Evaluation of the Lingual Splitting Patterns and the Lateral Bone Cut Ends Following Mandibular Bilateral Sagittal Split Osteotomy Using Cone Beam Computed Tomography (CBCT).

The bilateral sagittal split osteotomy (BSSO) is the most popular orthognathic procedure performed by maxillofacial surgeons to treat skeletal class II and class III and to correct mandibular asymmetries. The study aimed to evaluate the lingual splitting patterns and lateral bone cut end (LBCE) in bilateral sagittal split osteotomy (BSSO) and their relation with the ramal thickness and the presence of impacted third molars using cone beam computed tomography (CBCT). This prospective observational study included patients with mandibular prognathism who were treated with BSSO with or without Le Fort I osteotomy. Cone beam computed tomography was used to measure the ramal thickness preoperatively and to evaluate the LBCE, and the lingual splitting patterns postoperatively. Twenty-one patients (42 sides) were included in this study. The most commonly observed lingual splitting pattern was type III (47.6%), while the most common LBCE was type B (59.5%). The bad split was encountered 8 times on 42 sides (16.7%). A nonsignificant relationship between the ramal thickness and bad splitting was observed ( P =0.901). Impacted third molars were present in 16 of the 42 sides (38.1%) and had no significant effect on the occurrence of bad splitting ( P =0.063). Type III lingual splitting pattern and type B LBCE were the most commonly observed patterns. No direct association was observed concerning the presence of impacted mandibular third molars and the thickness of the ramus with the occurrence of bad splitting.

Gingival tissue samples from periodontitis patients demonstrate epithelial-mesenchymal transition phenotype.

OBJECTIVE: To determine the expression of key epithelial-mesenchymal transition (EMT) markers in gingival tissue samples collected from patients with periodontitis. BACKGROUND: Epithelial-mesenchymal transition is a process responsible for shifting epithelial-phenotype to mesenchymal-phenotype leading to loss of epithelial-barrier function. Thus, EMT could be involved as a pathogenic mechanism in periodontitis as both conditions share common promoters and signalling pathways. MATERIALS AND METHODS: Gingival tissue samples were collected from patients with periodontitis (case) and healthy periodontium (control). Periodontal parameters including bleeding on probing, probing pocket depth (PPD), and clinical attachment loss were recorded. Paraffinized tissue samples were processed and immunohistochemically stained to determine the expression of key EMT markers which included E-cadherin, ß-catenin, Snail1 and vimentin. RESULTS: The majority of cases (n = 65, 72.2%) were diagnosed with periodontitis stage 3 or 4, grade b or c vs 25 (27.8%) subjects with intact healthy periodontium. Discontinuity of epithelium was detected in up to 80.9% of periodontitis cases associated with reduced number of epithelial layers as compared to controls. Immunohistochemical expression of epithelial markers (E-cadherin and ß-catenin) was significantly downregulated in periodontitis patients as compared with controls. Periodontitis cases exhibited significant upregulation of Snail1 expression. Furthermore, cytoplasmic vimentin (66.2%) and nuclear ß-catenin (27.7%) were solely expressed in periodontally diseased tissues compared with control. Epithelial markers, E-cadherin and ß-catenin, were significantly negatively correlated with increasing PPD, while vimentin showed positive correlation with this parameter. CONCLUSION: There were marked downregulation of epithelial molecules and upregulation of mesenchymal markers in gingival tissues derived from periodontitis patients, suggesting expression of the EMT phenotype in the pathological epithelial lining of periodontal pockets.

Pathogenesis of periodontitis - A potential role for epithelial-mesenchymal transition.

Epithelial mesenchymal transition (EMT) is a process comprising cellular and molecular events which result in cells shifting from an epithelial to a mesenchymal phenotype. Periodontitis is a destructive chronic disease of the periodontium initiated in response to a dysbiotic microbiome, and dominated by Gram-negative bacteria in the subgingival niches accompanied by an aberrant immune response in susceptible subjects. Both EMT and periodontitis share common risk factors and drivers, including Gram-negative bacteria, excess inflammatory cytokine production, smoking, oxidative stress and diabetes mellitus. In addition, periodontitis is characterized by down-regulation of key epithelial markers such as E-cadherin together with up-regulation of transcriptional factors and mesenchymal proteins, including Snail1, vimentin and N-cadherin, which also occur in the EMT program. Clinically, these phenotypic changes may be reflected by increases in microulceration of the pocket epithelial lining, granulation tissue formation, and fibrosis. Both in vitro and in vivo data now support the potential involvement of EMT as a pathogenic mechanism in periodontal diseases which may facilitate bacterial invasion into the underlying gingival tissues and propagation of inflammation. This review surveys the available literature and provides evidence linking EMT to periodontitis pathogenesis.

The Use of Osseodensification for Ridge Expansion and Dental Implant Placement in Narrow Alveolar Ridges: A Prospective Observational Clinical Study.

ABSTRACT: The osseodensification (OD) drilling technique was suggested as an alveolar ridge expansion technique, so the aim of this prospective clinical study was to evaluate the amount of bone expansion obtained by the OD drilling technique and its effect on implant stability in patients with narrow alveolar ridges. The width of the alveolar ridge was measured at the crest before and after implant site preparation, whereas the implant stability was measured using Osstell Beacon implant stability quotient (ISQ). The ISQ values were recorded immediately postoperatively and after 16 weeks. Twenty-three patients were included; they received 40 implants. The mean (± standard deviation [SD]) amount of expansion was 1.29 (± 0.41) mm, and the difference between preexpansion and post-expansion bone width was statistically significant ( P < 0.001). The mean (± SD) primary stability was 73.73 (± 2.85) ISQ, whereas the mean (± SD) secondary stability was 74.83 (± 2.73) ISQ, and the difference was statistically significant ( P = 0.043). The implant survival rate was 100%. It can be concluded that using the OD technique in narrow alveolar ridges resulted in bone expansion without dehiscence or fenestration and allowed simultaneous implant placement with high primary and secondary implant stability.

The Effects of Local Alendronate With or Without Recombinant Human Bone Morphogenetic Protein 2 on Dental Implant Stability and Marginal Bone Level: A Randomized Controlled Study.

ABSTRACT: The aim of this study was to evaluate the effects of local application of bisphosphonate gel and recombinant human bone morphogenic protein 2 gel, on titanium dental implant stability and marginal bone level. Twenty-seven patients with upper and lower missing posterior tooth/teeth were included in the study with a total of 71 implants that were used for rehabilitation. The implants were randomly divided into 4 groups: 3 study groups and 1 control. Group1; local application of bisphosphonate gel, group 2; local application of recombinant human bone morphogenic protein 2 gel, group 3; local application of a mixed formula of both gels. The gel application was immediately preimplant insertion, group 4; implant insertion without application of any medication. Using resonance frequency analyzer, implant stability was measured 4 times; primary, 8 weeks (second stage surgery), 12 weeks, and at least 14 weeks post functional loading. The level of the marginal bone around each implant were assessed using cone beam computed tomography. Four implants failed. Generally, there was a similar pattern of changes in implant stability over the study period in all groups and the stability was dependent on the healing time with no significant difference between groups. There was no significant treatment effect regarding marginal bone level differences of study groups against control, although there were significant differences on palatal and mesiodistal surfaces among the study (test) groups.

Comparison of Two Botulinum Toxin Injection Methods for Treatment of Excessive Gingival Display.

BACKGROUND: Hyperfunction of the muscles of the upper lip is considered as the most common cause of excessive gingival display (EGD). The aim of this study was to demonstrate the effectiveness of botulinum toxin (BT) injection as a conservative treatment for EGD due to muscular hyperfunction and to compare the outcome of 2 injection methods. MATERIAL AND METHODS: This study included 40 participants who were randomly assigned into 2 groups of 20 each, The first group received 2.5IU BT injection at 1 point per side (2-points group), while the second group received a total of 5 IU of BT at 2 points per side (4-points group). The outcome variables were the reduction in the central and lateral gingival display expressed as the difference between the pre- and post-injection measurements and the degree of satisfaction of the participants. The follow up visits were at 2- and 12-weeks postinjection. The study variables were statistically analyzed and probability values of <0.05 were considered significant. RESULTS: There was a significant improvement (P < 0.0001) in both groups throughout the follow up period, but the improvement achieved by 4-points group was significantly better than that of the 2-points group with respect to the gingival display and the degree of satisfaction (P < 0.0001). CONCLUSIONS: Botulinum toxin injection represents a safe and less invasive modality for treatment of EGD, the 4-points method results in better outcome in terms of clinical measurements and degree of satisfaction over the 2-points method.

The Effect of Bone Density Measured by Cone Beam Computed Tomography and Implant Dimensions on the Stability of Dental Implants.

ABSTRACT: The aim of this study was to evaluate the effect of bone density value in Hounsfield unit derived from cone beam computed tomography (CBCT), and implant dimensions in relation to implant stability parameters namely the resonance frequency analysis and the insertion torque (IT) value. It included 24 patients who received 42 dental implants (DI). The bone density of the planned implant site was preoperatively measured using cone beam computed tomography. The implant stability was measured using Osstell implant stability quotient (ISQ). The ISQ values were recorded immediately postoperatively and after 16 weeks. The IT value was categorized as 35 N/cm or > 35 N/cm. The mean (standard deviation) primary stability was 79.58 (5.27) ISQ, which was significantly higher than the secondary stability 74.31 (6.34) ISQ ( P < 0.0001). There was a significant moderate positive correlation of bone density with primary stability ( r = 0.4, P = 0.0099) and no correlation with secondary stability ( r = 0.003, P = 0.9867). The bone density of DI with 35 N/cm IT was significantly lower than with > 35 N/cm IT ( P = 0.0390). Better stability was recorded with wider implants. Whereas the length of the DI showed a nonsignificant correlation with primary and secondary stability ( P = 0.7633 and 0.4670, respectively). The DI dimensions showed a nonsignificant correlation with the IT. Cone beam computed tomography may be considered as a reliable method to assess bone density and predict the implant stability. The diameter of DI affected the implant stability favorably, whereas DI length showed no effect.

The Use of Screw Retained Hybrid Arch Bar for Maxillomandibular Fixation in the Treatment of Mandibular Fractures: A Comparative Study.

Introduction: The use of screw-retained hybrid arch bars (HABs) is a relatively recent development in the treatment of mandibular fractures. The purpose of this study is to compare the clinical outcome between HAB and the conventional Erich arch bar (EAB) in the closed treatment of mandibular fractures. Materials and Methods: This study included 18 patients who were treated for mandibular fractures with maxillomandibular fixation (MMF), patients were randomly assigned into a control group (n = 10) in which EAB was used and study group (n = 8) in which HAB was used. The outcome variables were time required for application and removal, gingival inflammation scores, postoperative complications, and incidence of wire-stick injury or gloves perforation. The groups were compared using unpaired t-test, Mann-Whitney test, Chi-square test, or Fisher test. The differences were considered significant at P < 0.05. Results: The mean application time was significantly more in EAB than HAB (61.6 ± 11.4 vs. 41.6 ± 6 min, respectively). The mean time of removal for EAB was significantly less than HAB (11.1 ± 2 vs. 14.2 ± 3 min, respectively). There was nonsignificant difference in gingival inflammation between the groups. No major complications were recorded. Screw loosening and mucosal overgrowth were recorded in 12.5% and 31.2% of the screws, respectively, in HAB group. The incidence of gloves tear in EAB group was 70%. Discussion: HAB can be used as an alternative to EAB for MMF in patients with mandibular fracture, it requires less time for application and provides more safety for the surgeons.

The effect of osseodensification on implant stability and bone density: A prospective observational study.

BACKGROUND: The aims of this study were to evaluate the effect of implant site preparation in low-density bone using osseodensification method in terms of implant stability changes during the osseous healing period and peri-implant bone density using CBCT. MATERIAL AND METHODS: This prospective observational clinical study included 24 patients who received 46 dental implants that were installed in low-density bone using the osseodensification method. CBCT was used to measure the bone density pre- and postoperatively and implant stability was measured using Periotest® immediately after implant insertion and then after 6 weeks and 12 weeks postoperatively. The data were analyzed using paired t-test and the probability value <0.05 was considered statistically significant. RESULTS: Of the 46 implants, 43 were osseointegrated making the early survival of the implants 93.5%. There was a significant increase in bone density postoperatively; 337.6 ±182.9 compared to 265.3 ±173.9 Hounsfield units preoperatively. The primary implant stability was -2.7 ± 2.13 Periotest values (PTV), at the 6th week it decreased significantly (p<0.0001) to become 0.7 (± 4) PTV, and at the 12th week (secondary stability) it increased significantly (p<0.0001) to become -2.1 (± 2.8) PTV. The difference between primary and secondary stability was statistically non-significant (p=0.0814). CONCLUSIONS: Osseodensification resulted in high primary stability and increased peri-implant bone density but it did not prevent the implant stability drop during the first 6 weeks after insertion of implants. Key words:Osseodensification, implant stability, low-density bone.