Different Surgical Techniques in the All-on-4 Treatment Concept: Evaluation of the Stress Distribution Created in Implant and Peripheral Bone with Finite Element Analysis.

PURPOSE: To examine the stresses caused by different All-on-4 surgical techniques-conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation-on the implant and the surrounding bone using 3D finite element analysis (FEA). MATERIALS AND METHODS: A 3D bone model of the atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. RESULTS: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. CONCLUSIONS: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications.

Different Surgical Techniques in the All-on-4 Treatment Concept: Evaluation of the Stress Distribution Created in Implant and Peripheral Bone with Finite Element Analysis.

PURPOSE: To examine the stresses caused by different All-on-4 surgical techniques-conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation-on the implant and the surrounding bone using 3D finite element analysis (FEA). MATERIALS AND METHODS: A 3D bone model of the atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. RESULTS: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. CONCLUSIONS: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications.

Comparison of the Efficacy of Botulinum Toxin, Local Anesthesia, and Platelet-Rich Plasma Injections in Patients With Myofascial Trigger Points in the Masseter Muscle.

PURPOSE: Masticatory myofascial trigger points (TrP) are one of the major causes of nondental pain in the orofacial region. Intramuscular injections are considered the first-line treatment for myofascial TrPs. The objectives of this study were to evaluate and compare the effectiveness of local anesthesia (LA), botulinum toxin (BTX), and platelet-rich plasma (PRP) injections for the treatment of myofascial TrPs in the masseter muscle. METHODS: In this retrospective study, the sample was composed of patients with myofascial TrPs in masseter muscle who were treated between 2016 and 2019. Patients were divided into 3 groups according to treatment methods: group I (LA injection), group II (BTX injection), and group III (PRP injection). Primary outcome variable was the average pain level at rest and while chewing, and pressure pain intensity (PPI), Jaw Functional Limitation Scale (JFLS) value, and quality-of-life (measured using Oral Health Impact Profile-14 (OHIP-14)) were secondary outcomes. The outcome variables were assessed at diagnosis, and 1, 3, and 6 months post-treatment. RESULTS: The study consisted of 82 patients (group I, 27; group II, 26; group III, 29). At 1 and 3 months, improvement in all parameters was recorded in all groups. Groups I and II showed superior improvement in all parameters compared with group III at 3 months. Improvements in VAS pain, JFLS, and OHIP-14 values were significantly better in group II than group I at 3 months (P = .009; P = .004; P = .002). At 6 months, significant improvement in VAS pain, JFLS, and OHIP-14 (P = .008; P < .001; P < .01) values was recorded only in group II. CONCLUSIONS: All procedures successfully improved the symptoms of TrPs in the masseter muscle at 1 and 3 months. However, BTX injection seemed superior at the 3-month follow-up and remained effective up to 6 months.