Stress distribution in delayed replanted teeth splinted with different orthodontic wires: a three-dimensional finite element analysis

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

Effect of alendronate sodium on tooth movement in ovariectomized rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Early loading of 6-mm-short implants with a moderately rough surface supporting single crowns: a prospective 5-year cohort study

AimTo evaluate prospectively the clinical and radiographic outcomes after 5years of early loading of 6-mm implants with a moderately rough (SLActive((R))) surface supporting single crowns in the posterior regions.Material and methodsThirty-five consecutive patients received 40 SLActive((R)) (Straumann) 6-mm implants with a diameter of 4.1mm (n=19) or 4.8mm (n=21). Insertion torque and resonance frequency analysis (RFA) were measured at implant installation. RFA was also measured at abutment connection. SynOcta abutments were tightened with 35Ncm after 6weeks of healing, and single porcelain fuse to metal crowns was cemented within 1week. Implant survival rate and marginal bone loss were evaluated at various time intervals until 5years after loading. The clinical crown/implant ratio was calculated as well.ResultsTwo of 40 implants were lost before loading (incorporation rate 95%), and no further implant loss or technical complications were encountered during the 5-year follow-up period. A mean marginal bone loss of 0.70.6mm was found after 5years of function. The clinical crown/implant ratio increased with time from 1.6 at the delivery of the prosthesis to 2 after 5years of loading.ConclusionSix millimeter implants with a SLActive((R)) moderately rough surface supporting single crowns in the posterior region and loaded after 6-7weeks maintained full function for at least 5year with low marginal bone resorption.

Optimizing maxillary aesthetics of a severe compromised tooth through orthodontic movement and dental implants

Treatment of severe compromised tooth in the maxillary anterior area still poses great challenge to the clinicians. Several treatment modalities have been proposed to restore the function and aesthetics in teeth with advanced periodontal disease. The present study aims to report a case of traumatic injury of a left-maxillary central incisor with ridge preservation, orthodontic movement, and implant therapy. A 45-year-old woman underwent the proposed treatment for her left central incisor: basic periodontal therapy, xenogenous bone graft, and guided bone regeneration (GBR). Six months after the graft procedure, orthodontic movement by means of alignment and leveling was made and a coronal displacement of the gingival margin and vertical bone apposition could be observed after 13 months of active movement. Afterwards, a dental implant was placed followed by a connective tissue graft and immediate provisionalization of the crown. In conclusion, orthodontic movement was effective to improve the gingival tissue and alveolar bone prior to implant placement favoring the aesthetic results. Six years postoperatively, the results revealed height and width alveolar bone gain indicating that the treatment proposed was able to restore all the functional and aesthetic parameters.

Implant rehabilitation in bruxism patient

A white female patient presented to the university clinic to obtain implant retained prostheses. She had an edentulous maxillary jaw and presented three teeth with poor prognosis (33, 34 and 43). The alveolar bone and the surrounding tissues were healthy. The patient did not report any relevant medical history contraindicating routine dental treatment or implant surgery, but self-reported a dental history of asymptomatic nocturnal bruxism. The treatment plan was set and two Branemark protocols supported by six implants in each arch were installed after a 6-month healing period. A soft occlusal splint was made due to the patient's history of bruxism, and the lack of its use by the patient resulted in an acrylic fracture. The prosthesis was repaired and the importance of using the occlusal splint was restated. In the 4-year follow-up no fractures were reported.

Clinical study on survival rate of short implants placed in the posterior mandibular region: resonance frequency analysis

Short implants are increasingly used, but there is doubt about their performance being similar to that of regular implants. The aim of this study was to compare the mechanical stability of short implants vs. regular implants placed in the edentulous posterior mandible. Twenty-three patients received a total of 48 short implants (5 × 5.5 mm and 5 × 7 mm) and 42 regular implants (4 × 10 mm and 4 × 11.5 mm) in the posterior mandible. Patients who received short implants had <10 mm of bone height measured from the bone crest to the outer wall of the mandibular canal. Resonance frequency analysis (RFA) was performed at time intervals T0 (immediately after implant placement), T1 (after 15 days), T2 (after 30 days), T3 (after 60 days), and T4 (after 90 days). The survival rate after 90 days was 87.5% for the short implants and 100% for regular implants (P < 0.05). There was no significant difference between the implants in time intervals T1, T2, T3, and T4. In T0, the RFA values of 5 × 5.5 implants were higher than values of 5 × 7 and 4 × 11.5 implants (P < 0.05). A total of six short implants that were placed in four patients were lost (three of 5 × 5.5 mm and three of 5 × 7 mm). Three lost implants started with high ISQ values, which progressively decreased. The other three lost implants started with a slightly lower ISQ value, which rose and then began to fall. Survival rate of short implants after 90 days was lower than that of regular implants. However, short implants may be considered a reasonable alternative for rehabilitation of severely resorbed mandibles with reduced height, to avoid performing bone reconstruction before implant placement. Patients need to be aware of the reduced survival rate compared with regular implants before implant placement to avoid disappointments.

Prosthetic rehabilitation of a patient after a partial mandibulectomy

The treatment of orofacial tumors may cause facial deformities by losses of structures that affect basic functions, i.e. feeding, speech, and the reduction of patient self-steam. A white male patient was diagnosed with epidermoid cancer on the mandibular alveolar ridge with infiltration staging IV A. The patient was submitted to a mandibulectomy associated with a complete extraction of mandibular teeth. For rehabilitation, a conventional denture for the mandibular arch and a removable partial denture for the maxillary arch were fabricated. A correct occlusal adjustment and a satisfactory amount of alveolar bone was favorable for conventional dentures of the prostheses bases improve their retention and stability. After one year of follow-up, the patient was adapted to the prostheses, satisfied with their retention, and reported an improvement on his feeding. The prosthetic rehabilitation of patients after a partial mandibulectomy is essential for their self-steam. Conventional dentures may have their retention and stability improved if they are well fabricated, recorded and have a balanced occlusion. A correct occlusal adjustment and an adequate retention of the prostheses bases may improve their retention and stability. Patients without xerostomy and with a satisfactory amount of alveolar bone may have a favorable prognosis for conventional dentures.

Diagnostic index of three-dimensional osteoarthritic changes in temporomandibular joint condylar morphology

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

Effect of the probiotic Saccharomyces cerevisiae on ligature-induced periodontitis in rats

This study assessed the effects of the local use of Saccharomyces cerevisiae as monotherapy and as an adjuvant to the mechanical treatment of ligature-induced periodontitis in rats. Periodontitis was induced in 72 rats via the installation of a ligature around the mandibular first molar. After 7 d, the ligature was removed and the rats were placed in one of the following groups: no treatment (C; n = 18); scaling and root planing (SRP; n = 18); local irrigation with probiotics (PRO; n = 18); and SRP followed by local irrigation with probiotics (SRP/PRO; n = 18). Six rats from each group were killed at 7, 15 and 30 d. The histological characteristics, alveolar bone loss (ABL) and immunolabeling of tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), interleukin-10 (IL-10) and TRAP on the furcation area of the first molar were assessed. The PRO group showed features of acceleration of the tissue-repair process during the entire experiment. On day 15, there was less ABL in the SRP/PRO group compared with the C group. There were fewer TRAP-positive cells in the SRP and SRP/PRO groups at 30 d. There was less immunostaining for TNF-α in the PRO and SRP/PRO groups and less immunostaining for IL-1β in the PRO group. However, there was more immunostaining for IL-10 in the PRO group on day 15. Local use of the probiotic did not result in any adverse effects on periodontal tissues. When used as monotherapy or as an adjuvant, the probiotic was effective at controlling periodontitis in rats.

Drifting of teeth in the mandible studied in adult human autopsy material

Increase in lower anterior crowding is a general problem among adult Caucasians. The tooth movement responsible for this phenomenon, however, is not fully elucidated. Aim of this study was to describe signs of ongoing tooth movement reflected in the thickness of the bundle bone around mandibular teeth and the distribution of eroding surfaces of the alveolar wall in human autopsy material. The distribution of bundle bone and eroding surfaces was assessed histomorphometrically on 106 mandibular teeth, and the surrounding bone obtained at autopsy from 35 deceased persons ranging from 19 to 55 years of age. By examining the mesio-distal and bucco-lingual aspects at the cervical and apical levels of the roots, a pattern of tooth movements could be established. The distribution of the bundle bone thickness and the vectors of eroding surfaces enabled the direction of tooth movement to be reconstructed. Mesial and lingual displacement was prevalent for the anterior teeth. The signs of ongoing displacement of lower teeth support the concept of crowding occurring in adult individuals and support the maintenance of retainers, even following cessation of growth.

Down-regulation of protease activated receptor 2, interleukin-17 and other pro-inflammatory genes by subantimicrobial doxycycline dose in a rat periodontitis model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radiographic assessment of potodynamic therapy as an adjunctive treatment on induced periodontitis in immunosupressed 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. he radiographic values were analyzed statistically by ANOVA and Tukey's test at a p value <0.05. RESULTS: Intragroup radiographic assessment (ND and D groups) showed that there was statistically signifcant 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.

Reparative phase events on periodontal disease progression: interpretation and considerations

Periodontal disease progress by destructive acute phases intercalated by reparative chronic phases. The aim of this study was to investigate the clinical and histological evidence of the periodontal disease reparative phase by analyzing bone wall conditions inside periodontal pockets and histologic images of periodontal pockets, identified in relevant publications. 81 patients with periodontitis, were randomly assigned into this study. Clinical and radiographic parameters were established to diagnose periodontal disease providing a sample of 133 diseased areas, which were treated by modified Widman flap. Documentation by digital photography were recorded in the surgery. Relevant publications showing histological images of periodontal pockets, were identified in Medline, PubMed and Google data base, were scanned and digitalized. All images obtained were evaluated and the presences of the reparative evidence in the zone around the underlying destroyed alveolar bone were critically analyzed. All periodontal bone defects, showed cortical bone reparations at different levels inside periodontal bone defects. All histologic images of periodontal pockets identified in relevant publications showed repaired gingival-attached connective tissue localized above underlying destroyed alveolar bone. All the evidences analyzed in this study suggested that periodontal disease is predominantly chronic, quiescent, showing reparative phases in different levels.

Reabsorção condilar progressiva: revisão de literatura

The progressive condylar resorption is a irreversible complication that can result in malocclusion and facial deformity that can happen especially in postoperative orthognathic surgery of mandibular advancement or combined surgery. Predominantly affect young women, bearers of malocclusions of skeletal class II and with incidence of temporomandibular disorders prior to surgical treatment. Its exact etiology and pathogenesis remain unclear. The purpose of this article is to make a literature review of the last 10 years on the progressive condylar resorption. For this, we used the Medline database for articles in the English language. Then, 13 articles were found, evaluated and compared on predisposing factors, etiology, diagnosis and clinical management.

Regeneração óssea guiada com o uso de matriz óssea bovina desmineralizada em defeitos ósseos experimentais em cães

Background: The principles of tissue regeneration to repair alveolar bone defects are based on the fabrication of a biologic barrier with different biomaterials. Therefore, the present study aimed to investigate the guided bone regeneration (GBR) by using membrane of demineralized bovine bone matrix (DBBM) on experimental defects in tibia of dogs. Methods: Four dogs were used and after anesthesia, shaving and antisepsis, two standardized bone defects were created on the right tibia of each animal with trephine drill. In the Control Group, the defects were filled with blood coagulum, while in the Treated Group, a membrane of DBBM was used to cover the defects. After 90 days, animals were sacrificed. Results: In the Treated Group, 67.4% of new bone formation was observed and, in the Control Group, 32.6% of the bone tissue reabsorbed when compared with initial bone volume. The membrane remained intact and no inflammatory tissue was observed on membrane/ bone interface. Conclusion: It was concluded that the use of DBBM is an osteoconductive material, presents biocompatibility and may be promise option to repair bone defects.