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BACKGROUND: This study aimed to analyze the influence of concave and cylindrical abutments on peri-implant soft tissue. Dimensions, collagen fiber orientation, and immunohistochemical data were assessed. METHODS: A multicenter, split-mouth, double-blind randomized clinical trial was conducted. Two groups were analyzed: cylindrical abutments and concave abutments. After a 12-week healing period, peri-implant soft tissue samples were collected, processed, and evaluated for dimensions, collagen fiber orientation, and immunohistochemical data. Inflammatory infiltration and vascularization were assessed, and the abutment surfaces were analyzed using scanning electron microscopy. The statistical analysis was performed using the SPSS version 20.0 statistical package. RESULTS: A total of 74 samples in 37 patients were evaluated. Histological evaluation of peri-implant soft tissue dimensions revealed significant differences between concave and cylindrical abutments. Concave abutments exhibited greater total height (concave: 3.57 ± 0.28 - cylindrical: 2.95 ± 0.27) and barrier epithelium extension (concave: 2.46 ± 0.17 - cylindrical: 1.89 ± 0.21) (p < 0.05), while the supracrestal connective tissue extension (concave: 1.11 ± 0.17 - cylindrical: 1.03 ± 0.16) was slightly greater (p > 0.05). Collagen fiber orientation favored concave abutments (23.76 ± 5.86), with significantly more transverse/perpendicular fibers than for cylindrical abutments (15.68 ± 4.57). The immunohistochemical analysis evidenced greater inflammatory and vascular intensity in the lower portion for both abutments, though concave abutments showed lower overall intensity (concave: 1.05 ± 0.78 - cylindrical: 1.97 ± 0.68) (p < 0.05). The abutment surface analysis demonstrated a higher percentage of tissue remnants on concave abutments (42.47 ± 1.32; 45.12 ± 3.03) (p < 0.05). CONCLUSIONS: Within the limitations of this study, concave abutments presented significantly greater peri-implant tissue height, linked to an extended barrier epithelium, versus cylindrical abutments in thick tissue phenotype. This enhanced soft tissue sealing, favoring a greater percentage of transversely oriented collagen fibers. The concave design reduced chronic inflammatory exudation with T and B cells, thus minimizing the risk of chronic inflammation. PLAIN LANGUAGE SUMMARY: This study looked at how 2 different shapes of dental implant abutments (the parts that connect the implant to the crown), specifically concave and cylindrical, affect the soft tissue around the implants. We wanted to see how these shapes influenced the tissue's size, structure, and health. We conducted a clinical trial with 37 patients, comparing the 2 types of abutments in the same mouth over 12 weeks. Our findings showed that the concave abutments led to a taller and more extensive layer of protective tissue around the implant compared to the cylindrical ones. This protective tissue had more favorable collagen fiber orientation, which is important for the strength and health of the tissue. Additionally, the concave abutments resulted in less inflammation and better tissue integration. In conclusion, concave abutments may provide better support and health for the soft tissue around dental implants, reducing the risk of chronic inflammation and potentially leading to better long-term outcomes for patients with dental implants.
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Angulated-screw channels (ASCs) allow the clinician to employ screw-retained restorations in almost all cases, as the access hole can be moved away from the vestibular portion of the crown, where it would jeopardize the final esthetic result. The objective of this study was to compare screw-retained restorations employing ASCs with restorations cemented on angled abutments. In this study, 30 subjects, equally divided into two groups: group 1 (cemented restorations on angulated abutments) and group 2 (screw-retained restorations adopting ASCs), were treated and retrospectively compared after 2 years using the pink esthetic score (PES) and the white esthetic score (WES). All restorations were in use at the last follow-up, with a survival rate of 100%. Three mechanical complications were observed (2 chippings and 1 crown came loose), with a success rate of 93% in group 1 and 87% in group 2 (p > 0.05). No statistically significant differences were reported regarding the esthetic outcome; the marginal bone loss (MBL) showed better results for the screw-retained restorations, both at the distal aspect (group 1 = 0.98 mm ± 0.16; group 2 = 0.45 mm ± 0.06; p = 0.006) and at the mesial aspect (group 1 = 1.04 ± 0.27; group 2 = 0.45 ± 0.005; p < 0.001). From an esthetical perspective, screw-retained restorations with ASCs and cemented restorations on angulated abutments are both effective means of restoring implants; both have excellent esthetic outcomes, but screw-retained restorations have reduced bone loss when compared to cemented ones but are more prone to mechanical complications. Still, our results must be cautiously observed given the reduced dimension of our sample. Larger studies are needed to confirm our findings.
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BACKGROUND: The aim of this case study is to present the rationality and scientific evidence of a new design for a double (DA) and triple (TA) dental abutment-implant with their specific new concept of biodynamic optimized peri-implant tissue (BOPiT). METHODS: The innovative design of these abutments with a paraboloid geometry was based on BOPiT, simultaneously involving the principles of mechanobiology, biotensegrity, and mechanotransduction. Thus, 37 consecutive individuals/43 cases rehabilitated with single dental implant using the innovative DA (n = 28) and TA (n = 15) on 43 implants were included in this case study. The DA and TA support 2 or 3 dental crowns on a single implant, respectively. Clinic and radiographic examinations were presented at T1 (loading after 4 months) and T2 [final examination with an average follow-up time of 7.2 years (>3 to 12 years)]. RESULTS: At T2, mean scores for plaque index, peri-implant bleeding on probing, and peri-implant probing depth were low, depicting healthy peri-implant conditions. All radiographic images showed insignificant annual marginal bone loss (0.022 ± 0.05 mm) when compared to T1, reflecting great bone stability. CONCLUSION: DA and TA, based on the BOPiT concept, represent an advantageous, simple and non-invasive mechanism for the longevity and healthy regulation of the peri-implant tissues.
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The objective of this study was to evaluate microbial leakage by means of genome counts, through the implant-abutment interface in dental implants with different Morse taper abutments. Fifty-six samples were prepared and divided in four groups: CMC TB (14 Cylindrical Implants-14 TiBase Abutments), CMX TB (14 Conical Implants-14 TiBase Abutments), CMX PU (14 Conical Implants-14 Universal Abutment) and CMX U (14 Tapered Implants-14 UCLA Abutments). Assemblies had their interface submerged in saliva as the contaminant. Samples were subjected either to thermomechanical cycling (2 × 106 mechanical cycles with frequency of 5 Hz and load of 120 N simultaneously with thermal cycles of 5-55 °C) or thermal cycling (5-55 °C). After cycling, the contents from the inner parts of assemblies were collected and analyzed using the Checkerboard DNA-DNA hybridization technique. Significant differences in the total genome counts were found after both thermomechanical or thermal cycling: CMX U > CMX PU > CMX TB > CMC TB. There were also significant differences in individual bacterial counts in each of the groups (p < 0.05). Irrespective of mechanical cycling, the type of abutment seems to influence not only the total microbial leakage through the interface, but also seems to significantly reflect differences considering individual target species.
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OBJECTIVE: To compare the implant-abutment connection microgap between computer-aided design and computer-aided manufacturing (CAD/CAM) milled or laser-sintered cobalt-chrome custom abutments with or without ceramic veneering and titanium stock abutments with or without crown cementation. MATERIAL AND METHODS: Six groups of six abutments each were prepared: (1) CAD/CAM cobalt-chrome custom abutments: milled, milled with ceramic veneering, laser-sintered, and laser-sintered with ceramic veneering (four groups: MIL, MIL-C, SIN, and SIN-C, respectively) and (2) titanium stock abutments with or without zirconia crown cementation (two groups: STK and STK-Z, respectively). Abutments were screwed to the implants by applying 30 Ncm torque. All 36 samples were sectioned along their long axes. The implant-abutment connection microgap was measured using scanning electron microscopy on the right and left sides of the connection at the upper, middle, and lower levels. Data were analyzed using the Kruskal-Wallis test (p < .05). RESULTS: Mean values (µm) of the microgap were 0.54 ± 0.44 (STK), 0.55 ± 0.48 (STK-Z), 1.53 ± 1.30 (MIL), 2.30 ± 2.2 (MIL-C), 1.53 ± 1.37 (SIN), and 1.87 ± 1.8 (SIN-C). Although significant differences were observed between the STK and STK-Z groups and the other groups (p < .05), none were observed between the milled and laser-sintered groups before or after ceramic veneering. The largest microgap was observed at the upper level in all groups. CONCLUSIONS: Titanium stock abutments provided a closer fit than cobalt-chrome custom abutments. Neither crown cementation nor ceramic veneering resulted in significant changes in the implant-abutment connection microgap.
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The purpose of this review was to evaluate the periodontal and peri-implant tissue responses to restorative approaches with and without cervical finish line on teeth and dental implants. An electronic search was performed in PubMed/MEDLINE, Embase, Cochrane Library, LILACS, Web of Science, and Scopus databases, and in the gray literature. Controlled clinical trials and prospective cohort studies were included. Analyzed outcomes included gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival thickness (GT), marginal stability (MS), and marginal bone loss (MBL). A meta-analysis was then performed in two parts: the first compared results of restorations on teeth with and without cervical finish line, and the second compared results of restorations on implant abutments with and without cervical finish line. Regarding the tooth-based restoration analysis, 7 out of 1,388 selected articles were included in the systematic review, and 2 were selected for the meta-analysis. For implantbased restorations on abutments with and without cervical finish line, 6 out of 707 selected articles were included in the systematic review, and 2 in the meta-analysis. No significant differences in periodontal and peri implant indexes were identified between both prosthetic approaches in situations with and without cervical finish lines.
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Reducing crestal bone loss (CBL) around implants allows for soft tissue stability and long-term success. The aim of the present study was to evaluate the extent of CBL in implants placed with the implant shoulder at the equi-crestal level and 2 mm below the alveolar ridge at 2, 12, 36, and 60 months. A split-mouth randomized controlled clinical trial was conducted by selecting subjects with Kennedy Class IV partial edentulism of the lower jaw. Two implants were inserted, of equal length and diameter, one equi-crestal and the other sub-crestal, in the site corresponding to the lateral incisor. Intraoral periapical radiographs with Rinn centering devices were performed at the time of implant insertion (T0), at 2 (T1), 12 (T2), 36 (T3), and 60 months (T4). Descriptive statistics and the T-test were used, setting the significance to P⩽ 0.05. Twenty-five subjects were recruited, with a mean age of 65 years (SD 9.88, range 42-82). No subject dropped out. A total of 50 implants were inserted, 25 at crestal and 25 sub-crest level. At the 60-month follow-up, no implant or prosthetic failure was recorded. An average loss of -0.81 mm was recorded in the crestal implant group (n.25; SD: 0.40; max-min: -1.6 - -0.1) while in the implants positioned below the crest the average CBL was -0.87mm (n.25; SD: 0.41; max-min: -2 - -0.2); however, the higher CBL in the sub-crestal implant group was not statistically significant (P=0.65). Comparing the mean CBL values of the two groups at the various follow-ups, a greater crestal bone resorption was recorded in sub-crest implants between T0 and T1 (-0.25 vs -0.1) and between T1 and T2 (-0.39 vs -0.23), while in subsequent follow-ups a greater, statistically significant (P=0.01), crestal bone loss was recorded in ridge implants between T3 and T4 (-0.05 vs -0.18). Over time, therefore, the extent of CBL seems to be reduced in implants placed below the crest, with bone retention above the implant shoulder. Ultimately, although the position of the implant shoulder relative to the crestal ridge doesn't affect the CBL, sub-crestal placement is recommended in order to reduce the risk of exposure of the rough surface of the implant.
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PURPOSE: To analyze the effectiveness of coating of abutments with antimicrobial agents and their influence on the physicochemical and biologic properties of the coated materials. MATERIALS AND METHODS: This work was registered in Open Science Framework (osf.io/6tkcp) and followed the PRISMA protocols. A search of two independent reviewers of articles published up to October 29, 2021, was performed in the Embase, PubMed, Science Direct, and Scopus databases. RESULTS: The databases found a total of 1,474 references. After excluding the duplicates, 1,050 remained. After reading the titles and abstracts and applying the inclusion criteria, 13 articles remained and were read in full. A total of 8 articles were included in this systematic review. Different antimicrobial agents have been used to coat abutments, including graphene oxide, polydopamine, titanium and zirconium nitride, lactoferrin, tetracycline, silver, and doxycycline with varied release times. Titanium-coated silver showed a better antimicrobial agent release time of up to 28 days. Chemical analysis confirmed the presence of antimicrobials on the surface after coating. Different pathogenic microorganisms, such as Streptococcus sanguinis, Streptococcus oralis, and Staphylococcus aureus, were inhibited when in contact with the coated surface. CONCLUSIONS: This review showed that there is still no consensus on which is the better antimicrobial agent and which coated materials have the better performance. However, the association of surface coating of abutments with antimicrobials is feasible and can benefit many patients, which can support their clinical use to favor the healing process and prevent infections that can lead to treatment failure with dental implants.
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Anti-Infecciosos , Dente Suporte , Humanos , Anti-Infecciosos/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Dente Suporte/microbiologia , Propriedades de Superfície , Titânio/químicaRESUMO
OBJECTIVE: The aim of this study was to evaluate the long-term (5 years) clinical efficacy of the one-abutment one-time protocol (test) versus the standard of care by placing the definitive abutment on the day of the prosthetic delivery (control). MATERIALS AND METHODS: In this study, 39 subjects with 60 implants were randomly allocated to either the test or the control group. Changes in the radiographic interproximal bone levels (DIB), modified sulcus bleeding index, probing depth, modified plaque index, papilla fill (Jemt score), incidence of peri-implantitis and peri-implant mucositis as well as patient-reported outcomes measures (PROMs) were collected and compared at 1, 3 and 5 years. RESULTS: At 5 years, the control group showed a greater, although not statistically significant, change in mean DIB values (0.97 mm vs. 0.53 mm). Regarding the other clinical parameters evaluated, no statistically significant differences were observed between groups at any time point. At 5 years, 51% of the implants presented peri-implant mucositis (25.5% in the control and 23.5% in the test), and only one implant in the test group developed peri-implantitis. CONCLUSIONS: The connection and disconnection of healing abutments during the healing period was not associated with higher long-term bone loss. Clinical outcomes and PROMs were similar between groups.
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Dente Suporte , Peri-Implantite , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Dente Suporte/efeitos adversos , Peri-Implantite/diagnóstico por imagem , Resultado do Tratamento , Índice Periodontal , Implantação Dentária Endóssea/métodos , Implantação Dentária Endóssea/efeitos adversos , Perda do Osso Alveolar/diagnóstico por imagem , Adulto , Idoso , Medidas de Resultados Relatados pelo Paciente , Implantes Dentários/efeitos adversos , Índice de Placa DentáriaRESUMO
Background: The objective of this study was to evaluate the pain and inflammatory response in soft tissues using healing and prosthetic abutments of different diameters and lengths. Methods: The study population was rehabilitated with Astra Tech EV single implants (Dentsply Sirona, Atlantis, Dentsply Sirona S.A., Barcelona, Spain) of 4.2 and 4.8 millimetres in diameter in the upper and lower maxilla and loaded with custom abutments digitally designed using Dentsply Sirona's Virtual Atlantis Design software (Atlantis WebOrder, Dentsply Sirona S.A., Barcelona, Spain), version 4.6.5. The custom abutments had a larger diameter than the healing abutments to evaluate for biomarkers through ELISA. Results: Rehabilitations in the mandible and with healing abutments with diameters less than 4.29 mm and rehabilitators with diameters less than 2.18 mm elicited a higher pain and inflammatory response and, in turn, higher interleukin-1ß values. Conclusions: Greater inflammation was evident in cases in which healing abutments with reduced diameter were used compared to the same subsequent rehabilitation with prosthetic abutments with larger diameters.
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AIM: A new implant system encompassing implants with a tri-oval cross-sectional design and a simplified site preparation protocol at low speed and no irrigation has been developed. The objective of this study was to assess the safety and efficacy of the new implant system using the minipig intraoral dental implant model. METHODS: Eight Yucatan minipigs were included. Twelve weeks after extractions, four implants per animal were randomly placed and allowed to heal transmucosal for 13 weeks: two Ø3.5 × 10 mm implants with a back-tapered collar and circular cross-section (control) and two Ø3.5 × 11 mm implants with tri-oval collar and cross-section (test). MicroCT and histological analysis was performed. RESULTS: Thirty-two implants were placed; one implant for the control group was lost. Histologically, BIC was higher in the test compared with the control group (74.1% vs. 60.9%, p < .001). At the platform level, inflammation was statistically significantly higher albeit mild in the test compared with the control group. No other significant differences were observed between groups. MicroCT analysis showed that bone-to-implant-contact (BIC) and trabecular thickness were statistically significantly higher for the test than the control group. Test group had significantly higher first BIC distance than controls on lingual sites. CONCLUSIONS: The present study results support the safety and efficacy of the new dental implant system and simplified site preparation protocol; human studies should be carried out to confirm these findings.
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Implantação Dentária Endóssea , Implantes Dentários , Animais , Estudos Transversais , Implantação Dentária Endóssea/métodos , Osseointegração , Suínos , Porco MiniaturaRESUMO
AIM: The aim of the study was to evaluate the 5 years clinical outcomes associated with implant-level connection (IL) versus abutment-level connection (AL) for implants with an internal conical connection (ICC) supporting a screw-retained fixed partial denture. MATERIALS AND METHODS: Fifty patients with 119 implants were randomly allocated to either the AL or IL group. Radiographic (Marginal bone loss) and clinical outcomes (Bleeding on Probing, probing pocket depth, plaque accumulation, incidence of peri-implantitis and peri-implant mucositis as well as prosthetic complications) were collected and compared at 1, 2, 3, and 5 years. A linear mixed model was used to evaluate the differences between groups. RESULTS: Five years after treatment, the MBL change was not significantly different between the groups at any point. The MBL was 0.23 ± 0.64 mm (AL) and 0.23 ± 0.29 mm (IL). The bleeding on Probing was 44% (AL) and 45% (IL) (p = .89). The mean probing depth was 2.91 ± 1.01 mm (AL) and 3.51 ± 0.67 mm (IL). This difference between the groups was statistically significant but clinical insignificant. Presence of plaque was slightly higher (p = .06) in the IL group (34.4%) compared with the AL group (26.3%). The overall technical, biological, and prosthetic complication rates were similar between groups. None of the implants developed peri-implantitis during the entire follow-up period. CONCLUSION: The results of this clinical trial indicated that all clinical and radiographical parameters were clinically comparable between the study groups.
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Implantes Dentários , Peri-Implantite , Humanos , Parafusos Ósseos , Implantes Dentários/efeitos adversos , Peri-Implantite/etiologiaRESUMO
A eficácia dos implantes osseointegrados é amplamente reconhecida na literatura científica. Contudo, infiltrações bacterianas na junção implante-pilar podem desencadear inflamação nos tecidos circundantes, contribuindo para a evolução de condições mais sérias, como a peri-implantite. O objetivo desse estudo foi produzir complexos polieletrólitos (PECs) de quitosana (Q) e xantana (X) em forma de membranas, carregá-las com ativos naturais e sintéticos antimicrobianos, caracterizálas estruturalmente e avaliá-las frente a degradação enzimática, cinética de liberação e ações antimicrobianas com finalidade de aplicação para drug delivery. Membranas de QX a 1% (m/v) foram produzidas em três proporções, totalizando doze grupos experimentais: QX (1:1); QX (1:2), QX (2:1), QX-P (com própolis) (1:1); QX-P (1:2); QX-P (2:1); QX-C (com canela) (1:1); QX-C (1:2); QX-C (2:1) e CLX (com clorexidina 0,2%) (1:1); CLX (1:2); CLX (2:1). Para os estudos de caracterização foram feitas análises da espessura em estado seco; análises morfológicas superficial e transversal em Microscopia Eletrônica de Varredura (MEV); análise estrutural de espectroscopia de infravermelho por transformada de Fourier (FTIR); análise de degradação por perda de massa sob ação da enzima lisozima; e análise da cinética de liberação dos ativos em saliva artificial. Para os testes microbiológicos, análises de verificação de halo de inibição e ação antibiofilme foram feitas contra cepas de Staphylococcus aureus (S. aureus) e Escherichia coli (E. coli). Os resultados demonstraram que a espessura das membranas variou conforme a proporção, sendo que o grupo QX (1:2) apresentou a maior média de 1,022 mm ± 0,2, seguida respectivamente do QX (1:1) com 0,641 mm ± 0,1 e QX (2:1) com 0,249 mm ± 0,1. Nas imagens de MEV é possível observar uma maior presença de fibras, rugosidade e porosidade nos grupos QX (1:2) e QX (1:1) respectivamente, e, no QX (2:1) uma superfície mais lisa, uniforme e fina. No FTIR foram confirmados os picos característicos dos materiais isoladamente, além de observar as ligações iônicas que ocorreram para formação dos PECs. Na análise de degradação, os grupos com ativos naturais adicionados tiveram melhores taxas de sobrevida do que os grupos QX. No teste de liberação, os grupos QX-P tiveram uma cinética mais lenta que os QX-C, cuja liberação acumulada de 100% foi feita em 24 h. Já nos testes do halo inibitório, somente os grupos CLX tiveram ação sobre as duas cepas, e os QX-P tiveram sobre S. aureus. Nas análises antibiofilme, os grupos CLX apresentaram as maiores taxas de redução metabólica nas duas cepas (± 79%); os grupos QX-P apresentaram taxas de redução similares em ambas as cepas, porém com percentual um pouco maior para E. coli (60- 80%) e os grupos QX-C tiveram grande discrepância entre as duas cepas: de 35 a 70% para S. aureus e 14 a 19% para E. coli. Pode-se concluir que, frente as análises feitas, o comportamento do material foi afetado diretamente pelos ativos adicionados a matriz polimérica. As proporções de Q ou X afetaram somente a espessura final. Quanto a aplicação proposta de drug delivery, os dispositivos apresentaram grande potencial, principalmente os grupos CLX e QX-P. (AU)
The effectiveness of osseointegrated implants is widely recognized in scientific literature. However, bacterial infiltrations at the implant-abutment interface may trigger inflammation in surrounding tissues, contributing to the development of more serious conditions, such as peri-implantitis. The aim of this study was to produce chitosan (Q) and xanthan (X) polyelectrolyte complexes (PECs) in the form of membranes, load and evaluate them for enzymatic degradation, release kinetics, and antimicrobial actions for drug delivery applications. QX membranes at 1% (w/v) were produced in three proportions, totaling twelve experimental groups: QX (1:1), QX (1:2), QX (2:1), QX-P (with propolis) (1:1), QX-P (1:2), QX-P (2:1), QX-C (with cinnamon) (1:1), QX-C (1:2), QX-C (2:1), and CLX (with 0.2% chlorhexidine) (1:1), CLX (1:2), CLX (2:1). Characterization studies included analyses of dry state thickness, surface and crosssectional morphology using Scanning Electron Microscopy (SEM), structural analysis by Fourier Transform Infrared (FTIR) spectroscopy, mass loss degradation analysis under lysozyme action, and active release kinetics analysis in artificial saliva. Microbiological tests included verification analyses of inhibition halos and antibiofilm action against strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Results showed that membrane thickness varied according to proportion, with group QX (1:2) presenting the highest average of 1.022 mm ± 0.2, followed by QX (1:1) with 0.641 mm ± 0.1, and QX (2:1) with 0.249 mm ± 0.1. SEM images showed greater presence of fibers, roughness, and porosity in groups QX (1:2) and QX (1:1) respectively, while QX (2:1) exhibited a smoother, more uniform, and thinner surface. FTIR confirmed characteristic peaks of the materials individually, besides showing ionic bonds formed for PECs. Degradation analysis revealed that groups with added natural actives had better survival rates than QX groups. In release tests, QX-P groups exhibited slower kinetics than QX-C, with 100% cumulative release achieved in 24 h. inhibitory halo tests, only CLX groups exhibited action against both strains, while QX-P acted against S. aureus. Antibiofilm analyses showed CLX groups with the highest metabolic reduction rates in both strains (± 79%); QX-P groups showed similar reduction rates in both strains, slightly higher for E. coli (60-80%), and QX-C groups had a significant discrepancy between strains: 35-70% for S. aureus and 14-19% for E. coli. In conclusion, material behavior was directly affected by added actives to the polymeric matrix. Proportions of Q or X only affected final thickness. Regarding proposed drug delivery applications, the devices showed great potential, especially CLX and QX-P groups.(AU)
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Sistemas de Liberação de Medicamentos , Quitosana , Projeto do Implante Dentário-Pivô , Compostos Fitoquímicos , PolieletrólitosRESUMO
Objective: The one-piece dental implant was originally designed to overcome the structural weaknesses of the two-piece implant. However, a fractured one-piece implant requires removal because the abutment cannot be repaired or replaced to support new prosthetic restorations. The aim of this study was to clarify the features and risk factors for fracture of the one-piece implant. Methods: This study was designed as a retrospective case series research. The subjects were patients who were treated for fractures of the one-piece implant at a clinic in Japan between 2012 and 2021. Fractures of the one-piece implant were diagnosed by cone-beam computed tomography, and the association between age and duration from implant placement to fracture was analyzed by one-way ANOVA followed by the Tukey test. Results: Eighteen patients and 20 one-piece implants (under 39 years: 5 patients and 6 implants; 40-59 years: 7 patients and 7 implants; over 60 years: 6 patients and 7 implants) had fractures in their one-piece implants. Of the fractured implants, 11 had a diameter of 3 mm, and 9 had a diameter of 4 mm. The mean durations up to implant fracture were 662 days in the younger group, 1467 days in the middle group, and 1239 days in older group, and the duration was significantly shorter in the younger group. In addition, 83.3% of fracture implants in the younger group were in the molar region. All fractures of the one-piece implants occurred under the bone margin. Two patients had torus mandibularis, and 1 patient was had bruxism. Conclusions: One-piece implants in younger patients that are located in the lower molar position are the most susceptible to implant fracture, and the fracture occurred under the bone margin in all cases.
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BACKGROUND: Peri-implant disease prevalence is associated with a multifactorial etiology and distinct clinical characteristics of inflammation. METHODS: The present study aimed to assess the prevalence of peri-implant diseases, identify related risk indicators, and associate specific clinical characteristics to peri-implant biological complications in the medium term. Peri-implant diseases were classified according to established case criteria. Patients' data, implant and/or prosthetic features, and maintenance records were collected. Clinical characteristics such as bleeding on probing (BOP), suppuration (SUPP), keratinized mucosa (KM), probing depth (PD), marginal recession (MR), and modified plaque index (mPI) were recorded. RESULTS: Ninety-nine patients with 266 implants with a mean functional duration of 30.26 months were evaluated. Peri-implant mucositis and peri-implantitis prevalence totaled to 49.5% and 15.15% (patient level), respectively. Peri-implant mucositis was associated with osteoporosis (odds ratio [OR] 6.09), age (OR 0.97), diabetes mellitus (OR 3.09), cemented-retained prosthesis (OR 3.81), and partial prosthesis (OR 2.21). Peri-implantitis was associated with osteoporosis (OR 7.74) and periodontitis (OR 2.74), cemented prosthesis (OR 10.12), partial and full arch prostheses (OR 12.35 and 19.86), implant diameter (OR 3.64), abutment transmucosal height (OR 3.39), and hygiene difficulty (OR 3.14). Furthermore, mPI score 3 (OR 3.27) and PD scores (OR 1.64) were associated with peri-implant mucositis, while mPI score 3 (OR 16.42), KM (OR 1.53), PD (OR 1.81), MR (OR 2.61), and the relationship between KM and PD (OR 0.63) were associated with peri-implantitis. CONCLUSION: In the medium term, peri-implant diseases were correlated with factors inherent to the patient's conditions, presurgical treatment plan, and hygiene maintenance care. The knowledge of the mentioned factors and featured clinical characteristics can be crucial for disease prevention and establishment of a superior implant therapy prognosis.
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This in vitro study aimed to assess the presence of microgaps at the implant-abutment interface in monolithic zirconia partial implant-supported fixed prostheses on transepithelial abutments versus Ti-base abutments. METHODS: Sixty conical connection dental implants were divided into two groups (n = 30). The control group consisted of three-unit bridge monolithic zirconia connected to two implants by a transepithelial abutment. The test group consisted of monolithic zirconia three-unit restoration connected to two implants directly by a titanium base (Ti-base) abutment. The sample was subjected to thermocycling (10,000 cycles at 5 °C to 55 °C, dwelling time 50 s) and chewing simulation (300,000 cycles, under 200 N at frequencies of 2 Hz, at a 30° angle). The microgap was evaluated at six points (mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual) of each implant-abutment interface by using a scanning electron microscope (SEM). The data were analyzed using the Mann-Whitney U tests (p > 0.05). RESULTS: The SEM analysis showed a smaller microgap at the implant-abutment interface in the control group (0.270 µm) than in the test group (3.902 µm). Statistically significant differences were observed between both groups (p < 0.05). CONCLUSIONS: The use or not of transepithelial abutments affects the microgap size. The transepithelial abutments group presented lower microgap values at the interface with the implant than the Ti-base group in monolithic zirconia partial implant-supported fixed prostheses. However, both groups had microgap values within the clinically acceptable range.
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AIM: To evaluate microspace and microleakage between implant and abutments subjected to pre- and post-calibrated cyclic stress. MATERIALS AND METHODS: Twelve screw-retained implant prostheses with BioHPP polyetheretherketone (PEEK) abutment (Noris Dental Implant System Ltd., Nesher, Israel) (Group I) and 12 screw-retained implant prostheses with computer-assisted design/computer-assisted manufacturing (CAD/CAM) milled zirconia abutment (DentGallop, Houston, TX, USA) (Group II) were connected to their respective implant, and the prosthetic screw was torqued to 30N/cm (Noris). The microspace was evaluated using scanning electron microscopy (SEM; TeScan, Brno, Czech Republic). Twenty-four samples were then induced to cyclic stress (Lokesh Industries, Pune, India) simulating 180 days duration of oral stress. The microspaces (Group IA and Group IIB) were measured post-cyclic stress. Group I and II were again renamed into Group Ia and Group IIb for microbial study. Both implant assemblies were immersed in fresh soybean casein digest broth (SCDB) (Himedia, Mumbai, India) and subsequently inoculated with 1.0µL E. coli suspension (Himedia) at the open end and incubated at 37ºC for seven days. After the incubation period, cellular activity was determined by the spread plate method, and total colony-forming units (CFU) were calculated. The results were evaluated using independent T and Mann-Whitney tests. RESULT: Average and microspace at the implant-abutment junction of Group I samples in the front right was 12.98µm, center 13.76µm, front left 13.22µm, and in Group II samples, the front right was 18.52µm, center 17.84µm, front left 18.58µm.After being subjected to cyclic loading, the mean levels of the vertical microgap for Group IA samples were: in the front right region 10.37µm, in the center 9.34µm, in the front left 10.51µm and in Group IIB samples front right was 14.59µm, center 13.39µm, front left 13.8µm. Independent t-tests showed insignificant differences between the two groups. The median value of microbial leakage of Group Ia samples after cyclic loading was 30 x 103 CFU/ml, and Group IIb samples were 42 x 103 CFU/ml and were significant. CONCLUSION: There was minimal variation in the mean microspace between the BioHPP PEEK abutment and CAD/CAM milled zirconia abutment, and it was insignificant before and after cyclic stress. BioHPP PEEK abutment-titanium implant interfaces showed significantly decreased microbial leakage than CAD/CAM milled zirconia abutment-titanium implant interfaces after cyclic stress.
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Background and Objectives: The insertion of the dental implant in the bone is an essential step in prosthetic rehabilitation. The insertion torque has the potential to distort the prosthetic platform, which can cause future biomechanical problems with the continuous action of occlusal forces. The aim of this study is to evaluate different insertion torques in the deformation of tri-channel platform connections through two- and three-dimensional measurements with micro-CT. Materials and Methods: A total of 164 implants were divided into groups (platform diameter and type): 3.5, 3.75, and 4.3 mm NP (narrow platform), and 4.3 mm RP (regular platform). Each implant-platform group was then divided into four subgroups (n = 10) with different torques: T45 (45 Ncm), T80 (80 Ncm), T120 (120 Ncm), and T150 (150 Ncm). The implant-abutment-screw assemblies were scanned and the images obtained were analyzed. Results: A significant difference was observed for the linear and volume measures between the different platforms (p < 0.01) and the different implant insertion torques (p < 0.01). Qualitative analysis suggested a higher deformation resistance for the 3.75 NP compared to the 3.5 NP, and RP was more resistant compared to the NP. Conclusions: The 0.25 mm increment in the implant platform did not increase the resistance to the applied insertion torques; the 4.3 mm implant was significantly stronger compared to the 3.5 mm implant; and the proposed micro-CT analysis was considered valid for both the 2D and 3D analyses of micro-gaps, qualitatively and quantitatively.
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Próteses e Implantes , Humanos , Microtomografia por Raio-X , TorqueRESUMO
This study investigated the effects of antirotational titanium bases on the mechanical behavior of CAD/CAM titanium bases used for implant-supported prostheses. The aim was to assess the impact on the marginal fit, fatigue behavior, stress concentration, and fracture load of implant-supported CAD/CAM zirconia crowns. Forty titanium implants were divided into two groups: those with antirotational titanium bases (ARs) and those with rotational titanium bases (RTs). Torque loosening and vertical misfit were evaluated before and after cyclic fatigue testing (200 N, 2 Hz, 2 × 106 cycles). Fracture resistance was assessed using a universal testing machine (1 mm/min, 1000 kgf), and failed specimens were examined with microscopy. Three-dimensional models were created, and FEA was used to calculate stress. Statistical analysis was performed on the in vitro test data using two-way analysis of variance and Tukey's test (α = 0.5). Results show that the presence of an antirotational feature between the implant and titanium base reduced preload loss and stress concentration compared to rotational titanium bases. However, there were no differences in vertical misfit and resistance to compressive load.
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This evaluation assessed the influence of a new implant shoulder design on cleanability using a now established in-vitro study model. Eight test (Botticelli, Di Meliora AG, Basel, Switzerland) and eight control implants (T3 Osseotite, ZimVie, Winterthur, Switzerland), were embedded in standardized defects in simulated bone. The implant surfaces were painted to be visually distinguishable and debrided with ultrasonic instruments (US) and an air powder waterjet device (AIR). Uncleaned implants served as positive controls. After the standardized cleaning, the implants were photographed and divided into three zones (upper marginal shoulder zone (A); lower marginal shoulder zone (B); fully threaded sub-shoulder zone (C)), and analyzed with an image processing software. On test implants, AIR was almost 100% efficacious compared to 80-90% with US, in both upper zones (A/B). In control implants, results of both AIR and US were almost 100% in zone A, but only 55-75% in zone B. In both implants, AIR showed statistically significant higher efficacy than US (P<0.05). Within the limitations of the present in-vitro model, a new macro-structured micro-rough dental implant shoulder with a new coronal vertical groove design shows similar cleanability in comparison to a smooth and machined surface.