Bone grafting the mandible

Injury Risk Estimation in Mandible-Related Surgical Procedures: A CBCT Study Based on Vital Interforaminal Anatomical Structures

The mandibular interforaminal region has been considered safe for surgical procedures; nevertheless, the risk of injury to neurovascular structures, such as the mental foramen (MF) and its related structures (anterior loop [AL] and lingual foramina [LF]) should not be overlooked. The study aimed to evaluate the relative risk of injury to these structures during surgical procedures in the anterior region of the mandible based on cone-beam computed tomography (CBCT) scans. A retrospective cross-sectional and observational study was performed on 250 CBCTs from adults (18-69 years) with dentate jaws. Linear measurements of the MF, AL, and LF were evaluated to estimate the risk of injury to these structures during chin-related surgical procedures. The most frequent distance between the base of the mandible (BM) and MF was 8 mm (30.2%). In addition, 20.4% of the CTs had 6 mm from the vestibular cortical bone to the LF. The commonly found measurement from LF to the apex of the nearest tooth was 7 mm (24.0%); 64.2% of the CTs showed a 2-mm distance between the most distal point of the dental implant site to the most anterior point of the AL. Safety distances for genioplasty techniques (MF to mandible base > 6 mm, 96.6% [CI 95%, 95.0%-98.2%]) were observed. Considering the 5-mm cut-off point between the lower limit of a hypothetical bone graft and the chin, 65.4% (CI 95%, 58.9%-71.9%) of CTs were within this distance. Regarding the safety margin of 8 mm, 85.6% (CI 95%, 80.8%-90.4%) were up to this value. This study found safety margins for genioplasty and chin bone grafting surgical techniques that adopt a 5-mm cut-off point. Further similar studies assessing other surgical methods and employing larger samples from different geographical origins may contribute to this field of investigation.

Evaluating risk factors and complications in mandibular ramus block grafting: a retrospective cohort study

OBJECTIVES

This retrospective cohort study aimed to identify the complications and risk factors associated with alveolar grafting using autologous mandibular ramus grafts, guided by the research question: What are the complications encountered in patients undergoing alveolar bone grafting using autologous mandibular ramus block and what are the risk factors associated with the development of these complications?

MATERIALS AND METHODS

The study included 70 patients who underwent alveolar crest augmentation with autologous mandibular ramus block grafting. Intraoperative, early postoperative, and late postoperative complications were analyzed, as were various risk factors.

RESULTS

The results showed that the majority of patients had successful outcomes with minimal complications. Sex was found to significantly influence the visibility of the inferior alveolar nerve (IAN). Early postoperative complications were associated with IAN visibility and the use of a single screw for graft fixation. Late postoperative complications were significantly associated with the presence of infection.

CONCLUSION

The findings emphasize the importance of careful surgical techniques, infection prevention, and patient selection in minimizing complications.

CLINICAL RELEVANCE

This article may contribute to clinicians' and so patients' understanding of potential risk factors associated with over all ramus block grafting procedure. Based on this information, clinicians can also improve their ability to manage risk factors and associated complications and compare ramus block grafting with other alternatives to determine the best treatment approach for that particular patient.

A randomized controlled trial comparing conventional and piezosurgery methods in mandibular bone block harvesting from the retromolar region

BACKGROUND

Although piezosurgery is now commonly used for various applications in maxillofacial surgery, its advantages over conventional rotary instruments in terms of postoperative edema, ecchymosis, postoperative morbidity, and prolonged osteotomy time have been questioned.

MATERIALS AND METHODS

This study aimed to compare the efficiency, postoperative morbidity, and complication rates of piezosurgery and conventional methods in harvesting autogenous ramus grafts. In this randomized controlled trial, 21 patients (32 sides) underwent autogenous graft harvesting from the ramus area, with 16 sites treated using piezosurgery and 16 using the conventional method. The primary outcomes measured were osteotomy time, total operation time, and postoperative morbidity. Complication rates were also evaluated.

RESULTS

The final analysis encompassed 19 patients, accounting for a total of 30 donor sites, following the exclusion of two patients who were unable to attend the scheduled follow-up visits. A total of 19 patients (30 donor sites) were included in the final analysis. No statistically significant difference was found in the mean osteotomy time between the piezosurgery group (mean: 10.35, SD: 2.74 min) and the conventional group (mean: 8.74, SD: 2.74 min) (95% CI: -3.67 to 0.442, p = 0.119). The total operation time, postoperative pain, and swelling were not significantly different between the two groups (p > 0.05). The complication rates, including wound dehiscence and inferior alveolar nerve exposure, were similar in both groups.

CONCLUSIONS

Piezosurgery can be safely used for harvesting autogenous ramus grafts and does not increase osteotomy or total operation time compared to the conventional method. The postoperative morbidity and complication rates were also similar, indicating that both techniques can be effectively employed in clinical practice.

CLINICAL TRIAL REGISTRATION

The protocol was registered on clinicaltrials.gov (ID: NCT05548049, First registration date: 21/09/2022).

Prospective evaluation of morbidity in patients who underwent autogenous bone-graft harvesting from the mandibular symphysis and retromolar regions

BACKGROUND

Autogenous bone grafts are the most favorable and predictable types of bone graft due to their osteogenic, osteoinductive, and osteoconductive properties. The advantages of harvesting from mandibular bone are that it requires only local anesthesia, is less invasive, has less morbidity, and avoids harvesting from distant sites, thus making it the best choice for maxillary bone reconstruction.

PURPOSE

The aim of this study was to evaluate inferior alveolar nerve (IAN) neurosensory disturbances after autogenous bone graft harvesting from the mandibular symphysis and retromolar region to reconstruct maxillary sinus height for posterior dental implant placement and the effect of these disturbances on patient satisfaction.

MATERIALS AND METHODS

Fifty-four patients were invited to participate in this study. Autogenous bone graft was harvested from the mandibular symphysis and retromolar regions. After the procedure, the patients were evaluated by means of an adapted questionnaire to determine if they had complaints of neurosensory disturbances at the following time intervals: immediately, 1, 2-5, 6, 7-11, and 12 months postsurgery.

RESULTS

Immediately after surgery, 28 patients described sensory changes and 25 reported paresthesia of inferior lip. Only three patients reported pain, and one patient experienced dental hypersensitivity after the surgical procedure. During the evaluation period, the patients reported a decrease in paresthesia and a return of sensation to areas innervated by the IAN. After 12 months, five patients still reported paresthesia of areas innervated by the IAN. Beside this, patients reported significant clinical improvement from the beginning of the evaluation, as 49 patients were satisfied with their treatment outcomes.

CONCLUSION

Harvesting bone grafts from the mandibular symphysis results in greater postoperative morbidity upon immediate evaluation compared with bone graft harvesting from the retromolar region. Nevertheless, during clinical follow-up, the results of both treatments showed that sensation was eventually recovered, depending on the healing period.

In-Site Monocyte Implantation in Bone Grafting for Maxillary Atrophy Reconstruction: A Preliminary Observational Proof of Concept Study

PURPOSE

The main objective of this study, involving 11 patients, is to share our experience on an integrated treatment modality, namely, the use of cellular therapy simultaneously with surgical reconstruction. Published works show that the implantation of monocytes in ischemic tissue enhances healing by providing neo-angiogenesis, a key mechanism in tissue regenerative processes.

MATERIALS AND METHODS

Our approach included the utilization of autologous monocytes and endothelial precursor cells in the bone graft itself to improve the success rate of the integration of the bone graft and its long-term viability/survival by promoting angiogenesis. We compared the standard regenerative procedures, namely sinus lift grafting performed with xenogeneic particle bone graft and posterior mandible grafting performed with on-lay or in-lay autologous cortical/medullary bone-block graft harvested from the iliac crest, with and without the use of cellular implementation. We evaluated results by both radiological and histological assessment.

RESULTS

Autologous cortical/medullary bone-block graft had a different response to implementation with monocytes, showing a better osteointegration than expected conversely to the xenogeneic particle bone graft.

CONCLUSIONS

Monocytes seem to improve autologous bone-block graft according to the "Therapeutic Angiogenesis" concept. Implementation with monocytes does not always improve xenogeneic particle bone graft.

Tissue engineering for bone regeneration and osseointegration in the oral cavity

OBJECTIVE

The focus of this review is to summarize recent advances on regenerative technologies (scaffolding matrices, cell/gene therapy and biologic drug delivery) to promote reconstruction of tooth and dental implant-associated bone defects.

METHODS

An overview of scaffolds developed for application in bone regeneration is presented with an emphasis on identifying the primary criteria required for optimized scaffold design for the purpose of regenerating physiologically functional osseous tissues. Growth factors and other biologics with clinical potential for osteogenesis are examined, with a comprehensive assessment of pre-clinical and clinical studies. Potential novel improvements to current matrix-based delivery platforms for increased control of growth factor spatiotemporal release kinetics are highlighting including recent advancements in stem cell and gene therapy.

RESULTS

An analysis of existing scaffold materials, their strategic design for tissue regeneration, and use of growth factors for improved bone formation in oral regenerative therapies results in the identification of current limitations and required improvements to continue moving the field of bone tissue engineering forward into the clinical arena.

SIGNIFICANCE

Development of optimized scaffolding matrices for the predictable regeneration of structurally and physiologically functional osseous tissues is still an elusive goal. The introduction of growth factor biologics and cells has the potential to improve the biomimetic properties and regenerative potential of scaffold-based delivery platforms for next-generation patient-specific treatments with greater clinical outcome predictability.

Tomographic imaging of fragmented cortical bone heteroimplant and methylmethacrylate in segmental bone defect of rabbit tibia

PURPOSE

To evaluate the performance of composites consisting of fragmented cortical bone heteroimplant in association with methylmethacrylate preserved in 98% glycerin, in segmental bone defect of rabbit tibia medial metaphysis.

METHODS

In this study were used twelve adult New Zealand rabbits, divided into three groups of four animals each: G30 (30 days), G60 (60 days) and G90 (90 days). The bone defects previously created in the tibia were filled with composites and both were evaluated by cone-beam computed tomography, immediately after surgery and after 30, 60, and 90 days.

RESULTS

The composites fulfilled and remained in the sites of bone defects in all cases and were not registered signals of infection, migration or rejection.

CONCLUSIONS

The implanted composites promoted the bone defects repair without signals of infection and/or rejection. The composites are one more option for bone defects repair.

Role of cone beam computed tomography in rehabilitation of a traumatised deficient maxillary alveolar ridge using symphyseal block graft placement

Deficiencies in the alveolar ridges cause multiple problems in achieving aesthetic and functional outcome of implant therapy and are commonly restored by using onlay graft from intraoral source. Careful assessment of the recipient as well as the donor site using cone beam computed tomography (CBCT) is a prerequisite to ideal treatment planning. This paper highlights the critical role of CBCT in planning a successful rehabilitation of traumatised deficient anterior maxillary alveolar ridge using autogenous block graft from mandibular symphysis, followed by implant placement. A 21-year-old male reported with missing right maxillary lateral incisor due to traumatic avulsion 6 months back. A concavity was found on the labial aspect of edentulous area. Serial transplanar images on CBCT revealed gross irregular radiolucency in place of labial cortical plate. Using CBCT, size of the required block was estimated, and mandibular symphyseal area was evaluated for the feasibility of harvesting a graft of suitable dimension. Onlay block graft was harvested from mandibular symphysis and placed at the edentulous site to augment the alveolar ridge. Implants were placed 5 months later and loaded successfully after osseointegration. After 1 year of followup, implant-based prosthesis is working well, without any complications.