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.

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.

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.

pH influences the biocompatibility of methylene blue solutions.

OBJECTIVE: The aim of this study was to investigate the biocompatibility of methylene blue at different pH levels through the method of implantation in subcutaneous tissue. MATERIALS AND METHODS: Eighty-four sterilized polyethylene tubes were allocated in the subcutaneous tissue of 28 rats, each one receiving four tubes, set into four groups: group tube (G-T)-empty tube, fibrin group (G-F)-tube filled with fibrin sponge, group methylene blue pH 7 (G-MB/pH 7)-tube filled with fibrin sponge soaked by methylene blue (100 µg/ml) at pH 7.0, and group methylene blue pH 1 (G-MB/pH 1)-tube filled with fibrin sponge and soaked by methylene blue (100 µg/ml) at pH 1.0. After 7, 15, and 30 days, seven animals from each group were euthanized, and the tubes involved by the surrounding tissue were removed and fixed with 4% buffered formaldehyde solution. The collected pieces were processed and histological sections (4 µm) were stained with hematoxylin and eosin and analyzed by light microscopy. Scores were assigned to analysis of histopathologic parameters. The results were statistically analyzed by the Kruskal-Wallis test (p ≤ 0.05). RESULTS: At 7 and 30 days, the G-MB/pH 1 group showed no significant difference in the G-T control group, while G-MB/pH 7 had a significant increase on tissue reaction, also when compared to G-T. At 15 days, there was no statistical difference between the groups. CONCLUSION: Within the limits of this study, it is concluded that methylene blue at pH 1.0 provides better biocompatibility than at pH 7.0.

Effects of low-level laser therapy on bone healing of critical-size defects treated with bovine bone graft.

OBJECTIVE: To histomorphometrically analyze the effect of low-level laser therapy (LLLT) on bone formation process in surgically created critical-size defects (CSDs) treated with bovine bone graft (BBG) and its influence over particles' resorption of BBG. METHODS: A 10-mm diameter CSD was surgically created in the calvaria of 64 male rats, which were distributed into 4 experimental groups: the C group (control), only blood clot; the LLLT group, LLLT (GaAlAs, 660nm) and blood clot; the BBG group, CSD filled with BBG; the BBG/LLLT group, LLLT and CSD filled with BBG. Animals were euthanized at either 30 or 60days post-operation. A histological analysis was performed. Additionally, the percentage of newly formed bone area (NFBA) and remaining particles areas (RPA) of BBG were histometrically evaluated and data statistically analyzed. RESULTS: The LLLT (5.82±2.05; 7.34±1.01) group presented significantly greater NFBA when compared to the C group (1.61±0.30; 5.59±0.94) at 30 and 60days post-operation (p<0.05). The BBG/LLLT group (7.39±1.45; 9.44±2.36) presented significantly greater NFBA than the BBG group (3.85±1.56; 8.02±0.63) at 30 and 60days postoperation (p<0.05). There was no significant difference in the mean percentage of implanted material RPA between the BBG and the BBG/LLLT groups. CONCLUSIONS: LLLT can improve bone formation process in CSD filled or not with BBG in rat calvaria, but it is not able to accelerate particles resorption of this material in the interior of bone defect.