A comparative study of the clinical application of anatomical healing abutments versus finished healing abutments for mandibular first molar implants / 口腔疾病防治

Objective @#To evaluate the effect of anatomical healing abutments for mandibular first molars on the morphological changes of gingival soft tissue after implant restoration, as well as on peri-implant gingival molding, food ingrowth and patient satisfaction, to provide a basis for clinical selection. @*Methods @# Twenty-six patients who received implant restoration for a single missing mandibular first molar between September 2020 and September 2021 at the Oral Implant Center of Changsha Stomatological Hospital were randomly divided into a control group (13 cases with 14 implants) and a trial group (13 cases with 14 implants), of which 12 were male and 14 were female; the trial group had anatomical healing abutments applied for 4 weeks and then underwent crown restoration, while the control group finished five time points (before the second stage surgery, 4 weeks after the second stage surgery, immediately after the crown restoration, 4 weeks after the crown restoration, and 12 weeks after the crown restoration). A 3Shape intraoral scanner was used to scan the jaw before and 4 weeks after the second stage surgery to quantify the soft tissue changes and compare the effect of the healing abutment on gingival molding between the two groups. The incidence of food impaction was recorded and compared between the two groups at 4 weeks and 12 weeks after crown restoration. Patient satisfaction was recorded and compared between the two groups immediately after crown restoration, 4 weeks after crown restoration and 12 weeks after crown restoration@*Results @# Four weeks after implant surgery, it was observed that the gingival proximal and distal gingival papillae increased on the coronal side in the test group compared to the control group, 0.50 (0.26, 0.72) mm in the near-medium test group and 0.27 (0.24, 0.38) mm in the control group, with a statistically significant difference (P = 0.029), and 0.48 (0.26, 0.62) mm in the far-medium test group and 0.23 (0.13, 0.39) mm in the control group, with a statistically significant difference (P = 0.004). There was no statistically significant difference (P>0.05) in the buccolingual to gingival margin apex to coronal molding or in the buccolingual to lingual soft tissue at 0, 1, or 2 mm of the root of the middle 1/3 apex of the buccal and lingual gingival margins between the two groups. Compared to the control group, there was no statistically significant difference in the incidence of food impaction observed 4 weeks and 12 weeks after crown restoration in the test group (P>0.05). The satisfaction scores were higher in the trial group than in the control group immediately, 4 weeks, and 12 weeks after crown restoration, and the difference between the groups was statistically significant (P < 0.05). @*Conclusion @# The anatomical healing abutment for the implant mandibular first molar was superior to the finished healing abutment in terms of soft tissue contouring with an increase in the coronal aspect of the proximal and distal gingival papillae, resulting in high patient satisfaction.

The assessment of periimplant soft tissue condition with morse taper abutment connection: a rapid review

Aim: This study aims to evaluate the clinical assessment results of periimplant soft tissue with morse taper (internal abutment connection). Methods: The study was conducted using a rapid review by searching the articles from PubMed NCBI and Cochrane by using keywords. All articles were selected by the year, duplication, title, abstract, full-text, and finally, all selected articles were processed for final review. Following clinical parameters were included; Periimplant Probing Pocket Depth (PPD), Plaque Score (PS), modified Plaque Index (mPI), Mucosal Thickness (MTh), Gingival Height (GH), periimplant mucosal zenith, Pink Esthetic Score (PES), Bleeding On Probing (BOP), Sulcus Bleeding Index (SBI), and modified Gingival Index (mGI). Results: 9 selected articles were obtained from the initial literature searching count of 70 articles. The overall samples included 326 morse taper implants. Based on the evaluation, 3 out of 4 articles reported pocket depth < 4 mm, no bleeding was reported in 2 out of 4 articles. 4 out of 4 articles reported low plaque accumulation, low soft tissue recession was reported in 3 out of 3 articles, and 4 out of 4 articles reported acceptable PES values. Conclusion: The evaluations indicate that the morse taper (internal abutment connection) has favorable assessment results based on various clinical parameters

Patient Satisfaction and Pink Esthetics of PEEK Versus Zirconium Abutments in the Esthetic Zone (A Randomized Controlled Trial) / Satisfação do paciente e estética rosa dos pilares PEEK versus Zircônia na zona estética (um ensaio clínico randomizado)

Objective: This study was performed to evaluate the use of PEEK abutments versus zirconium abutments with lithium disilicate superstructure on the esthetic acceptance and peri-implant clinical parameters. Zirconium abutments were found to have high surface roughness even after polishing. This causes a remarkable collapse of the soft tissue papilla that is a primary factor in the Pink Esthetic Score(PES), resulting in failed esthetic restoration in the anterior esthetic zone. Material and Methods:Twenty patients who needed a single implant restoration in the esthetic zone were included in this study. Eighteen patients completed screening, baseline, three-month, six-month, and twelve-month follow-up visits. At the screening visit, the patients were randomly allocated into two groups: Zirconia abutments (A) Group, and PEEK abutments (B) Group, both of which were restored with IPS e.max CAD superstructure. Patients Satisfaction was assessed by visual analogue scale (VAS). Pink esthetics score (PES), modified plaque index (mPI) and modified gingval index (mGI) were also assessed. Results: All implants were successfully osseo-integrated with a 100% survival rate over one year. Patient satisfaction was significantly higher for the PEEK group than the zirconium group. The pink esthetic score showed no statistical significance between both groups. The modified plaque index was significantly lower for the PEEK group than the zirconium group. The modified gingival index showed no statistical difference between both groups. Conclusion: PEEK revealed to be a versatile material to replace zirconium for implant abutments, due to its lower plaque affinity and higher patient satisfaction (AU)

Objetivo: Este estudo foi realizado para avaliar o uso de pilares PEEK versus pilares de zircônia com estrutura de dissilicato de lítio quanto a aceitação estética e parâmetros clínicos peri-implantares. Os pilares de zircônia apresentam alta rugosidade superficial, mesmo após o polimento. Isso causa um colapso notável da papila do tecido mole, que é um fator primário no índice estético rosa (Pink Esthetic Score - PES), resultando em falha na restauração estética na zona estética anterior. Materiais e Métodos:Vinte pacientes que precisavam de um implante unitário na zona estética foram incluídos neste estudo. Dezoito pacientes completaram a triagem, a consulta inicial e as visitas de acompanhamento de três, seis e doze meses. Durante a triagem, os pacientes foram aleatoriamente divididos em dois grupos: Grupo Pilares de Zircônia (A) e Grupo de Pilares PEEK (B), ambos foram restaurados com IPS e.max CAD. A satisfação dos pacientes foi avaliada pela escala visual analógica (VAS). O PES, o índice de placa modificado (mPI) e o índice gengival modificado (mGI) também foram avaliados. Resultados: Todos os implantes foram osseointegrados com sucesso, com uma taxa de sobrevivência de 100% ao longo de um ano. A satisfação do paciente foi significativamente maior para o grupo PEEK quando comparado com o grupo de pilares de zircônia. O índice da estética rosa não apresentou significância estatística entre os dois grupos. O índice de placa modificado foi significativamente menor para o grupo PEEK quando comparado com o grupo de pilares de zircônia. Conclusão: O PEEK revelou-se um material versátil para substituir a zircônia em pilares de implante, devido a sua menor afinidade de placa e maior satisfação do paciente. (AU)

Internal and marginal fit and fracture strength of narrow diameter dental implant-abutment assembly

Abstract The aim of this study was to assess the internal and vertical marginal fit of metallic copings to abutments and the fracture strength of different narrow diameter dental implant/abutments, either submitted to thermomechanical cycling or not. Sixty-four implant/abutments (n=16) were divided into 4 groups according to diameter and abutment type: G3.5-UAC (morse taper implant Ø3.5mm + universal abutment with beveled chamfer finish); G2.9-UAS (morse taper implant Ø2.9mm + universal abutment with shoulder finish); G2.8-AA (morse taper friction implant Ø2.8mm + anatomical abutment) and G2.5-HP (one-piece implant Ø2.5mm with indexed hexagonal platform). Each group was divided into two subgroups (n=8): submitted and not submitted to thermomechanical cycling (TMC). To assess internal and vertical marginal fit of metallic copings, the assemblies were scanned using microtomography (micro-CT) (n=5). The samples were subjected to the compressive strength test on a universal test machine. Group G3.5-UAC showed the highest marginal misfit regardless of TMC (p<0.05). All other groups were similar after TMC. Group G2.8-AA showed the lowest internal misfit both with and without TMC (p<0.05). Group G2.8-AA showed the highest fracture strength, similar only to G2.5-HP without TMC and G3.5-UAC with TMC. The type of abutment affects the internal and marginal fit of metallic copings and the anatomical abutment led to the best internal and marginal coping fit. The narrow diameter dental implant/abutments differ in terms of fracture strength, the strongest assembly was that composed by implant of type V grade titanium without internal threads (friction implant).

Resumo O objetivo deste estudo foi avaliar a adaptação marginal e interna de cópings metálicos em pilares sobre implantes, e a resistência a fratura de diferentes conjuntos de implantes/pilares de diâmetro reduzido, submetidos à ciclagem termomecânica ou não. Sessenta e quatro implantes/pilares (n=16) foram divididos em 04 grupos de acordo com o tipo de pilar e diâmetro do implante: G3.5-UAC (implante cone morse Ø3.5mm + munhão universal com término em chanfro); G2.9-UAS (implante cone morse Ø2.9mm + munhão universal com término em ombro); G2.8-AA (implante cone morse friccional Ø2.8mm + munhão anatômico); e G2.5-HP (implante de corpo único de Ø2.5mm com plataforma hexagonal indexada). Cada grupo foi dividio em dois subgrupos (n=8): submetidos ou não à ciclagem termomecânica (TMC). As amostras foram escaneadas por microtomografia (micro-CT) para avaliar a adaptação interna e marginal vertical dos copings metálicos. As amostras foram submetidas à resistência à compressão em uma maquina de ensaios universal. O grupo G3.5-UAC apresentou os maiores valores de desadaptação marginal independentemente da TMC (p<0,05). Todos os outros grupos foram similares entre si após TMC. O grupo G2.8-AA demonstrou o menor desajuste interno independentemente de TMC (p<0,05). O grupo G2.8-AA demonstrou a maior resistência à fratura, similar apenas ao grupo G2.5-HP sem TMC e G3.5-UAC com TMC. O tipo de pilar influencia a adaptação interna e marginal vertical de copings metálicos. O grupo do pilar anatômico (sem entalhes na superfície) levou à melhor adaptação, enquanto o grupo com plataforma expandida hexagonal e os grupos com munhão universal (com entalhes na superfície) proporcionaram os maiores desajustes (especialmente com termino em chanfro). Os implantes/pilares de diâmetro reduzido diferem em termos de resistencia à fratura, sendo que o conjunto mais resistente foi aquele composto por titânio tipo V e sem roscas internas (implante friccional).

Three-dimensional misfit between Ti-Base abutments and implants evaluated by replica technique

Abstract An important factor affecting the biomechanical behavior of implant-supported reconstructions is the implant-abutment misfit. Objective: This study evaluated the misfit between Ti-Base abutments and implants by means of polyvinyl siloxane replica technique using microcomputed tomography (μCT). Methodology: Volumetric and linear (central and marginal) gaps of four Ti-base abutments (n=10/group): (i) Odontofix LTDA (OD), (ii) Singular Implants (SING), (iii) EFF Dental Components (EFF), and (iv) Control Group (S.I.N implants) compatible with an implant system (Strong SW, S.I.N Implants) were measured using μCT reconstructed polyvinyl siloxane replicas. Results: The results showed significantly lower volume gap for Control S.I.N (0.67±0.29 mm3) and SING (0.69±0.28 mm3) Ti-base abutments relative to OD (1.42±0.28 mm3) and EFF groups (1.04±0.28 mm3) (p<0.033), without significant difference between them (p=0.936). While gap values were homogenous in the central region, EFF presented a significantly higher marginal gap. Accordingly, the Control S.I.N and Singular Ti-base abutments showed improved volumetric and marginal fit relative to Odontofix and EFF. Conclusion: The method of manufacturing abutments influenced the misfit at the implant-abutment interface.

Avaliação da interface entre o componente protético reto e a conexão interna tipo Cone Morse do implante dentário por meio da microscopia eletrônica de varredura / Evaluation of the interface between the straight prosthetic component and the Morse Cone-type internal connection of the dental implant in cross section by scanning electron microscopy

Resumo Introdução A interface implante-pilar protético e a formação dos seus microgaps são aspectos relevantes na transferência das cargas e na resposta biológica, estando ligadas ao sucesso da reabilitação. Objetivo Avaliar microgaps na interface entre a conexão interna do implante do tipo Cone Morse e a superfície do componente protético por meio da microscopia eletrônica de varredura (MEV). Material e método Foram utilizados 20 implantes dentários de tamanho 3,75 × 11,0mm do tipo Cone Morse com seus respectivos pilares protéticos da Singular® (Singular Implants, RN, Brasil). Os munhões retos foram acoplados aos implantes com torque de 32N/cm2 e o conjunto resultante foi emergido em base de Resina Epóxi ES260, para permitir secção longitudinal da amostra. As amostras foram analisadas e os microgaps mensurados no MEV (JEOL JCM-5700, MA, USA), e posteriormente os dados foram analisados. Resultado A média e o desvio padrão dos maiores microgaps foram observados na parte apical do implante nos lados direito e esquerdo, sendo 1,44±2,68 e 1,16±1,49 μm, respectivamente. Os menores microgaps foram na parte superior do implante nos lados direito e esquerdo, sendo 0,60±0,73 e 0,66±0,67 μm, respectivamente. Contudo, no teste de Kruskal-Wallis, não houve diferença estatisticamente significativa entre as regiões dos implantes, tanto para o lado esquerdo (p=0,692) como para o direito (p=0,865). No teste de Mann-Whitney, não houve diferenças estatisticamente significativas entre os lados para as diferentes regiões dos implantes. Conclusão Mesmo com a presença de microgaps na interface implante-pilar protético, estes apresentam tamanho inferior ao que causaria problemas biológicos e mecânicos. As amostras analisadas quanto à sua compatibilidade de encaixe foram satisfatórias.

Abstract Introduction The implant-prosthetic abutment interface and the formation of its microgaps are relevant aspects in load transfer and biological response and are linked to the success of the rehabilitation. Objective To evaluate microgaps at the internal connection interface of the Cone Morse implant and the prosthetic component surface by means of scanning electron microscopy (SEM). Material and method Twenty 3.75 x 11.0 mm Cone Morse dental implants with their respective Singular® prosthetic abutments were used (Singular Implants, RN, Brazil). The straight trunnions were attached to the implants with a 32N/cm2 torque and the ES260 Epoxy Resin-based set emerged to allow longitudinal sectioning of the sample. The samples were analyzed and the microgaps measured in SEM (JEOL JCM-5700, MA, USA), and later the data were analyzed. Result The mean and standard deviation of the largest microgaps were observed in the apical part of the right and left side 1.44±2.68 and 1.16±1.49 μm, respectively. The smallest microgaps were on the upper implant right and left sides 0.60±0.73 and 0.66±0.67 μm, respectively. However, in the Kruskal-Wallis test there was no statistically significant difference between the implant regions, both for the left side (p=0.692) and right side (p=0.865). The Mann-Whitney test, there were no statistically significant differences between the sides for the different regions of the implants. Conclusion Even with the presence of microgaps in the implant-post interface, it presents a smaller size than the one presenting biological and mechanical problems. The samples analyzed for their fitting compatibility were satisfactory.

Prótese Parcial Fixa em Cantilever, uma opção de tratamento: Revisão da Literatura / Fixed Partial Denture with Cantilever an option for therapeutic: Literature Review

Hoje em dia no consultório a indicação de uma prótese fixa em cantilever, ainda gera muitas dúvidas, levando o clinico inseguro, muitas vezes a sua contra indicação. Com intuito de esclarecer as características relacionadas à prótese parcial fixa em cantilever realizou- -se uma revisão de literatura. Uma busca foi realizada nas bases de dados Scielo e Pubmed usando-se as palavras-chaves: Prótese fixa, cantilever, dentes suportes. Os artigos dentro do escopo do estudo foram selecionados e pode-se concluir que estas próteses são uma excelente alternativa conservadora para restabelecimento de dentes perdidos, porém para obtenção de resultados satisfatórios com boa longevidade, especial atenção deve ser desprendida aos princípios biomecânicos dos preparos e um controle rigoroso de placa bacteriana deve ser estabelecido.

Actuality the use of Fixed Partial Denture with Cantilever until causes many doubts, making de dentist do not indicate this treatment. To making clear the characteristics relation to this prosthesis, was done a literature review. A search was performed in the Scielo and Pubmed databases using the keywords: Fixed prosthesis, cantilever, supporting teeth. The articles within the scope of the study were selected and it can be concluded that these were an alternative excellent to reestablish the follow teeth, therefore to obtain the good results with respect long-term prosthetic appliances, special attention should be dispensed to the biomechanics principles and optimal hygiene with plaque control should be established.

The Biomechanical Influence of Angled Abutment in Dental Implants: A Review / 医用生物力学

The influence of angled abutments on stress of peri-implant bone is a controversial issue. It is widely accepted that the use of angled abutments will increase adverse stress distributions on implants and surrounding bones. However, comparisons of clinical success rates of implants restored with angled and straight abutments indicate no significant differences. This review summarized the clinical application and biomechanical research associated with angled abutments. The use of angled abutments did not detrimentally affect the retention of dental implants, and tt was possible that the magnitude of stress within peri-implant bone increased or decreased under different conditions. Therefore, further researches should be conducted to confirm that favorable peri-implant stress levels may be induced if suitable angulation of abutments is selected.

Cicatrizadores personalizados: relato de caso / Customized healing abutments: case report

Quando feita a instalação de um implante imediato pode se optar entre a instalação de uma coroa provisória clínica, um cicatrizador ou pode se optar pelo fechamento do implante para um tratamento em duas etapas cirúrgicas. O uso de cicatrizadores personalizados sela os implantes e leva a uma cicatrização individualizada, que favorece a confecção das coroas subsequentes. O presente trabalho objetiva relatar um caso clínico envolvendo um implante imediato e a instalação de um cicatrizador personalizado, demonstrando os resultados e a importância de conhecimento dessa técnica pelo cirurgião-dentista.

When installing an immediate implant, you can choose between installing a temporary clinical crown, healing abutments, or to close the implant for a two-step surgical treatment. The use of customized healing abutments seals the implants and leads to individualized healing, which favors the creation of subsequent crowns. The present study aims to report a clinical case involving an immediate implant and the installation of customized healing abutments, demonstrating the results and the importance of knowledge of this technique by the dentist.

Effect of a Customised Chairside Polishing Protocol for Zirconia- A Comparative Analysis

The purpose of this study was to develop a customized polishing protocol using standard zirconia polishing kit with polishers of different grit and to study their effect on the surface roughness of zirconia and compare it to that of laboratory polished zirconia samples and machine polished titanium implant abutments. Methods: The samples used in this study were 15 zirconia blocks and 10 machine polished titanium implant abutments (5 Biohorizon and 5 MIS). The 15 zirconia blocks were again divided into three groups. The first group consisted of 5 zirconia samples polished by customised polishing protocol (coarse + medium+ fine). The second group consisted of 5 zirconia samples which were sent to lab1 which used Komet company burs and 5 zirconia samples were sent to lab2 which used carborundum burs and sandpaper for polishing. The fourth group consisted of 5 machine polished titanium implants from MIS system and fifth group consisted of 5 machine polished titanium implants from Biohorizon system. After polishing, the mean surface roughness values (Ra) of zirconia samples and titanium implant abutments were calculated quantitatively by optical profilometer and qualitatively by scanning electron microscope (SEM). Results: The mean surface roughness value of customised polishing protocol using coarse+medium+fine polisher was 0.11 µm which was almost equal to the mean surface roughness values of lab1 polished zirconia samples - 0.131 µm and that of machine polished titanium implant abutments –Biohorizon: 0.201 µm MIS: 0.0859 µm and was within the optimal range of 0.2µm. Conclusions: Within the limitations of this study it was concluded that, the mean surface roughness values of zirconia samples polished by customised polishing protocol , lab1 polished samples and machine polished titanium implant abutments were found to be similar & closer to the critical Ra values (0.2µm) suggesting that the chairside polishing of zirconia can be carried out using the customized polishing technique

Influence of abutment collar height and implant length on stress distribution in single crowns

Abstract This in silico study evaluated the influence of the abutment collar height and implants length on the biomechanical behavior of morse taper single dental implants with different crown-to-implant ratio. Six virtual models were constructed (S11, M11, L11, S13, M13 and L13) by combining short (S: 2.5 mm), medium (M: 3.5 mm) or long (L: 4.5 mm) abutment collar heights with different implant lengths (11 or 13-mm). An upper central incisor of 11-mm height was constructed on top of each abutment. Each set was positioned in a virtual bone model and exported to analyze mathematically. A 0.60-mm mesh was created after convergence analysis and a 49 N load was applied to the cingulum of the crown at an angle of 45°. Load-generated stress distribution was analyzed in the prosthetic components according to von Mises stress criteria (σvM) and in the cortical and cancellous bone by means of shear stress (εmax). The use of longer collar abutments (L11) increased the stress on the abutment by 250% and resulted in 40% higher stresses on the screw and 92% higher cortical shear stresses compared to short collared abutments (S11). Increasing the implant length produced a slight stress reduction on cortical bone. Cancellous bone was not affected by the crown-to-implant ratio. Longer abutment collars concentrate stresses at the implant level and cortical bone by increasing the crown-to-implant ratio.

Resumo Este estudo avaliou a influência da altura da porção transmucosa do pilar protético com junção cone morse e do comprimento dos implantes no comportamento biomecânico coroas unitárias com diferentes proporção coroa-implante. Seis modelos virtuais (S11, M11, L11, S13, M13 e L13) foram construídos combinando pilares protéticos com transmucoso considerado: curto (S: 2,5 mm), médio (M: 3,5 mm) ou longo (L: 4,5 mm) com diferentes comprimentos de implantes (11 ou 13 mm). Um incisivo central superior de 11 mm de altura foi construído para cada pilar. Cada conjunto foi posicionado em um modelo de osso virtual e exportado para análise matemática. Uma malha de 0,60 mm foi criada após análise de convergência e uma carga de 49 N foi aplicada ao cíngulo da coroa em um ângulo de 45°. A distribuição de estresse gerada por carga foi analisada nos componentes protéticos de acordo com o critério de tensão de von Mises (σvM) e no osso cortical e medular por meio da tensão de cisalhamento (εmax). O uso de pilares com porção transmucosa mais longa (L11) aumentou a tensão no pilar protético em 250%, e resultou em tensões 40% maiores no parafuso e 92% no osso cortical em relação aos pilares com transmucoso curto (S11). O aumento do comprimento do implante produziu uma ligeira redução da tensão de cisalhamento no osso cortical. O osso medular não foi afetado pela relação coroa-implante. Pilares protéticos com porção transmucosa mais longa concentram tensões no implante e no osso cortical, quando a proporção coroa-implante é aumentada.

All-ceramic versus titanium-based implant supported restorations: Preliminary 12-months results from a randomized controlled trial

PURPOSE: The aim of the present randomized controlled study was to compare prefabricated all-ceramic, anatomically shaped healing abutments followed by all-ceramic abutments and all-ceramic crowns and prefabricated standard-shaped (round-diameter) titanium healing abutments followed by final titanium abutments restored with porcelain-fused-to-metal (PFM) implant crowns in the premolar and molar regions. MATERIALS AND METHODS: Forty-two patients received single implants restored either by all-ceramic restorations (test group, healing abutment, final abutment, and crown all made of zirconia) or conventional titanium-based restorations. Immediately after prosthetic incorporation and after 12 months of loading, implant survival, technical complications, bone loss, sulcus fluid flow rate (SFFR) as well as plaque index (PI) and implant stability (Periotest) were analyzed clinically and radiologically. RESULTS: After 12 months of loading, an implant and prosthetic survival rate of 100% was observed. Minor prosthetic complications such as chipping of ceramic veneering occurred in both groups. No statistical significant differences were observed between both groups with only a minimum of bone loss, SFFR, and PI. CONCLUSION: All-ceramic implant prostheses including a prefabricated anatomically shaped healing abutment achieved comparable results to titanium-based restorations in the posterior region. However, observational results indicate a benefit as shaping the peri-implant soft-tissue with successive provisional devices and subsequent compression of the soft tissue can be avoided.

Effect of Consecutive Removal and Placement of Abutments during Prosthetic Procedures on an Increase in Proinflammatory Cytokine Levels around Dental Implants

Objective: To evaluate the effect of repeated removal and placement of abutments during prosthetic stages on increasing proinflammatory cytokine levels around dental implants. Material and Methods: All the patients with dental implants, referring to the prosthodontics private office during a 3-month period, were examined in relation to the health of the implants and included in the present study based on inclusion criteria; the patients had a multi-unit abutment on one side of the jaw and a conventional healing abutment on the implant on the other side of the jaw. Samples of gingival crevicular fluid were taken from all the eligible subjects for immunological analyses. The samples were taken from the sulcus around each implant in each subject. The samples were sent to the immunology laboratory for determination of IL-6 and IL-1ß proinflammatory cytokines with the use of an ELISA kit. Data were analyzed with SPSS 16 and Descriptive statistics and T-test was used. Statistical significance was set at p<0.05. Results: The results showed that the mean concentrations of IL-1ß and IL-6 in the group with multi-unit abutment were less than those in the conventional abutment group. In addition, comparison of the means of IL-6 and IL-1ß concentrations showed that in both groups the concentration of IL-6 was higher than that of IL-1ß. Conclusion: The use of multi-unit abutments resulted in less inflammation compared to the use of conventional two-segment abutments, which require repeated removal and placement during the prosthetic stage.

Influence of scaling procedures on the integrity of titanium nitride coated CAD/CAM abutments

PURPOSE: To determine the extent of treatment traces, the roughness depth, and the quantity of titanium nitride (TiN) removed from the surface of CAD/CAM abutments after treatment with various instruments. MATERIALS AND METHODS: Twelve TiN coated CAD/CAM abutments were investigated for an in vitro study. In the test group (9), each abutment surface was subjected twice (150 g vs. 200 g pressure) to standardized treatment in a simulated prophylaxis measure with the following instruments: acrylic scaler, titanium curette, and ultrasonic scaler with steel tip. Three abutments were used as control group. Average surface roughness (Sa) and developed interfacial area ratio (Sdr) of treated and untreated surfaces were measured with a profilometer. The extent of treatment traces were analyzed by scanning electron microscopy. RESULTS: Manipulation with ultrasonic scalers resulted in a significant increase of average surface roughness (Sa, P < .05) and developed interfacial area ratio (Sdr, P < .018). Variable contact pressure did not yield any statistically significant difference on Sa-values for all instruments (P=.8). Ultrasonic treatment resulted in pronounced surface traces and partially detachment of the TiN coating. While titanium curettes caused predominantly moderate treatment traces, no traces or detectable substance removal has been determined after manipulation with acrylic curettes. CONCLUSION: Inappropriate instruments during regular plaque control may have an adverse effect on the integrity of the TiN coating of CAD/CAM abutments. To prevent defects and an increased surface roughness at the transmucosal zone of TiN abutments, only acrylic scaling instruments can be recommended for regular maintenance care.

Implantes adjacentes nas posições dos incisivos centrais maxilares: caso clínico com 18 meses em função / Adjacent dental implants in the central incisor's positions: a clinical case with 18 months of function

Implantes adjacentes na região anterior constituem um verdadeiro desafio para a Peri-Implantodontia estética. São diversas variáveis a serem analisadas, e a principal está em preservar a arquitetura tecidual pré-existente. Neste artigo, são discutidas as variáveis mais importantes e é apresentada uma sequência de tratamento de dois implantes osseointegrados adjacentes na região de centrais, cirurgicamente muito conservador e bem planejado, o que possibilitou um resultado estético final extremamente harmônico e natural.

Adjacent implants in the anterior region are a real challenge to esthetic Perio-Implantology. There are several variables to be analyzed, and the main one is preserving the pre-existing tecidual architecture. In this article we discuss the more important variables and present a treatment sequence of two adjacent osseointegrated implants at the central incisor's positions, surgically very conservative and well planned, which made possible an extremely harmonic and natural esthetic outcome.

Advance and review: implant-abutment microgap / 中华口腔医学杂志

Implant-abutment microgap (IAM) exists in two-piece implant systems. Researchers have proved that IAM influences success rate of dental implants in the long term. The relationship between IAM and the biological, mechanical complication of dental implants has been proven in some studies. Implant-abutment connection type, abutment material and insertion torque may all have impact on IAM size. On the other hand, ways to reduce or seal this gap are discussed in some literature. The relationship between IAM and bacteria colonization, long-term implantation complication and its influencing factors are discussed in this review.

Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages

Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.

Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages

Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.

Three-dimensional finite element analysis of platform switched implant

PURPOSE: The purpose of this study was to analyze the influence of the platform switching concept on an implant system and peri-implant bone using three-dimensional finite element analysis. MATERIALS AND METHODS: Two three-dimensional finite element models for wide platform and platform switching were created. In the wide platform model, a wide platform abutment was connected to a wide platform implant. In the platform switching model, the wide platform abutment of the wide platform model was replaced by a regular platform abutment. A contact condition was set between the implant components. A vertical load of 300 N was applied to the crown. The maximum von Mises stress values and displacements of the two models were compared to analyze the biomechanical behavior of the models. RESULTS: In the two models, the stress was mainly concentrated at the bottom of the abutment and the top surface of the implant in both models. However, the von Mises stress values were much higher in the platform switching model in most of the components, except for the bone. The highest von Mises values and stress distribution pattern of the bone were similar in the two models. The components of the platform switching model showed greater displacement than those of the wide platform model. CONCLUSION: Due to the stress concentration generated in the implant and the prosthodontic components of the platform switched implant, the mechanical complications might occur when platform switching concept is used.

Corrosion behavior of zirconia in acidulated phosphate fluoride

ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study.