Abstract This case-control study evaluated the gene expression levels of interleukin (IL)-4, macrophage inflammatory protein type 1 alpha (MIP-1α), and metalloproteinase (MMP)-9, factors involved in the formation of giant cells in healthy peri-implant tissue and peri-implantitis. Thirty-five subjects (15 healthy and 20 with peri-implantitis), who met the inclusion and exclusion criteria, were included in this study. The peri-implant tissue biopsies were subjected to total RNA extraction, DNAse treatment, and cDNA synthesis. Subsequently, the reaction of real-time PCR was performed to evaluate the gene expression levels of IL-4, MIP-1α, and MMP-9 concerning the reference gene. IL-4 gene expression showed higher (18-fold) values in the Peri-Implantitis Group of Patients when compared with the Healthy (Control) Group (p<0.0001). Although MIP- 1α and MMP-9 gene expression levels were higher in diseased implants, they showed no significant differences (p=0.06 and p=0.2337), respectively. Within the limitations of this study, the results showed that in tissues affected by peri-implantitis, only levels of Il-4 were increased when compared with tissues in the control group.

Resumo Este estudo caso-controle teve como objetivo avaliar a expressão gênica dos níveis de interleucina (IL)-4, proteína inflamatória de macrófagos tipo alfa 1 (MIP-1α) e metalopreoteinase (MMP)-9, todos fatores envolvidos na formação de células gigantes em tecidos peri-implantares saudáveis e com peri-implantite. Trinta e cinco indivíduos (15 saudáveis e 20 com peri-implantite) foram incluídos nesse estudo seguindo os critérios de inclusão e exclusão. Os tecidos peri-implantares foram submetidos a extração do RNA total, tratamento de DNAse e síntese de cDNA. Subsequentemente, a reação de PCR em tempo real foi realizada para avaliar os níveis da expressão de IL-4, MIP-1α, e MMP-9 em relação ao gene de referência. O nível de expressão de IL-4 foi estatisticamwente maior (18 vezes) nos tecidos de pacientes com peri-implantite quando comparados aos pacientes saudáveis (grupo controle) (p<0,0001). Embora os níveis de expressão de MIP- 1α e MMP-9 apresentassem maiores valores nos implantes doentes, esses níveis não foram estatisticamente significantes (p=0.06 and p=0.2337) respectivamente. Dentro das limitações desse estudo, os resultados mostraram que nos tecidos afetados pela peri-implantite, apenas os nívies de IL-4 estavam aumentados quando comparados ao grupo controle.

Abstract When periodontal disease is diagnosed, it is difficult to predict the clinical response of treatment of a tooth over time because the result of treatment is affected by several factors and will depend on the maintenance and support of periodontal treatment. Rehabilitation with removable dental prostheses, fixed prostheses, and dental implants makes it possible to restore the function and esthetics of patients with tooth loss due to periodontal disease. The predictive factors of tooth loss in periodontitis patients should be assessed by dentists to inform their clinical decision-making during dental treatment planning. This will provide detailed individualized information and level of risk of patients considered suitable for dental rehabilitation. Therefore, the aim of this article was to review the subject of “Impact of tooth loss due to periodontal disease on the prognosis of rehabilitation” and the effect of fixed, removable, and implant-supported prostheses in periodontal patients.

Abstract Observational studies have indicated that crestal bone level changes at implants are typically associated with clinical signs of inflammation, but still mechanical overload has been described as possible factor leading to hard–tissue deficiencies at implant sites without mucosal inflammation. The aim of this paper was systematically review the literature regarding the possible effect of traumatic occlusal forces on the peri-implant bone levels. Literature search was conducted using PubMed, Scielo and Lilacs, including the following terms: oral OR dental AND implant$ AND (load OR overload OR excessive load OR force$ OR bruxism) AND (bone loss OR bone resorption OR implant failure$). Databases were searched for the past 10 years of publications, including: clinical human studies, either randomized or not, cohort studies, case control studies, case series and animal research. Exclusion criteria were review articles, guidelines and in vitro and in silico (finite element analysis) research, as well as retrospective studies. The PICO questions formulated was: “does traumatic occlusal forces lead to peri-implant bone loss?” The database searches as well as additional hand searching, resulted in 807 potentially relevant titles. After inclusion/exclusion criteria assessment 2 clinical and 4 animal studies were considered relevant to the topic. The included animal studies did not reveal an association between overload and peri-implant bone loss when lower overloads were applied, whereas in the presence of excessive overload it seemed to generate peri-implant bone loss, even in the absence of inflammation. The effect of traumatic occlusal forces in peri-implant bone loss is poorly reported and provides little evidence to support a cause-and-effect relationship in humans, considering the strength of a clinically relevant traumatic occlusal force.

Abstract Soft tissue defects around dental implants, such as papilla or volume loss, peri-implant recession and alterations of the ridge color and/or texture, lead to esthetic and functional complaints. Treatments of these defects in implants are more demanding than in teeth because peri-implant tissue exhibits different anatomical and histological characteristics. This narrative review discusses the proposed treatments for soft tissue defects around implants in the current literature. Several clinical and pre-clinical studies addressed methods to augment the quantity of the peri-implant keratinized mucosa. Autogenous grafts performed better than soft tissue substitutes in the treatment of soft tissue defects, but there is no clinical consensus on the more appropriate donor area for connective tissue grafts. Treatment for facial volume loss, alterations on the mucosa color or texture and shallow peri-implant recessions are more predictable than deep recessions and sites that present loss of papilla. Correction of peri-implant soft tissue defects may be challenging, especially in areas that exhibit larger defects and interproximal loss. Therefore, the regeneration of soft and hard tissues during implant treatment is important to prevent the occurrence of these alterations.

Abstract The aim of this study was to evaluate the effects of adjunct systemic antibiotic treatment with metronidazole (MTZ) and amoxicillin (AMX) in patients receiving non-surgical subgingival debridement (NSD) for peri-implantitis. Forty subjects presenting with at least one implant with severe peri-implantitis were randomized into an experimental group [treated with NSD plus MTZ (400 mg) and AMX (500 mg) three times a day for 14 days] and a control group treated with NSD plus placebo. Clinical parameters and submucosal biofilm profiles were evaluated up to 1 year post-treatment. Overall, both treatments improved clinical parameters over time. At 1 year, mean probing depth (PD), mean clinical attachment (CA) level and proportions of red complex pathogens did not differ significantly between the two groups. In addition, mean PD and CA changes to 1-year posttreatment did not differ significantly between the two groups between baseline and 1-year post-treatment. These results suggest that the addition of MTZ and AMX to the treatment protocol of patients undergoing NSD for with severe peri-implantitis does not improve the clinical and microbiological outcomes of NSD. The fact that half of the implants in both groups did not achieve clinical success (PD < 5 mm, no BoP, no bone loss) suggest that neither of the tested protocols were effective for treating severe peri-implantitis.

Abstract This study evaluated the effect of implantoplasty on different bone insertion levels of exposed implants. A model of the Bone Level Tapered implant (Straumann Institute, Waldenburg, Switzerland) was created through the Rhinoceros software (version 5.0 SR8, McNeel North America, Seattle, WA, USA). The abutment was fixed to the implant through a retention screw and a monolithic crown was modeled over a cementation line. Six models were created with increasing portions of the implant threads exposed: C1 (1 mm), C2 (2 mm), C3 (3 mm), C4 (4 mm), C5 (5 mm) and C6 (6 mm). The models were made in duplicates and one of each pair was used to simulate implantoplasty, by removing the threads (I1, I2, I3, I4, I5 and I6). The final geometry was exported in STEP format to ANSYS (ANSYS 15.0, ANSYS Inc., Houston, USA) and all materials were considered homogeneous, isotropic and linearly elastic. To assess distribution of stress forces, an axial load (300 N) was applied on the cusp. For the periodontal insert, the strains increased in the peri-implant region according to the size of the exposed portion and independent of the threads’ presence. The difference between groups with and without implantoplasty was less than 10%. Critical values were found when the inserted portion was smaller than the exposed portion. In the exposed implants, the stress generated on the implant and retention screw was higher in the models that received implantoplasty. For the bone tissue, exposure of the implant’s thread was a damaging factor, independent of implantoplasty. Implantoplasty treatment can be safely used to control peri-implantitis if at least half of the implant is still inserted in bone.

Abstract The fit of the implant-abutment interface was assessed by the metallographic technique and by scanning electron microscopy (SEM), using solid abutment types at different torque levels. Forty Morse taper connections and forty solid abutments were used at different torque levels (repeated after 10 minutes) in the following groups (n = 10): 25 Ncm (group g1), 30 Ncm (group g2), 35 Ncm (group g3), and 40 Ncm (group g4). The samples were embedded in a metallographic resin, sectioned lengthwise, and polished. SEM images were used to measure the linear contacts and the fits between abutments and the internal walls of the implant. The overall mean gap and standard deviation were as follows: 9.0 ± 1.36 µm for group g1, 7.9 ± 2.81 µm for group g2, 2.0 ± 0.76 µm for group g3, and 0.3 ± 0.40 µm for group g4. A significant difference was observed in the average fit values between the groups (p < 0.05). The linear area of contact between the abutment and the implant increased as torque augmented. This study demonstrated that higher insertion torque values in a conical internal connection increase the fit (contact) of the implant-abutment interface.

OBJETIVO: O objetivo do presente estudo foi investigar os efeitos térmicos do laser de Er,Cr:YSGG (1,5W/20Hz) em zircônia tetragonal policristalina estabilizada com ítrio (Y-TZP). MATERIAL E MÉTODO: Quinze discos de Y-TZP (AS Technology Titanium FIX, São José dos Campos, Brasil) com 5 mm de diâmetro e 3 mm de altura padronizados com CAD-CAM (computer-aided design e computer-aided manufacturing) foram usados. Os discos de Y-TZP foram randomicamente distribuídos em três grupos (n=5): Y-TZP-G1 = controle (sem irradiação); Y-TZP-G2 = Y-TZP + Er,Cr:YSGG (proporção resfriamento ar-água 80%/25%); Y-TZP-G3 = Y-TZP + Er,Cr:YSGG (proporção resfriamento ar-água 80%/0%). Um termopar (SmartMether, Novus, Porto Alegre, RS, Brasil) acoplado a um termômetro digital (SmartMether, Novus, Porto Alegre, RS, Brasil) foi fixado na face oposta à superfície irradiada. Os gradientes de temperatura ΔT foram calculados (ΔT = Temperatura final - Temperatura inicial) para cada grupo. Os valores foram analisados estatisticamente por one-way ANOVA com 95% de confiança e comparados pelo teste Tukey (α=0,05). Uma amostra de cada grupo foi analisada por microscopia confocal de luz branca. RESULTADO: O teste ANOVA mostrou diferenças significativas para o fator "laser" (p< 0,001). Os gradientes de temperatura (valores de ΔT) apresentaram os seguintes resultados: Y-TZP-G1 = 0 ºC; Y-TZP-G2 = -1,4 ºC e Y-TZP-G3= 21,4 ºC. O valor de ΔT (ºC) do grupo sem refrigeração foi maior do que o grupo refrigerado. Os valores de rugosidade (Ra) variaram de 4,50 até -33,65 µm. CONCLUSÃO: A refrigeração com água para a irradiação do laser de Er,Cr:YSGG é essencial para evitar o aumento de temperatura de Y-TZP.

OBJECTIVE: The objective of the present study was to investigate the thermal effects of Er,Cr:YSGG laser irradiation (1.5W/20Hz) on yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIAL AND METHOD: Fifteen disks of Y-TZP (AS Technology TitaniumFIX, São José dos Campos, Brazil) with 5 mm diameter and 3 mm high standardized with CAD-CAM were used. The Y-TZP disks were randomized in three groups (n=5): Y-TZP-G1 = control (no laser treatment); Y-TZP-G2 = Y-TZP + Er,Cr:YSGG laser (air-water cooling proportion 80%/25%); Y-TZP-G3 = Y-TZP + Er,Cr:YSGG laser (air-water cooling proportion 80%/0%). A thermopar (SmartMether, Novus, Porto Alegre, RS, Brazil) was attached to a digital thermometer (SmartMether, Novus, Porto Alegre, RS, Brazil) fixed to the opposite irradiated surface. The temperature gradients (ΔT) were calculated (ΔT = Final Temperature - Initial Temperature) for each group. Values were statistically analyzed by one-way ANOVA at the 95% confidence level and compared by Tukey post-hoc test (α=0.05) for each material. One sample of each group was analyzed by confocal white light microscopy. RESULT: The ANOVA test showed significant differences for the factor "laser" (p<.001). The temperature gradients (ΔT value) showed the following results: Y-TZP-G1 = 0 ºC; Y-TZP-G2 = -1.4 ºC and Y-TZP-G3 = 21.4 ºC. The ΔT values (ºC) of the non-refrigerated group were higher than the refrigerated group. The roughness value (Ra) ranged from 4.50 to -33.65 µm. CONCLUSION: The water refrigeration for Er,Cr:YSGG irradiation is essential to avoid thermal increase in the Y-TZP.