Effect of augmented corticotomy-assisted presurgical orthodontic treatment on alveolar bone fenestration and dehiscence in skeletal class III patients.

Background/purpose: Alveolar bone fenestration and dehiscence is common in untreated patients and potentially harmful. This study was to evaluate the effect of augmented corticotomy (AC) on the prevention and treatment of alveolar bone defects in skeletal class III high-angle patients during presurgical orthodontic treatment (POT). Materials and methods: Fifty patients with skeletal Class III high-angle malocclusion were enrolled, of whom 25 patients (G1) underwent traditional POT and 25 patients (G2) received AC during POT. The alveolar bone fenestration and dehiscence around the upper and lower anterior teeth were measured by CBCT. The incidence and transition of fenestration and dehiscence in the two groups were compared by the chisquare and Mann‒Whitney rank-sum tests. Results: Before treatment (T0), the incidence of fenestration and dehiscence around the anterior teeth of all patients was 39.24% and 24.10%, respectively. After POT (T1), the incidence of fenestration in G1 and G2 was 49.83% and 25.86%, respectively, and the incidence of dehiscence in G1 and G2 was 58.08% and 32.07%, respectively. For teeth without fenestration and dehiscence at T0, more anterior teeth in G1 exhibited fenestration and dehiscence at T1 than in G2. For teeth with fenestration and dehiscence at T0, most transitions in G1 were maintained or worsened, but "cure" cases were observed in G2. After POT, the cure rates of fenestration and dehiscence in G2 were 80.95% and 91.07%, respectively. Conclusion: During the POT of skeletal Class III high-angle patients, augmented corticotomy can significantly treat and prevent alveolar bone fenestration and dehiscence around anterior teeth.

Digital Workflow for Full-Arch Immediate Implant Placement Using a Stackable Surgical Guide Fabricated Using SLM Technology.

The failing dentition of partially edentulous individuals may be used as an initial reference for stackable restrictive surgical guides during full-arch immediate implant placement. The stackable guide option derived from a digital workflow increases the predictability of the performance of bone reduction, immediate implant placement, and immediate loading of provisional implant-supported fixed dental prostheses. The present paper aims to report a practical approach to design and produce a metal framework with occlusal rests to facilitate the use of a tooth-supported surgical guide when full-arch immediate implant placement is indicated in patients with failing dentition.

Nomogram prediction of vulnerable periodontal condition before orthodontic treatment in the anterior teeth of Chinese patients with skeletal Class III malocclusion.

OBJECTIVE: To establish and verify models predictive of thin periodontal phenotype and alveolar fenestration/dehiscence in the anterior teeth of patients with skeletal Class III malocclusion. MATERIAL AND METHODS: Retrospective data of 669 anterior teeth (305 in maxillae and 364 in mandibles) from 80 patients with skeletal Class III malocclusion before augmented corticotomy were collected. Distribution of thin periodontal phenotype and alveolar fenestration and dehiscence were evaluated and their associations with potential influencing factors were explored using univariate and multivariate analyses. The predictive models were visualized as nomograms, the accuracy of which was tested by receiver operating curve analyses. RESULTS: Thin phenotype was associated with Mazza bleeding index, sex, tooth type, probing depth and width of keratinized gingiva (WKG). Labial dehiscence was associated with age, jaw, labial bone thickness, mandibular plane angle, sagittal root position (SRP), sex, tooth type, and WKG. Labial fenestration was associated with sex, tooth type, SRP, and periodontal phenotype. The areas under the curves of nomogram prediction models for periodontal phenotype, alveolar dehiscence, and alveolar fenestration were 0.84, 0.81, and 0.73, respectively. CONCLUSIONS: Female sex, lateral incisor, and limited WKG may be risk factors for thin periodontal phenotype. Age, canine, male sex, mandible, thin labial bone thickness, and root positioned against the labial plate may be risk factors for labial dehiscence; and female sex, thick phenotype, root positioned against the labial plate, lateral incisor, and canine may be risk factors for labial fenestration. The predictive performance of the models was acceptable.

Prevalence of and risk factors for alveolar fenestration and dehiscence in the anterior teeth of Chinese patients with skeletal Class III malocclusion.

INTRODUCTION: This study investigated the prevalence of and risk factors for alveolar fenestration and dehiscence in the anterior teeth of Chinese patients with skeletal Class III malocclusion. METHODS: This study included clinical and radiographic examinations and intraoperative observations of 460 anterior teeth from 54 patients who underwent corticotomy and periodontal regenerative surgery before orthodontic treatment. Fenestration and dehiscence were detected and recorded during open-flap surgery. Univariate and multivariate analyses were performed to assess relationships between fenestration and dehiscence and age, sex, history of previous orthodontic treatment, mandibular plane angle, dentition, tooth position, sagittal root position, periodontal biotype, gingival recession, width of keratinized gingiva, and width of the basal bone. RESULTS: The prevalence of buccal alveolar bone defects was 16.1% (fenestration) and 20.7% (dehiscence) at the tooth level. Multivariate logistic regressions showed that fenestration was significantly associated with tooth position (canine vs central incisor, odds ratio [OR] = 3.324; P = 0.006; lateral incisor vs central incisor, OR = 5.588; P  <0.001), and sagittal root position (buccally positioned vs centrally positioned, OR = 5.865; P = 0.025). Dehiscence was significantly associated with dentition (mandible vs maxilla, OR = 11.685; P  <0.001), tooth position (canine vs central incisor, OR = 3.863; P = 0.007), age (OR = 1.227; P = 0.010), sex (male vs female, OR = 5.530; P = 0.026), and history of orthodontic treatment (yes vs no, OR = 4.773; P = 0.028). CONCLUSIONS: Buccally positioned teeth in the osseous housing, lateral incisors, and canines were more likely to exhibit alveolar fenestration. Mandibular teeth and canines, patients who were older, were male, and had a history of orthodontic treatment, were more likely to exhibit alveolar dehiscence.

Periodontal soft- and hard-tissue changes after augmented corticotomy in Chinese adult patients with skeletal Angle Class III malocclusion: A non-randomized controlled trial.

BACKGROUND: To investigate soft- and hard-tissue changes after augmented corticotomy in Chinese adult patients with skeletal Angle Class III malocclusion. METHODS: This non-randomized controlled trial included 357 anterior teeth from 30 Chinese adult patients with skeletal Angle Class III malocclusion for whom the proposed treatment was augmented corticotomy. Jaws receiving surgery were allocated to a test group (S, surgical group, n = 47) and jaws not receiving surgery were allocated to a control group (NS, non-surgical group, n = 13). Changes in the periodontal biotype, width of the keratinized gingiva (WKG), and labial and lingual horizontal bone thicknesses (BTs) were compared 6 months after surgery by univariate and multivariate analyses. RESULTS: After adjustment for confounding variables, average gains of 0.473 mm in the WKG and 0.649 mm in the labial BT were found in the S group relative to the NS group (P <0.05). The odds of transition from a thin periodontal biotype to a thick biotype in the S group were about 230 times those in the NS group, and the odds of the reverse biotype transition in the NS group were about 83 times those in the S group (P <0.05). CONCLUSIONS: Within the limitations of the present study, augmented corticotomy is a promising approach to improve insufficient periodontal soft and hard tissues in Chinese adult patients with skeletal Angle Class III malocclusion.

Association between Periodontal Biotype and Clinical Parameters: A Cross-sectional Study in Patients with Skeletal Class III Malocclusion.

OBJECTIVE: To evaluate the prevalence of periodontal biotypes in patients with skeletal Class III malocclusion and to explore its association with age, gender, other periodontal clinical parameters and width of keratinized gingiva (WKG). METHODS: Data were collected for the buccal-middle site of 310 anterior teeth from 26 subjects who received periodontally accelerated osteogenic orthodontics (PAOO) surgery before orthodontic treatment. Univariate and multivariate analysis were performed to calculate and test the correlations between periodontal biotype and age, gender and bleeding index (BI), gingival recession (GR), plaque index (PLI), probing depth (PD) and WKG. RESULTS: Prevalence of thin periodontal biotype was 33.9% in the anterior region. Mean WKG was 4.37 mm. Univariate analysis showed that a moderately positive correlation was found between WKG and thick biotype (r = 0.544, P < 0.001). A low positive correlation was detected between mandibular teeth and thick biotype (r = 0.387, P < 0.001) and a low negative correlation was detected between GR and thick biotype (r = -0.308, P < 0.001). Multi-level logistic regression showed that biotype was significantly associated with dental arch (odds ratio [OR] = 0.174, P = 0.015) and WKG (OR = 2.043, P = 0.002). No significant associations were detected between biotype and other factors. CONCLUSION: Dental arch and WKG were associated with periodontal biotype in patients with skeletal Class III malocclusion.

A six-site method for the evaluation of periodontal bone loss in cone-beam CT images.

OBJECTIVES: In contrast to two-dimensional planar images, a measuring point is hardly repeatedly determined in a CBCT image when alveolar bone loss is assessed. Thus, the aim of the present study was to propose a six-site measuring method, which is closely related to anatomical structure, for the evaluation of alveolar bone loss in CBCT images. METHODS: 150 measuring points in 11 molars and 14 premolars from 6 patients (2 males and 4 females) were included. CBCT images of the teeth were acquired prior to periodontal surgery. Four observers measured the distances between cemento-enamel junctions and the apical bases of the periodontal bone defect at the mesio-buccal, mid-buccal, disto-buccal, mesio-lingual/palatal, mid-lingual/palatal and disto-lingual/palatal sites in CBCT images. Direct measurements of the six sites were correspondingly obtained in the subsequent periodontal surgeries. Differences between the distances measured in the CBCT images and during the surgery were analysed. Interobserver and intraobserver variances were tested. RESULTS: No statistically significant difference was found between the surgical and CBCT measurements (p = 0.84). Diagnostic coincidence rates of four observers were 86.7%, 87.3%, 88.7% and 88.0%, respectively. The interobserver (p = 0.95) and intraobserver (p = 0.30) variances were not significant. CONCLUSIONS: The six-site measuring method validated in the present study may be a useful three-dimensional measuring method for the evaluation of periodontal disease.

[Effect of recombinant human S100A8 on the proliferation and migration of periodontal ligament cells].

OBJECTIVE: To investigate the effect of S100A8 on the proliferation and migration of periodontal ligament cells (PDLCs), and to learn the role of S100A8 in the development of periodontitis. METHODS: PDLCs were treated with S100A8 in vitro before MTT and flow cytometry assays were performed. Transwell assay and wound assay were conducted to test the migratory activity of the PDLCs as well. RESULTS: In the study, 10⁻7-10⁻5 mol/L recombined human S100A8 suppressed the proliferation of the PDLCs, while their proliferation was significantly inhibited with 10⁻5 mol/L S100A8 treatment for 48 h. And 10⁻9-10⁻7 mol/L S100A8 enhanced the migratory activity of the PDLCs while the effect of 10⁻9 mol/L S100A8 was statistically significant. CONCLUSION: Increased level of S100A8 in periodontitis could lead to the inhibition of cell proliferation and apoptosis of PDLCs, but S100A8 could promote the migration of PDLCs when its concentration decreased after treatment.

[Effect of periodontal surgery on the subgingival periodontal microbiota in artificial class III furcation defects: an experimental study in monkeys].

OBJECTIVE: This study was to longitudinally evaluate the change of prevalence of five periodontal putative pathogens in the subgingival plaque of artificial class III furcation defects at the three time-points, including before the establishment of furcation defects, before and 6 months after periodontal surgery. METHODS: Eighteen chronic infected class III FI defects were created at the mandibular first molars, second molars and second premolars of three adult male Macaca fascicularis. The samples of subgingival plaque were obtained from the subgingival area of furcation defects in buccal and lingual sites before the establishment of furcation defects, before and 6 months after periodontal surgery. 36 samples were obtained at one time-points. Five periodontal putative pathogens, including Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema dinticola (Td), Actinobacillus actinomycetemcomitans (Aa) and Fusobacterium nucleatum (Fn), were detected with 16SrRNA based PCR. RESULTS: 1. The prevalence of Pg, Tf, Td and Fn was gradually increased, from 58.3% to 69.4% to 88.9%, 47,2% to 69.4% to 83.3%, 13.9% to 36.1% to 61.1% (P<0.01), and 69.4% to 91.7% to 91.7% (P<0.05), respectively during the experimental period. The prevalence of Fn was higher than Pg, Tf and Td. The prevalence of Aa was the lowest and no obvious difference among the three samplings(from 25.9% to 13.9% to 33.3%)was detected. 2. The prevalence of more than 3 species simultaneously detected was increased from 38.9% to 61.1% to 83.3% (P <0.01). The red complex (Pg + Tf + Td) was detected from 8.3% to 27.8% to 44.4% (P<0.01) at the different time point. 3. The combined detection frequency of red complex in the inflammatory sites (87.5%), which were histologically defined as inflammatory cells infiltrated in furcation area 6 months post-surgery, and the same sites pre-surgery (62.5%) was more than that in pre-creation of furcation defects (P<0.01). But there were no significant differences compared to that in non inflammatory area (60.0%, 40.0%), respectively. CONCLUSION: The prevalence of periodontal pathogenic bacteria correlated with the severity of local inflammation. The increase of coexistent rate of red complex at the second and third sampling times suggests that the red complex play important role in the pathogenesis of periodontitis. Fn may be a resident bacteria in the subgingival plaque, play a bridge role on the biofilm formation and maturation. Aa may not be a major causative bacteria in the clinical periodontitis.

[Clinical and radiographic evaluation of class III furcation defects in the treatment using autogenous periodontal ligament cells with or without enamel matrix derivatives].

OBJECTIVE: To evaluate whether the use of periodontal ligament cells(PDLC) with or without enamel matrix derivatives(EMD) influences periodontal tissue repair in class III furcation defects. METHODS: Three adult male Macaca fascicularis monkeys were used. Class III furcation defects were created at the mandibular second pre-molars, first molars and second molars. The autogenous PDLC were cultured in vitro with Bio Oss Collagen. Six furcation defects in the 3 monkeys were divided as follows, Group A (one second molar): PDLC/Bio Oss Collagen+EMD; Group B (another second molar): Bio Oss Collagen+EMD; Group C (one first molar): PDLC/ BiojOss Collagen; Group D(another first molar): Bio Oss Collagen; Group E (one second pre-molar): EMD; Group F (another second pre-molar): the empty control. All sites (including buccal and lingual side) were covered with collagen membranes. The monkeys were euthanized at the end of 6 months. The periodontal depth (PD) and clinical attachment level (AL) at the buccal and lingual furcation defects were examined before and 6 months after the implantation. X-rays were also obtained at the same time points. RESULTS: PD and AL were decreased in most sites, the reductions in groups E and F (the second pre- molars) were the most significant, and then in turn were in groups A, C, B and D. The repaired alveolar bones were almost full of furcation area in the second pre-molars, and the relatively clear lamina dura was also found. The alveolar bones in the other sizes only had a little repair, and the obviously low density area still remained in the coronal of the defects. CONCLUSION: The results of this study indicate that class III furcation defects can not be predictably resolved even with the combination of autogenous PDLC and EMD, although they may increase the repair of periodontal tissue in the area of class III furcation defects separately. The sizes of furcation defects and the coverage of gingival flap would influence the outcome of the treatment of class III furcation defects.

[Hypoxia regulates osteogenic differentiation of human periodontal ligament stem cells].

OBJECTIVE: To investigate the effect of hypoxia on isolated human periodontal ligament stem cells (hPDLSC) in vitro. METHODS: hPDLSC were exposed to normoxia (20% O(2)) and hypoxia (1.5% - 2% O(2)). Total cellular RNA and protein were collected on day 1, 2, 4 and 6 after culture. Western analysis and semi-quantitative RT-PCR were used to analyze osteogenic differentiation of hPDLSC, including alkaline phosphatase (ALP), osteocalcin (OCN), secreted protein acidic and rich in cysteine (SPARC) and bone morphogenetic protein-2 (BMP-2). RESULTS: In the first two days hypoxia slightly increased the growth of hPDLSC [A value was 0.697(hypoxia) vs 0.617 (nomoxia)] and after the third day hypoxia dramatically decreased the growth of the hPDLSC [A value was 0.870(hypoxia) vs 1.242 (nomoxia)]. Up to 90% reduction of ALP activity was observed in hPDLSC after 5 days of hypoxia [A value was 0.004(hypoxia) vs 0.049(nomoxia)]. Hypoxia decreased SPARC expression at protein level and down-regulated ALP, OCN and BMP-2 expression at mRNA level in comparison with nomoxia. CONCLUSIONS: Hypoxia inhibited proliferation of hPDLSC and down-regulated BMP-2 mRNA expression, then down-regulated their target genes such as ALP, OCN, and SPARC, thus inhibiting critical steps in osteogenic differentiation of hPDLSC.

[Effect of 17-beta estradiol on the expression of receptor activator of nuclear factor kappaB ligand and osteoprotegerin of human periodontal ligament cells during their osteogenic differentiation].

OBJECTIVE: To investigate the effect of 17-beta estradiol (E(2))on the expression of receptor activator of nuclear factor kappaB ligand(RANKL) and osteoprotegerin(OPG) in human periodontal ligament cells( hPDLCs) during their osteogenic differentiation. METHODS: hPDLCs of passage four were treated with 0.1% absolute ethyl alcohol (control), 10(-10) mol/L(physiological dose) or 10(-7) mol/L(high dose) E(2) in DMEM supplemented with 10% FBS, 10 mmol/L beta-glycerophosphate and 5 microg/mL ascorbic acid for 24 hours, 48 hours and 72 hours. Levels of RANKL and OPG mRNA were detected with real-time quantitative RT-PCR. RESULTS: High dose E(2) induced a time-dependent decrease of RANKL mRNA and expression levels were 31.0%, 23.6% and 15.4% of the controls at 24 h, 48 h and 72 h respectively while expression levels with physiological dose E(2) were 28.4%, 87.3% and 22.6% of the controls respectively. On the other hand, E(2) increased OPG mRNA expression levels of hPDLCs which reached the maximum at 72 h with physiological dose E(2), 210.1% of the controls and with high dose E(2), 171.3% of the controls. CONCLUSION: These results suggest that estrogen may exert anti-resorptive effects on alveolar bone by regulating the expression of RANKL and OPG in hPDLCs during their osteogenic differentiation.

[The in vivo formation of cementum-like tissue by bovine cementoblasts].

OBJECTIVE: To test the bovine cementoblasts (CBs) cementum-forming ability in vivo. METHODS: Root fragments of newborn bovine freshly extracted mandibular incisor were cultured routinely and 4th-5th passages of CBs were harvested. CBs were then cultured in the medium supplemented with 50 mg/L alpha-ascorbic acid and 10 mmol/l beta-glycerolphosphate to form a thick layer as tissue engineering scaffold for cementum formation. Collagen membrane was used as control scaffold. 2 x 10(6) cells were attached to the CBs-made carrier as well as collagen membrane scaffolds and transplanted subcutaneously into immunodeficient mice. Transplants were harvested at 7th week. Histological sections were stained with HE, alizarin red S and van Kossa methods as well as monoclonal Ab against bovine cementum attachment protein (CAP). RESULTS: CBs-made scaffold supported more cementum-like tissue (CLT) formation than collagen-made scaffold. The CLT formed on CBs scaffold was partly calcified with embedded cells. Uncalcified cementoid-like material could be seen on the surface and was encircled by cubical CB-like cells. The CLT was also positive to CAP and van Kossa staining. CONCLUSIONS: These results suggest that the bovine CBs can form cementum-like tissue. The cell-made carrier is a better scaffold than collagen membrane.