[Cone-beam CT measurement of morphological changes of the root and alveolar bone of the central incisor during orthodontic treatment with extraction].

PURPOSE: To study the effect of orthodontic treatment with extraction on root resorption and alveolar bone morphology of the central incisor in adult patients. METHODS: Eleven adult patients receiving orthodontic treatment were enrolled, and asked to take cone-beam CT(CBCT) scanning before and after treatment. Root resorption of the upper and lower central incisors after treatment, changes in alveolar bone thickness and height of alveolar bone were measured and compared. Statistical analysis was performed using SPSS 23.0 software package. RESULTS: The length of the tooth and root was reduced to a certain degree. The change in root length of the maxillary incisor was larger than that of the mandibular incisor. The alveolar bone width of the lingual and palatal neck of the central incisor showed some reduction, and alveolar bone width of the palatal neck of the upper central incisor and the middle lingual side of the mandibular central incisor changed to a certain extent. The width of the alveolar bone in the middle labial side of the mandibular central incisor increased, but the alveolar bone on the lingual and palatal side increased after orthodontic treatment, which was more obvious than that of the maxillary central incisor. CONCLUSIONS: Orthodontic treatment with tooth extraction is accompanied by a certain degree of root resorption of the central incisor and alveolar bone on the lingual and palatal side. However it is also accompanied by an increase in the amount of alveolar bone on the labial side. More fenestration and dehiscence are observed in the mandible.

Three-D imaging of dental alveolar bone change after fixed orthodontic treatment in patients with periodontitis.

OBJECTIVES: The objective of this study was to radiographically quantify bone height and bone density in patients with periodontitis after fixed orthodontic treatment using cone beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 81 patients including 40 patients with chronic periodontitis (group 1) and 41 patients with normal periodontal tissues (group 2) were selected. CBCT scanning for anterior teeth were taken before and after orthodontic treatment. Measurements of bone height and bone density were performed using CBCT software. RESULTS: The group 1 presented a statistically lesser bone density and bone height when compared to group 2 before treatment. There was a significant loss of bone density for both groups after orthodontic treatment, but bone density loss was significantly greater in the group 1. There was no statistically significant bone height change in two groups after treatment. CONCLUSIONS: This study demonstrated that orthodontic treatment can preserve bone height but not capable of maintaining bone density, especially for patients with periodontitis. It is indicated that the change of bone density may be more susceptible than that of bone height when radiographically evaluating bone status under this combined periodontal and orthodontic therapy.

[Osteogenic gene expression of human periodontal ligament stem cells during osteogenic induction].

URPOSE: To isolate and identify the human periodontal ligament stem cells, evaluate osteogenetic capacity, and investigate the changes of osteogenic bone related gene expression in mineralized medium at different times. METHODS: PDLSCs were isolated by tissue culture and magnetic activated cell sorting. Immunofluorescence staining was used for identification. The general situation of osteogenesis was assessed with alkaline phosphatase (ALP) and alizarin red staining. Real-time PCR was used to detect the expression of genes in osteoinduction. SPSS12.0 software package was used for data analysis. RESULTS: Tissue culture with magnetic cell sorting could isolate high-purity human periodontal ligament stem cells. During the osteogenic process, the expression of FoxO1 and Runx2 firstly increased and then decreased, ALP and OCN gene levels continued to increase. CONCLUSIONS: Similar to osteogenesis, ALP, Runx2, FoxO1 and OCN are regularly expressed during osteogenic induction.

Bone grafting, corticotomy, and orthodontics: treatment of cleft alveolus in a chinese cohort.

Objective : A multimodal therapy was applied to solve a set of related problems including collapse of the posterior segment, high level gingival margin of canine, and resorption of grafted bone in a cohort of Chinese youngsters with cleft lip and palate. This study aimed to evaluate the benefits of this treatment procedure. Methods : Thirty patients with unilateral cleft lip and palate were included in this prospective study. All patients had previously undergone only cleft lip and palate repair and presented with alveolar cleft and an obvious step in the gingival margin between the canine tooth and the teeth beside it. A multimodal therapy that included bone grafting, corticotomy, and orthodontics was applied to solve these problems. Grafted bone volume, parallelism of the roots, root resorption, gingival margin, and mobility of the canine on the cleft side were established before surgery, 1 week after surgery, and after straightening of the canine. Results : Less than 25% of the grafted bone was reabsorbed in 25 of the 30 patients, while less than 50% was resorbed in the remaining five. The roots of the canines on the cleft side were mostly parallel to the adjacent teeth. Root resorption and mobility of the canines were slight. The difference in the gingival margin between the canines on the cleft side and the other side was small. Conclusions : Canines moved into the grafted bone safely and effectively, thus achieving a normal gingival margin and retaining grafted bone volume in one operation.

[Measurement of alveolar bone thickness of adult skeletal Class III patients in mandibular anterior region].

PURPOSE: To describe alveolar bone thickness in mandibular anterior region of skeletal Class III malocclusion with the help of Cone-beam CT. METHODS: The subjects were selected from consecutive adult patients seeking orthodontic treatment in Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from January 2008 to March 2011, which included 64 patients diagnosed to be skeletal Class I malocclusion (Class I group) and 66 patients diagnosed to be skeletal Class III malocclusion (Class III group). Both Class I and Class III groups were divided into 3 divisions respectively according to different vertical facial types. Mandibular left central incisor of each subject was chosen for measurement. The labial (L1), lingual (L2) and total (L0)alveolar bone thickness of skeletal Class III patients in mandibular anterior region were assessed using a CBCT analyzing method with Class I group as the control group. Data was processed with SAS8.02 software package. RESULTS: L1(P<0.05),L2(P<0.01) and L0(P<0.01) of Class III group were thinner than those of Class I group. L1 of high-angle Class III malocclusion was thinner than that of average-angle(P<0.01)and low-angle(P<0.01) ones ; L2 of average-angle Class III malocclusion was thinner than that of low-angle ones(P<0.01) and thicker than that of high-angle ones(P<0.05); L0 of low-angle Class III malocclusion was thicker than that of average-angle ones(P<0.01),which was thicker than that of high-angle ones(P<0.01). L1 of Class III group with different vertical facial types was thicker than L2(P<0.01). CONCLUSIONS: Skeletal Class III malocclusion exhibits thinner alveolus around the mandibular incisor apices compared with Class I malocclusion, which shows strong connection with different vertical facial types. Root apices of mandibular anterior teeth of skeletal Class III malocclusion situated closer to labial cortical bone than lingual cortical bone. It is necessary to access the alveolar bone thickness of adult skeletal Class III patients in mandibular anterior region before orthodontic camouflage or surgical-orthodontic treatment. Orthodontic camouflage might not be a reasonable treatment alternative for these patients.

Treatment of severe skeletal open bite deformity in patients with Möbius syndrome: a report of 3 cases.

PURPOSE: To investigate the treatment of severe skeletal open bite deformities in Möbius syndrome patients. MATERIALS AND METHODS: Three patients aged 17 to 24 years (2 male patients and 1 female patient) with Möbius syndrome were evaluated and treated with preoperative orthodontics, orthognathic surgery, and postoperative orthodontic management. One patient was treated by bilateral V osteotomies of the mandibular body and one patient with bilateral V osteotomies of the mandibular body plus a Le Fort I osteotomy. The third patient had bilateral mandibular ramus sagittal split osteotomies in combination with maxillary osteotomies. Two of the patients had preoperative electromyographic studies on the temporalis and masseter muscles. RESULTS: Postoperative and post-orthodontic stability was good in 2 cases, whereas a 5-mm anterior open bite developed after treatment in 1 case and additional orthodontic management was required to re-establish good occlusion. Potential to redevelop anterior open bites may likely be related to the functional deficiencies of the muscles of mastication and facial paralysis. Two patients who had electromyographic studies to evaluate muscle function showed lower-than-normal function of the temporalis and masseter muscles. Lower lip ptosis remained a significant esthetic issue in 2 of 3 patients. CONCLUSIONS: Patients with Möbius syndrome with severe skeletal open bite deformities can be treated with combined orthodontic and orthognathic surgery; however, there is a tendency for redevelopment of an anterior open bite with the surgical and orthodontic techniques used in these cases.

[Clinical study of ramus implant anchorage for mandibular arch distalization].

PURPOSE: To evaluate the efficiency of ramus implant anchorage for mandibular arch distalization, and determine the feature of tooth movement. METHODS: Six patients were selected to distalize mandibular arch with ramus implant anchorage. Position changes of mandibular first molars and incisors were measured in sagittal and vertical direction to evaluate the amount of molar and incisor distalization and character of tooth movement. SPSS17.0 software package was used for statistical analysis. RESULTS: The average amount of distalization of mandibular first molar was 4.88mm at crown level and 3.1mm at root level, and of mandibular incisor was 5.02mm at crown level and 1.03mm at root level. All of the lower arches were distalized successfully and achieving normal overjet and overbite. CONCLUSIONS: Significant true distalization of lower arch could be obtained by ramus implant as bony anchorage. The method could be used to correct anterior cross bite and mandibular anterior crowding or flaring without extraction.

[Exploration on the sliding mechanism of implant anchorage assisted self-ligating appliance].

PURPOSE: To investigate non-extraction treatment of borderline cases through analysis of cases treated by maxillary implant anchorage assisted self-ligating appliance. METHODS: Twenty adult patients with moderate-crowding malocclusion were reviewed. The patients were divided into 2 groups. G1 group comprised 10 patients, 6 males, 4 females, aged 18-26 years(mean: 22 years old), treated by implant anchorage assisted self-ligating appliance; G2 group comprised 10 patients, 5 males, 5 females, aged 19-25 years(mean: 23 years old), treated by self-ligating appliance. Dental casts and lateral cephalometric radiographs were measured before and after orthodontic treatment (or after leveling and alignment). SAS8.02 software package was used for statistical analysis. RESULTS: Significant increase in inter-premolar arch width and inter-molar arch width were noted after orthodontic treatment or first treatment phase in both groups, with no significant difference between the G1 and G2 groups. No significant difference was observed in molar inclination within the treatment process in both groups. UI-SN and UI-NA increased significantly after orthodontic treatment or first treatment phase in two groups with statistical difference between the G1 and G2 groups, indicating that implant-anchorage contributed better control of the upper incisor. G1 also showed a statistically greater molar distal movement than G2. CONCLUSIONS: During the non-extraction treatment of borderline cases, maxillary implant-anchorage assisted self-ligating appliance can entirely retract the upper dental arch, expand the arch width and show better control of the upper incisor, so the fine naso-labial relationship, upper lip protrusion and soft-tissue profile can be maintained. Compared with headgear and pendulum, implant anchorage assisted self-ligating appliance is a better way to handle borderline cases with non-extraction approach.

[Cephalometric analysis of implant anchorage-assisted retraction of anterior teeth].

PURPOSE: The purpose of this study is to compare the different effects of alveolar bone remolding due to retraction of anterior teeth by two types of anchorage mini-screw implant or regular maximum anchorage. METHODS: The sample comprised 26 orthodontic patients with upper dental alveolar bone protrusion and mild crowding. The treatment plan was to remove the four first bicuspids. 14 patients,3 males,11 females, aged 20-54 years old (mean: 25 years) were treated with implant anchorage to retract the maxillary anterior teeth. 12 patients, 1 male,11 females, aged 18-30 years old (mean: 21 years) were treated with regular maximum anchorage to retract maxillary anterior teeth. Lateral cephalograms of all patients were evaluated at two stages: pretreatment, post-treatment.The changes of the long axis of the anterior teeth and dental alveolar were measured.SPSS11.0 software package was used for statistical analysis. RESULTS: The cephalometric findings showed that the anterior teeth were retracted with implant anchorage significantly more than the maximum anchorage, there was no significant difference in the dental alveolar bone remolding between two groups. The first molars moved anteriorly slightly (less than 1mm) with implant anchorage, but significantly (3.08 mm) with regular maximum anchorage. CONCLUSIONS: The maxillary anterior teeth are significantly retraced with the implant anchorage; the molars move mesially significantly less in the implant group than the maximum group. There are no significant differences in dental alveolar bone remolding between both groups. Support by Shanghai Leading Academic Discipline Project (Grant No.Y0203) and Research Fund of Science and Technology Committee of Shanghai Municipality (Grant No. 05B224).

[Clinical evaluation of implant anchorage for molar intrusion: report of the short-term results].

PURPOSE: The purpose of this study is to evaluate the efficiency and security of self-drilling mini-screw implant anchorage for molar intrusion, to achieve the right position of the mini-screw implant. METHODS: Ten patients with overerupted maxillary molars were selected, aging from 25 to 53 years old, the average age was 33 years old. There were 2 men and 8 women. All the overerupted molars were intruded in gingival direction with mini-screw implants anchorage. RESULTS: The mean intrusive movement of the overerupted maxillary molars was 3 mm, the mean treatment time were 3.5 months.All of the missing teeth were treated by prosthetic treatment. No obvious root resorption, pulp necrosis and tooth loosen were found. CONCLUSIONS: Significant true intrusion of maxillary molars could be obtained by mini-screw implant as bony anchorage.Supported by Shanghai Leading Academic Discipline Project (Grant No.Y0203) and Research Fund of Science and Technology Committee of Shanghai Municipality (Grant No.05B224).

[A preliminary study of nasoalveolar molding for infants born with cleft lip and palate].

PURPOSE: The purpose of this study was to apply nasoalveolar molding appliance in infants with cleft lip and plate and to observe the preliminary effects on nasal cartilage and columella. METHODS: Ten infants were treated with nasoalveolar molding. The other ten infants without any presurgical orthopedic treatment were chosen as the control group. Each patient was photographed at the initial visit (T0), after nasoalveolar molding (T1), 2 weeks (T2), and half a year (T3) after cheiloplasty. Six measurements were made on the photographs and the nasal symmetry was analyzed with paired t test. RESULTS: The percentage of the deviation from perfect symmetry was significantly improved at T0-T1, T1-T2 stage (P<0.05), and the improvement relapsed at T2-T3 (P<0.05). There was significant difference between the orthopedic group and the control group with the changes in nasal symmetry in vertical dimension (P<0.01), and there was no significant difference in horizontal dimension (P>0.05). CONCLUSIONS: Nasal asymmetry was significantly improved after nasoalveolar molding. Half a year after the primary cheiloplasty, although there was a relapse tendency of nasal asymmetry, the shape of the nasal dome was ideal.