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 The literature describes multiple ways to stimulate wound healing to reduce the patient's perception of pain. This systematic review aimed to evaluate if methods that enhance wound healing can reduce the patient’s perception of pain after free gingival graft removal from the palate region compared to natural healing. A systematic review protocol was written following the PRISMA checklist. Electronic searches of five databases were performed to identify randomized clinical trials (RCTs) that assessed the patient’s perception of pain after the removal of a free gingival graft from the palate. The primary outcome was the visual analog scale (VAS) score assessing the patient’s perception of pain 7 days after the free gingival graft removal from the palate region. Of the 1,622 potentially relevant articles retrieved from the electronic databases, 16 RCTs were selected for qualitative analysis, and of these, 6 RCTs were included in the meta-analysis. RCTs showed a significant VAS reduction associated with the use of methods to enhance wound healing. The pooled estimates revealed a significant overall VAS reduction of 2.20 (95% CI 2.32, 2.07) 7 days after surgery. The methods that presented the greatest reduction in the perception of pain were platelet-rich fibrin, hyaluronic acid, and autologous fibrin glue. Methods that enhance wound healing, including platelet-rich fibrin, hyaluronic acid, and autologous fibrin glue, can reduce pain perception after free gingival graft removal in the palate region. However, only 1 RCT investigated each approach, which hinders the conclusion regarding the best procedure to reduce the perception of pain.

Resumo A literatura descreve diferentes formas de estimular a cicatrização para reduzir a percepção de dor do paciente. Esta revisão sistemática teve como objetivo avaliar se métodos que melhoram o reparo de feridas podem reduzir a percepção de dor do paciente após a remoção de enxerto gengival livre da região do palato quando comparado a cicatrização natural. Um protocolo de revisão sistemática foi escrito seguindo a lista de verificação PRISMA. Pesquisas eletrônicas em cinco bancos de dados foram realizadas para identificar ensaios clínicos aleatorizados (ECA) que avaliaram a percepção de dor do paciente após a remoção do enxerto gengival livre do palato. O desfecho primário foi o escore da escala visual analógica (VAS) avaliando a percepção de dor do paciente 7 dias após a remoção do enxerto gengival livre da região do palato. Dos 1.622 artigos potencialmente relevantes recuperados das bases de dados eletrônicas, 16 ECAs foram selecionados para análise qualitativa, e destes, seis ECAs foram incluídos na meta-análise. Os estudos analisados demonstraram uma redução significativa de VAS associada ao uso de métodos para melhorar a cicatrização de feridas. As estimativas agrupadas revelaram uma redução global significativa do VAS de 2,20 (95% CI 2,32, 2,07) 7 dias após a cirurgia. Os métodos que apresentaram maior redução na percepção de dor foram fibrina rica em plaquetas, ácido hialurônico e cola de fibrina autóloga. Métodos que melhoram a cicatrização de feridas podem reduzir a percepção de dor após a remoção do enxerto gengival livre na região do palato, especialmente fibrina rica em plaquetas, ácido hialurônico e cola de fibrina autóloga. No entanto, apenas um ECA avaliou cada abordagem, o que impossibilita a conclusão sobre qual é o melhor procedimento para reduzir a percepção de dor.

Resumo Implantes dentários em titânio (Ti) são reconhecidos como principal modalidade terapêutica para a reabilitação oral de pacientes edêntulos, demonstrando uma alta taxa de sucesso e longevidade clínica. No entanto, após inserção no ambiente bucal, os implantes dentários agem como substrato para adesão e acúmulo microbiano. A formação de biofilmes em implantes dentários tem sido considerada o principal fator etiológico para induzir doenças inflamatórias conhecidas como mucosite peri-implantar e peri-implantite, sendo está última reconhecida como principal razão para falha tardia dos implantes dentários. Diferentes fatores têm sido atribuídos por promover o acúmulo microbiano em implantes dentários, levando a uma mudança microbiológica e favorecendo o dano tecidual, como a matriz do biofilme, exposição a carboidratos e interação entre reinos. Esses fatores combinados com a organização espacial de biofilmes, reduzida suscetibilidade microbiana, complexa composição microbiológica e a superfície irregular dos implantes dificultam o controle do biofilme e a morte microbiana. Apesar da etiologia bem conhecida, ainda não há consenso sobre o melhor protocolo clínico para controlar o acúmulo microbiano nas superfícies dos implantes dentários e tratar a doença peri-implantar. Nesse sentido, diferentes coberturas e tratamentos de superfície no Ti têm sido desenvolvidos objetivando a redução dos níveis microbianos e o controle das infecções polimicrobianas em implantes. Portanto, essa revisão crítica objetiva discutir a atual evidência em relação ao acúmulo de biofilmes em implantes dentários e fatores chave relacionados ao processo patogênico das infecções peri-implantares. Além disso, o potencial de alterações de superfícies com propriedades antimicrobianas para implantes dentários é discutido para ressaltar futuras estratégias promissoras no controle da peri-implantite.

Abstract Dental implants made of titanium (Ti) material is recognized as the leading treatment option for edentulous patients’ rehabilitation, showing a high success rate and clinical longevity. However, dental implant surface acts as a platform for microbial adhesion and accumulation once exposed to the oral cavity. Biofilm formation on implant surfaces has been considered the main etiologic factor to induce inflammatory diseases, known as peri-implant mucositis and peri-implantitis; the latter being recognized as the key reason for late dental implant failure. Different factors, such as biofilm matrix production, source of carbohydrate exposure, and cross-kingdom interactions, have encouraged increased microbial accumulation on dental implants, leading to a microbiological community shift from a healthy to a pathogenic state, increasing inflammation and favoring tissue damage. These factors combined with the spatial organization of biofilms, reduced antimicrobial susceptibility, complex microbiological composition, and the irregular topography of implants hamper biofilm control and microbial killing. In spite of the well-known etiology, there is still no consensus regarding the best clinical protocol to control microbial accumulation on dental implant surfaces and treat peri-implant disease. In this sense, different coatings and Ti surface treatments have been proposed in order to reduce microbial loads and control polymicrobial infections on implantable devices. Therefore, this critical review aims to discuss the current evidence on biofilm accumulation on dental implants and central factors related to the pathogenesis process of implant-related infections. Moreover, the potential surface modifications with anti-biofilm properties for dental implant devices is discussed to shed light on further promising strategies to control peri-implantitis.

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 Additive manufacturing (AM) is an emerging process for biomaterials and medical devices. Direct Laser Metal Sintering (DLMS) is an AM technique used to fabricate Ti–6Al–4V implant materials with enhanced surface-related properties compared with wrought samples; thus, this technique could influence microbial adsorption and colonization. Therefore, this in vitro study was conducted to evaluate the impact of different implant production processes on microbial adhesion of periodontal pathogens. Titanium discs produced using two different processes—conventional and AM—were divided into three groups: conventional titanium discs with machined surface (G1), AM titanium discs with chemical treatment (G2) and AM titanium discs without chemical treatment (G3). Subgingival biofilm composed of 32 species was formed on the titanium discs, and positioned vertically in 96-well plates, for 7 days. The proportions of microbial complexes and the microbial profiles were analyzed using a DNA–DNA hybridization technique, and data were evaluated using Kruskal–Wallis and Dunnett tests (p < 0.05). Lower proportions of the red complex species were observed in the biofilm formed in G2 compared with that in G1 (p < 0.05). Moreover, the proportions of the microbial complexes were similar between G2 and G3 (p > 0.05). Compared with G1, G2 showed reduced levels of Porphyromonas gingvalis , Actinomyces gerencseriae, and Streptococcus intermedius , and increased levels of Parvimonas micra , Actinomyces odontolyticus, and Eikenella corrodens (p < 0.05). The microbial profile of G3 did not differ from G1 and G2 (p > 0.05). The results of this in vitro study showed that titanium discs produced via AM could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm these findings.

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 objective of this paper was to evaluate the current evidence reporting on the prevalence of peri-implantitis and to determine the influencing factors. An electronic search for articles published until February 2019 reporting on the prevalence of peri-implantitis was performed in MEDLINE. Included criteria were published in international peer-reviewed journals, written in English language, reported on the prevalence of peri-implantitis, included implants with a minimum follow-up of one year after functional loading and used a clear definition for peri-implantitis and/or peri-implant mucositis with a clear cutoff for bone level changes according to the case definitions of Sanz and Chapple and Berglundh et al. 2018. Included papers were anaylized for factors affecting the reported prevalences for peri-implantitis. Twenty-five papers were included in the present review and a wide range for the reported prevalence of peri-implantitis was seen. Case definitions for peri-implantitis with various thresholds for bone loss together with the type of reporting on patient- or implant-level were the most significant factors that lead to a large variety of the occurrence of the disease. Additionally, follow-up time and the evaluation in a certain “convenience” population may have influenced the prevalence values. In conclusion, it can be stated that a wide range for reporting the prevalence of peri-implantitis can be found and no real estimation of the global burden of the disease can be made. Applying accurate case definitions for peri-implantitis is the most important factor for reporting the prevalence and should be strictly followed in future reports.

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.