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Los implantes extra-cortos son cada vez más utili-zados en la práctica clínica diaria. La utilización de estos implantes con carga inmediata supone un reto añadido. Clásicamente se ha postulado que la carga inmediata debe realizarse después de 24 horas de la cirugía. En la siguiente serie de casos analizamos diferentes tiempos a la hora de realizar la carga in-mediata y su posible repercusión. Fueron recolec-tados de forma retrospectiva datos sobre casos de implantes extra-cortos (5,5 y 6,5 mm) en los que fue realizada una carga inmediata en sectores poste-riores. El implante fue la unidad de análisis para la estadística descriptiva en cuanto a la localización, dimensiones del implante, y mediciones radiográ-ficas. El paciente fue la unidad de medida para el análisis de la edad, sexo y la historia clínica. La prin-cipal variable estudiada fue la supervivencia de los implantes extra-cortos con carga inmediata en tres períodos de tiempo determinados: 24 hs, 48 hs y 7 días y como variables secundarias se han estudiado, la estabilidad del hueso crestal en general y en los tres períodos de carga anteriormente mencionados, las complicaciones protésicas y la supervivencia de las prótesis. Fueron reclutados 74 pacientes en los que se insertaron 146 implantes que cumplieron con los criterios de inclusión. Todos los implantes fueron cargados mediante carga inmediata en tres perío-dos determinados de tiempo: 24 hs (40 implantes), 48 hs (42 implantes) y 7 días (42 implantes). Todos los implantes fueron ferulizados a otros implantes ge-nerándose puentes de dos o más unidades, con di-ferente longitud. En el grupo de implantes con carga inmediata en 24 hs la media de la pérdida ósea distal de todos los implantes fue de 0,21 mm (+/-0,84) y la media de la pérdida ósea mesial en este grupo fue de 0,33 mm (+/- 0,53). En el grupo de carga inmediata en 48 hs, la media de la pérdida ósea distal de todos los implantes fue de 0,20 mm (+/- 0,82) y la media de la pérdida ósea mesial fue de 0,22 mm (+/- 0,81). En el grupo de carga de 7 días, la pérdida ósea me-sial del grupo fue de 0,28 mm (+/- 0,51) y la media de la pérdida ósea distal fue de 0,17 mm (+/- 0,81). Cuando comparamos las medias de pérdida ósea me-sial y distal entre los tres grupos, no se observaron diferencias estadísticamente significativas (mesial p=0,062, distal p=0,067). En conclusión, no se obser-varon diferencias significativas en la pérdida ósea crestal ni en la supervivencia de los implantes cortos entre los 3 tiempos estudiados de aplicación de car-ga inmediata. Por ello, utilizar cualquiera de los tres protocolos puede ser adecuado, mientras se realice un correcto análisis de la situación clínica de cada paciente (AU)

Extra-short implants are increasingly used in daily clinical practice. The use of these implants with immediate loading poses an added challenge. Classically it has been postulated that immediate loading should be performed 24 hrs after surgery. In the following case series, we analyze different times of immediate loading and their possible repercussions. We retrospectively collected data on cases of extra-short implants (5.5 and 6.5 mm) in which immediate loading was performed in posterior sectors. The implant was the unit of analysis for descriptive statistics in terms of location, implant dimensions, and radiographic measurements. The patient was the unit of measurement for the analysis of age, sex and medical history. The main variable studied was the survival of immediately loaded extra-short implants in three specific time periods: 24 hrs, 48 hrs and 7 days. Secondary variables studied were crestal bone stability in general and in the three loading periods mentioned above, prosthetic complications and prosthesis survival. Seventy-four patients were recruited and 146 implants that met the inclusion criteria were inserted. All implants were loaded by immediate loading in three specific time periods: 24 hrs (40 implants), 48 hrs (42 implants) and 7 days (42 implants). All implants were splinted to other implants generating bridges of two or more units, with different lengths. In the 24-hr immediate loading group the mean distal bone loss of all implants was 0.21 mm (+/- 0.84) and the mean mesial bone loss in this group was 0.33 mm (+/- 0.53). In the 48-hr immediate loading group, the mean distal bone loss for all implants was 0.20 mm (+/- 0.82) and the mean mesial bone loss was 0,22 mm (+/- 0,81). In the 7-day loading group, the mesial bone loss of the group was 0.28 mm (+/- 0.51) and the mean distal bone loss was 0.17 mm (+/- 0.81). When we compared the mean mesial and distal bone loss between the three groups there were no statistically significant differences (mesial p=0.062, distal p=0.067). In conclusion, no significant differences were observed in crestal bone loss or in the survival of short implants between the 3 immediate load application times studied. Therefore, using any of the three protocols can be appropriate, as long as a correct analysis of the clinical situation of each patient is performed (AU)

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Statement of the problem: Narrow implants have been recommended in high esthetic demand regions to ensure greater buccal bone thickness (BBT) and minimize soft-tissue recession due to insufficient bone support. However, a limited area of bone-implant interface can increase the risk of peri-implant bone resorption due to occlusal forces. Purpose: This article encourages the use of evidence-based finite element analysis to optimize the aesthetic outcomes in maxillary lateral incisor single-supported implant crown by accurate biomechanical planning. This study aimed to analyze the best implant dimensions that would preserve the maximum BBT and avoid peri-implant bone resorption due to occlusal forces. Materials and methods: A maxilla segment was constructed based on anthropological measurements. Four implant diameters (Ø = 3.25; 3.50; 3.75 or 4.00 mm) and two lengths (L = 10 or 13 mm) were simulated. The occlusal force parameters were defined to simulate clinical conditions. The bone resorption risk analysis was based on Frost's mechanostat theory altering the strain output to strain energy density (SED). The peri-implant bone resorption risk indexes (PIBRri) were calculated by dividing the average of the top ten SED elements of the cortical and trabecular buccal wall by the pathologic resorption limit for each bone. Results: For trabecular bone, only the model Ø4.00L13 exhibited a low PIBRri. For cortical bone, all models presented a low PIBRri, except for models Ø3.25. Conclusion: The selection of a 3.25 mm dental implant to preserve a 2 mm BBT should be avoided since it generates a high peri-implant bone resorption risk induced by occlusal overload.

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Abstract The aim of the present case-control observational study was to evaluate the peri-implant clinicoradiographic status among betel-quid chewers and controls. Self-reported betel-quid chewers and controls were included. Participants were categorized into 3 groups: Group-1: Individuals chewing betel-quid with tobacco; Group-2: Individuals chewing betel-quid without tobacco; and Group-3: Controls (individuals not using tobacco in any form). Demographic data was collected using a questionnaire. Periodontal and peri-implant clinicoradiologic parameters (plaque and gingival indices [PI and GI], probing depth [PD] and crestal bone loss/marginal bone loss [CBL/MBL]) were assessed. Clinical attachment loss (AL) around teeth was also assessed. Group comparisons were done using the one-way analysis of variance and Bonferroni Post-hoc adjustment tests. Correlation of periodontal and peri-implant inflammatory parameters with the duration of betel-quid chewing habit and duration of placement in the mouth were assessed using logistic regression analysis. P<0.05 was considered statistically significant. Thirty, 30 and 30 patients were included in groups 1, 2 and 3, respectively. Full-mouth PI (P<0.01), GI (P<0.01), clinical AL (P<0.01), PD (P<0.01) and mesial and distal MBL (P<0.01) were higher in groups 1 and 2 than Group-3. Peri-implant mPI (P<0.01), mGI (P<0.01), PD (P<0.01) and MBL/CBL (P<0.01) were significantly higher in groups 1 and 2 than Group-3 with no significant difference in groups 1 and 2. Betel-quid chewing habit either with or without tobacco is a risk-factor of peri-implant soft-tissue inflammation and CBL.

Resumo O objetivo do presente estudo observacional de casos-controles foi avaliar o estado clínico-radiográfico periimplantar dos usuários de bétele. Foram incluídos usuários que relataram utlizar a substância bétele como tabaco de mascar. Os participantes foram categorizados em 3 grupos: Grupo-1: Indivíduos que mascam bétele com tabaco; Grupo-2: Indivíduos que mascam bétele sem tabaco; e Grupo-3: Controle (indivíduos que não usam tabaco sob qualquer forma). Os dados demográficos foram recolhidos utilizando um questionário. Foram avaliados parâmetros clínico-radiográfico e periimplantares (índices placa e gengivais [IP e IG], profundidade de sondagem [PS] e perda de crista óssea/ perda óssea marginal [PCO/POM]). Também foi avaliada a perda inserção clínica (IC) em torno dos dentes. As comparações de grupo foram feitas utilizando a análise de variância unidireccional e os testes de ajustamento post-hoc de Bonferroni. A correlação dos parâmetros inflamatórios periodontais e periimplantares com a duração do hábito de mastigação da bétele e duração da colocação na boca foi avaliada utilizando a análise de regressão logística. P<0,05 foi considerado estatisticamente significativo. Foram utilizados 30 pacientes em cada grupo. O IP de boca inteira (P<0,01), IG (P<0,01), IC clínica (P<0,01), PS (P<0,01) e POM mesial e distal (P<0,01) foram mais elevados nos grupos 1 e 2 do que no grupo 3. O mPI peri-implantar (P<0,01), '(P<0,01), PD (P<0,01) e POM/PCO (P<0,01) foram significativamente mais elevados nos grupos 1 e 2 do que no grupo 3, sem diferença significativa nos grupos 1 e 2. O hábito de mastigar a substância bétele com ou sem tabaco é um fator de risco de inflamação dos tecidos moles periimplantares e PCO.

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Objective: To analyze the amount of crestal bone loss of the mandible around implants of different diameters one year after implantation. Material and Methods: The study included a total of 42 male and female patients. A total of 73 implants were evaluated (12 implants of diameter 3.5 x 10 mm and 61 implants of diameter 4.0 x 8 mm). Dental panoramic radiographs were made before surgery, immediately after surgery and one year later. The measurements were performed using Kodak dental software 6.11.7.0 after implantation and one year later. The data were analyzed using the IBM SPSS v.17 software package (descriptive statistics, paired samples t-test). Results: Among male patients, 43.5% were smokers, while among females, 57.9% were nonsmokers. Crestal bone resorption was greater mesially than distally, although differences were not statistically significant (p<0.05). Conclusion: All implants showed successful tissue integration. Crestal bone resorption was greater mesially than distally, although differences were not statistically significant...

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Introdução e Justificativa. No tratamento com implantes osseointegrados, o tecido ósseo peri-implantar sofre um processo de aposição e reabsorção, durante o primeiro ano após a restauração protética. Tem sido relatado que a platform switching reduz a remodelação óssea esperada, muito embora os mecanismos responsáveis por este processo não estejam claramente elucidados. Objetivo. O objetivo deste trabalho foi avaliar a distribuição de tensões no tecido ósseo peri-implantar, nos implantes e componente protéticos de coroa metalocerâmica implantossuportada, utilizando o conceito de platform switching e comparando-o com uma conexão regular abutment-implante, por meio do método de elementos finitos tridimensional (MEF-3D). Material e métodos. Dois modelos 3D reproduziram uma conexão regular entre abutment-implante com componentes de mesmo diâmetro (grupo Plataforma Regular - PR) e uma conexão com o conceito de platform switching (grupo Platform Switching - PS). Um implante regular (plataforma protética de 4.1mm) e um implante largo (plataforma protética de 5.0mm) foram utilizados para representar PR e PS, respectivamente, nos quais um componente protético regular de 4.1mm foi conectado para simular a coroa protética. Uma carga de 100N foi aplicada utilizando-se o programa ANSYS. Resultados. PS diminuiu a concentração de tensões no implante quando comparado com PR, alterando a distribuição das tensões na plataforma protética, o que resultou em diminuição das tensões no parafuso e tecido ósseo e aumento das tensões na coroa. Conclusões. Platform switching reduziu as tensões no tecido ósseo peri-implantar, o que pode resultar em uma diminuição da reabsorção óssea marginal. A utilização de componentes protéticos de menor diâmetro que a plataforma protética do implante diminuiu a concentração das tensões nos implantes e no parafuso, podendo resultar em uma diminuição das complicações nas próteses implantossuportadas parafusadas.

Statement of problem. After implant insertion and loading, crestal bone usually undergoes remodeling and resorption during the first year following prosthetic restoration. It has been reported that the platform switching seems to reduce or eliminate the expected postrestoration crestal bone remodeling, although the mechanisms responsible for this process are not yet clearly drawn. Purpose. The objective of this study was to evaluate the stress distribution in periimplant bone tissue, implants and prosthetic components of single crown implantssupported with the use of platform switching concept, using three-dimensional Finite Element Analysis (3D- FEA). Material and methods. Two 3D finite element models reproduced a external hexagonal implant system with peri-implant bone tissue, in which a regular matching diameter connection of abutment-implant (Regular Platform group - RPG) and a platform switching connection (Platform Switching group - PSG) were simulated. A regular implant (prosthetic platform of 4.1mm) and a wide implant (prosthetic platform of 5.0mm) were used to represent the RPG and PSG, respectively, in which a regular prosthetic component of 4.1mm was connected to represent the crown. A load of 100N was applied on the models using ANSYS software. Results. PSG diminished the stress concentration at the implant when compared to RPG by altering the stress distribution at the prosthetic platform of the implant, which results in a decrease of stress into the screw and supporting bone and an increase of stress in the crown. Conclusions. Platform switching improved biomechanically the stress distribution in peri-implant bone tissue of implant system, which might result in a reduced marginal bone loss. The use of mismatching prosthetic components in relation to the implant prosthetic platform diameter seems to decrease stress concentration at implant and screw, which might represent less clinical complications.

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