Estudo retrospectivo de implantes osseointegrados instalados imediatamente após exodontias

Objectives: to evaluate implant survival immediately placed after tooth extraction considering different sites, prosthodontic modalities, and the need for biomaterials. Material and methods: dental records of 500 patients treated with dental implants between 2004 and 2011 were screened. Results: only 200 records (20%) corresponded to immediate implants. Reasons for tooth extraction included extensive caries, bone loss, and root fractures. From the 197 immediate dental implants, 86 were placed in the maxilla with a survival rate of 93.9% and 111 in the mandible (survival rate of 99.1%). The overall survival rate was 97.46%. Prosthodontic modalities identified were: Brånemark classic complete denture screwed prostheses (36%), overdentures (5.6%), fixed partial denture (31%), and single-tooth prostheses (27.4%). Also, it was observed that in 33% of cases there was a need for the use of grafts and/or biomaterials. Conclusion: it can be concluded that, when correctly indicated, immediate implants are an excellent choice. The anterior mandibular region, screwed and overdenture-type prostheses presented higher success rates when associated to immediate implant placement. The need for bone graft/biomaterial does not affect the clinical results.

Remodelação óssea com as forças contínua, contínua interrompida e intermitente: movimentação dentária induzida em ratos

Pós-graduação em Odontologia - FOA

Estudo comparativo do desempenho de diferentes membranas oclusivas de Látex Natural no reparo ósseo

Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.

Inflamassomos NLRC4 E NLRP3 na Doença Periodontal Experimental Induzida por Aggregatibacter Actinomycetemcomitans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da perda de peso sobre o metabolismo ósseo de pacientes submetidos à cirurgia bariátrica de Bypass Gástrico em Y de Roux: efeitos da cirurgia bariátrica sobre o metabolismo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Inflamassomos NLRC4 E NLRP3 na Doença Periodontal Experimental Induzida por Aggregatibacter Actinomycetemcomitans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da perda de peso sobre o metabolismo ósseo de pacientes submetidos à cirurgia bariátrica de Bypass Gástrico em Y de Roux: efeitos da cirurgia bariátrica sobre o metabolismo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Role of teeth adjacent to implants installed immediately into extraction sockets: an experimental study in the dog

Aim: To evaluate the influence of the presence of both adjacent teeth on the level of alveolar bony crest at sites where implants were installed into the socket immediately after tooth extraction. Material and methods: Six Labrador dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in the right side of the mandible, after full-thickness flap elevation. In the left side of the mandible, an endodontic treatment of the mesial root of the third and fourth premolars was performed. Full-thickness flaps were elevated, the teeth hemisected, and the distal roots removed. Immediately after, implants were bilaterally installed with the margin flush to the buccal bony crest. The implants were placed in the center of the alveolus at the third premolars and toward the lingual bony plate of the alveolus at the fourth premolars. After 3 months of healing, the animals were euthanized. Results: All implants were integrated in mature bone. More bone resorption was observed at the test compared to the control sites. At the buccal aspect, a resorption of 2.8 +/- 0.5 and 1.6 +/- 0.4 mm at the third premolars and of 2.4 +/- 0.6 and 0.8 +/- 0.7 mm at the fourth premolars were found, at the test and control sites, respectively. At the lingual aspect, the bony crest was apically located in relation to the implant shoulder 1.5 +/- 0.3 and 0.5 +/- 0.5 mm at the third premolars and 1.6 +/- 0.6 and 0.3 +/- 1.1 mm at the fourth premolars, at the test and control sites, respectively. A lower buccal bone resorption was found at the control implants placed lingually. Conclusion: Multiple extractions of teeth adjacent to a socket into which implants were installed immediately after, tooth extraction induced more alveolar bone recession compared to sites where the adjacent teeth were preserved. Moreover, an implant placed more lingually yielded less recession of the buccal aspect of the implant.

Inward-Inclined Implant Platform for the Amplified Platform-Switching Concept: 18-Month Follow-up Report of a Prospective Randomized Matched-Pair Controlled Trial

Purpose: This prospective randomized matched-pair controlled trial aimed to evaluate marginal bone levels and soft tissue alterations at implants restored according to the platform-switching concept with a new inward-inclined platform and compare them with external-hexagon implants. Materials and Methods: Traditional external-hexagon (control group) implants and inward-inclined platform implants (test group), all with the same implant body geometry and 13 mm in length, were inserted in a standardized manner in the posterior maxillae of 40 patients. Radiographic bone levels were measured by two independent examiners after 6, 12, and 18 months of prosthetic loading. Buccal soft tissue height was measured at the time of abutment connection and 18 months later. Results: After 18 months of loading, all 80 implants were clinically osseointegrated in the 40 participating patients. Radiographic evaluation showed mean bone losses of 0.5 +/- 0.1 mm (range, 0.3 to 0.7 mm) and 1.6 +/- 0.3 mm (range, 1.1 to 2.2 mm) for test and control implants, respectively. Soft tissue height showed a significant mean decrease of 2.4 mm in the control group, compared to 0.6 mm around the test implants. Conclusions: After 18 months, significantly greater bone loss was observed at implants restored according to the conventional external-hexagon protocol compared to the platform-switching concept. In addition, decreased soft tissue height was associated with the external-hexagon implants versus the platform-switched implants. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:927-934.

Rehabilitative treatment of cleft lip and palate: experience of the Hospital for Rehabilitation of Craniofacial Anomalies - USP (HRAC-USP) - Part 3: Oral and Maxillofacial Surgery

This paper presents the treatment protocol of maxillofacial surgery in the rehabilitation process of cleft lip and palate patients adopted at HRAC-USP. Maxillofacial surgeons are responsible for the accomplishment of two main procedures, alveolar bone graft surgery and orthognathic surgery. The primary objective of alveolar bone graft is to provide bone tissue for the cleft site and then allow orthodontic movements for the establishment of an an adequate occlusion. When performed before the eruption of the maxillary permanent canine, it presents high rates of success. Orthognathic surgery aims at correcting maxillomandibular discrepancies, especially anteroposterior maxillary deficiencies, commonly observed in cleft lip and palate patients, for the achievement of a functional occlusion combined with a balanced face.

Celecoxib treatment does not alter recruitment and activation of osteoclasts in the initial phase of experimental tooth movement

In a previous study, we reported that the short-term treatment with celecoxib, a nonsteroidal anti-inflammatory drug (NSAID) attenuates the activation of brain structures related to nociception and does not interfere with orthodontic incisor separation in rats. The conclusion was that celecoxib could possibly be prescribed for pain in orthodontic patients. However, we did not analyze the effects of this drug in periodontium. The aim of this follow-up study was to analyze effects of celecoxib treatment on recruitment and activation of osteoclasts and alveolar bone resorption after inserting an activated orthodontic appliance between the incisors in our rat model. Twenty rats (400420 g) were pretreated through oral gavage with celecoxib (50 mg/kg) or vehicle (carboxymethylcellulose 0.4%). After 30 min, they received an activated (30 g) orthodontic appliance, set not to cause any palate disjunction. In sham animals, the appliance was immediately removed after introduction. All animals received ground food and, every 12 h, celecoxib or vehicle. After 48 h, they were anesthetized and transcardiacally perfused through the aorta with 4% formaldehyde. Subsequently, maxillae were removed, post-fixed and processed for histomorphometry or immunohistochemical analyses. As expected, incisor distalization induced an inflammatory response with certain histological changes, including an increase in the number of active osteoclasts at the compression side in group treated with vehicle (appliance: 32.2 +/- 2.49 vs sham: 4.8 +/- 1.79, P<0.05) and celecoxib (appliance: 31.0 +/- 1.45 vs sham: 4.6 +/- 1.82, P<0.05). The treatment with celecoxib did not modify substantially the histological alterations and the number of active osteoclasts after activation of orthodontic appliance. Moreover, we did not see any difference between the groups with respect to percentage of bone resorption area. Taken together with our previous results we conclude that short-term treatment with celecoxib can indeed be a therapeutic alternative for pain relieve during orthodontic procedures.

The influence of pore size on osteoblast phenotype expression in cultures grown on porous titanium

This study investigated the effect of pore size on osteoblastic phenotype development in cultures grown on porous titanium (Ti). Porous Ti discs with three different pore sizes, 312 mu m (Ti 312), 130 mu m (Ti 130) and 62 mu m (Ti 62) were fabricated using a powder metallurgy process. Osteoblastic cells obtained from human alveolar bone were cultured on porous Ti samples for periods of up to 14 days. Cell proliferation was affected by pore size at day 3 (p = 0.0010), day 7 (p = 0.0005) and day 10 (p = 0.0090) in the following way: Ti 62 < Ti 130 < Ti 312. Gene expression of bone markers evaluated at 14 days was affected, RUNX2 (p = 0.0153), ALP (p = 0.0153), BSP (p = 0.0156), COL (p = 0.0156), and OPN (p = 0.0156) by pore size as follows: Ti 312 < Ti 130 < Ti 62. Based on these results, the authors suggest that porous Ti surfaces with pore sizes near 62 mu m, compared with those of 312 mu m and 130 mu m, yield the highest expression of osteoblast phenotype as indicated by the lower cell proliferation rate and higher gene expression of bone markers.

Evaluation of a Maxillary Sinus Floor Augmentation in the Presence of a Large Antral Pseudocyst

Sinus floor augmentation has been established as a predictable technique to overcome maxillary bone loss. Antral cystic lesions may lead to intrasurgical complications and should be accurately diagnosed. However, antral pseudocysts have recently been described not to be contraindicated for sinus-grafting procedures. The current article sought to report clinical, cone beam computed tomographic, and histologic results of a maxillary sinus floor augmentation, performed with piezoelectric surgery, in the presence of a large antral pseudocyst. Success of graft maturation was confirmed with histologic analysis, which also indicated the absence of inflammatory infiltration in the tissue evaluated. On the basis of our findings, it is possible to perform a predictable treatment based on sinus floor augmentation in the presence of antral pseudocysts. Graft maturation can also be achieved 6 months after sinus-lifting surgeries.

Assessment of using digital manipulation tools for diagnosing mandibular radiolucent lesions

Objective: The purpose of this study was to analyse the use of digital tools for image enhancement of mandibular radiolucent lesions and the effects of this manipulation on the percentage of correct radiographic diagnoses. Methods: 24 panoramic radiographs exhibiting radiolucent lesions were selected, digitized and evaluated by non-experts (undergraduate and newly graduated practitioners) and by professional experts in oral diagnosis. The percentages of correct and incorrect diagnoses, according to the use of brightness/contrast, sharpness, inversion, highlight and zoom tools, were compared. All dental professionals made their evaluations without (T-1) and with (T-2) a list of radiographic diagnostic parameters. Results: Digital tools were used with low frequency mainly in T-2. The most preferred tool was sharpness (45.2%). In the expert group, the percentage of correct diagnoses did not change when any of the digital tools were used. For the non-expert group, there was an increase in the frequency of correct diagnoses when brightness/contrast was used in T-2 (p = 0.008) and when brightness/contrast and sharpness were not used in T-1 (p = 0.027). The use or non-use of brightness/contrast, zoom and sharpness showed moderate agreement in the group of experts [kappa agreement coefficient (kappa) = 0.514, 0.425 and 0.335, respectively]. For the non-expert group there was slight agreement for all the tools used (kappa <= 0.237). Conclusions: Consulting the list of radiographic parameters before image manipulation reduced the frequency of tool use in both groups of examiners. Consulting the radiographic parameters with the use of some digital tools was important for improving correct diagnosis only in the group of non-expert examiners. Dentomaxillofacial Radiology (2012) 41, 203-210. doi: 10.1259/dmfr/78567773

Study of the osteoconductive capacity of hydroxyapatite implanted into the femur of ovariectomized rats

Osteoporosis is a global public health that affects postmenopausal women due to the deficiency of estrogen, a hormone that plays an important role in the microarchitecture of bone tissue. Osteoporosis predisposes to pathological bone fracture that can be repaired by conventional methods. However, depending on the severity and quantity of bone loss, the use of autogenous grafts or biomaterials such as hydroxyapatite might be necessary. The latter has received increasing attention in the medical field because of its good biological properties such as osteoconductivity and biocompatibility with bone tissue. The objective of this study was to evaluate using histologic and radiographic analyses, the osteogenic capacity of hydroxyapatite implanted into the femur of rats with ovariectomy-induced osteoporosis. Eighteen rats were divided into three groups with six animals in each: group nonovariectomized, bilaterally ovariectomized not receiving estrogen replacement therapy, and bilaterally ovariectomized submitted to estrogen replacement therapy. Defects were created experimentally in the distal epiphysis of the femur with a surgical drill and filled with porous hydroxyapatite granules. The animals were sacrificed 8 weeks after surgery. The volume of newly formed bone in the implant area was quantified by morphometrical methods. The results were analyzed by ANOVA followed by the Tukey test (P < 0.05). The hydroxyapatite granules showed good radiopacity. Histological analysis revealed less quantity of newly formed bone in the ovariectomized group not submitted to hormone replacement therapy. In conclusion, bone neoformation can be expected even in bones compromised by estrogen deficiency, but the quantity and velocity of bone formation are lower. Microsc. Res. Tech., 2011. (c) 2011 Wiley Periodicals, Inc.