Bone grafting the mandible

Study on tensile, bending, fatigue, and in vivo behavior of porous SHS-TiNi alloy used as a bone substitute

Intermetallic porous SHS-TiNi alloys exhibit tangled and specific stress-strain characteristics. This article aims to evaluate the findings emanating from experiments using standard and proprietary instruments. Fatigue testing under repeated complex loading was used to measure the total number of load cycles before failure of the SHS-TiNi samples occurred. Of the tested samples, seventy percent passed through 10⁶ cycles without failure due to the reversible martensite transformation in the TiNi phase, one of the prevailing constituents of a multiphase matrix. The fractured surfaces were analyzed using scanning electron microscopy and confocal laser scanning instruments. Microscopy studies showed that the entire surface of the sample is concealed by miscellaneous strata that result from the SHS processand effectively protect the porous alloy in a corrosive environment. Numerous non-metallic inclusions, which are also attributed to the SHS reaction, do not have a significant impact on the deformation behavior and fatigue performance. In this context, the successful in vivo functioning of porous grafts assessed in a canine rib-plasty model allows the bone substitute to be congruentially deformed in the body without rejection or degradation; it thus has a long operational life, often greater than 17 ×10⁶ (22 × 60 × 24 × 540) cycles. It acknowledges the potential benefits of SHS-TiNi as a superior osteoplastic material and its high resistance to corrosion fatigue.

Decision-Making in Implantology-A Cross-Sectional Vignette-Based Study to Determine Clinical Treatment Routines for the Edentulous Atrophic Mandible

This cross-sectional study aimed to investigate the influence of possible factors in the patient history on decision making in the therapy for a severely atrophied edentulous mandible. A vignette-based survey among 250 maxillofacial and oral surgeons was conducted. Determinants that could influence the therapy decision were patient age, smoking, fear of surgery, and radiotherapy in the head and neck area (the implant region is not in the direct radiation area). To achieve a suitable implant site, the options offered to the surgeons were bone split, bone block, augmentation with bone substitute material, and bone resection. There also was the option of rejecting any therapy. The response rate was 47%. Patient age, radiotherapy, and fear of surgery did not influence the approval of a therapy. Smoking was associated with a significantly lower endorsement of a treatment. Resection was preferred by a large majority to all other forms of therapy, regardless of the four determinants. Surgeons tend to refrain from bone block transplants in older patients. In summary, it can be said that, of the four determinants, only smoking influenced treatment refusal. Bone resection is the preferred therapy independent of all determinants.

Mandibular Reconstruction With Block Iliac Crest: An Institutional Experience

STUDY DESIGN

Mandibular reconstruction is a challenge. Several reconstructive techniques are available, and the individualization of choice for each patient leads to better results and quality of life for the individual.

OBJECTIVE

The aim of this study is to evaluate the characteristics and complications of cases submitted to mandibular reconstruction with autogenous bone graft block of the iliac crest.

METHODS

Records of 45 patients undergoing mandibular reconstruction with autogenous bone graft block of the iliac crest were analyzed from January 2000 to December 2014. The data collected included age, gender, etiology and graft size, surgical approach, complications, comorbidities, and habits and addictions. Analysis of variance, chi-square test, and Fisher exact test were used for analysis of the variables with a significance level of P < .05.

RESULTS

The success rate of the 45 charts analyzed was 75.6%. No statistical differences were found between age and presence of complications, between defect size and presence or absence of complications, and between type of surgical approach and presence or absence of complications.

CONCLUSION

According to our study, medical history may influence postoperative complications and require attention, though further studies should be performed to further elucidate the relationship between diseases and postoperative complications.

Titanium Mesh Grafting Combined with Recombinant Human Bone Morphogenetic Protein 2 for Alveolar Reconstruction

There are several methods of regenerating the maxillary and mandibular ridge to achieve orthoalveolar form with bone grafting procedures, including block onlay grafting and guided bone regeneration. Traditionally, guided bone regeneration has focused on creating a space for bone regeneration to occur. The use of a formed titanium mesh to regenerate alveolar defects was popularized in the 1980s. With the advent of other adjuncts, such as resorbable membranes, and growth factors, such as recombinant human bone morphogenetic protein 2, the predictability of the procedure has increased and a wide variety of defects can be restored using this technology.

Comparative assessment of 3D reconstruction technique and Cavalieri's principle in predicting the mandibular bone defect volumes

Purpose

The objective of this study was to compare the accuracy of the Cavalieri's principle and 3D reconstruction in predicting the volume of a bony defect.

Materials and Methods

Defects of the same approximate size were created on nine artificial mandibles. The actual volume of the defect on each mandible was measured by water displacement, and served as the control. Each mandible was then scanned using a CBCT and volume measurements were made for each defect using two techniques: Cavalieri's principle and 3D reconstruction. For each defect, the volume obtained by each of the two techniques was compared to the control volume using the analysis of variances (ANOVA) with p<0.05.

Results

ANOVA between the control, 3D reconstruction and Cavalieri's principle groups showed no statistically significant differences (p=.058). When the control group was further analyzed by Dunnett's post-hoc test, the results from Cavalieri's principle were found to be statistically different than the control group (p=.035), whereas the results of 3D reconstruction technique did not reach the level of significance (p=.523).

Conclusion

Cavalieri's principle significantly underestimates the actual control volume, and is less accurate than the 3D reconstruction technique. The 3D reconstruction method is a reliable technique in measuring volume of bony defects.

Bone grafting for alveolar ridge reconstruction. Review of 166 cases

Objective:

to investigate the predictive factors of failure in bone grafts for alveolar ridge augmentation and implant surgery.

Methods:

we reviewed the charts of 166 patients operated between 1995 and 2014. A total of 248 grafting procedures were performed. We submitted the data to the binomial test at 5% significance.

Results:

grafts to gain width of the alveolar ridge (65.32%) were more frequent than sinus lifting (p<0.0001) and the number of grafts to the posterior maxilla (48.8%) was greater than in other regions (p<0.01); 6.04% of the grafts were lost. The losses in anterior (p<0.0309) and posterior (p<0.0132) maxilla were higher than in the mandible. There were 269 ​​implants installed in the grafted areas, of which only 4.83% were lost. The number of implants lost (4.51%) in areas of onlay grafts was not statistically higher than those placed after sinus lifting (2.63%, p<0.2424). Losses were greater in the anterior (53.85%) and posterior (38.46%) maxilla than in the mandible (p<0.031). Regarding patients' age, 76.92% of the lost grafts (p<0.006) and 80% of the lost implants (p<0.001) were installed in patients over 40 years.

Conclusion:

failure rate was higher both for grafts and dental implants in the maxilla and in patients over 40 years of age.

Objetivo:

investigar os fatores preditivos de falhas em enxertos ósseos para aumento do rebordo alveolar e cirurgia de implantes.

Métodos:

os prontuários de 166 pacientes, operados entre 1995 e 2014, foram revistos. Um total de 248 enxertos foi realizado. Os dados foram submetidos ao teste binomial a 5% de significância.

Resultados:

os enxertos para ganho em espessura do rebordo alveolar (65,32%) foram mais frequentes do que levantamentos de seio maxilar (p<0,0001) e o número de enxertos para a região posterior da maxila (48,8%) foi maior do que em outras regiões (p<0,01). Foram perdidos 6,04% dos enxertos. As perdas em maxila anterior (p<0,0132) e posterior (p<0,0309) foram maiores do que na mandíbula. Foram instalados 269 implantes nas áreas enxertadas e apenas 4,83% perdidos. O número de implantes perdidos (4,51%) em áreas de enxertos em bloco não foi estatisticamente maior do que na área de seios maxilares enxertados (2,63%) (p<0,2424). As perdas foram maiores na região anterior (53,85%) e posterior (38,46%) da maxila em relação a mandíbula (p<0,031) e, 76,92% dos enxertos (p<0,006) e 80% dos implantes perdidos (p<0,001), foram instalados em pacientes com mais de 40 anos de idade.

Conclusão:

maior taxa de falhas foi observada para enxertos e implantes dentários realizados em maxila e em pacientes com mais de 40 anos de idade.

Comparison between peri-implant bone level changes of implants placed during and 3 months after iliac bone grafting

OBJECTIVE

The aim of this study was to compare the peri-implant bone level changes of implants placed during and 3 months after bone grafting from the iliac crest.

STUDY DESIGN

A total of 103 implants were placed: 42 during the grafting and 61 at 3 months after the grafting procedure. All patients were grafted with iliac bone from the anterosuperior iliac crest. Bone resorption was evaluated with cone beam computed tomography in all patients at their last control visit. Periodontal health was assessed via the gingival and plaque indices and pocket depths around the dental implants.

RESULTS

Mean bone resorption values at the buccal, lingual, mesial, and distal sides of the implants were 1.08 mm, 0.36 mm, 0.30 mm, and 0.25 mm, respectively, in the delayed group, and 1.87 mm, 1.25 mm, 0.92 mm, and 1.23 mm, respectively, in the simultaneous group; the differences between the groups were significant. There were no significant between-group differences in the gingival or plaque indices or pocket depths. The mean follow-up period was 29 months.

CONCLUSIONS

For reconstructing atrophic jaws, bone grafting from the iliac crest and implant placement after 3 months is a reliable technique with a high success rate and less bone resorption.

The outcome of intraoral onlay block bone grafts on alveolar ridge augmentations: a systematic review

Aim: The purpose of this study was to systematically review clinical studies examining the survival and success rates of implants placed with intraoral onlay autogenous bone grafts to answer the following question: do ridge augmentations procedures with intraoral onlay block bone grafts in conjunction with or prior to implant placement influence implant outcome when compared with a control group (guided bone regeneration, alveolar distraction, native bone or short dental implants.)? Material and Method: An electronic data banks and hand searching were used to find relevant articles on vertical and lateral augmentation procedures performed with intraoral onlay block bone grafts for dental implant therapy published up to October 2013. Publications in English, on human subjects, with a controlled study design –involving at least one group with defects treated with intraoral onlay block bone grafts, more than five patients and a minimum follow-up of 12 months after prosthetic loading were included. Two reviewers extracted the data. Results: A total of 6 studies met the inclusion criteria: 4 studies on horizontal augmentation and 2 studies on vertical augmentation. Intraoperative complications were not reported. Most common postsurgical complications included mainly mucosal dehiscences (4 studies), bone graft or membrane exposures (3 studies), complete failures of block grafts (2 studies) and neurosensory alterations (4 studies). For lateral augmentation procedures, implant survival rates ranged from 96.9% to 100%, while for vertical augmentation they ranged from 89.5% to 100%. None article studied the soft tissues healing. Conclusions: Survival and success rates of implants placed in horizontally and vertically resorbed edentulous ridges reconstructed with block bone grafts are similar to those of implants placed in native bone, in distracted sites or with guided bone regeneration. More surgical challenges and morbidity arise from vertical augmentations, thus short implants may be a feasible option.

Key words:Alveolar ridge augmentation, intraoral bone grafts, onlay grafts, block grafts, dental implants.

Three years after transplants in human mandibles, histological and in-line holotomography revealed that stem cells regenerated a compact rather than a spongy bone: biological and clinical implications

Mesenchymal stem cells deriving from dental pulp differentiate into osteoblasts capable of producing bone. In previous studies, we extensively demonstrated that, when seeded on collagen I scaffolds, these cells can be conveniently used for the repair of human mandible defects. Here, we assess the stability and quality of the regenerated bone and vessel network 3 years after the grafting intervention, with conventional procedures and in-line holotomography, an advanced phase-imaging method using synchrotron radiation that offers improved sensitivity toward low-absorbing structures. We found that the regenerated tissue from the graft sites was composed of a fully compact bone with a higher matrix density than control human alveolar spongy bone from the same patient. Thus, the regenerated bone, being entirely compact, is completely different from normal alveolar bone. Although the bone regenerated at the graft sites is not of the proper type found in the mandible, it does seem to have a positive clinical impact. In fact, it creates steadier mandibles, may well increase implant stability, and, additionally, may improve resistance to mechanical, physical, chemical, and pharmacological agents.