Effect of platelet-rich plasma on the healing of mandibular defects treated with fresh frozen bone allograft: a radiographic study in dogs.

The purpose of this study was to radiographically analyze the effect of autologous platelet rich plasma (PRP) on the healing of fresh frozen bone allograft (FFBA) placed in surgically created resection defects in mandibles of dogs. Bilateral resection defects measuring 1.5 cm × 1 cm were surgically created on the inferior border of the mandible in 10 adult male dogs. The defects were randomly divided into three groups: C, FFBA, and FFBA/PRP. In Group C, the defect was filled by blood clot only. In Group FFBA, the defect was filled with particulate fresh frozen bone allograft. In Group FFBA/PRP, it was filled with particulate fresh frozen bone allograft combined with PRP. At 90 days postoperative, standardized radiographs of the mandibles were obtained and results were quantitatively evaluated. Analysis of digitized radiographs indicated that non-PRP grafts were significantly less dense than the PRP grafts. Group FFBA/PRP also presented a statistically greater mineralized tissue area than Groups C and FFBA. Within the limits of this study, it can be concluded that PRP enhanced the healing of FFBA in resection defects in mandibles of dogs.

Bone marrow aspirate combined with low-level laser therapy: a new therapeutic approach to enhance bone healing.

This study evaluated the influence of bone marrow aspirate (BMA), low-level laser therapy (LLLT) and their combination on bone healing in surgically created critical-size defects (CSDs) in rat calvaria. 40 rats were divided into four groups: C (control), BMA, LLLT and BMA/LLLT. A 5mmdiameter CSD was created in the calvarium of each animal. In Group C, the defect was filled by blood clot only. In Group BMA, the defect was filled with BMA. In groups LLLT and BMA/LLLT, the defect received laser irradiation (InGaAlP laser), was filled with blood clot or BMA respectively, and irradiated again. Animals were euthanized 30 days postoperatively. Histomorphometric and immunohistochemical analyses were performed. Newly formed bone area (NFBA) was calculated as percentage of the total area of the original defect. Proliferating cell nuclear antigen (PCNA), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) immunohistochemical staining were performed. PCNA-positive, Runx2-positive and OCN-positive cells were quantified. Data were statistically analyzed. Group BMA/LLLT had significantly greater NFBA than groups C, BMA or LLLT. Group BMA presented significantly greater NFBA than control, while group LLLT did not. Group BMA/LLLT presented a significantly higher number of PCNA-positive and OCN-positive cells than any of the other groups. Groups BMA/LLLT and BMA showed a significantly lower number of Runx2-positive cells than groups C or LLLT. The combination of BMA/LLLT yielded significantly greater bone formation in surgically created CSD in rat calvaria when compared to control, or either treatment alone.

Effectiveness of two methods for preparation of autologous platelet-rich plasma: an experimental study in rabbits.

OBJECTIVES: The purpose of this study was to compare the quantity and quality of platelets in platelet-rich plasma (PRP) samples prepared using either the single- or the double-centrifugation protocol. METHODS: Ten adult white New Zealand rabbits were used. Ten ml of blood were drawn from each animal via cardiac puncture. Each blood sample was divided into two equal parts for PRP preparation: 5 ml of blood were centrifuged according to a single-centrifugation protocol (Group I), and 5 ml were centrifuged according to a double-centrifugation protocol (Group II). Manual platelet counts were performed on the whole blood and PRP samples of each group. Smears were also done on all samples in order to see the morphology of the platelets. The data obtained in the manual platelet count were submitted to statistical analysis (repeated measures ANOVA, Tukey, P<.05). RESULTS: The average whole blood platelet count was 446,389/µl. The PRP samples in Group II presented an average platelet amount significantly higher than that of Group I (1,986,875 ± 685,020/µl and 781,875 ± 217,693/µl, respectively). The PRP smears from Group II were the only one to present platelets with altered morphology (75% of the smears). A few lymphocytes with increased cytoplasm were observed in the PRP smears of both Groups I (25% of the smears) and II (62.5% of the smears). CONCLUSIONS: Within the limits of this study, it can be concluded that the double-centrifugation protocol resulted in higher platelet concentrations than did the single-centrifugation protocol. However, the double-centrifugation protocol caused alterations in platelet morphology and was more sensitive to small processing errors.

Bone healing in critical-size defects treated with new bioactive glass/calcium sulfate: a histologic and histometric study in rat calvaria.

This study analyzed histologically the influence of new spherical bioactive glass (NBG) particles with or without a calcium sulfate (CS) barrier on bone healing in surgically created critical-size defects (CSD) in rat calvaria. A CSD was made in each calvarium of 60 rats, which were divided into three groups: C (control): the defect was filled with blood clot only; NBG: the defect was filled with NBG only; and NBG/CS: the defect was filled with NBG covered by CS barrier. Subgroups were euthanized at 4 or 12 weeks. Amounts of new bone and remnants of implanted materials were calculated as percentages of total area of the original defect. Data were statistically analyzed. In contrast to Group C, thickness throughout defects in Groups NBG and NBG/CS was similar to the original calvarium. At 4 weeks, Group C had significantly more bone formation than Group NBG/CS. No significant differences were found between Group NBG and either Group C or Group NBG/CS. At 12 weeks, Group C had significantly more bone formation than Group NBG or NBG/CS. NBG particles, used with or without a CS barrier, maintained volume and contour of area grafted in CSD. Presence of remaining NBG particles might have accounted for smaller amount of new bone in Groups NBG and NBG/CS at 12 weeks post-operative.

Treatment of gingival recessions associated to cervical abrasion lesions with subepithelial connective tissue graft: a case report.

Extensive gingival recessions associated with cervical abrasions are common among the population. Several different surgical and/or restorative therapies have been proposed to correct these lesions. This manuscript reports the treatment of multiple gingival recessions associated to cervical abrasions. The procedure involved the utilization of subepithelial connective tissue graft (SCTG) combined with coronally advanced flap onto a previously restored root surface. At the postoperative follow-up visits, the success of the restorative/surgical approach was confirmed by the absence of bleeding to probing and periodontal pockets as well as presence of gingival tissue with normal color, texture and contouring. After 18 months of follow-up, the clinical conditions are stable with satisfactory root coverage and periodontal health. An excellent esthetical outcome was achieved and the patient is satisfied with case resolution.

Effect of platelet-rich plasma on bone healing of autogenous bone grafts in critical-size defects.

AIM: This study histologically analysed the effect of autogenous platelet-rich plasma (PRP), prepared according to a new semiautomatic system, on healing of autogenous bone (AB) grafts placed in surgically created critical-size defects (CSD) in rabbit calvaria. MATERIAL AND METHODS: Sixty rabbits were divided into three groups: C, AB and AB/PRP. A CSD was created in the calvarium of each animal. In Group C (control), the defect was filled by blood clot only. In Group AB (autogenous bone graft), the defect was filled with particulate autogenous bone. In Group AB/PRP (autogenous bone graft with platelet-rich plasma), it was filled with particulate autogenous bone combined with PRP. All groups were divided into subgroups (n=10) and euthanized at 4 or 12 weeks post-operatively. Histometric and histologic analyses were performed. Data were statistically analysed (anova, t-test, p<0.05). RESULTS: Group C presented significantly less bone formation compared with Group AB and AB/PRP in both periods of analysis (p<0.001). At 4 weeks, Group AB/PRP showed a statistically greater amount of bone formation than Group AB (64.44 +/- 15.0%versus 46.88 +/- 14.15%; p=0.0181). At 12 weeks, no statistically significant differences were observed between Groups AB and AB/PRP (75.0 +/- 8.11%versus 77.90 +/- 8.13%; p>0.05). It is notable that the amount of new bone formation in Group AB/PRP at 4 weeks was similar to that of Group AB at 12 weeks (p>0.05). CONCLUSION: Within its limitation, the present study has indicated that (i) AB and AB/PRP significantly improved bone formation and (ii) a beneficial effect of PRP was limited to an initial healing period of 4 weeks.

Local application of tetracycline solution with a microbrush: an alternative treatment for persistent periodontitis.

OBJECTIVE: Topical antibiotics may overcome shortcomings of mechanical therapy for localized persistent periodontitis. This double-center, single-blind, randomized controlled study aimed to evaluate the microbiologic profile and clinical parameters of persistent periodontal pockets after treatment with tetracycline solution. METHOD AND MATERIALS: Thirty-seven patients who had at least 4 non-adjacent sites of persistent periodontal pockets with probing depth of at least 5 mm and bleeding on probing were randomly assigned to test and control groups. In the test group, 2 teeth received 4 applications of tetracycline solution (100 mg/mL) with a microbrush(T), while the other 2 teeth received the same treatment plus 1 session of scaling and root planing(SRP+T). In the control group, 2 teeth received 1 session of scaling and root planing(SRP), and the other 2 teeth received 4 applications of saline with a microbrush plus 1 session of scaling and root planing(SRP+S). Clinical parameters of probing depth, bleeding on probing, visible plaque index, gingival bleeding index, gingival recession, as well as clinical attachment level and subgingival plaque samples (evaluated by polymerase chain reaction) were measured at baseline and 1, 3, and 6 months. RESULTS: All therapies yielded statistically significant data on clinical measurements with no significant differences among groups. Presence of bacteria decreased in both groups, but only in the test group was a significant decrease of Porphyromonasgingivalis,Tannerellaforsythia, and Actinobacillusactinomycetemcomitans noted up to 6 months. CONCLUSION: Tetracycline applied with a microbrush may be an alternative treatment for persistent periodontitis that can probably be mediated by reduction of microorganism proliferation

Periodontal tissue response to coverage of root cavities restored with resin materials: a histomorphometric study in dogs.

BACKGROUND: The purpose of this study was to histomorphometrically evaluate the response of periodontal tissues covering Class V resin restorations in dogs. METHODS: After raising a mucoperiosteal flap, bony defects measuring 5 x 5 mm were created on the buccal aspect of the canines of five dogs followed by cavity preparations on the root surface measuring 3 x 3 x 1 mm. Before repositioning the flap to cover the bone defect, the cavities were restored with composite resin (CR) or resin-modified glass ionomer cement (RMGIC) or were left unrestored as control (C). The dogs were euthanized 90 days after surgery. Specimens comprising the tooth and periodontal tissues were removed, processed routinely, cut into longitudinal serial sections in the buccolingual direction, and stained with hematoxylin and eosin (H&E) or Masson's trichrome. The most central sections were selected for histomorphometric analysis. RESULTS: Histomorphometric analysis revealed apical migration of epithelial tissue onto the restorative materials (RMGIC and CR). The C group presented significantly longer connective tissue attachment (P <0.05) than the RMGIC and CR groups and significantly higher bone regeneration (P <0.05) compared to the RMGIC group. Histologically, the cervical third (CT) of all groups had the most marked chronic inflammatory infiltrate. CONCLUSIONS: Within the limits of this study, it can be concluded that the restorative materials used exhibit biocompatibility; however, both materials interfered with the development of new bone and the connective tissue attachment process.

Bone healing in surgically created defects treated with either bioactive glass particles, a calcium sulfate barrier, or a combination of both materials. A histological and histometric study in rat tibias.

OBJECTIVE: The purpose of this study was to histologically analyze the influence of bioactive glass and/or a calcium sulfate barrier on bone healing in surgically created defects in rat tibias. MATERIAL AND METHODS: Sixty-four rats were divided into 4 groups: C (control), CS (calcium sulfate), BG (bioactive glass), and BG/CS (bioactive glass/calcium sulfate). A surgical defect was created in the tibia of each animal. In Group CS, a calcium sulfate barrier was placed to cover the defect. In Group BG the defect was filled with bioactive glass. In Group BG/CS, it was filled with bioactive glass and protected by a barrier of calcium sulfate. Animals were sacrificed at 10 or 30 days post-operative. The formation of new bone in the cortical area of the defect was evaluated histomorphometrically. RESULTS: At 10 days post-operative, Group C presented significantly more bone formation than Groups CS, BG, or BG/CS. No statistically significant differences were found between the experimental groups. At 30 days post-operative, Group C demonstrated significantly more bone formation than the experimental groups. Groups CS and BG/CS showed significantly more bone formation than Group BG. No statistically significant differences were found between Group CS and BG/CS. CONCLUSIONS: (a) the control groups had significantly more bone formation than the experimental groups; (b) at 10 days post-operative, no significant differences were found between any of the experimental groups; and (c) at 30 days post-operative, the groups with a calcium sulfate barrier had significantly more bone formation than the group that used bioactive glass only.

Healing of dehiscence defects following root surface demineralization with tetracycline: a histologic study in monkeys.

BACKGROUND: The purpose of this study was to histologically evaluate the healing of experimental dehiscence defects after surface demineralization with tetracycline hydrochloride. METHODS: Six adult male monkeys (Cebus apella) were used in this study. Dehiscence defects were surgically created on the buccal aspect of the mandibular lateral incisors in all animals. The root surfaces were debrided and planed. In a split-mouth design, a 10% tetracycline hydrochloride solution was applied to one tooth for 4 minutes (T group), followed by irrigation with saline. The contralateral tooth served as a control (C group). The flaps were repositioned and sutured. The animals were sacrificed at 6 months postoperatively and histological sections were processed. Computer-assisted histomorphometric analysis was used to evaluate the formation of new cementum, new bone, new connective tissue attachment, and length of the epithelium (junctional and sulcular). RESULTS: Bone regeneration was similar in both groups (1.5 +/- 0.3 mm for the T group and 1.5 +/- 0.6 mm for the C group). The C group showed more new cementum than the T group (2.3 +/- 0.3 mm versus 2.2 +/- 0.3 mm) as well as a longer epithelium (1.0 +/- 0.3 mm versus 0.9 +/- 0.2 mm). The T group presented more new connective tissue attachment (3.1 +/- 0.2 mm) than the C group (2.9 +/- 0.6 mm). However, no statistically significant differences were detected between the two groups. CONCLUSIONS: The amount of new attachment was similar in both groups. Root conditioning with 10% tetracycline solution did not produce any additional new attachment in comparison to the controls.