Human non-decalcified histology of three dental implants 45 months under function-a case report.

BACKGROUND: Fracture of an implant is a quite rare event but represents an important opportunity to evaluate the peri-implant bone tissue response to implant overload in human beings. This study aimed to evaluate bone tissue around three fractured titanium implants retrieved from a human maxilla, by histomorphometric and birefringence analyses. CASE REPORT: For this, the implants and the surrounding bone were removed after having been united to a tooth in function for 45 months, by a 4-mm internal diameter trephine bur, following an undecalcified section was obtained. The results showed a rate of 77.3% of bone-to-implant contact (BIC) and 80.3% of bone area filling within the limits of the implant threads. Under circularly polarized light microscopy investigation, the amount of the transverse collagen fibers was of 48.11%, and the amount of the longitudinal collagen fibers was of 51.89%. CONCLUSION: Within the limitation of this study, the possible cause of the implant fracture could be the association of overload, inadequate implant diameter, and fragile internal hexagon connection.

Effect of the long-term administration of Cyclosporine A on bone healing around osseointegrated titanium implants: A histomorphometric study in the rabbit tibia.

The aim of this study was to investigate the effect of cyclosporine A (CsA) therapy on bone healing around osseointegrated implants in the rabbit by means of descriptive histologic and histomorphometric analyses. Eighteen rabbits received one implant each in the right tibia proximal metaphysis. After the bone-healing period of 3 months, 6 randomly selected animals were sacrificed (Group CTL-12) before the immunosuppression therapy initiation to obtain a standard of implant integration. Another six randomly selected animals were submitted to a daily subcutaneous (sc) injection of 10 mg/kg CsA (Group CsA) whereas the six remaining animals received daily sc injections of saline solution (Group CTL-24). Groups CTL-24 and CsA were sacrificed after another 12 weeks. Bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) within the implant threads were measured. Bone density (BD) and descriptive histological analyses were also accomplished. Rabbits under CsA therapy presented statistically lower percentage of BIC (33.28 ± 6.19) compared to the animals of CLT-24 (55.6 ± 17.73). No differences were found between CsA and CTL-12 (38.7 ± 7.87). Significant decreased percentage of BAFO between the implant threads in the CsA (48.43 ± 9.48) group compared to the CTL-24 (72.26 ± 11.72) was observed. No differences were found between CsA and CTL-12 (61.99 ± 13.94) groups. BD analysis showed significant lower BD in the CsA (48.56 ± 9.32) group compared to the CTL-12 (68.74 ± 10.89) and CTL-24 (77.96 ± 4.96) groups. Collectively, our findings demonstrated that CsA therapy negatively affect the bone healing around osseointegrated implants due to the significant lower values for BIC, BAFO, and BD.

Preemptive dexamethasone and etoricoxib for pain and discomfort prevention after periodontal surgery: a double-masked, crossover, controlled clinical trial.

BACKGROUND: Several anti-inflammatory drugs have been used to reduce pain and discomfort after periodontal surgeries. This study evaluates the efficacy of using etoricoxib and dexamethasone for pain prevention after open-flap debridement surgery. METHODS: For this prospective, double-masked, crossover, placebo-controlled, randomized clinical trial, open-flap debridement surgeries were performed on 15 patients (eight males and seven females, age range 20 to 56 years: mean age +/- SD: 40 +/- 9.7 years) who presented with chronic periodontitis after non-surgical periodontal therapy at three quadrants. Each patient underwent three surgical procedures at intervals of 30 days and received one of the following premedication protocols 1-hour before surgery: group 1 = placebo, group 2 = 8 mg dexamethasone, and group 3 = 120 mg etoricoxib. Rescue medication (750 mg acetaminophen) was given to each patient who was instructed to take it when necessary. Pain intensity and discomfort were evaluated by a 101-point numeric rate scale and a four-point verbal rate scale, respectively, hourly for the first 8 hours after surgery and three times a day on the following 3 days. RESULTS: The results demonstrate that groups 2 and 3 present reduced postoperative pain-intensity levels compared to group 1. There were statistically significant differences at the 4, 5, 6, 7, and 8 hour-periods after surgery (Friedman test; P <0.05). Furthermore, rescue-medication intake was significantly lower for groups 2 and 3 than for group 1 (analysis of variance; P <0.02). CONCLUSION: The adoption of a preemptive medication protocol using etoricoxib or dexamethasone may be considered effective for pain and discomfort prevention after open-flap debridement surgeries.

Evaluation of titanium implants with surface modification by laser beam. Biomechanical study in rabbit tibias.

The purpose of the present study was to evaluate, using a biomechanical test, the force needed to remove implants with surface modification by laser (Nd:YAG) in comparison with implants with machined surfaces. Twenty-four rabbits received one implant with each surface treatment in the tibia, machined surface (MS) and laser-modified surface (LMS). After 4, 8 and 12 weeks of healing, the removal torque was measured by a torque gauge. The surfaces studied were analyzed according to their topography, chemical composition and roughness. The average removal torque in each period was 23.28, 24.0 and 33.85 Ncm for MS, and 33.0, 39.87 and 54.57 Ncm for LMS, respectively. The difference between the surfaces in all periods of evaluation was statistically significant (p < 0.05). Surface characterization showed that a deep and regular topography was provided by the laser conditioning, with a great quantity of oxygen ions when compared to the MS. The surface micro-topography analysis showed a statistical difference (p < 0.01) between the roughness of the LMS (R(a) = 1.38 +/- 0.23 microm) when compared to that of the MS (R(a) = 0.33 +/- 0.06 microm). Based on these results, it was possible to conclude that the LMS implants' physical-chemical properties increased bone-implant interaction when compared to the MS implants.

Biological performance of chemical hydroxyapatite coating associated with implant surface modification by laser beam: biomechanical study in rabbit tibias.

PURPOSE: Considering the potential of the association between laser ablation and smaller scale hydroxyapatite (HA) coatings to create a stable and bioactive surface on titanium dental implants, the aim of the present study was to determine, by the removal torque test, the effects of a surface treatment created by laser-ablation (Nd:YAG) and, later, thin deposition of HA particles by a chemical process, compared to implants with only laser-ablation and implants with machined surfaces. MATERIALS AND METHODS: Forty-eight rabbits received 1 implant by tibia of the following surfaces: machined surface (MS), laser-modified surface (LMS), and biomimetic hydroxiapatite coated surface (HA). After 4, 8, and 12 weeks of healing, the removal torque was measured by a torque gauge. The surfaces studied were analyzed according to their topography, chemical composition, and roughness. RESULTS: Average removal torque in each period was 23.28, 24.0, and 33.85 Ncm to MS, 33.0, 39.87, and 54.57 Ncm to LMS, and 55.42, 63.71 and 64.0 Ncm to HA. The difference was statistically significant (P < .05) between the LMS-MS and HA-MS surfaces in all periods of evaluation, and between LMS-HA to 4 and 8 weeks of healing. The surface characterization showed a deep, rough, and regular topography provided by the laser conditioning, that was followed by the HA coating. CONCLUSIONS: Based on these results, it was possible to conclude that the implants with laser surface modification associated with HA biomimetic coating can shorten the implant healing period by the increase of bone implant interaction during the first 2 months after implant placement.

Fatigue and fluoride corrosion on Streptococcus mutans adherence to titanium-based implant/component surfaces.

PURPOSE: The influence of fatigue and the fluoride ion corrosion process on Streptococcus mutans adherence to commercially pure Titanium (Cp Ti) implant/component set surfaces were studied. MATERIALS AND METHODS: Thirty Nobel implants and 30 Neodent implants were used. Each commercial brand was divided into three groups. Group A: control, Group B: sets submitted to fatigue (10(5) cycles, 15 Hz, 150 N), and Group C: sets submitted to fluoride (1500 ppm, pH 5.5) and fatigue, simulating a mean use of 5 years in the oral medium. Afterward, the sets were contaminated with standard strains of S. mutans (NTCC 1023) and analyzed by scanning electronic microscopy (SEM) and colony-forming unit counts (CFU/mL). RESULTS: By SEM, bacterial adherence was verified only in group C in both brands. By CFU/mL counts, S. mutans was statistically higher in both brands in group C than in groups A and B (p < 0.05, ANOVA). CONCLUSION: The process of corrosion by fluoride ions on Cp Ti implant/component sets allowed greater S. mutans adherence than in the absence of corrosion and with the fatigue process in isolation.

Influence of a fluoridated medium with different pHs on commercially pure titanium-based implants.

PURPOSE: The objective of this study was to assess the influence of a fluoride medium with different pHs on the corrosion resistance of three commercially pure titanium-based dental implant commercial brands, under scanning electron microscopy (SEM) and EDS. MATERIALS AND METHODS: Forty-two dental implants, from three commercial brands, were used. Five years of regular use of mouth rinsing, with NaF 1500 ppm content and two different pHs, were simulated by immersing the specimens into that medium for 184 hours. RESULTS: SEM and EDS analyses demonstrated no evidence of corrosion on the specimens' surfaces after being submitted to fluoride ions or incorporation of fluoride ions to the set surface. CONCLUSION: It was possible to conclude that both the fluoride concentration and the pH of the solutions did not exert any influence upon implant corrosion resistance.

Avaliação de implantes modificados por feixe de laser Nd: YAG e implantes de superfície usinada empregando-se MEV e torque reverso / Evaluation of implants modified by laser beam Nd: YAG and machined surface implants employing SEM and reverse torque test

Implantes de Ti-cp foram irradiados utilizando-se feixe de laser Nd:YAG para serem comparados com implantes de superfície usinada. As amostras foram inseridas cirurgicamente na tíbia de coelhos. Após o período de oito semanas de cicatrização os animais foram sacrificados e os implantes retirados empregando-se teste de torque reverso. A análise por MEV-EDS da superfície irradiada com laser apresentou maior formação óssea em relação à superfície usinada. Ao teste de torque reverso o implante irradiado laser apresentou o valor de torque médio de 40 Ncm e o implante usinado 24 Ncm. Os resultados obtidos indicaram que a superfície irradiada por feixe de laser apresentou maior interação e adesão de tecido ósseo.

Ti-cp implants were irradiated using laser beam Nd:YAG to be compared with machined surface implants. The samples were inserted into rabbit tibia. After an eight-week healing period, the animals were sacrificed and the implants removed under reverse torque test. SEM-EDS analysis of the laser-irradiated surface showed higher bone formation than at the machined surface. The reverse torque test of the laser-irradiated implants showed medium torque values of 40 Ncm and machined implants of 24 Ncm. The results showed that the use of laser treatment imparts higher bone tissue interaction and adhesion.

Evaluation of titanium implants with surface modification by laser beam: biomechanical study in rabbit tibias

The purpose of the present study was to evaluate, using a biomechanical test, the force needed to remove implants with surface modification by laser (Nd:YAG) in comparison with implants with machined surfaces. Twenty-four rabbits received one implant with each surface treatment in the tibia, machined surface (MS) and laser-modified surface (LMS). After 4, 8 and 12 weeks of healing, the removal torque was measured by a torque gauge. The surfaces studied were analyzed according to their topography, chemical composition and roughness. The average removal torque in each period was 23.28, 24.0 and 33.85 Ncm for MS, and 33.0, 39.87 and 54.57 Ncm for LMS, respectively. The difference between the surfaces in all periods of evaluation was statistically significant (p < 0.05). Surface characterization showed that a deep and regular topography was provided by the laser conditioning, with a great quantity of oxygen ions when compared to the MS. The surface micro-topography analysis showed a statistical difference (p < 0.01) between the roughness of the LMS (Ra = 1.38 ± 0.23 ìm) when compared to that of the MS (Ra = 0.33 ± 0.06 ìm). Based on these results, it was possible to conclude that the LMS implants' physical-chemical properties increased bone-implant interaction when compared to the MS implants.

Recubrimiento de las recesiones gingivales con la técnica de injerto conjuntivo subepitelial asociado al deslizamiento coronario del colgajo: relato de caso clínico / Coronal positioned flaps associated with free subepitelial conective tissue graft for treatment of gingival recession: clinical case report

Recesión gingival es definida como la localización apical del margen gingival en relación a la unión cemento - esmalte, siendo predominante en la cara vestibular de los dientes. Además de provocar una desarmonía en la estética, puede causar sensibilidad destinaría. Para el tratamiento de recesiones gingivales han sido propuestas técnicas que pueden ser agrupadas en injertos pediculados, injertos libres y regeneración de tejidos guiada. El objetivo de este trabajo es relatar el caso clínico de un paciente con recesiones gingivales generalizadas. Luego de la anamnesis y examen clínico, se atribuye la etiología de las recesiones al cepillado incorrecta y trauma oclusal. Se realizó una adecuada instrucción de higiene bucal y ajuste oclusal. Se procedió a la aplicación de nitrato de potasio al 5 por ciento por dos meses, sin embargo, él paciente se quejaba de sensibilidad y del aspecto estético. Para el recubrimiento de las raíces expuestas fueron realizadas las técnicas de colgajo posicionado coronalmente asociado y no asociado al injerto conjuntivo subepitelial. Luego de un año los dientes muestran ausencia de sangramiento y sensibilidad destinaría, con profundidad de sondaje normal (<3mm). Los resultados de esta técnica se muestran satisfactorios, atendiendo las expectativas del paciente

Gingival recession is defined as the apical location of the gingival in relation to the cement-enamel junction, being predominant in buccal aspect. Other than causing esthetic disharmony, it can cause dentine sensitive. To treat gingival recession, the following techniques can be employed: pedicle gingival graft, free gingival graft, and guided tissue regeneration. The purpose of this study is to present a case report with generalized gingival recession. After anamneses and clinical exam, the etiology of the gingival recession was indicated as incorrect oral hygiene and occlusal trauma. The patient receive adequate oral hygiene instruction and the occlusion was adjusted. Five percent potassium nitrate was applied locally for two months, however, the patient still complained of dentine sensitivity and lack of esthetics. For root coverage, coronal positioned flaps were conduct with or without free subepithelial connective tissue. One year later the teeth presented absence of bleeding and dentine sensitive, with normal probe depth (<3mm). The results of this techniques fulfilled the patients esthetic need and eliminated the dentinal sensitivity

Avaliação da adesão bacteriana em titânio revisão de literatura / Evaluatíon of bacterial adhesion to titanium - Literature review

O estudo da adesão e colonização bacteriana sobre o titânio é de grande importância, pois são fatores principais na patogenia de infecções em biomateriais. A adesão e colonização bacteriana podem variar de acordo com o biomaterial, tipo de microrganismo, fase de crescimento e propriedades superficiais dos materiais. A rugosidade de superfícies sólidas intraorais também tem uma influência na adesão bacteriana. Regiões com uma alta rugosidade de superfícies acumulam e retém mais placa bacteriana. A rugosidade de implantes dentais à base de Ti c.p. pode ser alterada por meio de corrosão por fluoretos.

The influence of cyclosporin a on mechanical retention of dental implants previously integrated to the bone: a study in rabbits.

BACKGROUND: Immunosuppressive agents may induce severe changes on bone metabolism and may impair the osseointegration process during the implant healing. No data are available concerning the influence of cyclosporin A on dental implants previously integrated to the bone. The aim of this study was to evaluate the influence of cyclosporin A administration on the mechanical retention of bone previously integrated to dental implants. METHODS: Eighteen female New Zealand rabbits were submitted to an implant surgery. Each animal received one commercial dental implant of 10 x 3.75 mm. After 12 weeks of an undisturbed healing period, six animals were randomly sacrificed and the removal torque test was performed (group A). In addition, six animals were submitted to a daily injection of cyclosporin A in a dosage of 10 mg/kg (group C), and six animals received saline solution as a control (group B). After 12 weeks of cyclosporin A administration, groups B and C were sacrificed and submitted to a removal torque test in which higher values can be interpreted as higher mechanical bone retention to the implant surface or higher osseointegration. RESULTS: The removal torque results were 30.5 (+/-9.8) Ncm for group A, 50.17 (+/-17.5) Ncm for group B, and 26 (+/-7.8) Ncm for group C. The statistical analysis showed significant differences between groups A and B (P <0.05) and groups B and C (P <0.01). CONCLUSION: Cyclosporin A administration may impair the mechanical retention of dental implants previously integrated to the bone.

Dureza e caracterização do Ti c.p. quando submetido a tratamento térmicos e à ação de fluoreto de sódio / Hardness and characterization of the c.p. Ti when submitted to heat treatment and to the action of sodium fluoride solution

O objetivo deste trabalho foi analisar a dureza e a caracterização metalográfica doTi c.p. quando submetido a tratamentos térmicos e à corrosão por solução de fluoretos de sódioa 1%. As amostras foram submetidas a dois tipos de tratamento térmico, têmpera e recozimento.Em seguida, foram submersas em solução de fluoreto de sódio por 30 dias e depois por mais30 dias. Entre cada etapa, foi feita a caracterização por meio de teste de dureza e microscopia óptica.No ensaio de dureza Vickers, verificou-se diferenças estatísticas entre os grupos estudados e queos tratamentos térmicos realizados elevaram a dureza do Ti c.p. por aliviar a tensão do material etorná-lo uma estrutura cristalina, fato este que deve melhorar as propriedades do material. Alémdisso, verificou-se que os grupos estudados, ao serem submetidos à ação de íons fluoreto apósos tratamentos térmicos, tiveram seus valores de dureza aumentados devido, provavelmente, aoprocesso de friabilidade. Na análise metalográfica, foram observadas diferenças entre as amostrasquando submetidas à ação dos íons fluoreto, e essa exposição à solução fluoretada danificou asuperfície desse biomaterial.

The purpose of this study was to measure the c.p. Ti hardness and to analyze thestructure of the c.p. Ti surface using an optical microscopy, when submitted to heat treatmentsand to corrosion by 1% sodium fluoride solution. The samples were submitted to two types ofheat treatment, tempering and annealing, after been submitted to sodium fluoride solution by30 days and then by more 30 days, and the characterization was made through tests of hardnessand optical microscopy technique. Statistical differences amongst the studied groups were verifiedby the Vickers hardness test, which resulted higher hardness c.p. Ti when used the heat treatments,that could be explained by relieving the mechanical stress of the material and making the crystallinestructures more defined, and this fact should improve the material properties. Besides that, it wasverified that the groups submitted to ions fluoride action, after the heat treatments, had their valuesof hardness increased, due, probably, to the heat process that increases the material friability. Inthe optical metalograph analysis, differences amongst the samples were observed when they weresubmitted to ions fluoride action, probably because the exposure of the titanium to fluoride solutionresulted damages to the surface of this important biomaterial.

Influência de soluções fluoretadas sobre implantes de titânio - uma revisão de literatura / Influence of fluoride solutions on titanium implants - a literature review

O Titânio comercialmente puro (Ti c.p.), usado amplamente na confecção de implantes dentários, exibe uma alta estabilidade química e uma alta resistência à corrosão em ambientes fisiológicos, além de uma excelente resistência mecânica. Entretanto, quando o titânio é colocado em contato com um meio fluoretado, sua camadade óxido é danificada e o titânio começa a ser degradado. A utilização de fluoretos ácidos tópicos, pode levar a muitos efeitos colaterais notáveis, afetando as propriedades químicas e mecânicas do Titânio. Os trabalhos encontrados na literatura demonstram que o titânio, metal conhecido por sua excelente resistência à corrosão, sofre um processo de degradação frente aos íons fluoretos e que este processo é acelerado quando o ph torna-se ácido. Mais estudos devem ser realizados associando o meio fluoretado ácido com forças mecânicas compressivas, simulando deste modo, o uso de implantes dentais na cavidade oral.

Cirurgia periodontal estética - inter-relaçäo com a odontologia restauradora / Periodontal plastic surgery and its relation to the restorative dentistry

Os autores destacam a importância da inter-relaçäo Periodontia (cirurgia periodontal estética) e Odontologia Restauradora para a abordagem de uma paciente com sorriso gengival. Foi realizada uma cirurgia periodontal para recuperaçäo de distâncias biológicas e aumento no comprimento das coroas clínicas dos dentes ântero-superiores, previamente ao procedimento restaurador, levando-se em conta princípios biológicos (manutençäo das distâncias biológicas) e estéticos