Suzana Peres Pimentel

Photodynamic Therapy During Supportive Periodontal Care: Clinical, Microbiologic, Immunoinflammatory, and Patient-Centered Performance in a Split-Mouth Randomized Clinical Trial

BACKGROUND This study investigates the effect of photodynamic therapy (PDT) as monotherapy during supportive periodontal therapy. METHODS A split-mouth, randomized controlled trial was conducted in patients with chronic periodontitis (N = 22) presenting at least three residual pockets (probing depth [PD] ≥5 mm with bleeding on probing [BOP]). The selected sites randomly received the following: 1) PDT; 2) photosensitizer (PS); or 3) scaling and root planing (SRP). At baseline and 3 and 6 months, clinical, microbiologic (real-time polymerase chain reaction analyses), cytokine pattern (multiplexed bead immunoassay), and patient-centered (regarding morbidity) evaluations were performed. RESULTS All therapies promoted similar improvements in clinical parameters throughout the study (P <0.05), except that BOP was not reduced in the PS protocol (P >0.05). Lower levels of Aggregatibacter actinomycetemcomitans were observed in the PDT and SRP protocols at 3 months when compared with the PS protocol (P <0.05). An inferior frequency detection of Porphyromonas gingivalis was observed in the PDT protocol at 3 and 6 months and in the SRP protocol at 6 months from baseline (P <0.05). In addition, PDT protocol presented inferior frequency of P. gingivalis at 3 months when compared with the other therapies (P <0.05). Only patients in the PDT protocol exhibited augmented levels of anti-inflammatory interleukin (IL)-4 and reduced proinflammatory IL-1β and IL-6 throughout the study (P <0.05). Intergroup analyses showed reduced IL-10 and increased interferon-γ and IL-1β levels in the PS protocol when compared with the other therapies during follow-ups (P <0.05). No differences in morbidity were observed between the therapies (P >0.05), although the need for anesthesia was higher in SRP-treated sites (P <0.05). CONCLUSION PDT as an exclusive therapy may be considered a non-invasive alternative for treating residual pockets, offering advantages in the modulation of cytokines.

Resveratrol improves bone repair by modulation of bone morphogenetic proteins and osteopontin gene expression in rats

This study investigated the effect of resveratrol on bone healing and its influence on the gene expression of osteogenic markers. Two calvarial defects were created and one screw-shaped titanium implant was inserted in the tibia of rats that were assigned to daily administration of placebo (control group, n=15) or 10mg/kg of resveratrol (RESV group, n=15) for 30 days. The animals were then sacrificed. One of the calvarial defects was processed for histomorphometric analysis and the tissue relative to the other was collected for mRNA quantification of bone morphogenetic protein (BMP)-2, BMP-7, osteopontin (OPN), bone sialoprotein (BSP), osteoprotegrin (OPG), and receptor activator of NF-κB ligand (RANKL). Implants were removed by applying a counter-torque force. Histomorphometric analysis revealed higher remaining defect in the calvarial defects of the control group than the RESV group (P=0.026). Resveratrol increased the counter-torque values of implant removal when compared to control therapy (P=0.031). Gene expression analysis showed a higher expression of BMP-2 (P=0.011), BMP-7 (P=0.049), and OPN (P=0.002) genes in the RESV group than in the control group. In conclusion, resveratrol improved the repair of critical-sized bone defects and the biomechanical retention of implants. Indeed, this natural agent may up-regulate the gene expression of important osteogenic markers.

Protective effect of topical Cordia verbenacea in a rat periodontitis model: immune-inflammatory, antibacterial and morphometric assays

BackgroundThis study evaluated the effects of C. verbenacea essential oil topically administered in a rat periodontitis model.MethodsPeriodontitis was induced on rats in one of the mandibular first molars assigned to receive a ligature. Animals were randomly divided into two groups: a) non-treatment group (NT) (n = 18): animals received 1mL of vehicle; b) C. verbenacea group (C.v.) (n = 18): animals received 5mg/Kg of essential oils isolated from C. verbenacea. The therapies were administered topically 3 times daily for 11 days. Then, the specimens were processed for morphometric analysis of bone loss. The ligatures were used for microbiological assessment of the presence of Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Porphyromonas gingivalis using PCR. The gingival tissue was collected to Elisa assay of interleukin (IL)-1α and IL-10 levels.ResultsBone loss was inhibited by C. verbenacea when compared to the NT group (p < 0.05). A decrease in the levels of IL-1α and increase in the IL-10 amounts was observed in the C.v. group as compared to NT group (p < 0.05). A lower frequency of P. gingivalis was found in C.v. group (p < 0.05).ConclusionC. verbenacea essential oil topically administered diminished alveolar bone resorption, promoting a positive local imbalance in the pro/anti-inflammatory system and reducing the frequency of detection of P. gingivalis.

Influence of Dyslipidemia and Diabetes Mellitus on Chronic Periodontal Disease

BACKGROUND Periodontal disease is closely related to certain systemic conditions, such as type 2 diabetes mellitus (DM2), and, as recently described, dyslipidemia, a condition with alterations in blood lipids levels. However, more than acting as disease modifiers, these conditions commonly occur as comorbidities, possibly synergically affecting periodontal tissues. The aim of the current study is to identify whether DM2 and dyslipidemia are related to the occurrence and severity of chronic periodontitis. METHODS A total of 254 individuals participated: 56 were patients with DM2, 67 had dyslipidemia, 74 had DM2 and dyslipidemia, and 57 were systemically healthy individuals. The clinical examination included a full-mouth evaluation of periodontal probing depth, plaque score, bleeding on probing, and clinical attachment level (CAL). Blood samples were taken to assess fasting plasma glucose, low-density lipoprotein, high-density lipoprotein, and triglyceride levels. These parameters, as well as other medical conditions (i.e., smoking habits and body mass index), were considered in multiple regression analyses for data analyses (α = 5%). RESULTS Dyslipidemia was not related to periodontal disease (P >0.05). At the same time, DM2, age, and smoking showed a statistical and positive association, an increase in percentage of sites with CAL ≥3 and ≥5 mm. Regarding the percentage of sites presenting severe destruction (CAL ≥7 mm), only DM2 remained a significant risk factor (P <0.05). CONCLUSIONS It could be concluded that dyslipidemia did not influence periodontal conditions in participants with normal health or those with DM2. However, age, smoking habits, and especially DM2 were significantly associated with loss of CAL.

Influence of Glycemic Control on Peri-Implant Bone Healing: 12-Month Outcomes of Local Release of Bone-Related Factors and Implant Stabilization in Type 2 Diabetics

BACKGROUND The poor glycemic status seems to be an important factor affecting implant complication rates, including peri-implant bone loss. PURPOSE This trial evaluated the influence of glycemic control of type 2 diabetes mellitus (T2DM) patients on implant stabilization and on the levels of bone markers in peri-implant fluid during the healing. MATERIALS AND METHODS Systemically healthy patients (SH,n = 19), better-controlled T2DM (BCDM,n = 16), and poorly controlled T2DM (PCDM,n = 16) indicated for implant therapy were recruited. The implant stability quotient (ISQ) was determined at implant placement, 3, 6, and 12 months. Levels of transforming growth factor- β (TGF-β), fibroblast growth factor (FGF), osteopontin (OPN), osteocalcin (OC), and osteoprotegerin (OPG) in the peri-implant fluid were quantified at 15 days, and 3, 6, and 12 months, using the Luminex assay. RESULTS OPG and OPN levels were higher in SH at 12 months than at15 days (p < .05), whereas OC and TGF-β were lower in PCDM at 12 months compared with the 15-day and 3-month follow-ups, respectively (p < .05). Inter-group analyses showed lower OPN levels in PCDM compared with SH at 12 months (p < .05). The ISQ was higher at 12 months when compared with baseline and 3 months in SH (p < .05), whereas no differences were observed during follow-up in diabetics, regardless of glycemic control (p > .05). No difference in ISQ was observed among groups over time (p > .05). CONCLUSION Poor glycemic control negatively modulated the bone factors during healing, although T2DM, regardless of glycemic status, had no effect on implant stabilization.

Evaluation of the effect of an organic extract obtained from Ipomoea alba L. on experimental periodontitis in rats

The aim of this study was to evaluate the effect of an organic extract obtained from Ipomoea alba L. (Convolvulaceae or OE 1493), on experimental periodontal disease in rats. Periodontitis was induced in thirty six Wistar rats: a first mandibular molar was randomly assigned to receive a ligature, whereas the contralateral molar was left unligated. Animals were randomly assigned to two groups and treated topically, three times a day, for 11 days, as follows: Control Group - vehicle-treated (n = 18), and Test Group - OE 1493-treated (n = 18). The rats were sacrificed on the 12th day. Morphometrical measurements from the cementoenamel junction to the bone crest were performed to determine alveolar bone loss, using standardized photographs. Single- and multi-dose acute toxicity assays were carried out after OE 1493 treatment. Morphometrical analysis demonstrated that topically-administered OE 1493 showed no effect on reducing bone loss when compared with the control group (p > 0.05). In addition, OE 1493 did not present toxicity. Within the limits of this investigation, it may be concluded that OE 1493 did not show any positive influence on the progression of ligature-induced periodontitis in rats, when administered according to the regimen used in the present study.

Analysis and Proposal of Capacitor Voltage Control for an Asymmetric Cascaded Inverter

This work presents an analysis of the distribution of power handled by H-bridge cells of asymmetric cascaded multilevel converter. Applications of such converters require DC sources connected to DC link in order to establish constant voltage. The voltage must be independent of the modulation index and the load current. Even in applications like for SVAR compensation, where the inverter does not need to provide active power, the DC voltage must be present. The proposed control algorithm eliminates the need of additional isolated DC sources. The control strategy regulates the DC link voltages of capacitors connected to the two smallest voltages of a tree cells cascaded H-bridge inverter. Experimental results validate the voltage control strategy

Evaluation of the effects of buccal-palatal bone width on the incidence and height of the interproximal papilla between adjacent implants in esthetic areas.

BACKGROUND The presence of interproximal papilla depends on the distance between the contact point to the bone crest, as well as the mesio-distal distance between implants or between implants and teeth. The aim of this study is to evaluate the effects of buccal-palatal bone width on the presence of the interproximal papilla between adjacent implants in esthetic areas of the mouth. METHODS The presence or absence of the gingival papilla, distance from the base of the interproximal contact to the tip of the gingival papilla (black space), distance from the base of the interproximal contact to the alveolar crest (vertical distance), alveolar bone width (bone width) between adjacent implants as well as the spacing between the implants (horizontal distance), and soft-tissue biotype were assessed in 29 interimplant areas in the upper incisor, canine, and premolar regions of 18 patients. RESULTS The papilla was always present when vertical distance was ≤5 mm (P ≤0.04) and frequently present when the horizontal distance was ≥4 mm (P = 0.04). The black space was smaller when the vertical distance was ≤5 mm (P ≤0.04) and when the horizontal distance was ≥4 mm (P = 0.76). Bone width and soft-tissue biotype did not influence the incidence of gingival papilla (P ≥0.41) and black space (P ≥0.15). CONCLUSION Within the limits of this study, it can be concluded that bone width and tissue biotype do not have an effect on the incidence and height of papilla between adjacent implants in esthetic areas, and the incidence was greater when vertical distance was ≤5 mm or when horizontal distance was ≥4 mm.

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.

Histologic evaluation of the effect of nicotine administration on bone regeneration. A study in dogs.

The objective of this study was to investigate the histometric impact of nicotine on bone regeneration of surgically created alveolar ridge defects in dogs. Sixteen mongrel dogs were used. One defect was surgically created unilaterally in the mandible, and left to heal spontaneously. The animals were randomly assigned to one of the following groups: Group 1--control (n = 8) and Group 2--subcutaneous nicotine administration (2 mg/kg) twice a day (n = 8). After 4 months, the animals were sacrificed and the specimens routinely processed for semi-serial decalcified sections. Bone height (BH), bone width (BW), bone density (BD), and bone area (BA) of the newly-formed bone were evaluated. Intergroup analysis (Mann-Whitney rank sum test) showed that regardless of the presence of nicotine, no significant differences were observed regarding bone width (BW), bone area (BA) and bone height (BH) (p > 0.05). On the other hand, it was demonstrated that nicotine administration significantly influenced the proportion of mineralized tissue within the limits of the newly-formed bone (BD) (p < 0.001). Within the limits of the present study, it can be concluded that nicotine might affect but not prevent bone healing in defects left to heal spontaneously.