MRONJ of the Mandible-From Decortication to a Complex Jaw Reconstruction Using a CAD/CAM-Guided Bilateral Scapula Flap.

Medication-related osteonecrosis of the jaw (MRONJ) has been an integral part of the maxillofacial patient population for some time. The therapeutic concept ranges from conservative approaches over less extended decortications to major jaw resections, which can result in a considerable loss of quality of life. Based on three case reports, this paper presents the long-term history of patients with MRONJ of the mandible, whose disease ultimately resulted in partial or total mandibular resection and subsequent multisegmental reconstruction using a microvascular anastomosed bone flap. Furthermore, a suitable alternative for complex mandibular reconstruction is demonstrated when using a free fibula flap is not possible. The options are limited, particularly when multisegmental restoration of mandibular continuity is required. One case presents a mandible reconstruction using a CAD/CAM-guided bilateral scapular free flap (CAD/CAM = Computer-Aided Design and Manufacturing), which has not been described for this purpose before. Due to the complexity, computer-assisted surgery and patient-specific implants seem reasonable, which is why a special focus was applied to this topic.

[Principals of Osteosynthesis in the Facial Skeleton]. / Prinzipien der Osteosynthese im Bereich des Gesichtsschädels.

There were no major alterations of the basic principals of osteosynthesis in the facial skeleton over the past years. Nevertheless, by the reason of further developments of the osteosynthesis systems and Instruments as well as by the implementation of computer-assisted surgery including the use of anatomical or customized Implants crucial advancements of the treatment can be seen.

Dose Reduction in Dental CT: A Phantom Study With Special Focus on Tin Filter Technique.

OBJECTIVE. The purpose of this study was to determine in a phantom the dose exposure of different dental 3D sectional imaging methods (CT and cone-beam CT [CBCT]) and different CT protocols. The aim was to establish optimal protocols with the lowest possible dose and diagnostically high image quality with special consideration given to tin prefiltration. MATERIALS AND METHODS. Dose was determined with thermoluminescence detectors at 20 different measuring points on an anthropomorphic phantom. Eight different CT protocols with and without tin filtering were compared with iterative reconstruction methods and a standard CBCT protocol. Objective and subjective image evaluations and a figure-of-merit analysis of the image data were performed by radiologists and maxillofacial surgeons. RESULTS. The determined dose-length products of the nine examinations were 5.0-111.9 mGy · cm with a calculated effective whole body dose of 20.7-505.9 µSv. Cone-beam CT was in the upper midfield with an effective dose of 229.3 µSv. On the basis of dose, objective image quality, and clinical evaluation results, tin filter protocols performed best. Protocols with higher doses were significantly less useful in the figure of merit comparison but because of their detailed bony representation are particularly necessary to answer certain questions about trauma and tumors. CONCLUSION. The use of tin filtering can reduce dose in dental CT examinations, compared with standard low-dose examinations, while maintaining good image quality. The dose performance is significantly inferior even to that of a cone-beam CT examination. High-dose protocols are necessary only for certain questions.

Immunotherapy of B-cell non-Hodgkin lymphoma by targeting the chemokine receptor CXCR5 in a preclinical mouse model.

Bispecific antibodies are promising agents for immunotherapy. Here, we describe a quadroma-based trifunctional bispecific antibody binding the chemokine receptor CXCR5 and the T-cell antigen CD3 that efficiently prevents tumor growth in a mouse B-cell lymphoma model. CXCR5 regulates the tissue homeostasis of mature B cells and is highly expressed on B-cell non-Hodgkin and lymphocyte-predominant Hodgkin lymphoma, as well as on a subset of CD4(+) T cells known as follicular T-helper cells. In vitro, the bispecific CXCR5::CD3 antibody efficiently recruited effector T cells to CXCR5 expressing B cells and induced a co-stimulation-independent activation of CD8(+) and CD4(+) T cells as demonstrated by the de novo expression of CD25 and CD69, and secretion of the cytokines IFN-γ, TNF-α, IL-6 and IL-10 by peripheral blood mononuclear cells. Notably, at low antibody concentrations, CXCR5::CD3 displayed a significantly higher cytotoxic activity against autologous B cells than its parental antibodies or rituximab. In vivo imaging revealed that CXCR5::CD3 and its parental CXCR5 antibody efficiently prevent tumor growth in a xenograft model of B-cell lymphoma in mice and prolong their survival. Taken together, our results identify CXCR5 as a promising target for antibody-based therapies in the treatment of B-cell malignancies.

Intraoperative imaging in orbital and midface reconstruction.

The orbit is very often affected by injuries which can leave patients not only with esthetic deficits, but also with functional impairments if reconstruction is inadequate. Computer-assisted surgery helps to achieve predictable outcomes in reconstruction. Today, intraoperative three-dimensional (3D) imaging is an important element in the workflow of computer-assisted orbital surgery. Clinical and radiological diagnosis by means of computed tomography is followed by preoperative computer-assisted planning to define and simulate the desired outcome of reconstruction. In difficult cases, intraoperative navigation helps in the implementation of procedure plans at the site of surgery. Intraoperative 3D imaging then allows an intraoperative final control to be made and the outcome of the surgery to be validated. Today, this is preferably done using 3D C-arm devices based on cone beam computed tomography. They help to avoid malpositioning of bone fragments and/or inserted implants assuring the quality of complex operations and reducing the number of secondary interventions necessary.

Impact of antithrombotic therapy on acute and delayed intracranial haemorrhage and evaluation of the need of short-term hospitalisation based on CT findings after mild traumatic brain injury: experience from an oral and maxillofacial surgery unit.

PURPOSE: The primary aim was to compare the prevalence of acute and delayed intracranial haemorrhage (ICH) following mild traumatic brain injury (mTBI) in patients on antithrombotic medication referred to a clinic for oral and plastic maxillofacial surgery. The secondary aim was to evaluate the need for short-term hospitalisation based on initial radiological and clinical findings. METHODS: This was an observational retrospective single-centre study of all patients on antithrombotic medication who were admitted to our department of oral and plastic maxillofacial surgery with mTBI over a 5 year period. Demographic and anamnesis data, injury characteristics, antithrombotic medication, radiological findings, treatment, and outcome were analysed. Patients were divided into the following four groups based on their antithrombotic medication: (1) single antiplatelet users, (2) vitamin K antagonist users, (3) direct oral anticoagulant users, and (4) double antithrombotic users. All patients underwent an emergency cranial CT (CT0) at admission. Based on clinical and radiological evaluation, different treatment protocols were applied. Patients with positive CT0 findings and patients with secondary neurological deterioration received a control CT (CT1) before discharge. Acute and delayed ICH and patient's outcome during hospitalisation were evaluated using descriptive statistical analysis. RESULTS: A total of 696 patients (mean age, 71.6 years) on antithrombotic medication who presented at our department with mTBI were included in the analysis. Most injuries were caused by a ground-level fall (76.9%). Thirty-six patients (5.1%) developed an acute traumatic ICH, and 47 intracerebral lesions were detected by radiology-most of these in patients taking acetylsalicylic acid. No association was detected between ICH and antithrombotic medication (p = 0.4353). In total, 258 (37.1%) patients were admitted for 48 h in-hospital observation. The prevalence of delayed ICH was 0.1%, and the mortality rate was 0.1%. Multivariable analysis identified a Glasgow Coma Scale (GCS) of < 15, loss of consciousness, amnesia, headache, dizziness, and nausea as clinical characteristics significantly associated with an increased risk of acute ICH, whereas age, sex, and trauma mechanism were not associated with ICH prevalence. Of the 39 patients who underwent a control CT1, most had a decreasing or at least constant intracranial lesion; in three patients, intracranial bleeding increased but was not clinically relevant. CONCLUSION: According to our experience, antithrombotic therapy does not increase the rate of ICH after mTBI. A GCS of < 15, loss of consciousness, amnesia, headache, dizziness, and nausea are indicators of higher ICH risk. A second CT scan is more effective in patients with secondary neurological deterioration. Initial CT findings were not clinically relevant and should not indicate in-hospital observation.

Porcine-derived Acellular Dermal Matrix for Temporary Soft Tissue Coverage in Locally Advanced Angiosarcoma of the Face - A Soft Tissue Odyssey?

BACKGROUND/AIM: Angiosarcomas of the face are rare but present significant treatment challenges due to their origin in the supportive tissues of blood or lymphatic vessels. Achieving optimal balance between oncological efficacy and aesthetic outcomes requires a multidisciplinary approach, particularly in cases where radical R0 resection is necessary. Delays often occur, especially during histopathological examinations, which can complicate primary plastic reconstruction before definitive pathological findings. CASE REPORT: To address this issue, we present a case with the use of porcine-derived acellular dermal matrix for temporary soft tissue coverage as a viable option in a case of angiosarcoma of the face. This is particularly useful in situations where frozen sections risk the loss of critical anatomical structures and intraoperative diagnosis is not feasible. This approach allowed for satisfactory wound coverage and granulation during diagnostic phases, paving the way for oncologically manageable situations and functional rehabilitation. CONCLUSION: Temporary soft tissue coverage with porcine-derived acellular dermal matrix is a valuable option in tumor surgery of rare and complex situations.

Fibula Grafting for Oromandibular Reconstruction and its Effect on Patient Quality of Life - A Scoping Review.

Fibula osteoseptocutaneous flap has been widely used for oncologic bony reconstruction of both the mandible and maxilla. Early and late morbidities of the donor side such as leg weakness, ankle instability, limited ankle mobility, tibial stress fractures or incision area pain are well documented; however, there is a lack of information about the effects of fibula grafting on patient quality of life. To address this issue, a scoping literature search in the PubMed electronic database was performed to identify all relevant studies and reviews in the period between 2010 and 2022. The potential discomforts after free fibula grafting and their impact on different domains of everyday living were identified and evaluated. The present literature review indicates that donor site morbidity can negatively impact patients' quality of life, albeit generally classified as minor. However, the functional and aesthetic benefits of oromandibular reconstruction clearly outweigh the associated sequelae. Nevertheless, the authors of this review highlight the importance of a comprehensive clinical evaluation of the donor site besides the recipient site during follow-up examinations. This would help to subjectively evaluate the functional and esthetical limitations of a patient's site and promptly detect morbidities that could lead to long-term complications.

Ibuprofen Reduces 5-Year Overall Survival of Head and Neck Cancer Patients With Immunotherapy - A Retrospective Case-controlled Real-World Data Analysis of 10,000 Patients.

BACKGROUND/AIM: Resistance to immunotherapy can be explained by an abnormal microbiome of the gut. In Europe in particular, the use of ibuprofen, with or without proton-pump inhibitors to protect the gastric mucosa, is widespread. This study aimed to investigate the impact of ibuprofen use on the effectiveness of immunotherapy in patients with head and neck carcinoma. PATIENTS AND METHODS: Data from patients with head and neck carcinoma (ICD-10-Codes: C00-C14) receiving pembrolizumab, from the TriNetX network, were analyzed. Two groups were formed for the analyses: Cohort I received ibuprofen at least once within 6 months before and after immunotherapy, whereas patients in cohort II received ibuprofen with proton-pump inhibitors or no ibuprofen at all. Cohorts I and II were matched 1:1 with respect to age, sex, lymph node metastases, nicotine dependence, alcohol dependence, and body mass index (BMI). The primary outcome was death and a Kaplan-Meier analysis was performed, and the risk ratio (RR), odds ratio (OR), and hazard ratio (HR) were calculated. RESULTS: The analysis showed that 823 patients with ibuprofen and 724 patients without ibuprofen died within 5 years, showing a significant risk difference of 5.3% (p=0.001). The RR was 1.137 [95% confidence interval (CI)=1.053-1.227], OR was 1.245 (95% CI=1.093-1.418), and HR was 1.202 (95%CI=1.088-1.329). CONCLUSION: Ibuprofen significantly decreases the drug effectiveness of immunotherapy and may be related to changes in the human microbiome. However, further prospective, randomized, and double-blind studies are needed to validate our data and to adequately address confounders.

Evaluation of Different Patterns of Zygomaticoorbital Complex Fractures.

Study Design: Very few studies exist regarding the fracture pattern variability of the zygomaticoorbital (ZMO) complex. The retrospective evaluation of a large series of surgically treated unilateral ZMO fractures would in certain circumstances help intraoperative predictability and define sensitive indicators for open reduction and internal fixation. Objective: The aim of this study was to investigate the different fracture patterns after ZMO complex injury regarding the 5 anatomic sutures of the zygoma as well as the concomitance of the paranasal buttress and maxillary sinus wall fracture. Methods: The medical records of all patients with unilateral ZMO fractures who underwent surgical intervention in a single trauma center department between April 2015 and June 2020 were retrospectively reviewed. Demographic and anamnesis data, radiologic findings, and surgical reports were evaluated. According to the preoperative radiologic evaluation, ZMO fractures were classified as unisutural, bisutural, trisutural, tetrasutural, and complete based on the number of zygomatic sutures. The prevalence of various fracture patterns was analyzed. The impact of patient's age and trauma etiology on the fracture pattern was evaluated using descriptive statistical analysis. Results: The study included 492 patients with unilateral ZMO fractures, with a mean age of 49.93 years (SD = 20.66) and a male:female ratio of 2.23:1. The most affected age group was 19-44 years (41.67%) and tripping falls were the most common etiology (27.24%). Trisutural (57.32%) and unisutural fractures (23.17%) were the most common, followed by tetrasutural (8.94%), bisutural (8.54%), and complete fractures (2.03%). A trisutural fracture involving the zygomaticomaxillary suture, the infraorbital rim, and the zygomaticosphenoidal suture was the most common fracture pattern (52.03%). Most fractures were observed in the zygomaticosphenoidal suture (86.99%), followed by the infraorbital rim (74.59%) and the zygomaticomaxillary suture (68.29%). Fractures of the maxillary sinus wall and the paranasal buttress co-existed in 9.55% and 31.30% of all cases, respectively. No correlation was detected between age and fracture pattern (P = .4111). Tripping falls and bicycle accidents significantly influenced the fracture pattern (P < .0001). Conclusions: According to the results, knowledge of the fracture pattern variability of the ZMO complex could in certain circumstances designate CT or CBCT as mandatory before operating on ZMO fractures. Consequently, unnecessary incisions could be avoided. The high concomitance of paranasal buttress fracture also suggests its intraoperative surgical exploration. Further studies should correlate the clinical findings with indication for surgery and postoperative outcome for the different fracture patterns described.

Sex-specific Real-World 5-year Overall Survival Rates for (Radio)chemotherapy, Targeted Therapy, and Combinations in Patients With Head and Neck Cancer.

BACKGROUND/AIM: Sex-specific medicine, an emerging field in healthcare, has gained significant recognition and importance in recent years. To the best of our knowledge, there are currently no valid data on the influence of sex on 5-year overall survival of patients with head and neck cancer undergoing (radio)chemotherapy, targeted therapy, and combination treatments, using Real-World Data. We hypothesize that sex has a significant impact on 5-year overall survival across different therapy regimens for head and neck cancer. PATIENTS AND METHODS: Data from head and neck cancer patients treated with different regimens from the TriNetX network were analyzed. Two groups were formed: Cohort I (female) and cohort II (male), which were matched 1:1 with respect to certain confounders. After defining the primary outcome as "death", a Kaplan-Meier analysis was performed, and the risk ratio (RR), odds ratio (OR) and hazard ratio (HR) were calculated. RESULTS: A total of 16,529 patients with OSCC were analyzed. This retrospective case-matched analysis found a tendency for female patients to have a greater 5-year overall survival probability than male patients with respect to the various therapeutic regimens for OSCC. CONCLUSION: There is an urgent need for more personalized medicine in patients with head and neck cancer due to the limited data available. It is still questionable whether therapies are equally effective in men and women, although, according to the guidelines, the treatments are mostly the same for both sexes.

Evaluation of Five-year Overall Survival Rates Among 18,331 Head and Neck Cancer Patients Exposed to Different Targeted Therapies Through Real-world Data in a Case-controlled Study.

BACKGROUND/AIM: Targeted therapy is an important and fast developing aspect of modern tumor therapy including therapy of head and neck cancer (HNC). Surgically treated patients often experience significant limitations to their ability to swallow, speak, or mimic expressions. In cases of recurrent tumors or palliative situations, targeted therapies such as immune checkpoint inhibitors (ICI) are frequently employed. This study compared different targeted therapies focusing on survival probability. PATIENTS AND METHODS: Data from patients with head and neck cancer treated with different therapy regimens from the TriNetX network were analyzed. Two groups were formed: Cohort I received one targeted therapy, whereas patients in cohort II received a different targeted therapy. Cohorts I and II were matched 1:1 with respect to certain confounders. After defining the primary outcome as "death", a Kaplan-Meier analysis was performed, and the risk ratio (RR), odds ratio (OR), and hazard ratio (HR) were calculated. RESULTS: A total of 18,331 patients with HNC treated with targeted therapy were analyzed. Patients treated with VEGF inhibitors had a significantly longer overall survival than patients treated with c-MET or EGFR inhibitors. Patients treated with PI3K inhibitors showed a significantly reduced survival probability compared to those treated with c-MET, mTOR, and RET inhibitors. CONCLUSION: EGFR inhibitors are one of the most frequently used targeted therapies in HNC. However, in the present analysis, a survival advantage of patients treated with c-MET inhibitors or VEGF inhibitors was observed compared to those treated with EGFR inhibitors.

Influence of analytical procedures on miRNA expression analyses in saliva samples.

Aim of this study was to demonstrate the influence of different analytical procedures and techniques on the resulting miRNA expression profile in healthy control subjects and tumor patients using the oral squamous cell carcinoma (OSCC) model and to demonstrate the technical and biological reproducibility. Body fluids such as saliva are suitable for non-invasive miRNA analysis because ubiquitously circulating miRNA can be found in them. It was technically possible to distinguish between healthy and diseased samples based on the miRNA expression profile found. Regardless of the methodology used, good technical reproducibility of the results seems to be achievable. On the other hand, biological reproducibility was inadequate, which is why prompt sampling and sequencing is recommended. The data indicate that malignant lesions can be detected using miRNA signatures extracted from saliva. This could stimulate further research to establish standardized protocols and kits for sample collection, miRNA extraction, sequencing and interpretation of results.

Intraoperative imaging with a 3D C-arm system after zygomatico-orbital complex fracture reduction.

PURPOSE: During the repair of zygomatico-orbital complex (ZMC) fractures, the lateral orbital wall and/or the orbital floor is often reduced by merely reducing the zygoma. Intraoperative 3D imaging can help surgeons decide whether the orbit must be reconstructed as well. The purpose of this study was therefore to assess the usefulness of intraoperative 3D C-arm imaging in evaluating the adequacy of fracture reduction. METHODS: A total of 21 patients with unilateral ZMC fractures were enrolled in this retrospective study. Four fractures were treated with a closed reduction technique. Seventeen fractures were repaired with open reduction and internal fixation of the zygomaticomaxillary buttress area. Intraoperative 3D C-arm imaging was performed in all cases. All patients underwent postoperative computed tomography and a clinical examination no earlier than 5 months after the procedure. RESULTS: After reduction of the ZMC fractures, intraoperative 3D scans showed inadequate repair of the orbital floor in 2 patients and inadequate repair of the lateral orbit in 1 patient. Zygoma and zygomatic arch fracture reduction had to be corrected in 1 further case. The other 17 patients did not need an additional procedure. Postoperative imaging showed that no patient required a secondary operation. No postoperative diplopia or enophthalmos developed in any patient. CONCLUSIONS: Intraoperative 3D C-arm imaging appears to be an effective tool for evaluating ZMC fracture reduction. It helps avoid additional procedures and thus helps reduce morbidity. In addition, there appears to be no need for postoperative imaging.

First-Hand Experience and Result with New Robot-Assisted Laser LeFort-I Osteotomy in Orthognathic Surgery: A Case Report.

BACKGROUND: We report the world's first developer-independent experience with robot-assisted laser Le Fort I osteotomy (LLFO) and drill-hole marking in orthognathic surgery. To overcome the geometric limitations of conventional rotating and piezosurgical instruments for performing osteotomies, we used the stand-alone robot-assisted laser system developed by Advanced Osteotomy Tools. The aim here was to evaluate the precision of this novel procedure in comparison to the standard procedure used in our clinic using a computer-aided design/computer-aided manufacturing (CAD/CAM) cutting guide and patient-specific implant. METHODS: A linear Le-Fort-I osteotomy was digitally planned and transferred to the robot. The linear portion of the Le-Fort I osteotomy was performed autonomously by the robot under direct visual control. Accuracy was analyzed by superimposing preoperative and postoperative computed tomography images, and verified intraoperatively using prefabricated patient-specific implant. RESULTS: The robot performed the linear osteotomy without any technical or safety issues. There was a maximum difference of 1.5 mm on average between the planned and the performed osteotomy. In the robot-assisted intraoperative drillhole marking of the maxilla, which was performed for the first time worldwide, were no measurable deviations between planning and actual positioning. CONCLUSION: Robotic-assisted orthognathic surgery could be a useful adjunct to conventional drills, burrs, and piezosurgical instruments for performing osteotomies. However, the time required for the actual osteotomy as well as isolated minor design aspects of the Dynamic Reference Frame (DRF), among other things, still need to be improved. Still further studies for final evaluation of safety and accuracy are also needed.

BRAF inhibitors in BRAF V600E-mutated ameloblastoma: systematic review of rare cases in the literature.

BACKGROUND: Ameloblastoma in 66% of the cases harbor a somatic mutation of the "mitogen-activated protein kinase" signaling pathway (BRAF V600E). In V600E mutations, BRAF is in the permanent "on" state and relays the growth-promoting signals independently of the EGFR pathway. Therefore, mutant BRAF represents a target for handful of new drugs. METHODS: We conducted a literature search, with the search terms "Vemurafenib, Dabrafenib, Ameloblastoma, and BRAF." These included seven case reports with nine patients who underwent monotherapy with Dabrafenib or Vemurafenib or combination therapy with Dabrafenib and Trametinib. RESULTS: The patients age ranges from 10 years up to 86 years. The distribution of women and men is 4:5. Patients with an initial diagnosis of ameloblastoma, as well as recurrences or metastasized ameloblastoma were treated. Indications cover neoadjuvant therapy up to the use in metastasized patients in an irresectable state. Results ranging from "only" tumor size reduction to restitutio ad integrum. CONCLUSION: We see the use of BRAF Inhibitors to reduce tumor size with consecutive surgical treatment as a reasonable option for therapy. However, we are aware that at present the data are based only on case reports with the longest follow-up of just 38 months. We encourage further clinical trials in the use of BRAF Inhibitors for selecting ameloblastoma patients in a multi-center setting.

Accuracy Analysis of Computer-Assisted and Guided Dental Implantology by Comparing 3D Planning Data and Actual Implant Placement in a Mandibular Training Model: A Monocentric Comparison between Dental Students and Trained Implantologists.

The aim of this study was to investigate how precisely implantation can be realized by participants on a phantom head according to preliminary planning. Of particular interest here was the influence of participants' previous knowledge and surgical experience on the precision of the implant placement. The placed implants were scanned using an intraoral scanner, saved as STL files, and superimposed with the 3D-planned implant placement. Deviations from the planning were indicated in millimeters and degrees. We were able to show that on average, the deviations from computer-assisted 3D planning were less than 1 mm for implantologists, and the students also did not deviate more than 1.78 mm on average from 3D planning. This study shows that guided implantology provides predictable and reproducible results in dental implantology. Incorrect positioning, injuries to anatomical structures, and implant positions that cannot be prosthetically restored can thus be avoided.

Comparison of Laser-Sintered and Milled Patient-Specific Reconstruction Plates for Complications and Outcomes in Mandibular Defects-Comparative Analysis of a Single-Center Cohort.

CAD/CAM-manufactured implants are increasingly becoming the standard in current therapy. The question of whether the manufacturing-related rougher surface of selective laser fusion plates compared to milled, smoother reconstruction plates leads to increased postoperative complications such as infections, plate exposure, and fistulas has not yet been determined. A retrospective analysis of 98 patients who underwent surgical treatment with either a selective laser fusion plate or a milled reconstruction plate at our hospital was performed. The only significant predictors of the revision risk were the operation time and use of antiresorptive medication. In the KLS Martin® group, the risk of revision decreased by approximately 20% for each additional hour by which the operation time was increased (OR = 0.81). In the Depuy Synthes® group, the risk of revision increased by approximately 11% with each additional hour of operative time (OR = 0.81 × 1.37 = 1.11). Both groups showed no significant differences in the number of necessary revision surgeries as well as inpatient complications. In summary, we can say that the assumption that additively manufactured reconstruction plates have a rougher surface due to selective laser melting and thus make plaque accumulation and revisions more likely has not been confirmed. Overall, it seems imperative to select further studies regarding the clinical outcome depending on the selected plate system.

Dental Root Injuries Caused by Osteosynthesis Screws in Orthognathic Surgery-Comparison of Conventional Osteosynthesis and Osteosynthesis by CAD/CAM Drill Guides and Patient-Specific Implants.

BACKGROUND/AIM: The primary aim was to evaluate the prevalence and localisation of dental injuries caused by osteosynthesis screws during orthognathic surgery, comparing two different CAD/CAM planning/surgical approaches through retrospective evaluation of post-operative computed tomography. MATERIAL AND METHODS: This study considered all patients who underwent orthognathic surgery from 2010-2019. The examination for dental root injuries between conventional osteosynthesis (Maxilla conventional cohort) and osteosynthesis with patient-specific implant (Maxilla PSI cohort) was performed by evaluating the post-operative CT scans. RESULTS: A total of 126 patients were included in the study. Among the 61 patients of the Maxilla conventional cohort, 10 dental root injuries in 8 patients (13.1%) were detected in the post-operative CT scan, representing 1.5% (n = 10/651) of the osteosynthesis screws inserted in proximity of the alveolar crest. No dental injury occurred following osteosynthesis in the 65 patients of the Maxillary PSI cohort (n = 0/773 screws) (p < 0.001). During a mean follow-up period of 13 months after primary surgery, none of the injured teeth showed evidence of periapical alterations and no endodontic treatments were necessary. CONCLUSIONS: Maxillary positioning using CAD/CAM-fabricated drill/osteotomy guide and osteosynthesis with PSI can significantly reduce the risk for dental injury compared to the conventional procedure. However, the clinical significance of the detected dental injuries was rather minor.

Prosthetically guided oral implant surgery. A retrospective cohort study evaluating the 5-year surgical outcome.

Purpose: This study primarily evaluated the 5-year implant survival and success rate of prosthetically guided inserted implants. The secondary aim was to evaluate the impact of clinical variables on the development of mucositis, peri-implant bone resorption, peri-implantitis, as well as early and late implant failure. Materials and methods: An observational retrospective single-centre study was conducted on patients who were treated with dental implants in the department of oral and plastic maxillofacial surgery of the military hospital of Ulm University between 2008 and 2010. In all patients, computer-assisted 3D planning after wax-up of the prosthetic restoration and template-guided surgery with titanium implants were performed. Bone augmentation procedures were performed primarily if needed. Intraoperative and postoperative complications as well as technical and mechanical complications after prosthesis loading were evaluated. In a 5-year clinical and radiological follow-up, implant success and implant survival were assessed using descriptive statistics. A multivariable regression analysis evaluated the potential impact of augmentation procedures, wound healing complications, smoking, history of periodontitis, and preoperative API (approximal plaque index) and SBI (sulcus bleeding index) values on peri-implant mucositis, peri-implant bone resorption, peri-implantitis, as well as early and late implant failure. Results: In this study, 466 implants in 283 patients were considered for inclusion, and sufficient data were obtained for analysis from 368 (78.9%) implants in 229 (80.9%) patients. An overall implant survival rate of 98.1% (n=361/368) at the 5-year follow-up was revealed. According to the success criteria of the study, the 5-year success rate was 97.04% (n=263/271). An early implant failure of 1.07% (n=5/466) was recorded. 48.2% of the implants were affected by peri-implant mucositis (n=122/253), while peri-implant bone resorption was detected in 21.7% of the radiologically examined implants (n=59/271). Fifteen cases of peri-implantitis (5.5%) were detected. Peri-implant bone resorption increased significantly after bone augmentation procedures (p=0.028). Wound healing complications after implantation significantly increased the prevalence of late implant failure in the maxilla (p<0.001). Peri-implant bone resorption and peri-implantitis were significantly more prevalent in smokers (p=0.022/p=0.043). Implants in patients with API>20% presented significantly higher rates of peri-implant mucositis (p=0.042). Wound healing complications after augmentation, history of periodontitis, and SBI>20% had no significant impact on the study parameters. Conclusions: The study confirms the reliability of prosthetically guided implant surgery, showing a high implant survival and success rate in a 5-year follow-up. Intraoperative complications and technical or mechanical complications after prosthesis loading remain within acceptable clinical limits. The rate of peri-implant mucositis, peri-implant bone resorption, and peri-implantitis was within the current literature range. Optimizing periodontal health and reducing smoking would improve the outcome. Further studies need to clarify the clinical indications and investigate the long-term surgical outcome of this treatment concept.