Bone demineralization improves onlay graft consolidation: A histological study in rat calvaria.

BACKGROUND: Previous data suggest that bone demineralization may promote bone graft consolidation as well as proliferation and differentiation of pre-osteoblasts, but the biological mechanisms involved in this process need to be clarified. This study investigated the effects of bone demineralization with citric acid (CA) and tetracycline (TCN) on the repair of onlay bone grafts. METHODS: Onlay bone grafts were performed on the calvaria of 126 Wistar rats. The contacting surfaces between bone graft and receptor bone bed were demineralized for 15, 30, and 60 seconds with TCN (50 mg/mL), or 10% CA, (pH 1), constituting the following test groups (n = 18): TCN15, TCN30, TCN60, CA15, CA30, and CA60. Control grafts (C) were performed without demineralization (n = 18). After 7, 30, and 60 days, biopsies were obtained for quantitative and qualitative histological analysis (a = 6). RESULTS: Demineralization accelerated the bone repair early from 7 days of healing. Higher percentage area of newly formed bone was observed in CA15 and TCN60 groups when compared to C in all evaluation periods (P = 0.02). At 30 days, C specimens had lower percentage of consolidated surfaces than TCN60, TCN30 and CA15 (P = 0.0015). At 60 days, CA15, CA60, and TCN60 presented bone surfaces almost completely filled by newly formed bone, against about 75% in C specimens (P = 0.0015). CONCLUSIONS: Both CA and TCN were effective in accelerating osteogenesis at the interface between bone grafts and receptor bone beds, especially when applied for 15 seconds and 60 seconds, respectively.

Citric acid, but not tetracycline, improves the microscopic pattern of healing of particulate autogenous bone grafts in critical-size defects.

BACKGROUND: Bone demineralization has shown to be advantageous in autogenous onlay bone grafts and in pre-osteoblasts cultures, but such procedure has never been evaluated in particulate bone grafts. This study aimed to investigate the role of two demineralizing agents in the repair of the 8-mm critical-size defects in rats' calvaria. METHODS: Eighty adult male Wistar rats were randomly assigned to one of eight groups as follows: particulate autogenous bone demineralized with citric acid for 15 seconds (CA15), 30 seconds (CA30), or 60 seconds (CA60); particulate autogenous bone demineralized with tetracycline hydrochloride for 15 seconds (TCN15), 30 seconds (TCN30), or 60 seconds (TCN60); blood clot (NC), and non-demineralized autogenous bone (PC). The calvariae were harvested at 30 and 60 postoperative days (n = 5) for blinded histological and histometric analysis of the percentage area of newly formed bone within the defects. RESULTS: In the NC and TCN groups, bone formation was limited to the margins of the defects at 30 postoperative days, whereas complete closure was present in all the specimens from CA15 group. Both at 30 and 60 postoperative days, histomorphometry showed significant higher area of newly formed bone in specimens demineralized with CA than in those demineralized with TCN or non-demineralized (P < 0.05). TCN appeared to impair bone neoformation, as its use produced similar or inferior results compared to blood clot. CONCLUSIONS: Demineralization of particulate bone grafts with CA during 15s enhanced the regeneration of critical-size defects and may be a promising adjuvant in regenerative procedures. TCN seems to be improper for this purpose.

Osteogenic cells transfer improving root coverage: A randomized clinical trial.

BACKGROUND AND OBJECTIVE: The aim of this interventional, parallel-assignment, single-blinded, randomized, efficacy study was to investigate the efficacy of the treatment of gingival recessions by osteogenic cell transfer. This is the first randomized clinical trial of this nature. MATERIAL AND METHODS: Treatment of Miller class I or II gingival recessions >4 mm was randomly defined by casual sorting and performed by newly forming bone graft (NFBG) and coronally advanced flap (CAF) or subepithelial connective tissue graft (SCTG) and CAF (control). Clinical examinations were performed by a single blinded examiner at baseline and at 3, 6, and 9 months after surgery. Parameters investigated were recession height (REC), probing depth (PD), clinical attachment level, gingival bleeding index (GBI), plaque index (PlI), and keratinized gingiva width (KGW). RESULTS: Both techniques achieved similar percentage of root coverage, but NFBG was more effective in pocket depth reduction, attachment level gain, and reduction of plaque accumulation and of bleeding on probing. CONCLUSIONS: These findings suggest that the transfer of osteogenic cells by NFBG is able to improve clinical attachment level and to cover denuded roots. NFBG can be used as an alternative treatment of deep recessions (≥4 mm), where the restoration of lost periodontal tissues is intended.

Bone demineralization with citric acid enhances adhesion and spreading of preosteoblasts.

BACKGROUND: Previous studies have demonstrated that bone demineralization can improve consolidation in bone grafts. The biologic mechanisms underlying this phenomenon remain unclear. METHODS: Twelve adult male guinea pigs were used in this experiment. Forty-five bone samples removed from the calvaria of nine animals were divided in groups (n = 9) according to the time of demineralization with citric acid (50%, pH 1): 15, 30, 90, and 180 seconds and non-demineralized samples (control). Preosteoblasts (MC3T3-E1) were cultured on the bone samples for 24, 48, and 72 hours (n = 3). Fifteen samples removed from the remaining three animals were analyzed by scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) after demineralization (n = 3). RESULTS: The number of preosteoblasts increased significantly with time in all groups. The bone surface area covered by these cells increased with time, except in the control group. Intragroup differences occurred between 24 and 72 hours (P < 0.05). Samples demineralized for 30 seconds showed greater area covered by preosteoblast cells than for the other times of demineralization in all periods of cell culture (P < 0.05) without a statistically significant difference compared with 15 seconds. SEM/EDS showed diminished content of calcium (Ca) after 15 seconds of demineralization, but the Ca content increased after 180 seconds of demineralization (P < 0.05). The phosphorus (P) amount increased significantly only after 30 seconds of demineralization (P < 0.5). The sulfur (S) content was increased in demineralized samples in relation to non-demineralized ones, reaching the highest level after 90 seconds, when the difference became significant in relation to all the other times of demineralization (P < 0.05). Magnesium (Mg) content did not differ significantly between demineralized and non-demineralized samples. CONCLUSIONS: Bone surfaces demineralized for 30 seconds increased the spreading of preosteoblasts as well as the surface area covered by these cells. Bone demineralization deserves to be studied in periodontal and maxillofacial regenerative procedures.

Laser therapy as an effective method for implant surface decontamination: a histomorphometric study in rats.

BACKGROUND: To the best of the authors' knowledge, a standard protocol for treating peri-implantitis is not yet established. METHODS: A total of 150 titanium disks with smooth or rough surfaces contaminated with microbial biofilm were implanted subcutaneously in rats after undergoing one of three treatments: 1) low-intensity laser (LIL); 2) antimicrobial photodynamic therapy (aPDT); or 3) toluidine blue O (TBO). Sterile and contaminated disks served as negative (NC) and positive (C) control groups, respectively. After days 7, 28, and 84, tissue inflammation was evaluated microscopically by measuring the density of collagen fibers (degree of fibrosis) and concentration of polymorphonuclear neutrophils. RESULTS: Surface texture did not affect the degree of inflammation, but the area of reactive tissue was significantly greater for rough implants (2.6 ± 3.7 × 10(6) µm(2)) than for smooth ones (1.9 ± 2.6 × 10(6) µm(2); P = 0.0377). Group C presented the lowest and group NC presented the highest degree of fibrosis with significance only after day 7; these groups had the highest and lowest scores, respectively, for degree of inflammation. Group C showed the largest area of reactive tissue (9.11 ± 2.10 × 10(6) µm(2)), but it was not significantly larger than group LIL (P = 0.3031) and group TBO (P = 0.1333). Group aPDT showed the smallest area (4.34 ± 1.49 × 10(6) µm(2)) of reactive tissue among the treatment groups. After day 28, groups LIL, aPDT, TBO, and C resembled group NC in all the studied parameters. CONCLUSION: Group aPDT showed more favorable results in parameter area of reactive tissue than the other methods after day 7, but over longer time periods all methods produced outcomes equivalent to sterile implants.

A comparison of the dental health of Brazilian and Canadian independently living elderly.

OBJECTIVE: To compare the dental status of Brazilian and Canadian elderly populations with respect to socioeconomic and quality of life factors. MATERIALS AND METHODS: A total of 496 adults aged 60-75 years, having four or more teeth, and physically and cognitively suitable for a clinical oral examination were included. Subjects answered questions concerning their lifestyle and completed the Geriatric Oral Health Assessment Index (GOHAI) questionnaire. RESULTS: In all populations, the majority were females, aged between 60 and 65 years and married. Although the Canadian New Immigrant population had lower mean income, they had more remaining teeth (23.04 ± 6.1), more functional teeth (sound and restored teeth) (14.92 ± 5.7), more sound teeth (15.40 ± 7.6), but more carious teeth (2.97 ± 3.0). The Brazilian population had higher numbers of restored teeth (12.26 ± 6.8) and fewer remaining teeth (17.80 ± 7.6). In all populations, females, married and younger (60-65 years old) adults were more likely to retain 20 or more teeth. The mean GOHAI scores were similar for Canadians (40.55 ± 5.7) and Canadian New Immigrants (39.28 ± 6.5), but were higher than that among Brazilians (31.97 ± 8.9). CONCLUSIONS: The numbers of remaining teeth were related to greater education and higher income status for Brazilian and Canadian populations. However, Canadian New Immigrants with lower income and education retained more teeth than the other populations.

Surgical removal of an oral pyogenic granuloma and subsequent root coverage with a pedicle graft.

Pyogenic granuloma (PG) is a lesion characterized by non-neoplastic proliferation of endothelial cells, occurring in gingival tissue and representing an excessive reaction of the connective tissue to stimuli or injuries. The purpose of this report was to describe the treatment of an oral pyogenic granuloma, with emphasis on clinical, histopathological, and radiographic aspects. The surgical therapy comprised lesion excision followed by pedicle graft to cover the exposed root surface. The patient's pyogenic granuloma has been under control for a year, and recurrence has not been observed. The permanent teeth erupted correctly and the gingival tissue of both the receptor and donor sites shows a satisfactory clinical appearance.

Plástica periodontal em reabilitações implanto-suportadas: estética, função e / Periodontal plastic surgery around implant supported prosthesis: esthetic, function and marginal homeostasis

Com a sedimentação dos conhecimentos sobre a superfície osso-implante, passou-se a pesquisar e valorizar a interface tecido mole-implante, uma vez que a mesma serve como selado biológico, protegendo o tecido ósseo contra a ação de agressores externos. Desta forma se torna um item importante para a longevidade da osseointegração. O favorecimento da estética local deve ser levado em conta, já que em áreas sem mucosa ceratinizada há uma maior ocorrência de recessões gengivais. Este artigo tem o objetivo de demonstrar, por meio de aumento e/ou criação de mucosa ceratinizada, o manuseio de tecido mole via cirurgia plástica periodontal na Implantodontia tanto para otimização da estética quanto para manutenção da homeostasia marginal.

Histomorphometric study of the healing of human oral mucosa after gingivoplasty and low-level laser therapy.

BACKGROUND AND OBJECTIVES: The aim of the present study was to analyze the effects of diode laser irradiation on the healing of human oral mucosa. MATERIALS AND METHODS: After gingivoplasty, the right hemi-arch (test group) of 16 patients was irradiated with a diode laser. The left side (control group) was not irradiated. Incisional biopsies were performed on both sides at 7, 14, 21, and 60 days after surgery and morphometrically analyzed by light microscopy. RESULTS: Epithelium width ranged from 260.6 to 393.5 microm. Volume densities of basal (20.2%), prickle cell (55.6%), and cornified (24.2%) layers remained stable. The peak number of neutrophils were 6 cells/mm(2) and the mononuclear cells were 44 cells/mm(2). Collagen fibers (80%) and fibroblasts (14%) occupied the main volume of connective tissue. The one-way ANOVA and the paired Student's t-test were used for statistical analysis (P < 0.05). CONCLUSION: Low-level laser therapy did not accelerate the healing of oral mucosa after gingivoplasty.