The zygomatic bone as a potential donor site for alveolar reconstruction--a quantitative anatomic cadaver study

Evaluation of the osteoconductive properties of scaffold containing platete-enriched-fibrin (PRF) with three calcium phosphate (TCP) in the alveolar socket repair after tooth extraction: An animal study

Bone regeneration can be accomplished through osteogenesis, osteoinduction, and osteoconduction mechanisms. This study aimed to investigate the properties of the PRF scaffold with tricalcium phosphate nanoparticles in socket preservation in an animal model. Fabrication of PRF performed. In this experimental study, 18 rats were divided into three negative control, PRF, and PRF/TCP groups. The mechanical and chemical tests including swelling rate, degradation time, and MTT tests were applied to the scaffolds. In each animal, the first maxillary right molar was extracted, and extraction sites of test groups were filled with a resorbable biocompatible biomaterial in situ hardening bone substitute. After 2 and 4 weeks all animals were sacrificed and examined histopathologically and with qRT-PCR. Histological results showed TCP in combination with PRF accelerates bone regeneration with the highest amount of lamellar bone and collagen formation compared to the control and PRF alone. Mechanical and chemical tests on the scaffolds showed the addition of TCP to the PRF scaffold decreases the swelling rate and increases the degradation time. qRT-PCR showed expression of osteogenic genes increased significantly (p < 0.05) in PRF/TCP and PRF, respectively. In conclusion, the gelatin hydrogel containing PRF/TCP scaffold led to more bone formation after tooth extraction. Therefore, the injectable PRF\TCP hydrogel is a promising candidate for bone repair and regeneration.

The Zygomatic Buttress as an Efficient Intraoral Donor Site for Limited Maxillary Reconstructions: A Case Series and Brief Literature Review

Limited maxillary defects are commonly grafted with bone blocks harvested from the symphysis or the ramus; harvesting a second surgical site in the mandible increases both operative time and patient's postoperative morbidity. To overcome these disadvantages, the zygomatic buttress (ZB) was suggested as an alternative maxillary source of autogenous bone. This intraoral donor site has a natural convex shape and can be accessed along with the recipient site through the same flap design. We report a case series describing this uncommon technique of bone harvesting from the zygomatic buttress to reconstruct limited alveolar defects in the maxilla.

Preclinical and Clinical Applications of Biomaterials in the Enhancement of Wound Healing in Oral Surgery: An Overview of the Available Reviews

Oral surgery has undergone dramatic developments in recent years due to the use of biomaterials. The aim of the present review is to provide a general overview of the current biomaterials used in oral surgery and to comprehensively outline their impact on post-operative wound healing. A search in Medline was performed, including hand searching. Combinations of searching terms and several criteria were applied for study identification, selection, and inclusion. The literature was searched for reviews published up to July 2020. Reviews evaluating the clinical and histological effects of biomaterials on post-operative wound healing in oral surgical procedures were included. Review selection was performed by two independent reviewers. Disagreements were resolved by a third reviewer, and 41 reviews were included in the final selection. The selected papers covered a wide range of biomaterials such as stem cells, bone grafts, and growth factors. Bioengineering and biomaterials development represent one of the most promising perspectives for the future of oral surgery. In particular, stem cells and growth factors are polarizing the focus of this ever-evolving field, continuously improving standard surgical techniques, and granting access to new approaches.

Autogenous bone augmentation from the zygomatic alveolar crest: a volumetric retrospective analysis in the maxilla

BACKGROUND

Autogenous bone augmentation is the gold standard for the treatment of extended bone defects prior to implantation. Bone augmentation from the zygomatic crest is a valuable option with several advantages, but the current literature for this treatment is scant. The aim of this study was to evaluate the increase in bone volume after locoregional bone augmentation using autogenous bone from the zygomatic alveolar crest as well as the complications and success rate.

RESULTS

Analysis of the augmented bone volume in seven patients showed a maximum volume gain of 0.97 cm³. An average of 0.54 cm³ of autogenous bone (SD 0.24 cm³; median: 0.54 cm³) was augmented. Implantation following bone augmentation was possible in all cases. Complications occurred in three patients.

CONCLUSION

The zygomatic alveolar crest is a valuable donor site for autogenous alveolar onlay grafting in a locoregional area such as the maxillary front. Low donor site morbidity, good access, and its suitable convexity make it a beneficial choice for autogenous bone augmentation.

Bone grafting materials in dentoalveolar reconstruction: A comprehensive review

Bone deficits of the jaws are often attributed to accidents, surgical removal of benign lesions or malignant neoplasms, congenital abnormalities, periodontal inflammation, tooth abscess or extraction and finally jaw atrophy due to advanced age or general disease. These bone defects require rehabilitation for a variety of reasons, e.g. maintaining the normal anatomic outline, eliminating empty space, aesthetic restoration and placing dental implants. Today, several techniques have been developed to eliminate these bone deformities including bone grafting, guided bone regeneration, distraction osteogenesis, use of growth factors and stem cells. Bone grafts consist of materials of natural or synthetic origin, implanted into the bone defect site, documented to possess bone healing properties. Currently, a variety of bone restorative materials with different characteristics are available, possesing different properties. Despite years of effort the 'perfect' bone reconstruction material has not yet been developed, a further effort is required to make this objective feasible. The aim of this article is to provide a contemporary and comprehensive overview of the grafting materials that can be applied in dentoalveolar reconstruction, discussing their properties, advantages and disadvantages, enlightening the present and the future perspectives in the field of bone regeneration.

Alternative intraoral donor sites to the chin and mandibular body-ramus

Background

Provide a review of alternative intraoral donor sites to the chin and body-ramus of the mandible that bring fewer complications and that may be used to regenerate small and medium defects.

Material and Methods

A review was conducted using the search engine PUBMED and looking manually into scientific journals.

Results

From the 35 articles included, 6 corresponded to the coronoids, 3 corresponded to the zygomatic body, 5 corresponded to the anterior maxillary sinus wall, 3 corresponded to the zygomatic alveolar process, 2 corresponded to the incisive fossa, 2 corresponded to the anterior nasal spine, 2 corresponded to the palatal region, 5 corresponded to the tuberosity, and 7 corresponded to the palatal and mandibular tori.

Conclusions

Although there are few complications described when using alternative intraoral donor sites, the main problem with these types of grafts is their scarce bone volume, with only the zygomatic body, anterior sinus wall, and palate sites being able to be used in medium defects. More clinical trials are necessary in order to evaluate the behavior of the alternative donor sites over time. Key words:Grafting, autologous bone, autografts, mandible, maxilla, palate hard, zygoma.

The anterior maxilla as a potential source of bone grafts: a morphometric cone beam computed tomography analysis of different anatomical areas

The aim of this research was to use cone beam computed tomography (CBCT) to analyze the volume, density, and morphology of the bone available in the anterior region of the maxilla, in order to investigate its potential as a source of bone grafts. Three independent zones were evaluated: the palatine process of the maxilla (PPM), anterior nasal spine (ANS), and subnasal bone (SN). The latter was analyzed bilaterally (SNR, SNL). One hundred CBCT scans were evaluated. The morphometric analysis comprised volumetric and subsequent automatic density calculations, as well as linear measurements. Potential correlations among these parameters, including demographic characteristics, were investigated. The study comprised 52 women and 48 men (mean age 49.6±14.5 years). The calculated bone volume averaged 2.41±0.72cm(3) for PPM, 0.46±0.16cm(3) for ANS, 0.58±0.2cm(3) for SNR, and 0.57±0.21cm(3) for SNL. The anterior region of the maxilla can provide a considerable amount of bone volume from different anatomical zones and should be regarded as a potential donor site for the regeneration of maxillary atrophic bones. Further investigation is required before these findings can be applied in the routine clinical setting.

A clinical study of the outcomes and complications associated with zygomatic buttress block bone graft for limited preimplant augmentation procedures

PURPOSE

The aim of this study was to evaluate the possibility of using the zygomatic buttress as an intraoral bone harvesting donor site and determine the safety of this harvesting procedure for later optimal positioning of dental implants in accordance with prosthodontic and functional principles.

MATERIAL AND METHODS

A consecutive retrospective study was conducted on patients who had been treated at the Department of Oral and Maxillofacial Surgery of Ulm military and academic hospital, over a 3-year period (January 2008 to December 2010). Medical history, smoking status, area of surgery, and complications were recorded. The need for bone grafting was defined by the impossibility of installing implants of adequate length or diameter to fulfill prosthetic requirements, or for esthetic reasons. The patients were treated using a 2-stage technique. During the first operation, bone blocks harvested from the zygomatic buttress region were placed as lateral onlay grafts and fixed with titanium osteosynthesis screws after exposure of the deficient alveolar ridge. After 3-6 months of healing, the flap was reopened, the screws removed and the implants placed.

RESULTS

A total of 113 zygomatic buttress bone block grafts in 112 patients were performed. Graft loss and graft removal were defined as failure; swelling, wound dehiscence, infection with pus, temporary paresthesia, and perforations of the maxillary sinus membrane were defined as complications. According to our criteria, 4 (3.5%) of the patients presented postoperative complications of the donor site and 20 (17.8%) of the recipient site. Throughout, 93 (82.3%) of the bone grafts were successful and 20 (17.6%) had complications, regardless of the final success of the implant procedure. Smoking was associated with a high rate of complications and graft failure. Early graft exposure appeared to compromise the results, whereas pain and swelling were comparable to usual dentoalveolar procedures. However, in 1.7% of all cases, concerning 2 patients, the final rehabilitation with dental implants was not possible.

CONCLUSIONS

The zygomatic buttress block bone graft is a safe intraoral donor site for the reconstruction of small- to medium-sized alveolar defects, providing the greatest surgical access with minimal postoperative complications.

Zygomaticofacial foramen location accuracy and reliability in cone-beam computed tomography

OBJECTIVE

This study aimed to evaluate the possibility of detecting the zygomaticofacial foramen (ZFF) in cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This study evaluated ZFFs in 151 macerated skulls (302 zygomatic bones, ZBs) by physical inspection, in which the presence and diameters of the ZFFs were determined. These data were compared with the CBCT images of the skulls to determine the accuracy of CBCT in detecting ZFFs. The diameters were measured by insertion of steel wires with known thicknesses into the ZFFs. The CBCT images were acquired by an i-CAT Classic® (International Imaging Sciences, Hatfield, PA) connected to a workstation (Model ITOX Midtower Workstation; Imaging Sciences International®) with a 20-inch Eizo monitor. The images were generated in coronal, sagittal and axial slices to evaluate the best tomographic plane for ZFF visualization.

RESULTS

The incidence of ZFF found by physical inspection was one foramen in 44% of ZBs (n = 133), two foramina in 28% (n = 86), three foramina in 8% (n = 24) and four foramina in 1% (n = 2). ZFF was absent in 19% (n = 57) of ZBs. The average diameter was 0.57 mm (± 0.27 mm). All foramina were observed in all tomography images.

CONCLUSION

This preliminary study supports the conclusion that a CBCT scan has excellent accuracy in evaluating ZFFs.

Containment and contouring (CoCoon) technique: a biologically adequate approach to less invasive autogenous preimplant augmentation of bone

We have analysed retrospectively whether the less invasive zygomatic buttress graft is able to meet the dimensional and biological requirements of preimplant augmentation of bone. A total of 273 patients were treated by zygomatic buttress graft, of whom 42 (12 men and 30 women) met the criteria for inclusion. Intensity of pain was judged by a visual analogue score (VAS). Complications of grafting were evaluated, and dental implants were studied on clinical and radiographic examinations. The Schneiderian membrane was perforated in 13 cases (28%). The mean (SD) postoperative VAS was 3.1 (0.9) at the donor site. The mean (SD) follow-up after implant was 17(8) months. Two grafts were lost, one from initial dehiscence and later infection, and the other from infection. The mean (SD) marginal resorption of bone graft was 0.5 (0.7) mm. No implant was lost during the observation period. The zygomatic buttress graft meets the biological and dimensional requirements of augmentation of bone before implant that allows the dental implants to survive with satisfactory prosthetic rehabilitation.

Bone formation following implantation of bone biomaterials into extraction sites

BACKGROUND

Adequate bone volume is imperative for the osseointegration of endosseous implants, but postextraction resorption and remodeling may challenge implant placement. The use of bone biomaterials has been advocated to fill extraction sites and to enhance primary implant stability during osseointegration. The objective of the case series was to evaluate bone formation histologically and biomechanically in extraction sites following implantation of three commercially available bone biomaterials to compare their ability to allow guided bone regeneration.

METHODS

Thirty-six periodontally involved teeth were extracted from eight healthy non-smoking subjects. At least two bone biomaterials, a synthetic sponge based on polylactic-polyglycolic acid technology (FIS), bovine porous bone mineral (BPBM), or a natural coral derivative physically and chemically transformed into a calcium carbonate ceramic (COR), and one non-grafted control were applied to the extraction sockets within each subject and were covered by an expanded polytetrafluoroethylene device. The devices were removed after 2 months, and trephine biopsies were obtained from each site 4 months later. At that time, endosseous implants were placed in 25 of the sites, and healing abutments were placed; measurements were taken 4 to 6 months later with an electronic mobility testing device.

RESULTS

The percentage of residual biomaterial was 5.6% +/- 8.9% for FIS (P <0.001), 20.2% +/- 17.0% for BPBM (P <0.05), and 12.0% +/- 16.4% for COR (P <0.001). The amount of residual biomaterial after 6 months showed a significant relationship with the insertion torque measurements during the first third of implant insertion (P <0.05) and with values of the electronic mobility testing device at the abutment connection (P = 0.05). Histologically, new bone apposition was seen on BPBM particles. FIS sites showed similar ingrowth of blood vessels and osteocytes as empty controls.

CONCLUSION

All sites revealed good primary stability at implant insertion and proper implant rigidity at abutment placement, indicating that early implant osseointegration was not influenced by the application of bone biomaterials used in this study.

A new technique for the transcrestal sinus floor elevation and alveolar ridge augmentation with press-fit bone cylinders: a technical note

BACKGROUND

The minimally invasive sinus floor elevation as first described by Summers is limited in the volume of augmentation that is possible. In contrast, the more invasive approach is the sinuslift of Tatum which is indicated for greater bone deficiencies. Therefore, a new technique was developed for transcrestal elevation of the sinus floor and alveolar ridge augmentation with bone dowels in press-fit technique.

MATERIALS & METHODS

The crestal cortical bone is cut with a hollow grinder followed by an indirect sinus floor elevation with a plunger. The cylindrical defect is then filled with a cylindrical bone transplant with the press-fit technique.

RESULTS

The method was tested in ten fresh porcine skulls and was successful when applied subsequently in two fresh human cadavers (both female, age 60 and 92 years). This was followed by the insertion of another cylinder in overlapping mosaic manner with the dowel-lift technique in the left maxilla in one cadaver. A sinoscopy of the second cadaver experiment showed no perforation of the maxillary sinus membrane. The result was convincing.

CONCLUSION

A new method for transcrestal elevation of the maxillary sinus floor and alveolar ridge augmentation with bone cylinders in press-fit technique was developed. The operation combines the minimally invasive approach of Summers with a large augmentation volume otherwise requiring the direct technique of Tatum. These results should encourage further preclinical experiments.