Mônica Grazieli Corrêa

Histometric evaluation of bone around titanium implants with different surface treatments in rats exposed to cigarette smoke inhalation

OBJECTIVES There is a lack of histological information about the influence of cigarette smoke on bone around surface-treated implants. The aim of the present study was to test the influence of titanium surface treatment on osseointegration in animals that were exposed to intermittent cigarette smoke inhalation. MATERIAL AND METHODS Twenty-two male Wistar rats were used. One tibia, chosen at random, received a machined titanium implant (MI) while the other received an aluminum oxide-blasted surface implant (ABI). The animals were randomly assigned to one of the following groups: Group 1 - control (n=11) and Group 2 - intermittent cigarette smoke inhalation (n=11). Sixty days after surgery, the animals were sacrificed. The degree of bone-to-implant contact (BIC), bone filling (BF) within the limits of the threads of the implants and bone density (proportion of mineralized bone in a 500-mum-wide zone lateral to the implant - BD) were measured in the cortical (zone A) and cancellous bone (zone B) areas. RESULTS Data analysis showed significant differences when comparing the groups and implant surfaces in both zones for BIC (two-way ANOVA -P<0.05). The two groups presented higher BIC mean values for ABI, when compared with MI (P<0.05). In group 2, cigarette smoke inhalation negatively affected BF in both zones (P<0.05). Group 2 presented a significantly decreased BD in both zones (P<0.05). No statistically significant differences were observed between surfaces in any of the groups for BD. CONCLUSION Within the limits of the present study, it can be concluded that the aluminum oxide blast surface treatment may increase the degree of BIC but cannot overcome the detrimental effect of tobacco smoke on bone around titanium implants.

Systemic treatment with resveratrol and/or curcumin reduces the progression of experimental periodontitis in rats

BACKGROUND AND OBJECTIVE Periodontitis is a chronic inflammatory disease of periodontal tissues that leads to the destruction of bone and other connective tissues. Resveratrol and curcumin are plant-derived substances with biological properties that may have immunomodulatory properties. This study investigated the effect of continuous administration of resveratrol and curcumin and the association of resveratrol and curcumin on the progression of experimental periodontitis in rats. MATERIAL AND METHODS Forty Wistar rats were assigned randomly to the following groups: group 1, experimental periodontitis + placebo (PL) (n = 10); group 2, experimental periodontitis + resveratrol (RSV) (n = 10); group 3, experimental periodontitis + curcumin (C) (n = 10); and group 4, experimental periodontitis + resveratrol + curcumin (COMBI) (n = 10). Periodontitis was induced in rats by tying a silk suture, as a ligature, around one of the first molars. Daily administration of the placebo solution, 10 mg/kg of resveratrol, 100 mg/kg of curcumin or 10 mg/kg of resveratrol plus 100 mg/kg of curcumin was carried out from day 0 to day 30. At the end of the relevant experimental periods, rats were killed and the specimens obtained were processed for morphometric analysis of bone loss. Gingival tissues surrounding the first molar were collected for quantification of interleukin (IL)-1β, IL-4, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) using a Luminex/MAGPIX assay. RESULTS Intergroup comparisons of the morphometric outcomes revealed higher bone-loss values in the PL group (p < 0.05) when compared with RSV, C and COMBI groups. There was no difference in bone-loss values among RSV, C and COMBI groups (p > 0.05). The immunoenzymatic assay of the gingival tissue showed a lower concentration of IL-1β in the COMBI group in comparison with the PL group (p < 0.05). Higher values of IL-4 were demonstrated in groups RSV, C and COMBI in comparison with the PL group (p < 0.05). Only RSV caused a reduction in the levels of IFN-γ (p < 0.05). There was no difference in the concentration of TNF-α amongst the four groups (p > 0.05). CONCLUSION Resveratrol and curcumin are capable of reducing alveolar bone loss in an animal model of periodontitis. This occurred when these agents were added singly or in combination with one another, but there did not appear to be either synergistic or additive effects.

Short-term microbiological effects of photodynamic therapy in non-surgical periodontal treatment of residual pockets: A split-mouth RCT

Photodynamic therapy (PDT) has been used as a therapeutic alternative to treat periodontitis, especially in challenging sites that require additional periodontal therapy such as residual pockets. The aim of this split‐mouth randomized trial was to evaluate the microbiological and clinical effects of PDT on non‐surgical treatment of unresponsive pockets.

Histometric Analysis of the Effect of Enamel Matrix Derivative on the Healing of Periodontal Defects in Rats With Diabetes

BACKGROUND Diabetes mellitus (DM) involves metabolic changes that can negatively influence periodontal tissues, resulting in impaired periodontal repair. There is a lack of information about the outcomes of regenerative approaches under the influence of DM. Enamel matrix derivatives (EMDs) have been used in periodontal regenerative procedures, resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of DM. METHODS Twenty Wistar rats were randomly assigned to two groups: group 1 (G1): DM was induced with a single intraperitoneal injection of streptozotocin (STZ) (n = 10); group 2 (G2): rats were not exposed to STZ (n = 10). Seven days after DM induction, bilateral fenestration defects were created at the buccal aspect of the first mandibular molar. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated (control) and treated with EMD. The animals were euthanized 21 days later, and the percentage of defect fill (DF), newly formed bone density (BD), and new cementum formation (NCF) were histometrically assessed. The number of osteoclasts was determined by tartrate-resistant acid phosphatase. Weight and blood glucose were also analyzed. Mann-Whitney U test was used for comparison among groups and Wilcoxon test for comparison between the start and end times (weight and blood glucose) and between treatments (NCF and number of osteoclasts). One-way analysis of variance was used to assess DF and BD. Tukey test was used when the analysis of variance test detected significant differences (α = 5%). RESULTS G1 (DM) showed less DF and BD compared with G2. EMD provided an increased DF in both groups and enhanced BD and NCF only in G2. The number of TRAP-positive osteoclasts was significantly higher in EMD-treated sites of G1. CONCLUSIONS DM may produce a significant detrimental effect on BD. EMD may provide greater DF under diabetic or normal conditions; however, it may not significantly increase NCF in animals with DM.

Cigarette smoke inhalation increases the alveolar bone loss caused by primary occlusal trauma in a rat model.

BACKGROUND AND OBJECTIVE Occlusal trauma (OT) and smoking are both factors that alter alveolar bone metabolism and therefore could synergistically act on alveolar bone loss. The aim of this experimental study was to evaluate the influence of short-term cigarette smoke inhalation (CSI) on inter-radicular alveolar bone loss promoted by primary OT in a rat model. MATERIAL AND METHODS Forty-eight animals were randomly assigned to one of three groups based on treatment type: OT + CSI (n = 16), animals were exposed to CSI three times per day, for 8 min per exposure, and they concomitantly received unilateral vertical augmentation creating an occlusal interference inducing experimental OT; OT (n = 16), animals received only unilateral vertical augmentation; negative control (NC; n = 16), animals maintained for equal periods to achieve periodontal baseline values of periodontal ligament dimension. Each group was divided into two subgroups (n = 8) based on treatment length: 7 or 14 d. RESULTS After 7 d, the OT + CSI group exhibited significantly higher bone loss compared to the NC group (p = 0.0022). After 14 d, the OT (p < 0.0001) and OT + CSI (p < 0.0001) groups presented significantly higher bone loss compared to the NC group, and OT + CSI resulted in significantly higher bone loss than OT alone (p = 0.0241). The number of tartrate-resistant acid phosphatase-positive cells on the linear surface of the bone crest after 7 d was significantly higher in the OT + CSI group as compared to the NC and OT groups (p < 0.0001 and p = 0.0045, respectively) and remained significantly higher in the OT + CSI group after 14 d, compared to the OT group (p < 0.0001). CONCLUSION Short-term CSI increases early bone loss in association with OT after 7 d, and this worsens in severity after 14 d of exposure.

The Impact of Cigarette Smoke Inhalation on the Outcome of Enamel Matrix Derivative Treatment in Rats: Histometric Analysis

BACKGROUND Tobacco use is the most significant risk factor of periodontal disease. Clinical evidence has demonstrated that tobacco may negatively influence the results after surgical and non-surgical periodontal therapy. Enamel matrix derivative (EMD) have been used in periodontal regenerative procedures resulting in improvement of clinical parameters. The effect of EMD in the presence of tobacco compounds is unclear. Thus, the aim of the present study is to evaluate the impact of cigarette smoke inhalation (CSI) on the results of EMD treatment. METHODS Twenty-two Wistar rats were assigned to two groups: Group 1, CSI (n = 11); Group 2, non-exposed (n = 11). Thirty days after initiation of CSI, fenestration defects were created at the buccal aspect of the first mandibular molar. The study followed a split-mouth design. After the surgeries the defects were randomly assigned to two subgroups: non-treated control and treated with EMD. The animals were sacrificed 21 days later and the percentage of defect fill, density of newly formed bone, and new cementum formation were histometrically assessed. The number of osteoclasts was determined by tartrate-resistant acid phosphatase. RESULTS CSI was associated with less bone density compared to the non-exposed group. EMD provided an increased defect fill and new cementum formation in both groups. The number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in the CSI non-treated control group compared to the non-treated control of the non-exposed animals. CONCLUSIONS EMD may provide increased defect fill and cementum formation in the presence or absence of CSI. However, tobacco smoke produced a detrimental effect on bone healing when density of newly formed bone was considered.

Periodontitis increases rheumatic factor serum levels and citrullinated proteins in gingival tissues and alter cytokine balance in arthritic rats

This study investigated some immunological features by experimental periodontitis (EP) and rheumatoid arthritis (RA) disease interact in destructive processes in arthritic rats. Rats were assigned to the following groups: EP +RA; RA; EP; and Negative Control. RA was induced by immunizations with type-II collagen and a local immunization with Complete Freund’s adjuvant in the paw. Periodontitis was induced by ligating the right first molars. The serum level of rheumatoid factor (RF) and anti-citrullinated protein antibody (ACCPA) were measured before the induction of EP (T1) and at 28 days after (T2) by ELISA assay. ACCPA levels were also measured in the gingival tissue at T2. The specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for the quantification of interleukin IL-1β, IL-4, IL-6, IL-17 and TNF-α using a Luminex/MAGpix assay. Paw edema was analyzed using a plethysmometer. Periodontitis increased the RF and ACCPA levels in the serum and in the gingival tissue, respectively. Besides, the level of paw swelling was increased by EP and remained in progress until the end of the experiment, when EP was associated with RA. Greater values of IL-17 were observed only when RA was present, in spite of PE. It can be concluded that periodontitis increases rheumatic factor serum levels and citrullinated proteins level in gingival tissues and alter cytokine balance in arthritic rats; at the same time, arthritis increases periodontal destruction, confirming the bidirectional interaction between diseases.

Outcome of Enamel Matrix Derivative Treatment in the Presence of Chronic Stress: Histometric Study in Rats

BACKGROUND Psychologic stress and clinical hypercortisolism have been related to direct effects on bone metabolism. However, there is a lack of information regarding the outcomes of regenerative approaches under the influence of chronic stress (CS). Enamel matrix derivative (EMD) has been used in periodontal regenerative procedures, resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of CS in the rat model. METHODS Twenty Wistar rats were randomly assigned to two groups; G1: CS (restraint stress for 12 hours/day) (n = 10), and G2: not exposed to CS (n = 10). Fifteen days after initiation of CS, fenestration defects were created at the buccal aspect of the first mandibular molar of all animals from both groups. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated control and treated with EMD. The animals were euthanized 21 days later. RESULTS G1 showed less bone density (BD) compared to G2. EMD provided an increased defect fill (DF) in G1 and higher BD and new cementum formation (NCF) in both groups. The number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in G1 when compared to G2 and in EMD-treated sites of both groups. CONCLUSIONS CS may produce a significant detrimental effect on BD. EMD may provide greater DF compared to non-treated control in the presence of CS and increased BD and NCF in the presence or absence of CS.

Alcohol intake may impair bone density and new cementum formation after enamel matrix derivative treatment: histometric study in rats

BACKGROUND AND OBJECTIVE Alcohol intake may interfere with bone metabolism; however, there is a lack of information about the outcomes of regenerative approaches in the presence of alcohol intake. Enamel matrix derivative (EMD) has been used in periodontal regenerative procedures resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of alcohol intake. MATERIAL AND METHODS Twenty Wistar rats were randomly assigned to two groups: G1 = alcohol intake (n = 10) and G2 = non-exposed to alcohol intake (n = 10). Thirty days after initiation of alcohol intake, fenestration defects were created at the buccal aspect of the first mandibular molar of all animals from both groups. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated control and treated with EMD. The animals were killed 21 d later. RESULTS G1 showed less defect fill for non-treated controls. Bone density (BD) and new cementum formation were lower for G1 when compared to G2, for EMD-treated and non-treated sites. EMD treatment resulted in greater BD and new cementum formation in both groups and defect fill was not significantly different between groups in the EMD-treated sites. The number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in G1 when compared to G2 and in EMD-treated sites of both groups. CONCLUSION Alcohol intake may produce a significant detrimental effect on BD and new cementum formation, even in sites treated with EMD. A limited positive effect may be expected after EMD treatment under this condition.

Systemic treatment with resveratrol reduces the progression of experimental periodontitis and arthritis in rats

Rheumatoid arthritis and periodontitis are chronic inflammatory diseases which has been closely associated due to the nature of immune-inflammatory imbalance response. Resveratrol is a naturall product with biological proprieties that may promote immunomodulatory effects on host response. This study investigated resveratrol continuous administration effect on experimental periodontitis and arthritis progression in rats. Thirty-five rats were assigned to the following groups: 1—experimental arthritis + experimental periodontitis + placebo (RA+EP +PL) (n = 12); 2 –RA+EP+ ibuprofen (RA+PE+IB) (n = 11); 3—RA+EP+ resveratrol (RA+PE+RSV) (n = 11). After euthanasia, the specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for quantification of inflammatory markers using a Luminex/MAGpix assay and anti-citrullinated protein antibody (ACCPA) levels were measured by ELISA assay. Serum level of rheumatoid factor (RF) was measured by ELISA assay. Paw edema was analyzed using a plethysmometer. Higher bone loss was observed in PL group, when compared to IB and RSV groups. RSV group presented higher IL-4 concentration than PL and IB groups. Resveratrol reduced RF serum levels and both IB and RSV decreased ACCPA gingival levels. Besides, paw swelling level was significantly lower in IB and RSV groups in the 21th day and only in RSV group in the 28th day. Histological analyzes showed smooth articular surface and higher width of the subchondral cortical in RSV group. Resveratrol showed modulatory effect and seems to reduce the inflammatory signs of arthritis and articular damage throughout the time.