Excess Cement Research Articles

Local risk indicators – Consensus report of working group 2

In implant dentistry, plaque control and oral hygiene practices are essential to limit the risk of complication and failure in the long term. All conditions around an implant in function that influence the load and pathogenicity of the microbiota are considered local risk indicators. They concern the prosthetic suprastructure design and the possibility for the patient to easily access each implant for plaque removal. Use of cemented prostheses should be limited to avoid excess cement acting as a foreign body and leading to peri-implant disease. The crown margins should be supramucosal, and the connection should be precise to avoid a gap between the implant and the suprastructure. Every implant system is characterised by a specific design, surface texture and connection type. These features may influence peri-implantitis development and progression, and the clinician should consider the risk of infection when selecting an implant. The soft-tissue conditions around the implant, the width of keratinised mucosa, and the phenotype and thickness of the mucosa are also considered major risk indicators, as the presence of any mucosal defect around an implant can increase plaque accumulation and result in tissue inflammation. The pathogenicity of the microbiota around an implant is primarily dependent on pocket depth. Deep pockets around implants should be avoided and, if present, closely monitored and/or reduced. Proximity to natural teeth presenting endodontic and/or periodontal lesions may result in implant contamination, but the influence of the type of edentulism on perio-pathogen presence is still unclear. These local conditions around an implant have a clear influence on peri-implant diseases development and progression, but there is still only limited evidence regarding their role as true risk indicators.

Concepts for prevention of complications in implant therapy.

The use of dental implants is nowadays a well-accepted and highly predictable treatment modality for restoring the dentition and reestablishing the masticatory function of edentulous and partially edentulous patients. Despite the high predictability and excellent long-term survival rates reported for implant therapy, complications may still occur and can jeopardize both short- and long-term success. The present paper provides an overview on the most important aspects related to the etiology, prevention, and management of complications associated with implant therapy. Data from the literature indicate that a number of factors, such as surgical trauma, implant diameter, type of implant-abutment connection, abutment disconnection and reconnection, presence of microgap, and implant malpositioning, can substantially influence the biologic processes of bone remodeling and biofilm formation, thus increasing the rate of short- and long-term hard- and soft-tissue complications. Other factors, such as excess cement at cement-retained prosthetic restorations, abutment mobility, and infections (e.g. peri-implant mucositis and peri-implantitis) caused by bacterial biofilm, are further causes for complications and failures. More recent evidence also indicates that besides the need for sufficient bone volume surrounding the implant, the presence of an adequate width and thickness of attached mucosa may improve biofilm control and limit crestal bone resorption. Furthermore, emerging evidence points also to the pivotal role of human factors as one of the most important causes of complications in implant dentistry. It can be concluded that clinicians need to consider all biologic and biomechanical factors affecting implant placement and survival, as well as undergo adequate training to improve their surgical skills to control and prevent implant complications. Careful patient selection and control of environmental and systemic factors, such as smoking, diabetes etc., coupled with an accurate surgical and prosthetic planning, enable a better prevention and control of infections.

Effects of precementation on minimizing residual cement around the marginal area of dental implants

Statement of problemResidual cement is detrimental to the long-term success of dental implants with a cement-retained restoration. The complete elimination of excess cement remains a challenge. PurposeThe purpose of this in vitro study was to evaluate the effects of precementation technique on minimizing the residual cement and retention of restorations. Material and methodsFour custom cobalt-chromium alloy (Co-Cr) abutments were manufactured by computer-aided design and computer-aided manufacturing (CAD-CAM) as precementation abutments with height and radius reductions of 25 μm (A25), 50 μm (A50), 75 μm (A75), and 100 μm (A100). Fifty CAD-CAM–fabricated standard Co-Cr abutments and corresponding crowns were randomly matched and treated as follows: 10 specimens were cemented with the conventional cementation procedure with glass ionomer cement (G0), and 40 were precemented with precementation abutments (n=10) before the definitive cementation with standard abutments (G25, G50, G75, G100). The weight of the cement in the cement space was calculated, and the marginal sealing was evaluated by using a stereoscopic microscope. The effects of precementation with resin cement on minimizing residual cement around the marginal area of dental implants were further evaluated extraorally. The influence of precementation with glass ionomer and resin cement on the retention force was analyzed by using a universal testing machine at a crosshead speed of 0.5 mm/min. One-way ANOVA was used to analyze cement mass and marginal sealing values. Two-way ANOVA was used to compare the retention forces (α=.05). ResultsThe cement weight of G50 (7.2 ±0.6 mg) was significantly higher than that of G25 (6.0 ±1.1 mg, P<.05), while no significant differences in cement weights were found among G50, G75, and G100. Consistently, the G50, G75, and G100 had higher marginal sealing values than that of the G25 (P<.01). Extraoral experiments showed that the precementation with A50 reduced subgingival residual cement without affecting retention. ConclusionsThese in vitro results suggest that precementation with a precisely manufactured precementation abutment minimized the residual cement around implant abutments, and 50 μm could be a preferable precementation space.

RETAINED EXCESS RESIN CEMENT AROUND TISSUE LEVEL IMPLANTS USING TWO DIFFERENT CEMENTATION TECHNIQUES (AN IN VITRO STUDY)

INTRODUCTION: The main disadvantage of a resin cement-retained implant fixed prosthesis is the entrapment of residual excess cement in the peri-implant tissues. Remaining cement has been shown to be associated with peri-implant inflammation and bleeding. OBJECTIVES: The aim of this study was to detect the retained excess resin cement around tissue level dental implants, and to determine which method of cementation will show less amount of retained excess cement. MATERIALS AND METHODS: Fourteen tissue level implants (OCO Biomedical, Inc. Albuquerque, U.S.A.) were embedded in drilling models (Salvin Dental Specialties, Inc. Charlotte, U.S.A.) having rubber surface covering simulating the gingiva. Fourteen metal copings were fabricated (Realloy e.k, Sliemsdyk 50, Krefeld, Germany). RelyX U200 (TM3M, ESPE Dental Products. St. Paul, U.S.A.) dual cure resin cement was used for cementation of the metal copings to the implants. The implants were divided into two main groups according to cementation technique (n=7): Group (A): non vented tack curing of the excess cement for three seconds then the excess resin cement was carefully removed. Group (B): occlusal vent was performed on the occlusal surface of the metal copings to allow excess cement to be extruded through the vent hole; then all the excess cement from the vent and margins was removed. The rubber coverage was removed and the retained cement was collected and the net weight of the retained cement was determined. RESULTS: Mann-Whitney U test revealed a statistically significant differences (p < 0.05) between the non-vented tack cure and the occlusal vent groups in the amount of retained excess cement, with the occlusal vent group (B) had more excess cement percentage than the non vented tack cure group (A). CONCLUSIONS: Tack curing of the excess resin cement during the cementation of implant-supported restorations might reduce the cement residue, but still couldn’t remove the problem of excess resin cement around dental implants.

Fabricating a screw-retained, complete arch, fixed implant prosthesis using selective metal laser sintering: A clinical report

In contemporary prosthodontic practice, implant-supported therapy has consistently resulted in high success rates, with satisfactory and predictable outcomes for completely edentulous patients. Of the several options, complete-arch, fixed screw-retained solutions are generally considered to be the preferred treatment solution. Screw retention offers advantages such as predictable retrievability and potentially easy prosthodontic maintenance, as well as excess cement not being a concern. However, implant mispositioning and malalignment may often necessitate the use of cement-retained prostheses. This clinical report describes a method of fabricating a complete-arch, implant screw-retained, double framework metal-ceramic prosthesis, despite the unfavorable implant positioning, by using selective direct metal laser sintering technology.

Effect of temporary cement removal methods from human dentin on zirconia-dentin adhesion

This study evaluated the effect of temporary cement residue removal methods from human coronary dentin on the bond strength of adhesively-luted zirconia on dentin. Forty non-carious human molars were embedded in acrylic resin and the dentin surfaces were exposed. Temporary acrylic crowns were provisionally cemented with zinc oxide cement without eugenol and stored in distilled water (37 °C/15 days). After crown removal, the excess temporary cement was removed from dentin according to one of the following cleaning methods: (n = 8 per group): (a) air-water rinse (AW), (b) pumice paste (PP), (c) air-abrasion with aluminum oxide particles (Al2O3) (AA), (d) sodium bicarbonate spray (SB) or (e) glycine powder (CP). Forty zirconia cylinders were made and each cylinder was adhesively luted onto each tooth after adhesive resin (Scotch Bond Universal, 3 M ESPE-SBU) application using resin cement (RelyX Ultimate, 3 M ESPE) and photo-polymerized from each surface for 20 s. The bonded specimens were stored in distilled water (37 °C) for 90 days. The bonded interface was loaded under shear (1 mm/min). Data (MPa) were analyzed using 1-way ANOVA and Tukey's test (α = 0.05). Mean bond strength was significantly affected by the cleaning method (p = 0.0289). Cleaning with AA method resulted in significantly higher bond strength than with SB (p < 0.05) but similar to CP, PP and AW (p > 0.05). All cleaning methods were effective in removing temporary resin cement from dentin surfaces. Air-abrasion with aluminum oxide particles was more effective than with sodium bicarbonate spray promoting adhesion between zirconia and dentin.

Influence of margin location and luting material on the amount of undetected cement excess on CAD/CAM implant abutments and cement-retained zirconia crowns: an in-vitro study

BackgroundThe flexibility in designing the submucosal part of CAD/CAM customized implant abutments and the individual positioning of its shoulder line has been suggested to reduce the risk of leaving undetected cement residues, thus preventing adverse effects on peri-implant tissues. A high correlation between excess cement left in the soft tissues and the occurrence of increased biofilm accumulation with sulcular bleeding and/ or suppuration has been reported. This in turn may cause peri-implant inflammation and peri-implant marginal bone loss. The aim of this study was to assess the frequency of cement remnants after the luting of zirconia crowns on CAD/CAM custom molar abutments with different margin levels and to evaluate the impact of the luting material.Material and methodsA total of 20 titanium molar CAD/CAM implant abutments (BEGO Medical GmbH) with internal taper connection/ internal hex anti-rotation protection, and a convex emergence profile with different margin positions (0, 1, 2 and 3 mm below the mucosa), were virtually designed (Implant Studio, 3Shape) and manufactured. A master cast was scanned, duplicated by a 3D printer and individual gingival masks were produced to simulate peri-implant soft tissues. 20 corresponding zirconia crowns were designed (Cerec 3D, Dentsply Sirona), produced and cemented to the abutments with two different luting materials; a zinc oxide non-eugenol cement (Temp Bond NE) or a methacrylate cement (Panavia V5). To ensure retrievability of the crown/abutment connection, occlusal openings providing access to the abutment screws were designed. Excess cement was thoroughly removed and the crown/abutment units were unscrewed to evaluate the occurrence of cement residues. All the quadrants of each specimen were evaluated for calculation of the ratio between the cement remnant area and the total specimen area using Adobe Photoshop. Spearman analysis was performed to detect correlations between different variables. A two-sided t-test, ANOVA, Mann–Whitney, and Kruskal–Wallis tests were applied to detect differences between the groups.ResultsCement remnants were found in every depth of the crown abutment complex and in almost every area investigated. The amount of cement residues increased as the crown-abutment margin was located more submucosally. Lingual areas were more prone to cement remnants than other surface areas (p = 0.0291). Excess cement was not only found at the margins of the crown-abutment complex, but also underneath (basal) the abutment itself, where cleaning was impossible. No statistical difference in the effect of zinc oxide non-eugenol- and methacrylate cement on the frequency of excess material at the lateral abutment surfaces could be demonstrated in vitro. The proportion of basal abutment aspects covered with cement residues was, however, significantly smaller in Panavia V5 samples with an average of 4.9 ± 3.7% compared to Temp Bond samples with an average of 8.6 ± 5.5%.ConclusionsGiven the results obtained in the present investigation the margin of CAD/CAM molar abutments should be located as coronally as possible to minimize the amount of cement remnants. If an epigingival or supragingival margin location is not feasible due to esthetic concerns, it cannot be recommended to place the margin of molar CAD/CAM abutments deeper than 1.5 mm in the proximal and oral regions.

A Simplified Technique to Control Excess Cement Material Underneath Cement-Retained Implant Restorations: Technical Note.

Subgingival presence of remaining excess cement may lead to implant complications and failures. This is a technical report and advice on how to cement implant-supported restorations using a simple and universal method applying liquid petroleum jelly to the peri-implant sulcus after cementation. This simple and user-friendly method eliminates excess cement and should be used in the daily practice.

Peri-implantitis risk factors: A prospective evaluation.

The aim of the present study was to create a tool to evaluate the risk of peri-implantitis according its severity. After ethics committee approval, 43 patients provided signed consent and were included prospectively. Forty-five observations were recorded. The following criteria were recorded: number of implant faces showing bleeding and/or suppuration, pocket depth on at least two faces of the implant, bone loss as a function of the length of the implant evaluated on X-rays, number of implant faces with bacterial plaque, the parameters required for determination of excess cement (screwed or sealed prosthesis, burying of sealed prostheses), periodontal status, glycemia, and annual consumption of tobacco. Each of these parameters was plotted on a chart using Microsoft Excel. Seventeen of 45 (37.8%) cases were identified as having high peri-implantitis risk, two of 45 (4.4%) had low risk, and 11 of 45 (24.4%) had moderate risk; 33.3% patients did not have peri-implantitis and were considered at very low risk. The observed results applied to the evaluation model are an effective diagnostic tool in assessing the risk of peri-implantitis. The tool takes into account parameters, which have not been taken into account until now. The information is automatically processed and allows early management of peri-implantitis.

Mechanical properties of silica fume concrete designed as per construction practice

The effect of silica fume (SF) on the compressive, flexural and tensile splitting strengths of hardened concrete is studied. Seven concrete mixes are prepared using Portland slag cement (PSC) partially replaced with SF ranging from 0 to 30%. The mix proportions were obtained as per the construction practice at the site with 10% excess cement when SF is used. The optimum doses of SF for the maximal values of compressive, tensile splitting and flexural strengths at 28 d are determined. The results of this study are compared with similar results associated with the Portland cement available in the literature. A correlation, in the form of simplified equations, between the compressive, tensile splitting and flexural strengths of SF concrete and PSC is obtained. Ultrasonic pulse velocity (UPV) tests are carried out on all concrete specimens at 28 d before conducting the compression test. A relationship between UPV values and compressive strengths is proposed for SF concrete with PSC based on the experimental data.

Peri-implant Mucosal Tissues and Inflammation: Clinical Implications.

The purpose of this review was to explore the available literature and compile studies that discuss the relevance of the biofilm, onset and progression of disease, critical peri-implant pocket depth, frequency of supportive implant therapy, excess cement, and keratinized peri-implant tissues as related to peri-implant disease. PubMed, Cochrane Oral Health Group Specialized Trial Register, and hand searches of related journals were performed in relationship to the focused question. Reports describing techniques, preclinical studies, and case reports were excluded. Due to the absence of controlled studies, a meta-analysis could not be performed. Summaries of relevant publications were completed for each topic area. Clinical recommendations were developed to provide guidance to the practitioner. The importance of proper diagnosis, planning, and clinical treatment cannot be overstated. Patient factors including systemic disease, periodontal status, and oral hygiene significantly impact peri-implant health. Clinician factors such as implant position, excess cement, and restorative design can contribute to development of peri-implant disease. Surveillance of implant status is essential and can be assisted by the assessment of risk factors, establishment of a proper recall program, and monitoring changes in bone and peri-implant pocket depths.

Effect of Vented and Closed Abutments on Peri-Implant Soft and Hard Tissues - Clinical and Radiographic Assessment

Excess cement found on tooth-retained restorations with healthy periodontal tissues present few if any problems. The cement-retained implant restoration may be more vulnerable to the effects of cement entering the soft tissues and residual excess cement on the implant restoration when compared to a tooth. It has been hypothesized that an open/hollow abutment may provide an internal reservoir for cement.Materials and methods: The patients included in the study were divided into two groups according to the abutment design that was used after implant placement; closed abutment group (CA) where 7 crowns were cemented on closed abutments vented abutment group (VA) where 7 crowns were cemented on vented abutments. |Re-examination was scheduled 3, 6 and 12 months after crown cementation. Periodontal assessment included Bleeding Index (BI) and Probing depth (PD). Bone height measurements were performed using cone beam computed tomography to measure the marginal bone loss.Results: Considering different intervals of the follow-up period, the differences in BI and PD between tested groups (vented and closed abutments) were statistically non-significant (p>0.05), but there was a statistically significant increase in PD for comparison between PD at different time periods in each group after 6 months as well as from 6 months to 12 months. After 3, 6 as well as 12 months, Group CA showed statistically significantly higher mean amounts of bone loss than Group VA.Conclusions: (1) Vented abutments exhibit better soft tissue response and less marginal bone loss when compared to closed abutments through one year follow up. (2) Soft tissue response and marginal bone loss associated with both abutment designs were within the normal health limits after one year follow up period of the study.

Effect of a preseating cementation protocol on the retention of implant restorations using a definitive cement

Purpose: This investigation analyzed the effects of a preseating cementation protocol on the amount of cement excess at the crown margin and its associated tensile load using a glass ionomer definitive cement. Materials and Methods: The independent variable in this study was the cementation technique. The first protocol involved a conventional cementation procedure and the second one preseating on an abutment replica. Ten metallic copings were cemented using a definitive cement on ten implant abutments for each cementation protocol. Cement excess at the margin was weighted (mg), and axial tensile load was measured 24 h after cementation. Results were statistically analyzed using linear regression and one-way analysis of variance (α = 0.05). Results: The cementation protocol with preseating resulted in a significantly smaller amount of cement excess at the crown margin (P ≤ 0.001) without detriment on the tensile resistance when compared to the experimental group without preseating (P = 0.41). Linear regression failed to prove any correlation between the amount of cement excess and tensile load necessary for dislodgement. Conclusions: A preseating protocol can be performed when using a definitive cement. This procedure reduces significantly the amount of cement excess at the margin while maintaining an acceptable tensile load resistance.

Detection of Residual Excess Zinc Oxide-Based Cement With Laser Fluorescence (DIAGNOdent): In Vitro Evaluation.

Because of its importance in the development of peri-implant mucositis and peri-implantitis, detection of residual excess cement (REC) is often the focus of studies addressing cement-retained implant-supported restorations. The purpose of this study was to evaluate the sensitivity and specificity of laser fluorescence (DIAGNOdent) for detecting residual excess zinc oxidebased cement around dental implants. In this in vitro study, 15 tissue-level implants were embedded in acrylic resin. To simulate gingiva around the implants, the transgingival part of each implant was covered with a gingival mask silicon material. Cement (Tempobond; 1 × 1 × 1 mm) was applied to 30 areas, 4 mm below the gingival-mimicking line using a custom-made template. A DIAGNOdent laser device was used by 2 independent examiners to evaluate the presence or absence of cement in a selected area. The examiners were allowed to probe the gingival sulcus (2-mm depth) 2 times with a 5-minute interval between tests. The residual cement was recognized by gently walking the device tip around the implant. A detection score less than 16 indicated an absence of cement, and scores of 16 or greater indicated the presence of excess luting agent in the implant sulcus. The sensitivity and specificity of DIAGNOdent to detect REC in the sulcus were 100% and 96.67%, respectively. Based on our findings, we propose that DIAGNOdent could be used to detect REC in the sulcus of cement-retained implant supported restorations.

Comparison of the effects of cement removal from zirconia and titanium abutments: An in vitro study

Statement of problemExcess cement around dental implants is a significant cause of peri-implant inflammation. Research has focused on approaches to cement removal, the type of cement used, and the different instruments used for cement removal with titanium abutments. However, data comparing zirconia with titanium abutments are lacking. PurposeThe purpose of this in vitro study was to compare the effectiveness of excess cement removal from zirconia and titanium custom abutments using an explorer and to compare the effects of cement removal on the abutment surfaces. Material and methodsImplant analogs were placed in a cast in the position of the 2 maxillary central incisors. After creating similar emergence profiles for both the implant abutments, 18 zirconia and titanium custom abutments were fabricated with 1-mm subgingival finish lines on the facial and interproximal areas and an equigingival finish line on the palatal side. The crowns were cemented with zinc oxide-eugenol cement, and a steel explorer was used to remove the excess cement. All abutments were analyzed under a scanning electron microscope for cement remnants and scratches. ResultsThe mean surface area of cement remnants on the zirconia abutments was 778 ±113 μm2, and for titanium abutments, it was 1123 ±252 μm2, which in terms of the mean percentage area was 3.27% of the total surface area of zirconia and 4.71% of titanium abutments. Only a few abutments from each group showed scratches, and no deep scratches or gouges were observed. ConclusionsZirconia and titanium abutments had statistically similar cement remnants. Scratches were observed on only a few specimens.

Influence of margin location and luting material on the amount of undetected cement excess on CAD CAM implant abutments and cement‐retained zirconia crowns

Background As cement remnants of fixed implant-supported restorations have been associated with clinical and radiographic signs of peri-implantitis, there is a need for reducing the probability of leaving subgingival cement excess. High flexibility in designing the subgingival part of CAD CAM abutments and the individual positioning of the shoulder finish line may eliminate the problem of undetected cement residues. However, so far there is only little data available to support this hypothesis. Aim/Hypothesis To test whether or not an epimucosal position of an abutment margin with temporary zinc oxide non-eugenol cement or methacrylate cement is superior to a submucosal margin position in terms of remaining cement following cementation of reconstructions on customized CAD CAM molar abutments. Material and Methods A total of 20 titanium CAD CAM abutments (Semados, BEGO, Bremen, Germany) with a convex emergence profile and different margin positions (from 0 to 1, 2, and 3 mm below the mucosa) were virtually designed and centrally manufactured. The master cast was scanned, duplicated by a 3D printer, and individual gingival masks were produced to simulate peri-implant soft tissues. 20 zirconia crowns (Zirlux, Henry Schein, Germany) were produced and cemented to the abutments with two different luting materials (Temp Bond NE, Kerr Dental, Germany, Panavia V5, Kuraray, Japan). To ensure retrievability of the crown abutment connection, occlusal openings providing access to the abutment screws were designed. Cement excess was thoroughly removed and the crown abutment units were unscrewed to evaluate the occurrence of cement residues. All quadrants of each specimen were evaluated for calculation of the ratio between the cement remnant area and the total specimen area using Adobe Photoshop (p 0.05). Results Cement remnants were found in every depth of the crown abutment complex and in almost every area investigated. The amount of cement residues was influenced by the location of the crown-abutment margin. A significant increase in remnants was detected when the crown-abutment margin was located more submucosally. Deep crown–abutment margin positions (deeper than 1 mm below mucosa) increased the risk of cement excess. Oral and interdental areas are more prone to cement remnants than other surface areas. The investigation showed, that cement remnants were not only found at the margins of the crown-abutment complex, but also underneath (basal) of the abutment itself, where literally no cleaning was possible at all. No statistical difference in the effect of a temporary zinc oxide non-eugenol cement (Temp Bond NE, Kerr Dental) and a methacrylate cement (Panavia V5, Kuraray, Japan) on the frequency of excess cement could be demonstrated. Conclusions and Clinical Implications Given the results obtained in the present investigation the margin of CAD CAM molar abutments should be located as coronally as possible to minimize the amount of cement remnants. Due to esthetic reasons this ideal margin location is frequently not feasible. However, it cannot be recommended to place the margin of molar abutments deeper than 1.5 mm in the interdental and oral regions. There was no evidence that the type of cement had an influence on the amount of remnants after cleaning.

Prevention is Better Than Cure: A Key to Halt Peri-Implantitis

To evaluate and compare the effect of VENT holes in crown at two different places on extrusion of excess cement at crownabutment interface and associated tensile force in cement retained implant restorations- An In-Vitro Study.

Fatigue Behavior of Different CAD/CAM Materials for Monolithic, Implant-Supported Molar Crowns.

To evaluate the fracture resistance after the thermal and mechanical fatigue of feldspathic, lithium disilicate, and resin-modified CAD/CAM monolithic crowns cemented onto a universal post abutment. A right second mandibular molar was designed in CAD/CAM software, and 30 crowns were machined using three different materials (n=10): feldspathic ceramic, finished only with a glaze cycle (G1); lithium disilicate, sintered and finished with a glaze cycle (G2); and resin, modified by nanoceramic and finished with rubber (G3). All crowns were cemented under a constant 50N load, the excess cement was removed, and the crowns were light-cured for 30 seconds. After being immersed in deionized water for 7 days, the crowns were submitted to thermal cycling, which consisted of varying the temperature from 2 to 50°C for 350,000 cycles, and mechanical cycling in a fatigue simulator, where a 250N load was applied for 1,000,000 cycles at 2 Hz. The resistance of each crown was verified in a compression-to-failure test at 1mm/min in a universal test machine. The groups were compared using one-way ANOVA with a Bonferroni post hoc test and Weibull statistics. The resin-modified group was the least resistant group (1755±124N), followed by the feldspathic (2147±412N) and lithium disilicate groups (2804±303N). The Weibull statistics demonstrated that lithium disilicate is the most reliable material and has the lowest fracture probability. It was possible to conclude that all of the tested CAD/CAM materials can be used as monolithic, implant-supported molar crowns.

Peri-implant mucositis.

This narrative review was prepared for the 2017 World Workshop of the American Academy of Periodontology and European Federation of Periodontology to address key questions related to the clinical condition of peri-implant mucositis, including: 1) the definition of peri-implant mucositis, 2) conversion of peri-implant health to the biofilm-induced peri-implant mucositis lesion, 3) reversibility of peri-implant mucositis, 4) the long-standing peri-implant mucositis lesion, 5) similarities and differences between peri-implant mucositis at implants and gingivitis at teeth, and 6) risk indicators/factors for peri-implant mucositis. A literature search of MEDLINE (PubMed) and The Cochrane Library up to and including July 31, 2016, was carried out using the search strategy (peri-implant[All Fields] AND ("mucositis"[MeSH Terms] OR "mucositis"[All Fields])) OR (periimplant[All Fields] AND mucosits[All Fields]). Prospective, retrospective, and cross-sectional studies and review papers that focused on risk factors/indicators for peri-implant mucositis as well as experimental peri-implant mucositis studies in animals and humans were included. Peri-implant mucositis is an inflammatory lesion of the soft tissues surrounding an endosseous implant in the absence of loss of supporting bone or continuing marginal bone loss. A cause-and-effect relationship between experimental accumulation of bacterial biofilms around titanium dental implants and the development of an inflammatory response has been demonstrated. The experimental peri-implant mucositis lesion is characterized by an inflammatory cell infiltrate present within the connective tissue lateral to the barrier epithelium. In long-standing peri-implant mucositis, the inflammatory cell infiltrate is larger in size than in the early (3-week) experimental peri-implant mucositis lesion. Biofilm-induced peri-implant mucositis is reversible at the host biomarker level once biofilm control is reinstituted. Reversal of the clinical signs of inflammation may take longer than 3weeks. Factors identified as risk indicators for peri-implant mucositis include biofilm accumulation, smoking, and radiation. Further evidence is required for potential risk factors, including diabetes, lack of keratinized mucosa, and presence of excess luting cement. Peri-implant mucositis is caused by biofilm accumulation which disrupts the host-microbe homeostasis at the implant-mucosa interface, resulting in an inflammatory lesion. Peri-implant mucositis is a reversible condition at the host biomarker level. Therefore, the clinical implication is that optimal biofilm removal is a prerequisite for the prevention and management of peri-implant mucositis. An understanding of peri-implant mucositis is important because it is considered a precursor for peri-implantitis.

Peri-implant mucositis.

This narrative review was prepared for the 2017 World Workshop of the American Academy of Periodontology and European Federation of Periodontology to address key questions related to the clinical condition of peri-implant mucositis, including: 1) the definition of peri-implant mucositis, 2) conversion of peri-implant health to the biofilm-induced peri-implant mucositis lesion, 3) reversibility of peri-implant mucositis, 4) the long-standing peri-implant mucositis lesion, 5) similarities and differences between peri-implant mucositis at implants and gingivitis at teeth, and 6) risk indicators/factors for peri-implant mucositis. A literature search of MEDLINE (PubMed) and The Cochrane Library up to and including July 31, 2016, was carried out using the search strategy (peri-implant[All Fields] AND ("mucositis"[MeSH Terms] OR "mucositis"[All Fields])) OR (periimplant[All Fields] AND mucosits[All Fields]). Prospective, retrospective, and cross-sectional studies and review papers that focused on risk factors/indicators for peri-implant mucositis as well as experimental peri-implant mucositis studies in animals and humans were included. Peri-implant mucositis is an inflammatory lesion of the soft tissues surrounding an endosseous implant in the absence of loss of supporting bone or continuing marginal bone loss. A cause-and-effect relationship between experimental accumulation of bacterial biofilms around titanium dental implants and the development of an inflammatory response has been demonstrated. The experimental peri-implant mucositis lesion is characterized by an inflammatory cell infiltrate present within the connective tissue lateral to the barrier epithelium. In long-standing peri-implant mucositis, the inflammatory cell infiltrate is larger in size than in the early (3-week) experimental peri-implant mucositis lesion. Biofilm-induced peri-implant mucositis is reversible at the host biomarker level once biofilm control is reinstituted. Reversal of the clinical signs of inflammation may take longer than 3weeks. Factors identified as risk indicators for peri-implant mucositis include biofilm accumulation, smoking, and radiation. Further evidence is required for potential risk factors, including diabetes, lack of keratinized mucosa, and presence of excess luting cement. Peri-implant mucositis is caused by biofilm accumulation which disrupts the host-microbe homeostasis at the implant-mucosa interface, resulting in an inflammatory lesion. Peri-implant mucositis is a reversible condition at the host biomarker level. Therefore, the clinical implication is that optimal biofilm removal is a prerequisite for the prevention and management of peri-implant mucositis. An understanding of peri-implant mucositis is important because it is considered a precursor for peri-implantitis.