Letícia Helena Theodoro

A histologic assessment of the influence of low-intensity laser therapy on wound healing in steroid-treated animals

OBJECTIVE The aim of the present study was to evaluate the effect of low-intensity laser therapy on the wound healing process treated with steroid. BACKGROUND DATA Various biological effects have been associated with low-level laser therapy (LLLT). MATERIALS AND METHODS Forty-eight rats were used, and after execution of a wound on the dorsal region of each animal, they were divided into 4 groups (n = 12), receiving the following treatments: G1 (control), wounds and animals received no treatment; G2, wounds were treated with LLLT; G3, animals received an intraperitoneal injection of steroid dosage (2 mg/kg of body weight); G4, animals received steroid and wounds were treated with LLLT. The laser emission device used was a GaAIAs (904 nm), in a contact mode, with 2.75 mW gated with 2.900 Hz during 120 sec (33 J/cm(2)). After the period of 3, 7, and 14 days, the animals were sacrificed and the parts sent to histological processing and dyed using hematoxylin and eosin (HE) and Masson trichromium (MT) techniques. RESULTS The results have shown that the wounds treated with steroid had a delay in healing, while LLLT accelerated the wound healing process. Also, wounds treated with laser in the animals treated with steroid presented a differentiated healing process with a larger collagen deposition and also a decrease in both the inflammatory infiltrated and the delay on the wound healing process. CONCLUSION LLLT accelerated healing, caused by the steroid, acting as a biostimulative coadjutant agent, balancing the undesirable effects of cortisone on the tissue healing process.

Clinical and Microbiologic Follow-Up Evaluations After Non-Surgical Periodontal Treatment With Erbium:YAG Laser and Scaling and Root Planing

BACKGROUND This study compared erbium-doped: yttrium, aluminum, and garnet (Er:YAG) laser irradiation (100 mJ/pulse; 10 Hz; 12.9 J/cm(2)) with or without conventional scaling and root planing (SRP) to SRP only for treatment of periodontal pockets. METHODS Nineteen patients with pockets from 5 to 9 mm were included. In a split-mouth design, each site was allocated to a treatment group: 1) SRPL, SRP and laser; 2) L, laser; 3) SRP, SRP only; and 4) C, no treatment. Clinical parameters of probing depth (PD), gingival recession, and clinical attachment level (CAL) were evaluated at baseline and 1, 3, 6, and 12 months after treatment. Visible plaque index, gingival bleeding index (GI), bleeding on probing (BOP), and subgingival plaque samples were also measured 12 days postoperatively, in addition to the above mentioned months. Intergroup and intragroup statistical analyses were performed (P <0.05). RESULTS GI decreased for SRPL and increased for L, SRP, and C (P <0.05) 12 days postoperatively and decreased for SRPL and SRP (P <0.05) 3, 6, and 12 months after baseline; BOP and PD decreased for all treated groups (P <0.01) 3, 6, and 12 months after treatment. CAL gain was significant for SRPL, L, and SRP (P <0.05) 3, 6, and 12 months postoperatively. SRPL and L presented a significant reduction in the percentage of sites with bacteria 6 and 12 months after treatment (P <0.05). CONCLUSION Non-surgical periodontal treatment with Er:YAG laser may be an alternative treatment for reduction and control of the proliferation of microorganisms in persistent periodontitis.

Treatment of experimental periodontal disease by photodynamic therapy in immunosuppressed rats

BACKGROUND AND OBJECTIVE The aim of this study was to compare photodynamic therapy (PDT) as an adjunctive treatment of induced periodontitis with scaling and root planing (SRP) in dexamethasone-inhibited rats. MATERIAL AND METHODS The animals were divided into two groups: ND (n=90), saline solution treatment; D (n=90), dexamethasone treatment. In the ND and D Groups, periodontal disease was ligature-induced at the first mandibular molar. After 7 days, the ligature was removed and all animals received SRP and were divided according to the following treatments: SRP, saline solution; Toluidine Blue-O (TBO), phenothiazinium dye; and PDT, TBO and laser irradiation. Ten animals in each treatment were killed at 7, 15 and 30 days. The radiographic and histometric values were statistically analysed. RESULTS In the ND and D Groups, radiographic analysis showed less bone loss in animals treated by PDT in all the experimental periods than SRP and TBO at 15 days (p<0.05). After a histometric analysis was carried out in the ND and D groups, the animals treated by PDT showed less bone loss in all periods than SRP and TBO after 15 days (p<0.05). CONCLUSIONS The PDT was an effective adjunctive treatment of induced periodontitis compared with SRP in dexamethasone-inhibited rats.

The Role of Obesity as a Modifying Factor in Patients Undergoing Non-Surgical Periodontal Therapy

BACKGROUND Earlier studies have shown an association between obesity and periodontitis, which is mediated by cytokine production. The aim of this study is to assess the role of obesity as a modifying factor on periodontal clinical parameters and on circulating proinflammatory cytokine levels in subjects undergoing non-surgical periodontal treatment. METHODS Twenty-seven obese subjects and 25 normal-weight subjects were enrolled in this study. Subjects in both groups had generalized chronic periodontitis. The periodontal parameters measured before and 3 months after non-surgical periodontal therapy were: visible plaque index, bleeding gingival index, bleeding on probing, probing depth, and clinical attachment level. In addition, subjects underwent anthropometric measurements and serum analyses of fasting glucose, glycated hemoglobin, interleukin-1β, interleukin-6, tumor necrosis factor-α, and interferon-γ. RESULTS Periodontal therapy significantly decreased visible plaque index, bleeding gingival index, bleeding on probing, probing depth of 4 to 6 mm, probing depth ≥7 mm, clinical attachment level of 4 to 6 mm, and clinical attachment level ≥7 mm in both groups (P ≤0.05). Circulating proinflammatory cytokines significantly decreased in obese and normal-weight subjects after periodontal treatment (P ≤0.05). However, interleukin-6 and tumor necrosis factor-α levels remained higher in obese subjects 3 months after treatment (P ≤0.05). CONCLUSION Obesity does not seem to play a negative role by interfering in the improvement of the periodontal clinical response or decreasing circulating proinflammatory cytokine levels after periodontal treatment.

Adjunctive antimicrobial photodynamic treatment of experimentally induced periodontitis in rats with ovariectomy.

BACKGROUND The aim of this study is to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive therapy to scaling and root planing (SRP) for the treatment of experimentally induced periodontitis in rats with ovariectomy (OVX) that are or are not treated with estrogen replacement. METHODS A total of 270 female rats were divided into three groups: 1) normal rats; 2) rats with OVX; and 3) rats with OVX with estrogen replacement. Periodontal disease was induced through the introduction of a cotton thread around the mandibular left first molar. After 7 days, the ligature was removed, and the rats were randomly divided into the following treatment groups: 1) SRP plus saline solution; 2) SRP plus low-level laser therapy (LLLT); and 3) SRP plus toluidine blue O irrigation followed by LLLT. Ten rats from each group were euthanized at days 7, 15, and 30 after dental treatment. Bone loss (BL) in the furcation region was evaluated using histometric and immunohistochemical analyses. RESULTS aPDT treatment resulted in reduced BL compared with SRP treatment at all time points. Additionally, rats treated with aPDT exhibited reduced numbers of tartrate-resistant acid-phosphatase-positive cells and more proliferating cell nuclear antigen-positive cells in all treatment groups regardless of estrogen status. Whereas rats treated with aPDT showed weak immunoreactivity to the receptor activator of nuclear factor-κ B ligand at day 7 post-treatment, strong osteoprotegerin immunoreactivity was observed at day 15 post-treatment. CONCLUSION aPDT is an effective adjunctive therapy for the treatment of periodontitis in rats with OVX that are or are not given estrogen replacement therapy.

The effect of CO 2 laser irradiation on failed implant surfaces

The aim of this investigation was to evaluate the cleaning effect of CO2 on surface topography and composition of failed dental implant surfaces. Ten failed dental implants were retrieved from nine patients (mean age, 46.33 ± 5.81 years) as a result of early or late failure. The implants were divided into two parts: one side of the implant was irradiated with a CO2 laser (test side), while the other side did not receive irradiation (control side). The CO2 laser was operated at 1.2 W in a continuous wave for 40 seconds (40 J energy). The handpiece of the CO2 laser was kept at a distance of 30 mm from the implant surface, resulting in a spot area of 0.031415 cm2 (38.20 W/cm2; 1559 J/cm2) in scanning mode (cervical–apical). One unused dental implant was used as a negative control for both groups. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) for element analysis. SEM showed that the surface of the test sides consisted of different degrees of organic residues, appearing mainly as dark stains similar to those observed on the control sides. None of the test surfaces presented alterations such as crater-like alterations, lava-like layers, or melting compared with the nonirradiated surfaces. Foreign elements such as carbon, oxygen, sodium, calcium, and aluminum were detected on both sides. These results suggest that CO2 laser irradiation does not modify the implant surface, although the cleaning effect was not satisfactory.

Adjuvant Therapy With Sodium Alendronate for the Treatment of Experimental Periodontitis in Rats

BACKGROUND This study assesses the effects of topical sodium alendronate (SA) as an adjuvant to the mechanical treatment of ligature-induced periodontitis in rats. METHODS Ninety animals were subjected to the induction of periodontitis via the installation of a ligature around the mandibular left first molar. After 7 days, the ligature was removed, and the animals were distributed into the following groups: 1) NT group (n = 30), no treatment; 2) SRP group (n = 30), scaling and root planing (SRP) and local irrigation with physiologic saline solution; and 3) SRP/SA group (n = 30), SRP and local irrigation with SA (10(-5) M). Ten animals from each group were euthanized at 7, 15, and 30 days after treatment. Histologic and histometric analyses were performed in the furcation region. The percentage of bone in the furcation (PBF) was measured. Immunohistochemical analyses for detecting the receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), tartrate-resistant acid phosphatase (TRAP), and activated caspase-3 were performed at the furcation region. RESULTS Compared with the other groups, the SRP/SA group showed less local inflammation and better tissue reparation during the entire experiment. There was more PBF in the SRP/SA group than in the other groups at days 7 and 15. Stronger OPG immunolabeling and weaker RANKL immunolabeling were observed in the SRP/SA group at 15 and 30 days. There were fewer TRAP-positive cells in the SRP/SA group than in the NT group at all of the time points. There was no difference in the number of activated caspase-3-positive osteocytes among groups and time points. CONCLUSION It can be concluded that topical use of SA as an adjuvant to SRP is effective in the treatment of experimental periodontitis.

Experimental periodontal disease treatment by subgingival irrigation with tetracycline hydrochloride in rats

Objective The aim of this study was to compare subgingival irrigation with tetracycline hydrochloride (TTC-HCL) as adjunctive treatment to scaling and root planning (SRP) on induced periodontitis in rats. Material and methods In 60 rats, periodontal disease was ligature-induced at the mandibular left first molar. After 7 days, the ligature was removed and all animals were submitted to SRP, and divided into 2 groups according to the following treatment: C (n=30) - subgingival irrigation with 1 mL of saline; T (n=30) - subgingival irrigation with 1 mL of TTC-HCL (50 mg/mL). Ten animals in each group were euthanized at 7, 15 and 30 days posttreatment. The histometric values were statistically analyzed (p<0.05). Results In the histometric analysis, at 7, 15 and 30 days, Group T (0.72±0.05 mm2, 0.57±0.14 mm2, 0.62±0.07 mm2), showed less bone loss (p<0.05) than Group C (1.35±0.25 mm2; 1.40±0.31 mm2; 1.29±0.27 mm2), respectively. Conclusions Subgingival irrigation with TTC-HCL was an effective adjunctive treatment for periodontal disease induced in rats.

Morphologic analysis, by means of scanning electron microscopy, of the effect of Er: YAG laser on root surfaces submitted to scaling and root planing.

The purpose of this study was to morphologically evaluate, by means of scanning electron microscopy, the effects of Er:YAG laser on the treatment of root surfaces submitted to scaling and root planing with conventional periodontal instruments. Eighteen root surfaces (n = 18), which had been previously scaled and planed, were assigned to 3 groups (n = 6). The control Group (G1) received no further treatment; Group 2 (G2) was irradiated with Er:YAG laser (2.94 mum), with 47 mJ/10 Hz, in a focused mode with air/water spray during 15 s and with 0.57 J/cm of fluency per pulse; Group 3 (G 3) was irradiated with Er:YAG laser (2.94 mum), with 83 mJ/10 Hz, in a focused mode with air/water spray during 15 s and with 1.03 J/cm2 of fluency per pulse. We concluded that the parameters adopted for Group 3 removed the smear layer from the root surface, exposing the dentinal tubules. Although no fissures, cracks or carbonized areas were observed, an irregular surface was produced by Er:YAG laser irradiation. Thus, the biocompatibility of the irradiated root surface, within the periodontal healing process, must be assessed.

Radiographic assessment of photodynamic therapy as an adjunctive treatment on induced periodontitis in immunosuppressed rats

Objective The aim of this study was to assess radiographically the effect of photodynamic therapy (PDT) as an adjunctive treatment to scaling and root planing (SRP) on induced periodontitis in dexamethasone-induced immunosuppressed rats. Material and Methods The animals were divided into 2 groups: ND group (n=60): saline treatment; D group (n=60): dexamethasone treatment. In both ND and D groups, periodontal disease was induced by the placement of a ligature in the left first mandibular molar. After 7 days, ligature was removed and all animals received SRP, being divided according to the following treatments: SRP: saline and PDT: phenothiazinium dye (TBO) plus laser irradiation. Ten animals per treatment were killed at 7, 15 and 30 days. The distance between the cementoenamel junction and the height of the alveolar bone crest in the mesial surface of the mandibular left first molars was determined in millimeters in each radiograph. The radiographic values were analyzed statistically by ANOVA and Tukeys test at a p value <0.05. Results Intragroup radiographic assessment (ND and D groups) showed that there was statistically significant less bone loss in the animals treated with PDT in all experimental periods compared to those submitted to SRP. Intergroup radiographic analysis (ND and D groups) demonstrated that there was greater bone loss in the ND group treated with SRP compared to the D group treated with PDT at 7 and 30 days. Conclusion PDT was an effective adjunctive treatment to SRP on induced periodontitis in dexamethasone-induced immunosuppressed rats.