Ozone therapy effect in medication-related osteonecrosis of the jaw as prevention or treatment: microtomographic, confocal laser microscopy and histomorphometric analysis.

OBJECTIVE: This study aimed to evaluate the efficacy of ozone therapy in the preoperative (prevention) and/or postoperative (treatment) of MRONJ. MATERIAL AND METHODS: Forty male Wistar rats were caudally treated with zoledronic acid (ZOL) and to ozone therapy before extraction (prevention, POG), after extraction (treatment, TOG), or both (prevention and treatment, TPOG), and treated with saline (SAL). The animals received intramuscular fluorochrome (calcein and alizarin), and 28 days postoperatively, they were euthanized, and the tissues were subjected to microtomographic computed tomography (microCT), LASER confocal, and histomorphometric analyses. RESULTS: Micro-CT showed a higher bone volume fraction average in all groups than that in the ZOL group (P < 0.001), the ZOL group showed high porosity (P = 0.03), and trabecular separation was greater in the TOG group than in the POG group (P < 0.05). The mineral apposition rate of the POG group was high (20.46 ± 6.31) (P < 0.001), followed by the TOG group (20.32 ± 7.4). The TOG group presented the highest mean newly formed bone area (68.322 ± 25.296) compared with the ZOL group (P < 0.05), followed by the SAL group (66.039 ± 28.379) and ZOL groups (60.856 ± 28.425). CONCLUSIONS: Ozone therapy modulated alveolar bone repair in animals treated with ZOL, mainly after surgery trauma, leading to bone formation as healing tissue. CLINICAL RELEVANCE: Osteonecrosis has been a challenge in dentistry, and owing to the lack of a consensus regarding therapy, studies presenting new therapies are important, and ozone has been one of the therapies explored empirically.

Sodium alendronate is an effective adjunctive therapy for treating periodontitis in male rats treated with anticancer chemotherapy.

OBJECTIVES: To assess sodium alendronate as a local adjunctive therapy for treating experimental periodontitis in male rats treated with chemotherapy. DESIGN: One-hundred-eighty male rats were randomly divided into two groups (n = 90) based on the systemic treatments: PSS, physiological saline solution; and 5-Fluorouracil, and then, subdivided into three subgroups (n = 30): NT, no treatment; scaling and root planing; and sodium alendronate. Treatments were performed 7 days after induction of experimental periodontitis. Specimens were collected at 14, 22, and 37 days after induction. Alveolar bone level, percentage of bone in the furcation, percentage of non-vital bone in the furcation, histopathologic features, and immunolabeling pattern for tartrate-resistant acid phosphatase (TRAP) and osteocalcin (OCN) were evaluated. RESULTS: The lowest amount of alveolar bone and highest amount of non-vital bone was found in group 5-Fluorouracil when no treatment was performed. In animals receiving 5-Flurouracil and subjected to periodontal treatment, adjunctive sodium alendronate resulted in higher percentage of bone in the furcation and higher alveolar bone loss, when compared with scaling and root planing alone. Better structural and cellularity patterns were found in the periodontal tissues when sodium alendronate was used, regardless of systemic treatment. Higher TRAP-expression was found when no treatment was performed. Sodium alendronate didn't affect the immunolabeling pattern of osteocalcin in the presence of 5-Fluorouracil. CONCLUSION: Adjunctive therapy with local sodium alendronate prevented alveolar bone loss and improved the histopathological features of the periodontal tissues following scaling and root planing in male rats with experimental periodontitis receiving anticancer chemotherapy with 5-Fluorouracil.

Hand instrumentation provides improved tissue response over ultrasonic scaler and substantiates safe dental practice: An in vivo study in rats.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of hand debridement (HD) versus ultrasonic dental scaler (UDS) for the treatment of experimental periodontitis (EP) in rats. MATERIAL AND METHODS: Thirty 3-month-old male rats were used. EP was induced around the mandibular first molars (right and left). Seven days after induction, the treatments with either HD (n = 30) or UDS (n = 30) were randomly performed in each molar. Euthanasia were performed at 7, 15, and 30 days after treatment. Histometric (percentage of bone in the furcation [PBF]), histopathological, and immunohistochemical (for detection of tartrate-resistant acid phosphatase [TRAP] and osteocalcin [OCN]). Parametric data (PBF and TRAP) was analyzed by One-way ANOVA followed by Tukey's post-test. OCN was analyzed by Kruskal-Wallis followed by Student-Newman-Keuls post-test. The level of significance was 5%. RESULTS: Group HD presented higher PBF and lower TRAP-immunolabeling at 30 days as compared with UDS in the same period (p≤0.05). Group HD presented higher OCN immunolabeling at 30 days as compared with 7 and 15 days (p≤0.05). Persistent and exacerbated inflammatory process was observed in some specimens from group UDS at 30 days, as well as the bone trabeculae presented irregular contour, surrounded by many active osteoclasts. CONCLUSION: Nonsurgical periodontal therapy with HD resulted in higher PBF and lower expression of TRAP as compared with UDS. Also, HD increased the expression of OCN over time.

Modified one-stage technique of laterally positioned flap with sub-epithelial connective tissue graft for the treatment of peri-implant soft tissue dehiscence in the esthetic zone: A 5-year follow-up.

BACKGROUND: The state of art of tissue grafting allows significant improvements in the soft tissue phenotype. The importance of appropriate soft tissue phenotype around implants is supported by recent literature. The present case report aims to describe the application of a modified one-stage technique of laterally positioned flap with sub-epithelial connective tissue graft (CTG) for the treatment of peri-implant soft tissue dehiscence in the esthetic zone. METHODS AND RESULTS: A 38-year-old female presented 4 years following prosthetic restoration, with a localized soft tissue defect in height and thickness at the buccal aspect of the implant at #11, and the abutment exposed to the oral cavity. Incisions with internal and external bevels were performed in the medial and distal margins of the dehiscence, respectively, toward the alveolar mucosa. After intrasulcular incision, the area was de-epithelialized and a split thickness flap from mesial #11 to distal #14 was elevated. A tunnel was prepared at #21. CTG was stabilized mesially, within the tunnel prepared, and distally, through simple interrupted sutures. Vertical compressive sutures were performed on the CTG. The flap was laterally positioned and secured by means of suspended sutures. Healing was uneventful, increased thickness and height of the peri-implant mucosa were observed, with great esthetic outcome. The soft tissue margin was stable at the 5-year follow-up. CONCLUSION: The technique described in this case report showed promising results for covering exposed implant abutment in the esthetic zone, as well as for modification of the soft tissue phenotype around dental implants. KEY POINTS: Why is this case new information A modified one-stage technique that allows coverage of exposed metallic displays of titanium implants while modifying the soft tissue phenotype in the esthetic zone. What are the keys to successful management of this case? Meticulous incisions and internal and external bevels. Adequate elevation to allow repositioning without tension. Adequate graft size that extends through all the recipient bed; and tension-free suture. What are the primary limitations to success in this case? Presence of an implant installed in a non-satisfactory three-dimensional position. And poor hygiene and plaque accumulation postoperatively.

A new multiphase calcium phosphate graft material improves bone healing-An in vitro and in vivo analysis.

This study aims to evaluate the potential of a novel biomaterial synthesized from amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), and hydroxyapatite (HA) to repair critical-sized defects (CSD) in rabbit calvaria. In vitro analyses of cell viability, cell proliferation, formation of mineral nodules, and cell differentiation using qPCR were performed for comparing experimental calcium phosphate (ECP), deproteinized bovine bone (DBB), and beta-tricalcium phosphate (ß-TCP). Bilateral CSDs were created in 45 rabbit calvaria. Six groups were evaluated: ECP, ECP + fibrin sealant (ECP + S), coagulum, autogenous bone, DBB, and ß-TCP. Euthanasia was performed at 2, 4, and 8 weeks, followed by micro-computed tomography and histological and immunohistochemical analyses. Results from in vitro analyses revealed similar biocompatibility for all tested materials and a tendency for higher gene expression of some bone markers in the ECP group than in ß-TCP and DBB groups at 7 days. In contrast to that in DBB and ß-TCP groups, ECP displayed growing bone volume over total volume percentage (BV/TV%) with time in vivo. Histological analysis revealed a greater number of giant cells and reduced size of grafted particles in ECP during all periods of analysis. RUNX-2 expression was statistically lower in ECP than DBB at 2 and 4 weeks. Despite no statistical significance, ECP presented the highest absolute values for ALP-expression at 2, 4, and 8 weeks compared with other groups. Together, our findings indicate that a combination of the ACP, OCP, and HA phases into ECP is beneficial and promising for bone regeneration.

Tamoxifen improves homeostasis in the peri-implant bone remodeling of osseointegrated titanium implants.

BACKGROUND: The purpose of this preclinical study was to evaluate the influence of tamoxifen (TAM) on the peri-implant bone remodeling of osseointegrated titanium implants in ovariectomized female rats. MATERIALS AND METHODS: Seventy-two female rats underwent bilateral ovariectomy 20 weeks before implants placement. One titanium implant was inserted in each tibia of the animals. Six weeks following the implant surgery, animals were randomly divided into two experimental groups (n = 36), which received either saline solution (SS) or tamoxifen citrate (TAM) via gavage until euthanasia. Euthanasia was performed at 30, 60, and 90 days after the first gavage. Assessments of bone to implant contact (BIC), bone ingrowth percentage (BIN), morphological description of cellular and tissue reactions, immunohistochemistry for the detection of bone morphogenetic protein 2/4 (BMP2/4), runt-related transcription factor 2 (RUNX-2), osteocalcin (OCN) and tartrate-resistant acid phosphatase (TRAP), and bone chemical composition through scanning electron microscopy with energy-dispersive x-ray spectroscopy were performed. RESULTS: Tamoxifen group presented higher BIC, higher BIN, higher RUNX-2 and OCN, lower TRAP-positive cells/mm2 , and no differences regarding BMP-2/4 positive cells/mm2 than SS group in all periods. TAM group also showed higher Ca/P rate than SS group. CONCLUSION: Tamoxifen enhanced the remodeling of the bone surrounding titanium implants in ovariectomized rats.

Evaluation of antimicrobial photodynamic therapy with acidic methylene blue for the treatment of experimental periodontitis.

OBJECTIVE: To investigate the security and effectiveness of antimicrobial photodynamic therapy (aPDT) with a citric acid-based methylene blue (MB) on the periodontal repair following the treatment of ligature-induced experimental periodontitis (EP) in rats. MATERIAL AND METHODS: Were used 120 male rats, randomly divided into 4 experimental groups (n = 30): no treatment (NT), SRP alone (SRP), SRP plus aPDT using conventional MB pH 7.0 (aPDT-pH7), SRP plus aPDT using acidic MB pH 1.0 (aPDT-pH1). EP was induced at day 0 by the placement of a ligature around the mandibular left first molars. Ten animals per group/period were euthanized at 14, 22 and 37 days. Histopathological, histometric (percentage of bone in the furcation [PBF]) and immunohistochemical (for tartrate-resistant acid phosphatase [TRAP] and osteocalcin [OCN]) analyses were performed. Data were statistically analyzed. RESULTS: aPDT-pH1 showed the highest PBF as compared with the other treatments. Collectively, tissues' reaction to both dyes were controlled and healthy for the periodontium. Both aPDT protocols reduced the extent and intensity of the local inflammatory response, reduced the alveolar bone resorption, and promoted a better structural arrangement of the connective tissue as compared with SRP. TRAP expression was downregulated while OCN expression was upregulated by aPDT as compared with SRP alone. CONCLUSION: Our data implicate that the novel MB pH 1.0 is as safe as the conventional MB for use in aPDT and raises its additional benefit of increasing the amount of alveolar bone in the furcation.

The influence of antineoplastic agents on the peri-implant bone around osseointegrated titanium implants: an in vivo histomorphometric and immunohistochemical study.

BACKGROUND AND OBJECTIVE: The interaction between antineoplastic drugs used for treating cancer and non-affected tissues remains poorly assessed and may be critical for maintaining the quality of life for patients during and after treatment. This pre-clinical study evaluated the effects of cisplatin (CIS) and 5-fluorouracil (5-FU) on the peri-implant repair process around osseointegrated titanium implants installed in the tibiae of rats. MATERIAL AND METHODS: Were used 90 male rats, randomly divided into three groups (n = 30): physiological saline solution (PSS), CIS, and 5-FU. Titanium implants (4.0 × 2.2 mm) were inserted in both tibiae of all animals at day 0. The animals received either PSS, CIS, or 5-FU at 35 and 37 days. Euthanasia was performed at 50, 65, and 95 days after surgery. Histometric (bone/implant contact [BIC]) and bone area fraction occupancy (% BAFO), histological, and immunohistochemical (for bone morphogenetic protein 2/4 [BMP2/4], Runt-related transcription factor 2 [RUNX2], osteocalcin [OCN], and tartrate-resistant acid phosphatase [TRAP]) analyses were performed. Data were statistically analyzed. RESULTS: Groups CIS and 5-FU presented lower BIC and lower BAFO as compared with PSS in all time points. The imbalance in bone turnover was observed by the lower number of BMP2/4-, RUNX2-, and OCN-positive cells/mm2 and the higher number of TRAP-positive cells/mm in groups CIS and 5-FU as compared with PSS in all time points. Persistent and exacerbated inflammation was observed in groups CIS and 5-FU. CONCLUSIONS: Both antineoplastic agents interfered negatively in the bone turnover around osseointegrated titanium implants. CLINICAL RELEVANCE: Closer and more careful follow-up of patients with osseointegrated implants that will undergo chemotherapy with either CIS or 5-FU shall be performed.

Antineoplastic agents aggravate the damages caused by nicotine on the peri-implant bone: an in vivo histomorphometric and immunohistochemical study in rats.

OBJECTIVE: To assess the interaction between chemotherapy and normal tissues is critical to assure quality of life during and after the treatment of cancer. This study evaluated the influence of cisplatin (CIS) and 5-fluorouracil (5-FU) over the peri-implant tissues around osseointegrated titanium implants in animals previously exposed to nicotine. Materials and methods One hundred twenty male rats were divided into two groups, receiving via subcutaneous injection, either physiological saline solution (PSS) (n = 30) or nicotine hemissulfate (NIC) (n = 90) for 30 days prior to implants' placement. One titanium implant (4.0 × 2.2 mm) was installed in each tibia of all animals. PSS and NIC were continued for 30 days after surgery. Five days after cessation, rats were subdivided into three subgroups in accordance with systemic treatments with either PSS, CIS, or 5-FU. Euthanasia was performed at 50, 65, and 95 days post-surgery. Histometric, histopathological, and immunohistochemical analyses were performed. RESULTS: NIC-CIS and NIC-5FU presented lower BIC (50, 65, and 95 days) and bone area fraction occupancy (BAFO) (65 and 95 days) than group NIC. Intense inflammatory infiltration, severe tissue breakdown, reduced expression of bone formation biomarkers, and upregulation of TRAP were observed in NIC-CIS and NIC-5FU when compared with group NIC. TRAP expression was significantly higher in NIC-5FU as compared with NIC-CIS at 50 and 95 days. Groups NIC, NIC-CIS, and NIC-5FU presented statistically significant negative impact in all outcome parameters than group PSS. CONCLUSION: CIS and 5-FU severely disrupted the peri-implant tissues around osseointegrated implants in animals previously exposed to nicotine. CLINICAL RELEVANCE: Assessing the interaction between chemotherapy and normal tissues is critical to assure quality of life during and after the cancer treatment.

Influence of the treatment with the antineoplastic agents 5-fluorouracil and cisplatin on the severity of experimental periodontitis in rats.

PURPOSE: The determination on how antineoplastic agents interfere on the progression of periodontitis is critical for improvement and even development of novel therapeutic approaches for periodontal management. This study evaluated the influence of chemotherapy with 5-fluorouracil (5-FU) or cisplatin (CIS) on healthy periodontal tissues and on the progression of experimental periodontitis (EP). METHODS: One hundred forty-four male rats were divided into six groups (n = 24). Each group was treated with physiological saline solution (PSS) 0.9%, 5-FU, or CIS. Experimental periodontitis (EP) was induced by ligature placement. Animals were euthanized at 7, 15, and 30 days after treatment. Data were statistically analyzed (p ≤ 0.05). RESULTS: The groups with EP and treated with 5-FU or CIS showed lower percentage of bone volume in the furcation region and higher percentage of alveolar bone loss, higher number of TRAP-positive cells, and lower number of PCNA-positive cells when compared group with EP and treated with PSS (p ≤ 0.05). Groups with EP and treated with 5-FU or CIS showed high immunolabelling pattern of RANKL, TNF-α, and IL-1ß, moderate of BAX, and low of HIF-1α. Histological analysis showed severe tissue breakdown in the groups with EP and treated with 5-FU or CIS. CONCLUSIONS: Chemotherapy with antineoplastic agents 5-FU and CIS increased the intensity and duration of the inflammation and compromised tissue repair by reduction in cellular and vascular turnover. The more severe periodontal breakdown was caused by 5-FU.

Adjuvant therapy with 1% alendronate gel for experimental periodontitis treatment in rats.

PURPOSE: The aim of this study was to evaluate the effects of locally delivered 1% alendronate (ALN) gel used as an adjunct to non-invasive periodontal therapy. METHODS: Ligature-induced periodontitis was performed in 96 rats. The ligature was tied in the cervical area of the mandibular left first molar. The animals were randomly divided into 4 groups: 1) NT, no treatment; 2) SRP, scaling and root planning; 3) SRP/PLA, SRP followed by filling the periodontal pocket with placebo gel (PLA); and 4) SRP/ALN, SRP followed by filling the periodontal pockets with 1% ALN gel. Histomorphometric (percentage of bone in the furcation region [PBF]) and immunohistochemical (receptor activator of nuclear factor-κB ligand, osteoprotegerin, and tartrate-resistant acid phosphatase) analyses were performed. Data were statistically analyzed, with the threshold of statistical significance set at P≤0.05. RESULTS: The SRP, SRP/PLA, and SRP/ALN groups presented a higher PBF than the NT group (P≤0.01) at 7, 15, and 30 days. The SRP/ALN group presented a higher PBF than the SRP/PLA group in all experimental periods, as well as a higher PBF than the SRP group at 15 and 30 days. No differences were observed in the immunohistochemical analyses (P>0.05 for all). CONCLUSIONS: Locally delivered 1% ALN gel used as an adjunct to SRP enhanced bone regeneration in the furcation region in a rat model of experimental periodontitis.

Laterally Positioned Flap with Subepithelial Connective Tissue Graft Modified One-Stage Procedure for the Treatment of Deep Isolated Gingival Recessions in Mandibular Incisors.

The laterally positioned flap (LPF) has been proposed as a promising treatment for isolated gingival recessions (GRs) in mandibular incisors. Several modifications have been proposed to reduce the risk of gingival recession (GR) at the donor tooth site. Therefore, the aim of this was to describe a modified one-stage procedure of performing the LPF associated with the subepithelial connective tissue graft (LPF + SCTG) with the modifications for the treatment of deep isolated GR in mandibular incisors. The modified one-stage technique (LPF + SCTG) is unique because it was presented being bilaminar with tunneled connective tissue graft (CTG) in the adjacent tooth and extended to the flap donor site, without a submarginal incision in the adjacent tooth, taking the entire band of the keratinized tissue (KT) into the flap. In addition, 3 clinical cases were described using this surgical technique. Three healthy patients with Cairo RT1 or RT2 GRs on teeth 31 or 41 were treated with the LPF + SCTG technique. Probing depth (PD), clinical attachment level (CAL), complete root coverage (CRC), mean root coverage (MRC), recession depth (RD), and keratinized tissue width (KTW) were assessed at baseline and in the follow-up periods of 18, 24, and 48 months, in the cases 1, 2, and 3, respectively. The LPF + SCTG with the modifications presented is a predictable approach for the treatment of deep isolated RT1 and RT2 GRs in mandibular incisors that are well positioned in the bone envelope with the presence of KTW adjacent to GR and adequate vestibule depth in the donor area of the flap.

Influence of immunosuppression on the progression of experimental periodontitis and on healthy periodontal tissue: A rat in vivo study.

Background. The potent anti-inflammatory and immunosuppressive properties of glucocorticoids (GCs) might influence the progression of some disorders, such as periodontitis. Hence, this study aimed to investigate the influence of dexamethasone (DEX) on the alveolar bone loss (ABL) of healthy and periodontally compromised molars in rats. Methods. Thirty male rats were randomly assigned to two groups: physiological saline solution (PSS) and DEX. The animals received subcutaneous injections of either 0.5 mL of PSS) (group PSS) or 2 mg/kg of DEX (group DEX) from one day before experimental periodontitis (EP) induction until euthanasia. EP was induced through ligature placement around the mandibular lower first molars at day 0. Contralateral molars remained unligated. Ten animals per period were euthanized on days 3, 7, and 14. Morphometric analysis was performed to access the ABL. Data were statistically analyzed with ANOVA followed by post hoc Tukey tests (P ≤ 0.05). Results. Higher ABL was observed in both groups on days 7 and 14 than on day 3 (P ≤ 0.05). Concerning periodontitis, higher ABL was observed in group DEX on days 3, 7, and 14 days than group PSS at the same time intervals (P ≤ 0.05). Also, even in the contralateral unligated molars, group DEX exhibited higher ABL on days 3, 7, and 14 days than group PSS at the same time intervals (P ≤ 0.05). Conclusions. Collectively, it can be concluded that DEX aggravates EP and induces spontaneous ABL in the healthy periodontium.

Platelet-rich fibrin for wound healing of palatal donor sites of free gingival grafts: Systematic review and meta-analysis.

BACKGROUND: Platelet-rich fibrin (PRF) has been referred to as a second-generation platelet concentrate, associated with improvements on the healing of palatal wounds followed by FGG harvesting. The aim of this systematic review and meta-analysis was to assess the complete wound epithelialization and postoperative pain when PRF was used in palatal wounds following free gingival graft (FGG) harvesting. MATERIAL AND METHODS: PubMed (Medline), EMBASE and Scopus were searched by two independent individuals up to and including March 2020 in order to identify controlled and randomized controlled clinical trials on the use of PRF at palatal donor sites of FGG. The outcomes assessed were epithelialization and postoperative pain. The risk of bias of the included studies was evaluated using Cochrane Collaboration's domain-based two-part tool. Random effects meta-analyses were conducted with 95% confidence intervals. RESULTS: The search strategy identified 555 potentially eligible articles, of which 6 randomized controlled clinical trials were included. In the qualitative analysis, most studies (83.3%) reported lower postoperative pain in treatment groups, while all studies accessing epithelialization demonstrated earlier complete wound closure in groups treated with PRF. The discomfort and complete re-epithelialization were more favorable in groups PRF when compared to control groups (P<0.00001). CONCLUSIONS: Within the limits of the present study, it can be concluded that the use of PRF for wound healing of palatal donor sites of FGG may decrease postoperative pain and induce earlier complete wound epithelialization. Key words:Wound healing, oral surgery procedures, pain, postoperative.

Influence of systemic strontium ranelate on the progression and as adjunctive therapy for the nonsurgical treatment of experimental periodontitis.

BACKGROUND: Strontium Ranelate (SR) presents overlapping osteoanabolic and anti-resorptive activity. However, the effects of SR on the progression of periodontitis through the alveolar bone and its potential applicability as adjunctive therapy to scaling and root planning remain poorly accessed. The aim of this study was to evaluate the effects of systemic (SR) both on the progression of experimental periodontitis (EP) and as adjunctive therapy to SRP. MATERIAL AND METHODS: Eighty male rats were divided into four groups (n=20): EP-PSS: EP induction and systemic administration of physiological saline solution (PSS); EP-SR: EP induction and systemic administration of SR; EP-SRP/PSS: EP induction, SRP and systemic administration of PSS; EP-SRP/SR: EP induction, SRP and systemic administration of SR. Seven days after ligature placement, SRP was performed in EP-SRP/PSS and EP-SRP/SR, as well as the systemic administration of either PSS or SR were initiated and continued until euthanasia in all groups. Animals were euthanized at 7 and 30 days after the beginning of the systemic treatments. Histological, histometric (percentage of bone in the furcation [PBF]) and immunohistochemical (tartrate-resistant acid phosphatase [TRAP], Osteocalcin [OCN] and leukocyte common antigen [CD 45]) analyses were performed. Data were statistically analyzed. RESULTS: EP-SRP/PSS showed a significantly more organized pattern of the connective tissue and alveolar bone structure than EP-SRP/SR. EP-SR showed significantly higher PBF than EP-PSS, however, EP-SRP/PSS showed no difference with EP-SRP/SR at 30 days. CONCLUSIONS: SR reduced the alveolar bone loss in non-treated animals and presented no standout benefits over the conventional forms of treating EP. Key words:Strontium Ranelate, periodontal disease, root planing, alveolar bone loss.

Association of hyaluronic acid with a deproteinized bovine graft improves bone repair and increases bone formation in critical-size bone defects.

BACKGROUND: This study is designed to evaluate the potential of different formulations of hyaluronic acid (HA) to improve new bone formation in critical-size calvaria defect (CSD) when combined with a deproteinized bovine graft (DBG) material. METHODS: Thirty male rats were used. A 5-mm-diameter CSD was created and three experimental groups (n = 10) were randomly assigned based on the treatments performed. Group DBG: CSD filled with a DBG; group DBG/LV: CSD filled by the combination of DBG and HA in a low-viscosity crosslinking agent; group DBG/HV: CSD filled by the combination of DBG and HA in a high-viscosity crosslinking agent. Animals were euthanized 30 days postoperatively. Histological, histometric (percentage of newly formed bone [PNFB], percentage of remaining graft particles, histochemical, and immunohistochemical (bone morphogenetic protein 2/4 [BMP2/4], osteocalcin [OCN], and tartrate-resistant acid phosphatase [TRAP]) analyses were performed. RESULTS: The highest PNFB was observed in DBG/HV when compared with the other groups (P ≤0.05). DBG/LV and DBG/HV presented almost no inflammatory cells. In contrast, inflammation was observed in group DBG. Extensive resorption of graft particles was observed in group DBG, which was not present in DBG/LV and DBG/HV as confirmed by the larger size of the particles (P ≤0.05). BMP2/4 and OCN immunolabeling were higher in DBG/HV when compared with group DBG (P ≤0.05). Increased number of TRAP-positive cells was observed in DBG/LV and DBG/HV (P ≤0.05). Lower percentage of mature collagen fibers was observed in DBG/HV (P ≤0.05). CONCLUSION: The combination of HA in a high-viscosity crosslinking agent with DBG improves the bone repair process and increases the amount of newly formed bone towards CSDs in rat calvaria.

Chronic consumption of alcohol increases alveolar bone loss.

This study evaluated the effects of the chronic consumption of different concentrations of alcohol on the experimental periodontitis (EP). 160 rats were divided into 4 groups: (EP-NT) rats with EP and no alcohol exposure; (EP-A14) rats with EP exposed to 14% alcohol; (EP-A25) rats with EP exposed to 25% alcohol; (EP-A36) rats with EP exposed to 36% alcohol. The animals from the EP-A14, EP-A25 and EP-A36 groups were subjected to different concentrations of alcohol 30 days before EP induction. The histological characteristics, percentage of bone in the furcation (PBF) and bone metabolism in the furcation region were evaluated. The PBF and tartrate-resistant acid phosphatase (TRAP) data were subjected to statistical analysis. The EP-A14, EP-A25 and EP-A36 groups had lower PBFs compared with the EP-NT group. A more severe inflammatory process and a greater number of TRAP+ cells were also observed. In the EP-A14, EP-A25 and EP-A36 groups, the inflammatory process became more severe as the ingested alcoholic concentration increased. An increase in RANKL immunolabeling and a significantly higher number of TRAP+ cells were also observed. We conclude that chronic alcohol consumption increases the severity of experimental periodontitis in a dose-dependent manner by increasing the magnitude of local inflammatory responses and stimulating alveolar bone resorption.

Influence of adjuvant therapy with green tea extract in the treatment of experimental periodontitis.

AIM: This study evaluated the effects of topical green tea extract solution (GTE) as adjuvant therapy to mechanical debridement for the treatment of experimental periodontitis (EP). MATERIAL AND METHODS: We used 120 male rats (Rattus norvegicus albinus - Wistar), divided into the following four groups: NEP (sham) (n = 30): no experimental periodontitis (NEP), only simulation of EP by installation and removal of a ligature; EP (n = 30): EP induction by ligature; SRP (n = 30): EP, scaling and root planing (SRP), and irrigation with physiological saline solution; SRP/GT (n = 30): EP, SRP, and irrigation with GTE. Histologic analysis and immunohistochemistry were performed for detection of interleukin (IL)1ß, tumor necrosis factor-alpha (TNF-α), IL-10, and anti-tartrate resistant acid phosphatase (TRAP) in the furcation area. The percentage of bone in the furcation (PBF) was considered the primary variable and evaluated at 14, 22, and 37 days. The data from the histological analysis and the IL- 1B, TNF- A, and IL-10 were submitted to a Kruskal-Wallis variance test and Dunn's posttest (p ≤ 0.05). The histometric data and TRAP were submitted to analysis of variance (ANOVA) and Tukey's posttest (p ≤ 0.05). RESULTS: The SRP/GT group showed lower inflammatory process, lower immunolabeling pattern of IL-1ß and TNF-α, and greater immunolabeling pattern of IL-10 compared with the EP and SRP groups at 22 days. Fewer TRAP-positive multinucleated osteoclasts were observed in all periods in the SRP/GT group (5.22 ± 0.65; 7.33 ± 0.80; 8.55 ± 1.15) compared with the SRP group (30.67 ± 8.55; 13.22 ± 0.77; 13.87 ± 0.77). Higher PBF was observed in all periods in the SRP/GT group (74.65 ± 7.14; 76.61 ± 5.36; 79.24 ± 3.75) compared with the SRP group (61.60 ± 9.48; 54.84 ± 9.06; 53.25 ± 9.66). CONCLUSION: GTE adjuvant to SRP reduced inflammation, osteoclastic activity, and alveolar bone loss in EP.

Antineoplastic agents exacerbate periodontal inflammation and aggravate experimental periodontitis.

AIM: This study evaluated the effects of 5-fluorouracil (5-FU) and cisplatin (CIS) in healthy periodontal tissues and in the early stages of experimental periodontitis (EP) in rats. METHODS: One hundred and eighty male rats were divided into three groups, which were submitted to the following systemic treatments: physiological saline solution (PSS); CIS and 5FU. Each group was subdivided into two subgroups: without (NEP) and with (EP) induction of EP. Animals were euthanized at 3, 5 and 7 days post-treatment. Histological, histometric (percentage of bone in the furcation [PBF]) and immunohistochemical (for tumour necrosis factor-α, interleukin-1ß and receptor activator of nuclear factor-κB ligand) analyses were performed. Data were statistically analysed. RESULTS: CIS-NEP and 5FU-NEP showed more inflammation than PSS-NEP at 3, 5 and 7 days. CIS-EP and 5FU-EP showed more inflammation and lower PBF than PSS-EP at all periods of evaluation. 5FU-EP showed lower PBF than CIS-EP at 5 and 7 days. CONCLUSION: 5-FU and CIS exacerbated periodontal inflammation and aggravated the progression of EP in its early stages.

Application of Autologous Platelet-Rich Plasma on Tooth Extraction Site Prevents Occurence of Medication-Related Osteonecrosis of the Jaws in Rats.

This study evaluated the effects of local application of autologous platelet-rich plasma (PRP) on the tooth extraction site of rats presenting the main risk factors for medication-related osteonecrosis of the jaw (MRONJ). For seven weeks, senile rats were submitted to systemic treatment with vehicle (VEH and VEH-PRP) or 100 µg/Kg of zoledronate (ZOL and ZOL-PRP) every three days. After three weeks, the first lower molar was extracted. VEH-PRP and ZOL-PRP received PRP at the tooth extraction site. Euthanasia was performed at 28 days postoperatively. Clinical, histopathological, histometric and immunohistochemical analyses were carried out in histological sections from the tooth extraction site. ZOL showed lower percentage of newly formed bone tissue (NFBT), higher percentage of non-vital bone tissue (NVBT), as well as higher immunolabeling for TNFα and IL-1ß. In addition, ZOL presented lower immunolabeling for PCNA, VEGF, BMP2/4, OCN and TRAP. VEH and ZOL-PRP showed improvement in the tooth extraction site wound healing and comparable percentage of NFBT, VEGF, BMP2/4 and OCN. Local application of autologous PRP proved a viable preventive therapy, which is safe and effective to restore tissue repair capacity of the tooth extraction site and prevent the occurrence of MRONJ following tooth extraction.