Liat Chaushu

Maxillary sinus grafting with autograft vs. fresh frozen allograft: a split‐mouth histomorphometric study

BACKGROUND Surgical techniques as sinus floor augmentation have made it possible to increase the bone volume of the posterior maxilla so that implant placement may be feasible. A large variety of bone grafting materials have been utilized for sinus floor augmentation. A good alternative is allograft. Fresh frozen bone is harvested from live or cadaveric donors and then immediately frozen and stored at -80 °C. To date, studies about the effect of fresh frozen bone are scarce. OBJECTIVE Evaluation of new bone formation, following maxillary sinus grafting with autograft vs. fresh frozen allograft. MATERIALS AND METHODS A split-mouth edentulous design including 15 patients was used. Sinus floor augmentation was carried out using either autogenous bone harvested from the ramus area or fresh frozen bone from allogeneic femoral heads. The choice was determined randomly, using a randomized table. The grafted sinus was left to heal for 6 months. Biopsies were harvested from the lateral wall. The biopsies were used for bone histology and histomorphometric analysis. After collection of the biopsy, dental implants were placed. After a healing period of 6 months, the implants were loaded. RESULTS Implant survival, histology, and histomorphometry of sinuses grafted with autogenous or fresh frozen bone were similar. The new bone formation took place predominantly around and in-between particles. CONCLUSIONS The findings of the present study support the use of fresh frozen bone allografts for sinus floor augmentation.

Maxillary Sinus Grafting with Autograft Versus Fresh-Frozen Allograft: : A Split-Mouth Evaluation of Bone Volume Dynamics

PURPOSE To compare volumetric changes after sinus augmentation of completely edentulous maxillae with either autogenous or allogeneic fresh-frozen bone particles. MATERIALS AND METHODS This split-mouth study in patients who required bilateral sinus grafting used autograft particles for one sinus and allograft particles for the contralateral sinus. The grafted sinuses were left to heal for 6 months prior to implant insertion. All patients underwent four computed tomography scans: prior to augmentation and 1 week, 6 months, and 12 months after grafting. Computer software was used to analyze bone graft volume in each scan. RESULTS Fifteen patients (8 men, 7 women) with a mean age of 54 ± 5 years (range, 48 to 60 years) took part and underwent 30 sinus augmentation procedures. Mean autograft and allograft volumes were not statistically significantly different at each time point (1 week: 2.01 ± 0.43 cm³ vs 2.46 ± 0.79 cm³; 6 months: 1.53 ± 0.49 cm³ vs 1.75 ± 0.64 cm³; and 12 months: 1.38 ± 0.43 cm³ vs 1.59 ± 0.56 cm³, respectively). Mean volumetric reductions of 31.35% and 35.36% (23.9% and 29.9% in the 6 months prior to implant insertion, followed by an additional 9% and 9% in the following 6 months), relative to 1 week postgrafting, were noted for the autograft and allograft groups, respectively, after 12 months. CONCLUSION On the basis of this split-mouth study of 15 patients, there was no statistically significant volumetric difference after 12 months between the use of autograft or allografts for sinus augmentation. Fresh-frozen bone allograft may serve as an alternative that avoids the morbidity associated with autograft harvesting.

Reliability of retrievable cemented implant-supported prostheses.

STATEMENT OF PROBLEM One of the disadvantages of a cemented implant restoration is the potential difficulty of retrieving it. The restoration may be destroyed during removal. PURPOSE The purpose of this retrospective clinical study was to assess the long-term survival rates of cemented posterior metal ceramic implant-supported prostheses (ISPs) with a metal screw access hole. MATERIAL AND METHODS During a 12-year period, 274 cemented ISPs with an abutment screw access hole in the metal framework were assessed and served as the study group, and 119 conventional cemented ISPs (without access hole) served as the control group. Participants were followed every 6 months in the first year and once a year subsequently. Ceramic fracture, screw loosening, and refabrication were the prosthetic outcome parameters evaluated at the recall. The Pearson Chi square and Fisher exact test were used to compare the outcome parameters between the control and study groups. RESULTS A total of 1005 implants and 393 ISPs were evaluated. Ceramic fracture occurred in 6.6% of the ISPs (6.2% test and 7.6% control). Screw loosening occurred in 3.28% of the test group and 3.36% of the control group. Refabrication of ISPs was done in 2.79% of all restorations, (1.45% test and 6.72% control [P=.012]). CONCLUSIONS Within the limits of this study, preparing cemented ISPs with a screw access hole in the metal framework improves ISP survival rates over time and lowers the cost of maintenance without increasing the risk for porcelain fracture or screw loosening.

Volumetric Stability of Fresh Frozen Bone Blocks in Atrophic Posterior Mandible Augmentation

&NA; Fresh frozen bone allografts (FFB) have become an alternative for bone augmentation in the past decades, especially because of the absence of recent reports of disease transmission or immunologic reactions when it is used. The aim of this prospective controlled study is to evaluate volumetric changes of newly created bone following reconstruction of the atrophic posterior mandible. Twenty consecutive patients presenting for reconstruction of posterior mandibular alveolar bone ridge width ≤6.0 mm and/or height ≤6.0 who met all inclusion and exclusion criteria were included. FFB blocks were used. The main outcome variable investigated was bone volume dynamics. Vertical, horizontal, and 3‐dimensional bone gain data were measured from computerized tomography scans. The main predictor variable was time evaluated at 3 points: immediately after surgery (T1), at implant placement (T2), and 1 year after functional loading (T3). Secondary outcome parameters evaluated were implant survival, histologic findings, and microtomographic morphometry. The study included 28 hemi‐mandibles, 50 FFB bone blocks, and 15 female and 5 male patients (mean age, 51.8 years). Block and implant survival rates were 100% and 96%, respectively, after 31.75 months of follow‐up. Vertical and horizontal bone gain at T2 was 5.15 and 6.42 mm, respectively. Volumetric resorption was 31% at T2, followed by an additional 10% reduction at T3. Histologic evaluation showed newly formed vital bone in intimate contact with the remaining FFB. Microtomography revealed 31.8% newly formed bone, 14.5% remaining grafted bone, and 53.7% connective tissue and bone marrow. Thus, FFB blocks may lead to new bone formation and consolidation, with satisfactory volumetric bone maintenance, allowing implant‐supported rehabilitation with high success rates.

Evaluation of a topical herbal patch for soft tissue wound healing: an animal study.

Abstract Aim This study evaluated the effects of a topical herbal patch (PerioPatch®) for gingival wound healing in a rat model. Materials and Methods A mid‐crestal incision was performed on each side of the edentulous anterior maxilla in 48, 6‐month‐old, Wistar rats. Full‐thickness flaps were raised, repositioned and sutured. Four experimental groups were established: herbal patch, placebo patch, no patch and no patch and no surgery. Patches were placed immediately after surgery and replaced every 12 h for the following 3 days. Half of the animals were killed after 5 and the remaining ones after 12 days. Tissue blocks were retrieved and processed for histological and immunohistochemical evaluation. Epithelial gap, collagen contents, amount of macrophages, cellular proliferation and vascular contents were evaluated in the central incision area. Statistical analysis consisted of two‐way anova. Results The herbal patch group presented the smallest epithelial gap at 12 days, the highest collagen content both at 5 and 12 days, a larger number of proliferating cells at day 5 and more numerous blood vessels at day 12. Macrophage number was similar in all groups. Conclusion Herbal patch improved wound healing in this animal model.

Age-related new bone formation following the use of cancellous bone-block allografts for reconstruction of atrophic alveolar ridges

BACKGROUND An age-related decrease in the number of osteogenic progenitor cells may compromise bone augmentation. PURPOSE Histomorphometrical assessment of age-related new bone formation, following atrophic alveolar ridge reconstruction, using cancellous bone-block allografts. MATERIAL AND METHODS Ninety-three consecutive patients (58 females and 35 males) were referred for implant-supported restoration of 122 severe atrophic alveolar ridges. Alveolar ridge deficiency locations were classified as anterior maxilla (n = 58), posterior maxilla (n= 32), and posterior mandible (n = 32). A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) in the posterior mandible and anterior maxilla, served as inclusion criteria. In the posterior maxilla, a residual alveolar ridge up to 4 mm vertically according to CT served as inclusion criteria. Augmentation was performed by the use of cancellous bone-block allografts. Bone biopsies (9-month posterior maxilla, 4 months anterior maxilla and posterior mandible) of young (≤40 years) versus older (>40 years) patients were histomorphometrically evaluated. RESULTS In the posterior maxilla, no statistically significant histomorphometric differences were noted. While at the anterior maxilla and posterior mandible, statistically significant more newly formed bone was found in young versus older individuals, respectively (38.6% vs 19.8%, P = 0.04 and 69% vs 31%, P = .05). CONCLUSION New bone formation following residual alveolar ridge bone grafting is age-related. Longer bone consolidation and healing time may be recommended for older individuals.

The Feasibility of Flapless Approach to Sinus Augmentation Using an Implant Device Designed According to Residual Alveolar Ridge Height

Hydraulic sinus lift and augmentation may be successfully performed using a dedicated implant device designed according to residual bone height (RBH). The aim of this study was to evaluate whether a flapless surgical approach might negatively influence the outcome. A total of 40 consecutive patients (16 men and 24 women) were included in the study, 20 in each group (minimal flap/control versus flapless/study). Inclusion criteria were ≥ 3 mm RBH, ≥ 6 mm width of the residual alveolar ridge according to preoperative cone beam computerized tomography, and ≥ 8 mm buccopalatal keratinized gingiva for the flapless group. Primary outcome parameters included intraoperative membrane perforation. Secondary outcome parameters included postoperative infection, soft tissue healing, bone gain, and short-term dental implant survival. Mean RBH was 4.6 mm. No intraoperative membrane perforations and no postoperative infections were observed. Mean bone gain height was similar for both groups, at 11 mm. Soft tissue healing was observed within 2 months. In all cases, second-stage surgery allowed generation of at least 2 mm of keratinized gingiva buccally. All implants were osseointegrated at second-stage surgery. The use of a flapless approach to maxillary sinus augmentation using an implant device based on RBH yields predictable results.

Bone-to-Implant Contact and New Bone Formation Within Human Freeze-Dried Bone Blocks Grafted Over Rabbit Calvaria

PURPOSE To assess the extent of osseointegration with rough-surface implants and new bone formation (NBF) within human freeze-dried bone blocks (h-FDB) grafted over rabbit calvaria. MATERIALS AND METHODS A total of 18 rectangular h-FDB blocks were stabilized bilaterally to the calvaria of nine New Zealand rabbits by two mini titanium screws each. A total of 18 rough-surface implants (5.0 × 6.0-mm) were placed, 9 simultaneously (immediate placement [IP]) on one side and 9 at 3 months after block grafting (delayed placement [DP]) on the contralateral side. At 12 weeks after the second surgical procedure, block biopsies were harvested and processed for histologic analysis. Morphometric measurements consisted of bone-to-implant contact (BIC) and the extent of NBF from the calvarial surface and outward into the block. A paired t test was applied for statistical analysis. RESULTS All h-FDB blocks were integrated, and the implants showed clinical stability. Histologically, the BIC was primarily between the apical end of the implants and the host rabbit calvaria. Bone growth between the implant threads was minimal and inconsistent among all animals. Morphometric measurements showed that the mean BIC of the IP and DP implants with the blocks was 10.50% ± 5.99% and 23.06% ± 9.58%, respectively (P < .001). NBF was observed primarily in the cancellous compartment of the block adjacent to the recipient calvarial bed. The extent of NBF into the block around the IP and DP implants was 9.95% ± 8.41% and 12.90% ± 11.07%, respectively (P = 0.2). CONCLUSION In this model, a significantly lower BIC was demonstrated when implants were placed simultaneously with h-FDB block grafting compared to those placed in a two-stage mode. However, both techniques showed limited osseointegration.