients treated with two-jaw surgery.

PURPOSE: The purpose of this study was to compare changes in hard and soft tissues and the treatment efficacy of 2-jaw surgery combined with nonextraction treatment for skeletal Class III malocclusion in patients who received minimal presurgical orthodontics (MPO) versus those who received conventional presurgical orthodontics (CPO). MATERIALS AND METHODS: Thirty-two patients (16 in each group) with skeletal Class III malocclusion who underwent 2-jaw surgery were included in the study. Serial lateral cephalometric films were traced at 4 stages: before treatment (T0), before surgery (T1), 1 month after surgery (T2), and at debonding (T3). Cephalometric measurements and treatment duration were compared using independent t test and Mann-Whitney U test. RESULTS: After the presurgical treatment phase, the angle between the lower incisor axis and mandibular plane, overjet, and soft tissue pogonion to the vertical reference line showed larger changes (P < 0.01) in the CPO group, whereas the pogonion to the horizontal reference line showed larger changes (P < .05) in the MPO group. In the postsurgical phase (T2 to T3), there were no significant differences between the 2 groups. Total treatment duration was significantly shorter in the MPO group. CONCLUSIONS: There were no significant differences between the MPO and CPO groups in the hard and soft tissue cephalometric variables. The MPO group had a shorter total treatment time. It is therefore recommended that clinicians consider these results when selecting MPO as a treatment option for accurate diagnosis and treatment planning of Class III surgical patients.

Combined multisegmental surgical-orthodontic treatment of bialveolar protrusion and chin retrusion with severe facial asymmetry.

LeFort I osteotomy, anterior segmental osteotomy, bilateral sagittal split ramus osteotomy, and genioplasty are frequently used methods for correcting facial deformities. However, in patients with an abnormally shaped maxilla or mandible, more complex surgical techniques or multiple combinations must be considered for improved esthetic results. This article presents a patient with bialveolar protrusion, mandibular prognathism, chin retrusion, a long face, and severe facial asymmetry. A combination of LeFort I asymmetric impaction, anterior segmental osteotomy, and 3-piece segmentation of the maxilla, and bilateral sagittal split ramus osteotomy, anterior segmental osteotomy, genioplasty advancement, and angle shaving in the mandible were conducted simultaneously. In patients with complicated deformities that cannot be classified by simple conventional classification methods, multisegmental osteotomy can be an option for improved esthetic results.

The frontal soft tissue changes in the lower facial portion after orthodontic treatment combined with anterior segmental osteotomy.

AIM: To evaluate changes of the lower facial portion on the frontal view before and after orthodontic treatment combined with anterior segmental osteotomy (ASO) in patients with bimaxillary protrusion. METHODS: The sample consisted of 16 women in the experimental group who had received ASO and 24 women in the untreated control group. Twelve linear measurements, 5 angular measurements, and the lip perimeter and area were measured and analyzed using unpaired and paired t tests. RESULTS: The upper lip height and lower lip to chin length were significantly greater after treatment. The upper and lower vermilion heights and all vermilion areas decreased significantly, while lip width did not change. Upper lip height was significantly greater in the posttreatment group than in the control group, but there was no difference in upper and total lip areas. CONCLUSION: Treatment combined with ASO significantly improved the frontal soft tissue proportions. Anticipated frontal soft tissue changes of the lower face should be considered by clinicians for accurate diagnosis and treatment planning.

Alveolar bone loss around incisors in surgical skeletal Class III patients.

OBJECTIVE: To test the hypothesis that there is no difference in the vertical alveolar bone levels and alveolar bone thickness around the maxillary and mandibular central incisors in surgically treated skeletal Class III malocclusion patients. MATERIALS AND METHODS: The study sample comprised 20 Korean patients with skeletal Class III malocclusion with anterior crossbite and openbite (9 male, 11 female, mean ages 24.1). Three-dimensional cone beam computed tomography images were taken at least 1 month before the orthognathic surgery, and sagittal slices chosen at the labio-lingually widest point of the maxillary and mandibular right central incisor were evaluated. Measurement of the amount of vertical alveolar bone levels and alveolar bone thickness of the labial and lingual plate at the root apex was made using the SimPlant Pro 12.0 program. RESULTS: The mandibular incisors showed reduced vertical alveolar bone levels than the maxillary incisors, especially on the lingual side. The alveolar bone thickness was significantly greater on the lingual side in the maxillary incisors, whereas the mandibular incisors exhibited an opposite result (P < .05). The percentage of vertical bone loss to root length showed a statistically significant difference between the upper labial and lower labial alveolar bone and also between the upper lingual and lower lingual alveolar bone, showing more bone loss in the lower incisors (P < .001). CONCLUSIONS: The hypothesis is rejected. For the skeletal Class III patients undergoing orthognathic surgery, special care should be taken to prevent or not aggravate preexisting alveolar bone loss in the anterior teeth, especially in the mandible.

Effects of substance P on osteoblastic differentiation and heme oxygenase-1 in human periodontal ligament cells.

Although substance P (SP) is associated with osteoclast differentiation and bone resorption, little is known about the osteogenic differentiation-inducing effects of SP in periodontal ligament (PDL) cells. This study investigated whether PDL cells could differentiate into osteoblastic-like cells by SP. The expression of osteoblastic differentiation markers such as osteopontin (OPN), osteonectin (ON), osteocalcin (OCN) and bone sialoprotein (BSP) were evaulated by Western blotting. Additionally, SP-mediated heme oxygenase-1 (HO-1) pathways were further clarified. SP increased HO-1 and osteogenic differentiation in concentration- and time-dependent manners, as determined by OPN, ON, OCN and BSP expression. Furthermore, treatment with inhibitors of p38, ERK MAPK, and NF-kappaB abolished SP-induced osteogenic differentiation and HO-1 expression. SP-induced translocation of Nrf-2 was also observed. The combined results suggest that SP activates the stress-response enzymes HO-1 and Nrf-2, subsequently leading to upregulation of osteogenic differentiation in human PDL cells.

Two-component mini-implant as an efficient tool for orthognathic patients.

A new type of orthodontic mini-implant called the C-implant can be an effective alternative to conventional 1-component screws in orthognathic patients because of its particular design. Its small size and 2-component structure make it easily applicable for various types of difficult intermaxillary fixation cases such as 2-jaw orthognathic surgery, 1-jaw surgery with genioplasty, and orthognathic surgery without presurgical orthodontic treatment. The 2-part design highly resists fracture or deformation during placement and removal, and the long-span head allows the patient to easily attach intermaxillary elastics for traction. This mini-implant can be used not only as an intermaxillary fixation screw but also as anchorage during presurgical and postsurgical orthodontic treatment. Better osseointegration potential of the surface-treated screw part allows it to endure heavy and dynamic forces. In this article, we attempted to show that this mini-implant is a good tool for effective anchorage in presurgical treatment, intermaxillary fixation during surgery, and postsurgical treatment of orthognathic patients.

Surgical positioning of orthodontic mini-implants with guides fabricated on models replicated with cone-beam computed tomography.

INTRODUCTION: This article illustrates a new surgical guide system that uses cone-beam computed tomography (CBCT) images to replicate dental models; surgical guides for the proper positioning of orthodontic mini-implants were fabricated on the replicas, and the guides were used for precise placement. The indications, efficacy, and possible complications of this method are discussed. METHODS: Patients who were planning to have orthodontic mini-implant treatment were recruited for this study. A CBCT system (PSR 9000N, Asahi Roentgen, Kyoto, Japan) was used to acquire virtual slices of the posterior maxilla that were 0.1 to 0.15 mm thick. Color 3-dimensional rapid prototyping was used to differentiate teeth, alveolus, and maxillary sinus wall. A surgical guide for the mini-implant was fabricated on the replica model. Proper positioning for mini-implants on the posterior maxilla was determined by viewing the CBCT images. RESULTS: The surgical guide was placed on the clinical site, and it allowed precise pilot drilling and accurate placement of the mini-implant. CONCLUSIONS: CBCT imaging allows remarkably lower radiation doses and thinner acquisition slices compared with medical computed tomography. Virtually reproduced replica models enable precise planning for mini-implant positions in anatomically complex sites.

Peg-shaped and small lateral incisors not at higher risk for root resorption.

The purpose of this study was to examine the pattern of external root resorption for peg-shaped and small lateral incisors according to various conditions and to compare it with that of normal-shaped lateral incisors. The periapical radiographs of 114 patients with 60 peg-shaped and 54 small lateral incisors were measured before and after treatment. Crown shape was assessed by examining pretreatment study casts. Findings showed that there was no significant difference in external root resorption between peg-shaped (1.09 mm) and normal lateral incisors (0.88 mm). However, a statistically significant difference in apical root resorption between small lateral incisors (1.03 mm) and normal lateral incisors (1.62 mm) was found. Peg-shaped laterals were also coincidentally found to occur more frequently on the left side of the arch.