Comparison of stress distribution around all-on-four implants of different angulations and zygoma implants: a 7-model finite element analysis.

BACKGROUND: In recent years, zygomatic implants and the all-on-four treatment concept have been increasingly preferred for rehabilitation of atrophic maxillae. However, debate continues regarding the optimal configuration and angulation of the implants. The aim of this study was to analyze the biomechanical stress in implants and peri-implant bone in an edentulous maxilla with zygomatic implants and the all-on-four concept, using multiple implant configurations. METHODS: A total of 7 models consisting different combinations of 4-tilted dental implants and zygomatic implants were included in the study. In each model, a total of 200 N perpendicular to the posterior teeth and 50 N with 45° to the lateral tooth were applied. A finite element analysis was performed for determination of stress distribution on implants and peri-implant bone for each model. RESULTS: Higher stress values were observed in both cortical and trabecular bone around the 45°-tilted posterior implants in all-on-four models when compared to zygomatic implants. In cortical bone, the highest stress was established in an all-on-four model including 45°-tilted posterior implant with 4,346 megapascal (MPa), while the lowest stress was determined in the model including anterior dental implant combined with zygomatic implants with 0.817 MPa. In trabecular bone, the highest stress was determined in an all-on-four model including 30°-tilted posterior implant with 0.872 MPa while the lowest stress was observed in quad-zygoma model with 0.119 MPa. Regarding von Mises values, the highest stress among anterior implants was observed in an all-on-four model including 17° buccally tilted anterior implant with 38.141 MPa, while the lowest was in the including anterior dental implant combined with zygomatic implants with 20,446 MPa. Among posterior implants, the highest von Mises value was observed in the all-on-four model including 30°-tilted posterior implant with 97.002 MPa and the lowest stress was in quad zygoma model with 35.802 MPa. CONCLUSIONS: Within the limits of the present study, the use of zygoma implants may provide benefit in decreasing biomechanical stress around both dental and zygoma implants. Regarding the all-on-four concept, a 17° buccal angulation of anterior implants may not cause a significant stress increase while tilting the posterior implant from 30° to 45° may cause an increase in the stress around these implants.

Extraoral approach to a bilateral unfavourable mandibular fracture under local anaesthesia: A case report.

OBJECTIVE: To present a feasible treatment method for fractures of severely atrophic mandibles in high-risk patients undergoing general anaesthesia (GA). CASE REPORT: A 77-year-old man presented with bilateral unfavourable fractures in an atrophic mandible. Pre-anaesthetic consultation revealed that the patient was at high risk for GA due to significant medical comorbid conditions of the patient, such as advanced age, chronic obstructive respiratory disease, diabetes mellitus and atherosclerosis. Thus, a modified treatment, consisting of open reduction and internal fixation using a combination of reconstruction plates and miniplates via an extraoral approach, was planned under local anaesthesia. The patient tolerated the surgical procedure well, without the need for sedation, and uneventful healing was achieved during postoperative period. CONCLUSION: Local anaesthesia may be considered as the anaesthetic technique of choice when managing atrophic mandible fractures to reduce the risk of complications and shorten the time needed for recovery, especially in elders with significant medical comorbidities.

Promising results of surgical management of advanced medication related osteonecrosis of the jaws using adjunctive leukocyte and platelet rich fibrin.

BACKGROUND: Leukocyte- and platelet-rich fibrin (L-PRF) is an autologous matrix scaffold which regulates inflammation by stimulating cytokines and growth factors that are involved in the immune response. L-PRF is suggested as a viable adjunctive method to surgical interventions due to its advantages on tissue healing. This study aims to retrospectively evaluate the adjunctive role of L-PRF in surgically treated medication-related osteonecrosis of the jaws (MRONJ) patients. METHODS: Between January 2012 and December 2020, patients with AAOMS stage II and III MRONJ lesions, who were treated surgically with adjunctive use of L-PRF in the authors' institution were enrolled. Surgical interventions consisted of either marginal resection or sequestrectomy with peripheral ostectomy (SPO) or curettage and L-PRF application. Medical records of these patients were retrospectively reviewed and healing was assessed according to certain parameters including mucosal closure and presence of infection, exposed bone, fistula or radiologic markers of disease progression for a minimum of 12 months. RESULTS: Thirteen patients (7 women and 6 men) with an average age of 72.4 years (± 10.61, range 54-84) were included in the study, nine of whom had AAOMS stage III and four stage II MRONJ. Three patients had a marginal resection, nine patients had sequestrectomy with peripheral ostectomy (SPO) and one patient underwent a curettage procedure. All marginal resection and six SPO patients showed complete healing while four patients, who had SPO or curettage experienced incomplete healing. Mean follow up was 20.1 ± 18.29 months. CONCLUSION: The use of L-PRF may be a favorable adjunctive option in the treatment of MRONJ owing to its favorable effects on tissue repair, ease of application, minimally invasive and cost-effective character and autogenous nature. Trial registration Retrospectively registered.

Evaluation of the Efficacy of EDTA Chelation on Alveolar Bone Healing After Ultrasonic and Conventional Surgery Under Bisphosphonate Medication: A Rat Model.

PURPOSE: The aims of the present study were 1) to investigate the effects of local ethylenediaminetetraacetic acid (EDTA) chelation on alveolar bone healing after systemic administration of bisphosphonates; and 2) to compare the healing in alveolar defects created with ultrasonic and conventional surgery. MATERIALS AND METHODS: A total of 40 male Wistar rats were divided into 4 equal groups of 10 rats each (zoledronate and piezosurgery, zoledronate and bur, placebo and piezosurgery, and placebo and bur). The first 2 groups received weekly intraperitoneal injections of zoledronic acid (0.06 mg/kg), and the second 2 groups received saline solution for 4 weeks. After the last injections, horizontal defects 4 × 2 × 1 mm in size were created on the mandibular alveolar bone using piezosurgery or conventional bur surgery. The zoledronate groups received 10 minutes of local application of EDTA on 1 side and saline solution on the other side. In the placebo groups, only 1 side was treated (one half of the group with the bur and one half of the group with piezosurgery). All the rats were euthanized at 4 postoperative weeks for comparative histomorphometric evaluation of bone healing in the created defects. RESULTS: Bone formation was found to be the greatest in the placebo groups (P < .05). Although a greater amount of bone formation was observed with piezosurgery and EDTA among the bisphosphonate-treated groups, the difference between the zoledronate groups was not statistically significant (P > .05). Similarly, no statistically significant difference was found between the use of piezosurgery and conventional bur surgery within the placebo groups (P > .05). CONCLUSIONS: The findings of the present study revealed improved bone healing with the use of piezosurgery and EDTA chelation, although the difference did not reach statistical significance. Further research should be performed to clearly identify the role of EDTA as a chelating agent and in prevention of medication-related osteonecrosis of the jaws development.

Does the Intake of Selective Serotonin Reuptake Inhibitors Negatively Affect Dental Implant Osseointegration? A Retrospective Study.

The success of osseointegration is influenced by several factors that affect bone metabolism and by certain systemic medications. Selective serotonin reuptake inhibitors (SSRIs) have been previously suggested to be among these medications. This study aims to investigate the association between systemic intake of SSRIs and failure of osseointegration in patients rehabilitated with dental implants. A retrospective cohort study was conducted, including a total of 2055 osseointegrated dental implants in 631 patients (109 implants in 36 SSRI \users and 1946 in 595 nonusers). Predictor and outcome variables were SSRI intake and osseointegration failure, respectively. The data were analyzed with Mann-Whitney test or Fisher exact test accordingly. Both patient-level and implant-level models were implemented to evaluate the effect of SSRI exposure on the success of osseointegration of dental implants. Median duration of follow-up was 21.5 months (range = 4-56 months) for SSRI users and 23 months (range -60 months) for nonusers ( P = .158). Two of 36 SSRI users had 1 failed implant each; thus, the failure rate was 5.6%. Eleven nonusers also had 1 failed implant each; thus, the failure rate was 1.85%. The difference between the 2 groups failed to reach statistical significance at patient and implant levels ( P = .166, P = .149, respectively). The odds of implant failure were 3.123 times greater for SSRI users compared with nonusers. Patients using SSRIs were found to be 3.005 times more likely to experience early implant failure than nonusers. The results of this study suggest that SSRIs may lead to increase in the rate of osseointegration failure, although not reaching statistical significance.

Comparing the effects of low-level laser therapy and gaseous ozone as a preventive measure on medication-related osteonecrosis of the jaws following tooth extraction: a rat model.

OBJECTIVES: Use of numerous medications such as tyrosine kinase inhibitors (sunitinib), monoclonal antibodies (bevacizumab), fusion proteins (aflibercept), mTOR inhibitors (everolimus), radiopharmaceuticals (radium 223), selective estrogen receptor modulators (raloxifene), and immunosuppressants (methotrexate and corticosteroids) has been reported to be a risk factor for development of medication-related osteonecrosis of the jaws till date. This study aimed to evaluate the preventive effect of low-level laser therapy (LLLT) and gaseous ozone on the onset of MRONJ following tooth extraction. MATERIALS AND METHODS: A total of 40 male Wistar rats were randomly allocated into 4 groups of 10 rats each. The groups laser (L), ozone (O), and control (C) received weekly intraperitoneal injections of zoledronic acid (0.06 mg/kg), while group sham (S) received saline solution for 4 weeks. After the 4th injection, all subjects underwent mandibular first molar extraction and adjunctive laser or ozone was applied according to the groups. All the rats were sacrificed at 4 postoperative weeks for comparative histomorphometric evaluation of bone healing in extraction sites. RESULTS: Laser and ozone groups demonstrated significantly higher bone formation compared to control group (p < 0.05), while no significant difference was found between laser and ozone groups (p = 1.00). Furthermore, the greatest bone formation was observed with the sham group (p < 0.05). CONCLUSIONS: Findings of the current study support that adjunctive LLLT and ozone therapy following tooth extraction may help prevent MRONJ and improve bone healing in subjects under zoledronic acid therapy. CLINICAL RELEVANCE: Since the introduction in 2003, great effort has been devoted to developing a certain management protocol for MRONJ. Several publications have appeared in recent years documenting promising results of adjunctive LLLT and ozone application in treatment of MRONJ. However, experimental data are limited on this regard and the present study, for the first time, aimed to evaluate and compare the effects of LLLT and ozone in prevention of MRONJ.

Comparative evaluation of the efficacy of ozone therapy and low level laser therapy on oral mucosal wound healing in rat experimental model.

OBJECTIVE: The aim of the present study was to evaluate and compare the effectiveness of ozone therapy and low-level laser therapy (LLLT) on healing of oral mucosal wounds in rats through histological assessment. METHODS: Thirty male Wistar rats were employed in this study. Following a 5-mm surgical wound created on the buccal mucosa, the rats were randomly distributed into 3 groups of 10: (1) ozone group (treated with topical gaseous ozone), (2) laser group (treated with LLLT), and (3) control group (received no treatment). Following the sacrifice of rats on day 21, samples were taken from rats' buccal mucosa for histological assay and scoring. The data were analyzed using Mann-Whitney test. RESULTS: Ozone and laser groups demonstrated reduced acute inflammation scores compared to control group (p=.01), while no significant differences were observed between the ozone and laser groups (p = 1.00). Similarly, ozone and laser groups showed higher histological tissue repair scores than the control group (p=.00), and no difference was found between ozone and laser groups (p=.76). On the other hand, no significant difference in expression of TNF-α (p=.33) and TGF-ß1 (p=.13) was identified between ozone, laser and control samples. CONCLUSION: The present study demonstrated that both adjunctive ozone therapy and LLLT with a 940 nm diode laser provided significant improvement in parameters of acute inflammation and tissue repair in surgical oral mucosal wounds in rats.

Synchronous occurrence of multiple distinct jaw lesions in Simpson-Golabi-Behmel Syndrome: A case report.

Simpson-Golabi-Behmel Syndrome (SGBS) is an X-linked overgrowth syndrome characterized by pre- and post-natal overgrowth, typical facial appearance and multiple visceral, skeletal, and neurological anomalies. There is only few information in the current literature, on clinical and particularly dentofacial findings due to recent identification of the syndrome and its clinical overlap with other overgrowth syndromes. The aim of this case report is to present dentofacial findings in a 16-year-old boy who had been diagnosed with SGBS. Following comprehensive clinical, radiographic and histopathological examinations, six pathologically distinct lesions including odontogenic keratocyst, ameloblastoma, lateral periodontal cyst, dentigerous cyst and mucous retention cyst in both mandible and maxilla were identified. The clinical report is followed by a discussion aimed to clarify unique features of this condition and how practitioners should consider similar cases.

Proton pump inhibitor intake negatively affects the osseointegration of dental implants: a retrospective study.

OBJECTIVES: This study sought to investigate the association between the systemic intake of proton pump inhibitors (PPI) and the early failure of dental implants. MATERIALS AND METHODS: A retrospective cohort study involving 1,918 dental implants in 592 patients (69 implants in 24 PPI users and 1,849 implants in 568 nonusers, respectively) was conducted. The effect of PPI intake on the osseointegration of dental implants was evaluated using patient- and implant-level models. RESULTS: Among 24 PPI users, two patients experienced implant failure, one of whom had three and the other of whom had one failed implant, respectively. Thus, the rate of failure for this population was 8.3%. Separately, 11 nonusers each experienced one implant failure, and the failure rate for these patients was 1.9%. Fisher's exact test revealed statistically significant differences between PPI users and nonusers at the implant level (P=0.002) but failed to show any significance at the patient level (P=0.094). The odds of implant failure were 4.60 times greater among PPI users versus nonusers. Dental implants that were placed in patients using PPIs were found to be 4.30 times more likely to fail prior to loading. CONCLUSION: The findings of this study suggest that PPI intake may be associated with an increased risk of early dental implant failure.

Recurrent Aphthous Stomatitis as a Result of Zinc Deficiency.

PURPOSE: The purpose of this study is to evaluate the results of patients, with a chief complaint of recurrent aphthous stomatitis (RAS), who were found to have zinc deficiency as the predisposing factor and received appropriate replacement therapy. MATERIALS AND METHODS: A retrospective study was conducted using data from the medical records of patients with a chief complaint of RAS. Patients with potential ulcer-causing conditions were excluded. All patients were intraorally examined to rule out trauma-associated aetiologies. Blood tests were ordered to measure total blood count, serum transferrin, ferritin, zinc, folic acid and vitamin B12 levels. RESULTS: A total of 48 patients, 34 with zinc deficiency and 14 with both zinc and iron deficiencies, were included in this study. Patients received an initial three-monthly replacement treatment and blood tests for the certain deficiencies were repeated at the end of this time interval. Two patients with zinc deficiency reported no relief due to incorrect intake of tablets with milk. Following correct instructions, all patients reached normal serum mineral levels and reported no recurrences. All patients remained asymptomatic and their mineral levels were monitored in every 3 months to detect any abnormalities. Overall mean follow-up for this study was 12.06 months (range: 8-28 months, SD: ± 5.7). CONCLUSION: Zinc deficiency should be considered and investigated as part of the diagnostic process of RAS. A simple blood test may aid in correct diagnosis and complete resolution of this recurring condition rather than constant prescription of certain medicines to suppress the symptoms.

Quantification of volumetric, surface area and linear airway changes after orthognathic surgery: a preliminary study.

PURPOSE: The aim of this study was to conduct a retrospective evaluation of the volumetric, cross-sectional surface area and the linear airway changes in healthy subjects undergoing orthognathic surgery. MATERIALS AND METHODS: A total of 10 patients were included in this study and categorized into two groups. The first group consisted of five patients who underwent maxillary and mandibular advancements (MMA) with genioplasty. The remaining five patients who underwent maxillary advancement with mandibular setback (MAMS) comprised the second group. The changes in airway volume, surface area, and linear values obtained from defined hard and soft tissue parameters were evaluated using preoperative and postoperative cone-beam computed tomography. A paired t-test was used to explore the statistical significance. RESULTS: A statistically significant increase in the airway volume (34.3%) was observed in the MMA group. The changes in the MAMS group were not statistically significant, although an average volumetric decrease of 8.8% was observed. The minimal axial surface area measurements in the MMA group at the levels of the soft palate and the tongue were significantly increased (56.8% and 44.9%, respectively). However, MAMS resulted in no significant changes at these levels (11.2% and 9.1% decrease, respectively). Linear changes showed a statistically significant increase in the airway in the MMA group, whereas the same measurements failed to produce significant changes in the MAMS group. CONCLUSION: As there were no significant changes in the measured parameters, surgeons can have greater confidence that MAMS does not have any negative influence on the airway.

Evaluation of temperature rise following the application of diode and ErCr:Ysgg lasers: an ex vivo study.

PURPOSE: Erbium, chromium: yttrium, scandium, gallium, garnet (ErCr:Ysgg) lasers have been frequently used in oral surgical procedures and are almost seen as alternatives to diode lasers. The aim of this comparative study was to analyze in an animal model the thermal elevation induced by ErCr:Ysgg and diode lasers in soft tissue and bone. MATERIALS AND METHODS: Thirty freshly dissected sheep mandibles containing bone and soft tissue were divided into 120 equal parts. Gallium-aluminum-arsenide (Ga-Al-As) diode laser (λ=940 nm) with 1, 2 and 5 W output powers and ErCr:Ysgg laser (λ=2780 nm) with 2.75, 4.5 and 6 W output powers were used on soft and bone tissues separately for 3 seconds with point application. Mean temperature values before and after application of the lasers were compared in soft tissue and bone. RESULTS: The minimum mean temperature value was observed with 2.75 W ErCr:Ysgg laser while irradiation with 5 W diode laser created the maximum values (p<0.05). CONCLUSION: ErCr:Ysgg laser (λ=2780 nm) with 2.75 W power generates low levels of heat compared to diode lasers and may provide safer surgery in soft and bone tissues without destructive effects of temperature increase.

Comparing the precision of panoramic radiography and cone-beam computed tomography in avoiding anatomical structures critical to dental implant surgery: A retrospective study.

PURPOSE: The aim of this study was to evaluate the correlations between measurements made using panoramic radiography and cone-beam computed tomography (CBCT) based on certain anatomical landmarks of the jaws, with the goal of preventing complications due to inaccurate measurements in the pre-surgical planning phase of dental implant placement. MATERIALS AND METHODS: A total of 56 individuals who underwent panoramic radiography and a CBCT evaluation before dental implant surgery were enrolled in the study. Measurements were performed to identify the shortest vertical distance between the alveolar crest and neighboring anatomical structures, including the maxillary sinus, nasal floor, mandibular canal, and foramen mentale. The differences between the measurements on panoramic radiography and CBCT images were statistically analyzed. RESULTS: Statistically significant differences were observed between the measurements on panoramic radiography and CBCT for all anatomical structures (P<.05). The correlation coefficients (r) between the paired samples obtained from panoramic radiography and CBCT were closely correlated (P<.05), with r values varying from 0.921 and 0.979 for different anatomical regions. CONCLUSION: The results of this study support the idea that panoramic radiography might provide sufficient information on bone height for preoperative implant planning in routine cases or when CBCT is unavailable. However, an additional CBCT evaluation might be helpful in cases where a safety margin cannot be respected due to insufficient bone height.

Langerhans Cell Histiocytosis: A Diagnostic Challenge in the Oral Cavity.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disorder of the reticuloendothelial system with unknown etiology. This report aims to present a case of LCH with diffuse involvement of the oral cavity and to raise awareness of the distinguishing features of this diagnostically challenging entity. CASE REPORT: A 26-year-old male patient presented with complaints of teeth mobility, intense pain, and difficulty in chewing. Intraoral and radiological examinations revealed generalized gingival hyperplasia and severe teeth mobility with widespread alveolar bone loss. Periodontal therapy was performed with no significant improvement. An incisional biopsy revealed Langerhans cells and positive reaction to S-100 and CD1, and the patient was diagnosed with LCH. The patient underwent systemic chemotherapy with vinca alkaloids and corticosteroids. Regression of gingival lesions, as well as significant decrease in mobility of the remaining teeth and severity of pain, was achieved during 12 months of follow-up. CONCLUSION: The rarity and variable system involvement of LCH necessitate a multidisciplinary approach be carried out for accurate diagnosis, effective treatment, and an uneventful follow-up. Awareness of oral manifestations of LCH may aid clinicians greatly in reducing morbidity and mortality associated with this debilitating condition.

Evaluation of the Short-Term Efficacy of Transdermal Ozone Therapy in Turkish Patients with Internal Derangement of the Temporomandibular Joint

Objective: To investigate the efficacy of transdermal high-frequency ozone therapy in the management of pain and pain-related restricted jaw movements in patients with internal derangement of the temporomandibular joint (TMJ). Material and Methods: This retrospective study included 40 patients who had received transdermal high-frequency ozone therapy for the management of disc displacement with reduction of the TMJ. Subjects were treated 3 times for one week with a bio-oxidative high-frequency ozone generator with an intensity of 80% for ten minutes bilaterally. Pain scores and maximal interincisal opening (MIO) values of the patients were evaluated before and after the treatment. Results: An increase in the mean MIO value was achieved following the ozone therapy, however, the difference was not statistically significant (p=0.350). A statistically significant decrease in the mean pain score (48.13 ± 27.75) was observed following the ozone therapy. Conclusion: Transdermal application of high frequency ozone may be a good alternative for management of pain and pain-related restricted jaw movements in patients with internal derangement of the TMJ.

Does Third Molar Surgery Alter Cardiac Parameters? A Retrospective Study

Objective: To investigate perioperative changes in the cardiac parameters of anxiety, which are blood pressure and heart rate, in patients undergoing surgical extraction of third molars. Material and Methods: Patients who reported anxiety before scheduled procedures were monitored for cardiac parameters before, during and after the surgery. The obtained data were analyzed to determine if there is a certain pattern of change within these values in systemically healthy patients. Alterations in selected parameters with regard to duration and difficulty of operation were also studied. IBM SPSS Statistics was used for data analysis. Repeated-measures of analysis of variance (ANOVA), paired samples t-test and Kruskal-Wallis tests were applied and a significance level of 5% was assessed. Results: Difficulty was categorized as minimally, moderately or very difficult in 9, 28 and 3 patients respectively. Mean operation time was 36.18 minutes with a range of 8 to 91 minutes. Operation time showed no variations with different levels of difficulty (p = 0.268). No statistical differences in any of the parameters listed above could be identified. Conclusion: Despite the common belief that dental procedures initiate anxiety, this study reveals that physiological parameters of anxiety show no significant changes over the course of third molar surgery, likewise difficulty and duration of surgery do not cause noteworthy changes in these parameters.