Peri-implant microflora of implants with cemented and screw retained suprastructures

Clinical Evaluation of Pink Esthetic Score of Immediately Impressed Posterior Dental Implants

PURPOSE

While comparative outcome results for peri-implant crestal bone levels, mucosal margin position, and peri-implant indices have been reported, no studies are available that evaluate and compare the esthetic result of impressions performed immediately with that of impressions performed of healed implants. The purpose of this cross-sectional study was to evaluate the Pink Esthetic Score (PES) of posterior implants restored with an immediate impression workflow compared to implants restored with a delayed impression workflow.

MATERIAL AND METHODS

Twenty-eight eligible participants who had received a single implant crown either in the premolar or molar regions at least 4 months before the study, were identified by an electronic health record review and scheduled for a single-visit study appointment. Esthetic outcomes were measured using the Pink Esthetic Score (PES). Several local- and prosthesis-related factors were recorded and their association with the selected outcome was assessed. Two-sample t-test was used for comparisons between the groups.

RESULTS

PES ranged between 4 and 12 (mean: 8). No significant difference between immediate (8.36 ± 1.12) and delayed (7.76 ± 2.14) impression workflow groups were seen for the total PES (p = 0.25). In addition, individual comparisons between immediately and delayed impressed implants for mesial papilla (1.27 ± 0.47; 0.88 ± 0.78), distal papilla (0.73 ± 0.65; 0.76 ± 0.83), tissue margin (1.73 ± 0.47; 1.47 ± 0.51), tissue contour (1.27 ± 0.65; 0.82 ± 0.64), alveolar process (0.82 ± 0.60; 1.00 ± 0.87), color (1.27 ± 0.65; 1.29 ± 0.69), and texture (1.36 ± 0.50; 1.53 ± 0.62) did not show significant differences.

CONCLUSIONS

The current study suggests that the Pink Esthetic Score is not significantly different between single posterior implants impressed with the immediate and delayed implant workflows. This article is protected by copyright. All rights reserved.

The Efficacy of a Diode Laser on Titanium Implants for the Reduction of Microorganisms That Cause Periimplantitis

The paper presents the optimisation of a safe diode laser irradiation process applied to the surface of titanium implants in order to reduce microbial numbers in the treatment of inflammation classified as periimplantitis. The study comprised isolation and identification of microorganisms inhabiting surfaces of dental implants, crowns, teeth and saliva from patients with fully symptomatic periimplantitis. Microorganisms were detected by a culture-dependent method and identified with the use of MALDI-TOF mass spectrometry. The isolated microorganisms were inoculated on the surface of a new implant and then irradiated by a diode laser (wavelength of 810 ± 10 nm) in one, two or three repetitions and biocidal efficacy was assessed. To evaluate impact of laser irradiation on roughness, morphology and structure of the implant surface, optical profilometry, scanning electron microscopy and optical microscopy were used. Examination of the tested surfaces and saliva revealed the presence of Gram-positive and Gram-negative bacteria and one fungal species. In all patients, cultures from the endosseous part of the implant revealed the presence of the pathogenic and pyogenic bacterium Streptococcus constellatus. In 13 out of 20 samples laser-irradiated in duplicate and triplicate, all microorganisms were eliminated. The irradiation used did not cause any changes in the properties of the implant surface.

Comparative evaluation of microleakage of metallic copings luted with three different commercially available luting cements: An in vitro study

Aim

To evaluate the microleakage of metallic copings luted with three different commercially available luting cements.

Setting and Design

Comparative evaluation in vitro study.

Materials and Methods

Thirty replicas of abutment analog were milled and divided into 3 groups. Nickel chromium copings were fabricated; marginal gap was evaluated with optical microscope and luted with Zinc Oxide Non Eugenol cement, Zinc Polycarboxylate cement and Zinc Phosphate cement. After Thermocycling, cemented specimens were placed into 0.5% aqueous solution of basic fuchsin solution for 24 hours for dye penetration. Copings were longitudinally sectioned and microleakage scores were evaluated.

Statistical Analysis Used

Kruskal-Wallis analysis of variance (ANOVA) followed by Chi-Square test. Pairwise comparison of groups with Mann Whitney U test.

Result

Mean microleakage score was least for Zinc Phosphate cement (1.075 ± 0.85) followed by Zinc Polycarboxylate cement (1.80± 0.23) and most for Zinc Oxide Non Eugenol (2.1± 0.37). The results of the study were statistically significant, P < 0.05.

Conclusions

Within the limitations of the study, it was found that all cements exhibited certain amount of microleakage. Zinc Phosphate cement exhibited a mean microleakage score that was significantly lower than Zinc Oxide Non Eugenol cement and Zinc Polycarboxylate cement. When microleakage scores of Zinc Oxide Non Eugenol cement and Zinc Polycarboxylate cement were compared, the difference was found to be insignificant indicating that microleakage in these cements is similar.

Full-Mouth Screw-Retained Implant-Supported Rehabilitation with Multiunit Abutments Using Virtual Guided Surgery and Digital Prosthetics Protocol

Total rehabilitation is one of the most sophisticated kinds of dental implant-supported prosthetics. The usage of multiunit abutment system allows the clinician an accurate and passive fitting of screw-retained full-arch construction. In addition, it retains a condition of soft and bone tissues around prosthetic construction. The aim of this case is to demonstrate a modern approach in planning and realisation of full-mouth screw-retained dental implant prosthetics. A 59-year-old patient had an extraction of all failed teeth on upper and lower jaws with immediate 16 implant placement (8 implants on maxilla and 8 implants on mandible) using surgical template. Multiunit abutments were installed intraoperatively. Temporary constructions were fixed immediately after surgery. After 3 months of dental impressions, plaster models and their scan were prepared to make final screw-retained zirconium dioxide constructions. Reevaluation of functional and aesthetic result of the treatment was made after 12 months.

The biological width around implant

PURPOSE

The concept of biological width has been proposed and widely used in oral implantation. This review aimed to summarize the biological width around implant in detail.

STUDY SELECTION

An electronic search of the literature prior to March 2019 was performed to identify all articles related to biological width in periimplant soft tissue. The search was conducted in the MEDLINE (National Library of Medicine) database accessed through PubMed with no date restriction. The following main keywords were used: "implant", "biological width", "soft tissue", "junctional epithelium", "peri-implant epithelium", "connective tissue", "gingiva", "mucosa" (connecting multiple keywords with AND, OR).

RESULTS

The identified researches focused on several aspects related to biological width in oral implantation, namely the concept, formation, remodeling, dimension, structure and function.

CONCLUSIONS

Based on of the reviewed literature, the concept, formation, remodeling, structure, dimension, and functional significances of periimplant biological width are explored in this narrative review. The formation of biological width around implant is a complex process after several weeks of healing. The biological width around implant is a 3-4mm distance from the top of the peri-implant mucosa to the first bone-to-implant contact or the stabilized top of the adjacent bone, consisting of sulcular epithelium, junctional epithelium and fibrous connective tissue between the epithelium and the first bone-to-implant contact or the stabilized top of the adjacent bone. The biological width forms a biological barrier against the bacteria, influences the remodeling of soft and hard tissue around implant and has implications for clinical aspects of dental implantation.

Evaluation of subgingival microbiota around single tooth implants

Objectives

1. To provide information about the subgingival microbiota around single tooth implants.2. To assess the subgingival microbial flora around the teeth adjacent to single tooth implants.3. To clinically evaluate the gingival health surrounding the single-tooth implants.

Methods

Patients undergoing the single-tooth implant replacements, were selected as subjects for the study. The natural teeth adjacent to implant sites were taken as control sites. Clinically each peri-implant gingival tissue health was evaluated. Subgingival plaque samples were removed with sterile curette and evaluated for microbial flora, by microscopic examinations. Bacterial cultures of samples studied. The similar procedure was followed for the control sites also. Finally the data collected were statistically analyzed and interpreted.

Results

The subgingival microbiota around single tooth implants was cultured and studied. Enterobacter species, Klebsiella pneumonia, Pseudomonas aeruginosa and Streptococcus species were predominantly found. Klebsiella pneumonia and Pseudomonas aeruginosa were found more frequently around implant sites than control sites. Anaerobic Bacteroides species were found in only one case around the implant site.

Conclusions

Prevention and control of bacterial infection in the peri-implant region are among the key factors in determining the long term success or failure of dental implant therapy. The thorough knowledge about the subgingival microbiota around the healthy and diseased peri-implant mucosa is needed to determine the overall outcome of implant therapy.

The Deep Circumflex Iliac Artery Flap for Mandibular Reconstruction and Donor Site Reconstruction with a Patient-Specific Implant: A Case Report

Jaw defects may occur due to various causes such as tumors, trauma, and diseases caused by infection such as osteomyelitis. Reconstruction of jaw defects has been improved by the free flaps and refined microvascular techniques. The deep circumflex iliac artery (DCIA) flap offers a large amount of bone for complex reconstructions of the mandible. However, several complications and adverse effects can occur, such as abnormal hip contour, hernia, severe bleeding tendency, gait disturbance, and hypoesthesia. To reduce these complications, the monocortical DCIA flap can be used, or iliac crest bone defects can be restored with titanium mesh. However, these methods have limitations when used to reduce hip contour reproduction and gait disturbance. In this study, we report a case of iliac bone reconstruction using a 3D-printed patient-specific implant to reduce donor site morbidity in the reconstruction of the DCIA flap in a patient with oral squamous carcinoma.

Microbiological dynamics of red complex bacteria following full-mouth air polishing in periodontally healthy subjects-a randomized clinical pilot study

OBJECTIVES

Suppression of periodontal pathogens in the oral cavity of periodontally healthy individuals may lower the risk for periodontal or periimplant diseases. Therefore, the present study aimed to analyze the effect of supragingival debridement (SD) with adjunctive full mouth glycine powder air polishing (FM-GPAP) on the prevalence of periodontal pathogens in periodontally healthy individuals.

MATERIALS AND METHODS

Eighty-seven systemically and periodontally healthy intraoral carriers of red complex bacteria, i.e., Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola or other periodontal pathogens including Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Eikenella corrodens were enrolled into the study and randomly assigned to receive SD with adjunctive FM-GPAP (test, n = 42) or SD alone (control, n = 45). In the first observation period, microbiological samples were obtained prior to, and 2, 5, and 9 days following intervention. If one of these periodontal pathogens could still not be identified, additional microbial sampling was performed after 6 and 12 weeks.

RESULTS

The prevalence of red complex bacteria was significantly reduced in the test compared to the control group following treatment (p = 0.004) and at day 9 (p = 0.031). Intragroup comparison showed a significant (test, p < 0.001; control, p ≤ 0.01) reduction in the mean prevalence in both groups from BL through day 9 with an additional significant intergroup difference (p = 0.048) at day 9. However, the initial strong reduction returned to baseline values after 6 and 12 weeks.

CONCLUSION

In periodontally healthy carriers of periodontal pathogens, FM-GPAP as an adjunct to SD transiently enhances the suppression of red complex bacteria.

CLINICAL RELEVANCE

Whether the enhanced suppression of red complex bacteria by adjunctive FM-GPAP prevents the development of periodontitis in periodontally healthy carriers requires further investigations.

Influences of microgap and micromotion of implant-abutment interface on marginal bone loss around implant neck

OBJECTIVE

To review the influences and clinical implications of micro-gap and micro-motion of implant-abutment interface on marginal bone loss around the neck of implant.

DESIGN

Literatures were searched based on the following Keywords: implant-abutment interface/implant-abutment connection/implant-abutment conjunction, microgap, micromotion/micromovement, microleakage, and current control methods available. The papers were then screened through titles, abstracts, and full texts.

RESULTS

A total of 83 studies were included in the literature review. Two-piece implant systems are widely used in clinics. However, the production error and masticatory load result in the presence of microgap and micromotion between the implant and the abutment, which directly or indirectly causes microleakage and mechanical damage. Consequently, the degrees of microgap and micromotion further increase, and marginal bone absorption finally occurs. We summarize the influences of microgap and micromotion at the implant-abutment interface on marginal bone loss around the neck of the implant. We also recommend some feasible methods to reduce their effect.

CONCLUSIONS

Clinicians and patients should pay more attention to the mechanisms as well as the control methods of microgap and micromotion. To reduce the corresponding detriment to the implant marginal bone, suitable Morse taper or hybrid connection implants and platform switching abutments should be selected, as well as other potential methods.

Dental Implants with Locking Taper Connection versus Screwed Connection: Microbiologic and Scanning Electron Microscope Study

The aim of this study is to carry out an analysis of the Fixture-Abutment Interfaces (FAI), comparing different connection systems, to evaluate the role of geometric discrepancy, which is present between the abutment and the fixture, in favoring the permeability to bacterial colonization. Two types of commercially available FAI were studied, 16 screwed FAI (Sweden-Martina Italia) (4 of Ø 3.8 mm diameter, 4 of Ø 4.7 mm diameter, 4 of Ø 5.7 mm diameter and 4 of Ø 6.7 mm diameter) and 4 FAI (Bicon) (Ø 3.5mm diameter). The assays were carried out in vitro, placing the different dental implants in contact with broth culture of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Streptococcus pyogenes to test the infiltration inside the FAI. Furthermore, scanning electron microscope (SEM) analysis was carried out to evaluate the gap at the fixture-abutment interface. In all the locking taper FAI and in the screwed FAI with a diameter of 3.8 mm there was no trace of bacterial infiltration of the species examined. In the screwed FAI with a diameter of 4.7 mm, 5.7 mm and 6.7 mm there was an increasing level of bacterial infiltration in relationship to the diameter. Therefore, this paper shows that there exists an important correlation between the diameter of the screwed implant and the permeability to microbic infiltration that is directly proportional to the diameter of the implant.

Dental materials and their performance for the management of screw access channels in implant-supported restorations

Unsuccessfully sealed screw access channels of prosthetic implant abutments may lead to malodor or peri-implant diseases in gingival tissues adjacent to implant-supported restorations. Therefore, 72 sets of screw channel analogs with six different materials incorporated (Polytetrafluoroethylene (PTFE), wax, gutta-percha, cavit, endofrost-pellets and cotton pellets) were exposed (2.5 h, 37°C) to Streptococcus mutans, oralis and Candida albicans suspensions. Bacterial adherence was quantified by using the fluorescence dye, Alamar Blue/resazurin, and an automated multifunctional reader. For quantification of fungal adherence the ATP-based bioluminescence approach was used. High relative fluorescence and luminescence intensities (>10,000), indicating high adhesion of streptococci and fungi were found for cotton and endofrost-pellets and low intensities (<5,000) for wax, gutta-percha, cavit and PTFE. The quantity of bacterial and fungal adhesion differed significantly between the assessed various sealing materials. In conclusion and within the limitations of this study, wax, gutta-percha, cavit and PTFE should be preferred as sealing materials.

Microbial colonization at the implant-abutment interface and its possible influence on periimplantitis: A systematic review and meta-analysis

PURPOSE

The aim of this systematic review and meta-analysis was to evaluate the microbial colonization at the implant-abutment interfaces (IAI) on bone-level implants and to identify possible association with peri-implant conditions.

STUDY SELECTION

The focus question aimed to answer whether two-piece osseointegrated implants, in function for at least 1 year, in human, relate to higher bacterial count and the onset of periimplantitis, compared to healthy peri-implant conditions. Search strategy encompassed the on-line (MedLine, Google scholar, Cochrane library) literature from 1990 up to March 2015 published in English using combinations of MeSH (Medical Subject Headings) and search terms. Quality assessment of selected full-text articles was performed according to the ARRIVE and CONSORT statement guidelines. For data analysis, the total bacterial count of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, and Fusobacterium nucleatum was calculated and compared to IAI with or without peri-implant pathology.

RESULTS

A total of 14 articles, reporting data from 1126 implants, fulfilled the inclusion criteria and subjected to quality assessment. The selected studies revealed contamination of the IAI, in patients who received two-piece implant systems. Meta-analysis indicated significant difference in total bacterial count between implants affected by periimplantitis versus healthy peri-implant tissues (0.387±0.055; 95% CI 0.279-0.496). Less bacterial counts were identified in the healthy IAI for all the investigated gram-negative bacteria except for T. forsythia.

CONCLUSIONS

Significantly higher bacterial counts were found for periodontal pathogenic bacteria within the IAI of implants in patients with periimplantitis compared to those implants surrounded by healthy peri-implant tissues.

Effect of cement washout on loosening of abutment screws and vice versa in screw- and cement- retained implant-supported dental prosthesis

PURPOSE

The purpose of this study was to examine the abutment screw stability of screw- and cement-retained implant-supported dental prosthesis (SCP) after simulated cement washout as well as the stability of SCP cements after complete loosening of abutment screws.

MATERIALS AND METHODS

Thirty-six titanium CAD/CAM-made implant prostheses were fabricated on two implants placed in the resin models. Each prosthesis is a two-unit SCP: one screw-retained and the other cemented. After evaluating the passive fit of each prosthesis, all implant prostheses were randomly divided into 3 groups: screwed and cemented SCP (Control), screwed and noncemented SCP (Group 1), unscrewed and cemented SCP (Group 2). Each prosthesis in Control and Group 1 was screwed and/or cemented, and the preloading reverse torque value (RTV) was evaluated. SCP in Group 2 was screwed and cemented, and then unscrewed (RTV=0) after the cement was set. After cyclic loading was applied, the postloading RTV was measured. RTV loss and decementation ratios were calculated for statistical analysis.

RESULTS

There was no significant difference in RTV loss ratio between Control and Group 1 (P=.16). No decemented prosthesis was found among Control and Group 2.

CONCLUSION

Within the limits of this in vitro study, the stabilities of SCP abutment screws and cement were not significantly changed after simulated cement washout or screw loosening.

Efficacy of Gutta-Percha and Polytetrafluoroethylene Tape to Microbiologically Seal the Screw Access Channel of Different Prosthetic Implant Abutments

PURPOSE

To evaluate in vitro, the efficacy of gutta-percha (GP) and polytetrafluoroethylene (PTFE) tape to act as a seal against the penetration of Escherichia coli through prosthetic implant abutments (PIA) with external hexagon (EH) and morse taper (MT) connections.

MATERIALS AND METHODS

120 sets of implant analogs with their respective PIA were used. 60 sets from each system were divided into four groups (n = 15): I - GP sealing; II - PTFE tape sealing; III - no sealing (NS) and IV - negative control. Microbiological challenge was performed by placing bacterial colonies inside the titanium PIA before screwing them into their respective analogs. Each set was immersed in 5 mL of BHI and incubated for 14 days with daily checks for contamination, according to the nutrient medium turbidity.

RESULTS

The type of seal used influenced microbial penetration at all evaluation times (p < 0.05). Compared to GP, PTFE led to an increase in turbidity and its effectiveness against microbial penetration was equivalent to group NS. When the sealing efficacy of each group was compared in terms of time, Cochran's Q test revealed that in the two groups sealed with PTFE, there was a progressive increase in the number of turbid nutrient media (p < 0.0001), while in the group sealed with GP, this was only observed in the MT system (p = 0.0310).

CONCLUSIONS

Sealing the PIA channel with GP was a significantly superior approach to sealing it with PTFE tape. PTFE tape or NS led to a progressive increase in microbiological leakage over time in PIA channels, however, this only occurred with GP in the MT system.

An in vivo comparison of internal bacterial colonization in two dental implant systems: identification of a pathogenic reservoir

OBJECTIVES

The aim of this study was to compare internal bacterial colonization in two implant systems, one screw root form (SRF) with an external hexagon connection and one plateau root form (PRF) with a Morse taper internal connection.

MATERIALS AND METHODS

Thirty-two implants; 12 SRF and 20 PRF, were sampled in 15 patients. All implants had been in function for at least 6 months prior to sampling. The implant restoration was removed and 10 µl of sterile saline was introduced into the implant well via a sterile glass syringe. The saline was drawn back up and transferred to the laboratory for microbiological analysis. The number of aerobic and anaerobic colony forming units per millilitre was determined and the dominant micro-organism in each sample was identified by 16s rRNA gene amplicon sequencing.

RESULTS

There was a significant difference between bleeding on probing around the SRF implants (3%) and the PRF implants (28%) (p = 0.0496). Bacterial colonization was identified at 11 SRF and 19 PRF implants. The numbers of anaerobic bacteria recovered from PRF implants was significantly higher than that from SRF implants (p = 0.0002). Streptococcus species and Enterococcus faecalis were found to dominate.

CONCLUSIONS

This in vivo study demonstrated bacterial colonization in both types of implant systems, irrespective of the type of connection. Significantly greater anaerobic counts were found in the Morse taper internal connection implants.

Marginal adaptation of four inlay casting waxes on stone, titanium, and zirconia dies

STATEMENT OF PROBLEM

Different inlay casting waxes do not produce copings with satisfactory marginal accuracy when used on different die materials.

PURPOSE

The purpose of this study was to evaluate the marginal accuracy of 4 inlay casting waxes on stone dies and titanium and zirconia abutments and to correlate the findings with the degree of wetting between the die specimens and the inlay casting waxes.

MATERIAL AND METHODS

The inlay casting waxes tested were Starwax (Dentaurum), Unterziehwachs (Bredent), SU Esthetic wax (Schuler), and Sculpturing wax (Renfert). The marginal opening of the waxes was measured with a stereomicroscope on high-strength stone dies and on titanium and zirconia abutments. Photographic images were obtained, and the mean marginal opening for each specimen was calculated. A total of 1440 measurements were made. Wetting between die materials and waxes was determined after fabricating stone, titanium, and zirconia rectangular specimens. A calibrated pipette was used to place a drop of molten wax onto each specimen. The contact angle was calculated with software after an image of each specimen had been made with a digital camera. Collected data were subjected to a 2-way analysis of variance (α=.05). Any association between marginal accuracy and wetting of different materials was found by using the Pearson correlation.

RESULTS

The wax factor had a statistically significant effect both on the marginal discrepancy (F=158.31, P<.001) and contact angle values (F=68.09, P<.001). A statistically significant effect of the die material factor both on the marginal adaptation (F=503.47, P<.001) and contact angle values (F=585.02, P<.001) was detected. A significant correlation between the marginal accuracy and the contact angle values (Pearson=0.881, P=.01) was also found.

CONCLUSIONS

Stone dies provided wax copings with the best marginal integrity, followed by titanium and zirconia abutments. Unterziehwachs (Bredent), wax produced the best marginal adaptation on different die materials. A significant correlation was found between the marginal accuracy and the contact angle values. As the contact angle value became smaller, the marginal accuracy improved. All combinations of waxes and stone and titanium dies presented a high wettability.

Microbiological assessment of the implant-abutment interface in different connections: cross-sectional study after 5 years of functional loading

OBJECTIVE

To evaluate the bacterial microflora present inside the implant connection and in the peri-implant sulcus fluid of healthy implants, and to analyze the relationships between these harboring sites for four different implant systems after at least 5 years of functional loading.

MATERIALS AND METHODS

A cross-sectional study was performed involving 40 patients treated with metal-ceramic cemented bridges supported by at least two healthy implants functionally loaded for 5 years. Four different implant-abutment connections were studied: external hexagon (control group), double internal hexagon (test group 1), internal hexagon with external collar (test group 2), and conical connection (test group 3). Samples for microbiological analysis were obtained from three types of sites: peri-implant sulci, connections' inside and abutments surface and, as control, gingival sulci of neighboring teeth. Quantitative real-time PCR was carried out for Total Bacterial Count and for 10 microorganisms: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Prevotella intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Campylobacter rectus, Eikenella corrodens, and Candida albicans. The response variables were percentage of positive sites and absolute bacterial load. The relations of the response variables with the type of connection and of sampling site were assessed using generalized estimating equations.

RESULTS

Regarding the analysis of positivity to bacteria in the peri-implant sulcus no significant differences were observed. Analyzing the connection's inside, none of the connection designs had the capacity to prevent microbiological leakage through the implant/abutment microgap. Test group 3 presented the lowest mean values for red complex bacteria and control group the highest, although differences were non-significant. Statistical significance was only reached for Treponema denticola in the bacterial load analysis inside the connection. Test groups 1 and 2 yielded lower values for orange complex bacteria but only for Peptostreptococos micros the differences resulted significant. Test groups 2 and 3 had significantly lower total bacterial counts in the peri-implant sulcus and inside the connection.

CONCLUSIONS

Outcomes suggested that all the analyzed connections resulted contaminated after 5 years of functional loading. However, the connection design might influence bacterial activity levels qualitatively and quantitatively, especially inside the implant connection.

A 5- to 6-year radiological evaluation of titanium plasma sprayed/sandblasted and acid-etched implants: results from private practice

OBJECTIVES

This study aimed to determine bone level changes after 5-6 years of follow-up for a large group of one-stage dental implants consecutively placed in private practice. Potential confounding factors influencing crestal bone loss (CBL) were also assessed.

MATERIALS AND METHODS

A total of 378 transmucosal Straumann implants in 174 patients were examined radiographically. Half of the study population (189 implants) had a titanium plasma sprayed (TPS) surface, and the other half (189 implants) were sandblasted and acid-etched (SLA). Mean CBL was measured from 5 to 6 years post-operative radiographs on the basis of known implant landmarks. Correlations of increased CBL with various independent variables were also investigated. Statistical analyses were performed using generalized estimating equations.

RESULTS

Radiographic measurements showed a CBL ≤ 1.5 mm for 65% of studied implants. A CBL > 1.5 mm was found for 28% of implants, while 7% of implants had a CBL ≥ 3 mm. Three factors significantly influenced CBL (P < 0.05): implant surface texture (TPS > SLA), smoking status (smokers > non-smokers), and implant location (anterior > posterior).

CONCLUSIONS

CBL was ≤1.5 mm after 5-6 years for the majority of followed implants. For implants with a CBL > 1.5 mm, statistically significant correlations were found for TPS surface type, anterior jaw locations, and smoking. Implant length did not influence CBL.

Biofilm and dental implant: The microbial link

Mouth provides a congenial environment for the growth of the microorganisms as compared to any other part of the human body by exhibiting an ideal nonshedding surface. Dental plaque happens to be a diverse community of the microorganisms found on the tooth surface. Periodontal disease and the peri-implant disease are specific infections that are originating from these resident microbial species when the balance between the host and the microbial pathogenicity gets disrupted. This review discusses the biofilms in relation to the peri-implant region, factors affecting its presence, and the associated treatment to manage this complex microbial colony. Search Methodology: Electronic search of the medline was done with the search words: Implants and biofilms/dental biofilm formation/microbiology at implant abutment interface/surface free energy/roughness and implant, periimplantitis/local drug delivery and dental implant. Hand search across the journals - clinical oral implant research, implant dentistry, journal of dental research, international journal of oral implantology, journal of prosthetic dentistry, perioodntology 2000, journal of periodontology were performed. The articles included in the review comprised of in vivo studies, in vivo (animal and human) studies, abstracts, review articles.

Evaluation of Soft Tissues Around Single Tooth Implants in the Anterior Maxilla Restored With Cemented and Screw-Retained Crowns

Implant-supported restorations can be attached as screw-retained or cemented prostheses. In both situations, the characteristics of the soft tissues around the implants are crucial for oral rehabilitation and patient satisfaction. Therefore, this study uses the Pink Esthetic Score (PES), which allows evaluation of gingival esthetics around implants, to evaluate the soft tissues around implants in the anterior maxilla rehabilitated with cemented prostheses (CP) and screw-retained prostheses (SP). Forty implants placed in the anterior maxilla were evaluated, and these had been rehabilitated with prosthetic crowns for a minimum of 1 year. Periodontal examination was performed to evaluate probing depth (PD) and bleeding on probing (BOP) of the implant and the corresponding natural tooth. The total mean (±SD) PES for SP was 10.73 (±1.98) and 10.41 (±2.67) for CP, which was not statistically significant (P ≥ .05). Periodontal examination revealed that CP and SP showed no difference for BOP (P ≥ .05). Differences were only detected in PD when comparing the reference teeth of both groups to CP and SP (P ≤ .05). The present study demonstrates that the PES proved to be an efficient index to assess peri-implant tissues, and that the type of crown retention does not influence the health and quality of the soft tissues around implants.

Factors determining the retentiveness of luting agents used with metal- and ceramic-based implant components

OBJECTIVES

To investigate the factors that determine the retentiveness of copings made of cobalt-chromium (CoCr)-alloy or zirconia luted with permanent (solid-body like) and provisional (viscous, elastic-body-like) luting agents.

MATERIALS AND METHODS

We manufactured titanium implant analogs with four-, six-, and eight-taper degrees and copings of CoCr-alloy and zirconia and luted the copings according to a standardized protocol. Samples were thermally cycled, and we investigated the various degrees of roughness of the copings' inner surfaces as well as the various cement mixing ratios on the retentiveness. Copings were either pulled out slowly (by means of a universal testing machine) or knocked out quickly (using a CORONAflex crown replacement device).

RESULTS

The highest level of retentiveness was achieved with a four-taper degree for polycarboxylates followed by zinc-oxide-phosphates and glass ionomers or composite cements. Provisional cements and composite cements containing a plastifier showed significantly lower retentiveness levels. The pull-out and knock-out tests showed a relationship between retentiveness level and taper degree. However, the influence of taper degree was reduced with higher taper degrees as well as with cements that do not set as a solid body due to ingredients such as oily liquids or plastifiers. Thermal cycling further reduced the retentiveness level of these cements. Higher degrees of roughness only improved the retention force of cements setting as a solid body. Mixing errors may alter retentiveness levels in an unpredictable manner. When used within the same group of cements, metal-alloy, and zirconia copings did not differ with regard to their level of retentiveness.

CONCLUSION

Copings made of metal-alloy and zirconia showed no different level of retentiveness when set onto titanium abutments fixed with permanent or provisional cements.

CLINICAL RELEVANCE

Only cements setting as a solid body showed a clear relationship between retentiveness level and taper degree. In contrast, the retentiveness of provisional (viscous, elastic-body-like) luting agents was less predictable.

RCT comparing minimally with moderately rough implants. Part 2: microbial observations

BACKGROUND

Most current implants have a moderately rough surface (compared with older minimally rough "turned" implants) to facilitate osseointegration. This randomized controlled trial (RCT), with split-mouth design, examined whether this increased surface roughness influenced the initial subgingival plaque formation.

MATERIAL AND METHODS

Ten fully edentulous and eight partially edentulous patients, all with a history of severe periodontitis, received 4-6 implants (mandible or maxilla). Per jaw, both minimally (turned) and moderately rough (TiUnite) implants (MKIII; Nobel Biocare) were alternated. Also, the healing and final abutments had similar surface characteristics. Subgingival biofilm formation was followed up for 1 year, and samples were analyzed by culture technique, qPCR and checkerboard

RESULTS

Over the entire period, no statistically significant differences could be detected in subgingival microbiota between the minimally and moderately rough surfaces. In partially edentulous patients, the biofilm matured to a higher concentration of pathogens when compared with fully edentulous patients. The subgingival implant composition and concentration in partially edentulous patients were comparable to the subgingival microbiota along teeth.

CONCLUSION

The roughness of the more modern implants did not influence the biofilm formation during the first year of implant loading.

Prosthetic outcome of cement-retained implant-supported fixed dental restorations: a systematic review

The aim of the article is to assess the current literature in terms of the prosthetic outcome of cement-retained implant-supported fixed restorations, as well as to determine the type of cement that can be recommended for clinical application. A review of the literature published up to May 2010 was conducted to identify clinical studies about cement-retained implant-supported fixed restorations. The search strategy applied was a combination of MeSH terms and free text words, including the following keywords: implants, implant-supported fixed dental prostheses (FDPs), bridges, implant-supported single crowns (SCs), cement-retained, cement fixation, cement, cementation, cement failure, retention, and loss of retention, technical complications, mechanical complications, prosthetic complication, retrievability and maintenance. Thirty-two studies met the inclusion criteria. The studies were divided into two categories: 15 short-term clinical studies with an observation period of less than 5 years, and 17 long-term clinical studies with an observation period of 5 years and more. The most common technical complications of cement-retained implant-supported fixed restorations were loss of retention, chipping and abutment screw loosening. The results of the current review revealed no guidelines about cement or cementation procedures. It may be stated that despite the questionable retrievability of cement-retained implant-supported fixed restorations, this treatment modality is a reliable and effective option, especially for implant-supported SCs and short-span FDPs. The literature does not provide accurate information about the clinical outcome of cement-retained implant-supported fixed restorations nor about the ideal type of cement that facilitates stability and maintains retrievability. Standardised randomised clinical trials will provide valuable information to this issue.

Open or submerged healing of implants with platform switching: a randomized, controlled clinical trial

AIM

The temporal pattern of bone-level alterations in conventionally restored implants is dependent upon healing mode (open or submerged). This study examined the influence of healing on marginal bone levels at implants with a medium-rough surface including the implant collar and a clearance-fit implant-abutment connection restored according to a platform-switching concept.

MATERIAL AND METHODS

Two implants were placed in the posterior mandible of 21 test subjects, randomly assigned to open (OH) or submerged (SH) healing. Standardized radiographs were obtained after implant surgery, before re-entry, after crown mounting, 1 and 2 years after implant surgery, and evaluated for implant-bone-level alterations (ΔIBL). Bacterial samples of the implants' inner cavities were analysed by cultivation.

STATISTICS

Brunner-Langer Model, equivalence testings by Wilcoxon's (equivalence range ±0.4mm).

RESULTS

After 2 years, ΔIBL were -0.47±0.46mm (OH) and -0.54±0.38mm (SH). At the 1-year follow-up, all implants were contaminated with bacteria. ΔIBL (p<0.001) and the amount of bacterial contamination (p<0.001) significantly depended on time, but not on healing mode. ΔIBL of OH and SH were equivalent at all time points (all p0.044).

CONCLUSIONS

Platform-switched implants showed very limited peri-implant bone-level alterations. The healing-mode neither affected the total amount nor the temporal patterns of ΔIBL. Thus, the results for the tested implants with a non-rigid implant-abutment connection were similar to results reported previously for implants with a rigid implant-abutment connection.

Screw- versus cement-retained implant restorations: current concepts

The debate between screw- versus cement-retained implant prostheses has long been discussed but the best type of implant prosthesis remains controversial among practitioners. An understanding of their properties will help the clinician in selecting the ideal prosthesis for each clinical case while promoting final esthetic outcomes. With the evolving technology and knowledge, an update of the current trends is necessary. This article provides an overview of the different characteristics of screw- and cement-retained implant restorations, and how they may influence the esthetics, retrievability, retention, passivity, occlusion, accessibility, cost, and provisional restorations. Problems and complications frequently encountered are discussed and treatment solutions are proposed.

Retention and marginal leakage of provisional crowns cemented with provisional cements enriched with chlorhexidine diacetate

STATEMENT OF PROBLEM

Provisional crowns cemented with provisional luting agents are susceptible to washout, marginal leakage, and secondary caries when placed for a prolonged period.

PURPOSE

The purpose of this study was to examine the effect of incorporating chlorhexidine diacetate (antibacterial agent) into provisional cements on retention and marginal leakage of provisional crowns in vitro.

MATERIAL AND METHODS

Provisional crowns of acrylic resin (Duralay) were fabricated for 12 intact human molars with rounded-shoulder preparations. The 12 provisional crowns were luted individually with Temp Bond, Temp Bond NE, and Freegenol provisional cements with and without incorporation of chlorhexidine diacetate (CHDA) salt. Each test group included the same 12 specimens. Specimens with no luting agent served as the control (n=12). Specimens were thermal cycled 100 times (5 degrees C and 55 degrees C) with a 10-second dwell time, stored in 100% humidity at 37 degrees C for 6 days, and then immersed in a 0.5% basic fuchsin at 37 degrees C for 6 hours. Seven days after cementation, removal test of the crowns (tensile retention test) was conducted with a universal testing machine at a crosshead speed of 5 mm/min. Marginal leakage was assessed with a 5-level dye penetration scale. Results of the retention test were subjected to a 2-way ANOVA with repeated measures. A Bonferroni test was used to compare the means. Marginal leakage data were subjected to a nonparametric Wilcoxon signed ranks test. All hypothesis testing was conducted at the 95% level of confidence.

RESULTS

Retention of provisional crowns cemented with Freegenol enriched with CHDA increased 3-fold to an average level of 80.9 N. However, incorporation of CHDA into Temp Bond or Temp Bond NE did not affect retention. CHDA incorporated into the cements had no significant effect on the marginal leakage of all the tested cements.

CONCLUSIONS

The addition of CHDA increased retention of Freegenol and had no significant effect on the marginal leakage of the tested cements.

A systematic review of the 5-year survival and complication rates of implant-supported single crowns

OBJECTIVES

The objective of this systematic review was to assess the 5-year survival of implant-supported single crowns (SCs) and to describe the incidence of biological and technical complications.

METHODS

An electronic MEDLINE search complemented by manual searching was conducted to identify prospective and retrospective cohort studies on SCs with a mean follow-up time of at least 5 years. Failure and complication rates were analyzed using random-effects Poisson's regression models to obtain summary estimates of 5-year proportions.

RESULTS

Twenty-six studies from an initial yield of 3601 titles were finally selected and data were extracted. In a meta-analysis of these studies, survival of implants supporting SCs was 96.8% [95% confidence interval (CI): 95.9-97.6%] after 5 years. The survival rate of SCs supported by implants was 94.5% (95% CI: 92.5-95.9%) after 5 years of function. The survival rate of metal-ceramic crowns, 95.4% (95% CI: 93.6-96.7%), was significantly (P=0.005) higher than the survival rate, 91.2% (95% CI: 86.8-94.2%), of all-ceramic crowns. Peri-implantitis and soft tissue complications occurred adjacent to 9.7% of the SCs and 6.3% of the implants had bone loss exceeding 2 mm over the 5-year observation period. The cumulative incidence of implant fractures after 5 years was 0.14%. After 5 years, the cumulative incidence of screw or abutment loosening was 12.7% and 0.35% for screw or abutment fracture. For supra-structure-related complications, the cumulative incidence of ceramic or veneer fractures was 4.5%.

CONCLUSION

It can be concluded that after an observation period of 5 years, high survival rates for implants and implant-supported SCs can be expected. However, biological and particularly technical complications are frequent.

Retention and leakage of implant-supported restorations luted with provisional cement: a pilot study

Few data exist regarding cement failure load and marginal leakage of castings cemented to implant-supported abutments subjected to load and thermal cycling, especially with newer cements. This study evaluated the cement failure load and marginal leakage of castings cemented to Steri-Oss abutment/analog assemblies with one of seven luting protocols (n = 5). Protocols consisted of a zinc phosphate control, zinc phosphate with petroleum jelly, TempBond, TempBond NE, ImProv, ImProv with petroleum jelly and Provilink. Cemented castings were subjected to cyclic axial compression of 75 N for 100,000 cycles, 1000 thermal cycles (5-55 degrees C), and immersed 24 h in 0.5% basic fuchsin. The castings were then loaded in tension until cement failure. Cement failure load was analysed using anova and Fischer's PLSD (alpha = 0.05). Marginal leakage on the intaglio of the casting was scored with the unaided eye on a scale of 0-2, and analysed with Duncan's multiple range (alpha = 0.05). Similar groups are noted by superscript. Cement failure load (from lowest to highest): ImProv with petroleum jelly(a), TempBond(a), ImProv(a), Tempbond NE(a), Provilink(a), zinc phosphate with petroleum jelly(b), zinc phosphate(c) (P < 0.0001). Marginal leakage scores (from lowest to highest): ImProv(a), Provilink(a), ImProv with petroleum jelly(a), zinc phosphate(ab), zinc phosphate with petroleum jelly(ab), TempBond(bc), and TempBond NE(c) (P = 0.01). Addition of petroleum jelly to zinc phosphate lowered cement failure load without affecting marginal leakage. ImProv and Provilink demonstrated relatively low cement failure load, as well as lowest marginal leakage.

In vitro sealing ability of two materials at five different implant-abutment surfaces

BACKGROUND

The aim of the present study was to test the sealing ability of two materials at five different implant-abutment surfaces.

METHODS

In the first phase, 2 mul brain-heart infusion (BHI) broth was deposited into the implant wells and glass culture tubes. A varnish or silicon sealant was applied at the cervical implant portion of experimental groups. The control group remained unexposed. The abutments were torque-tightened to 20 Ncm with a manual torque driver. Implants were immersed in 4 ml BHI broth at 37 degrees C for 2 hours to exclude contamination. In the second phase, 100 mul Enterococcus faecalis American Type Culture Collection (ATCC) strain 29212 was deposited into the glass culture tubes. After periods of 7, 14, 21, 35, 49, and 63 days, the sealing capacity was checked. Abutments were removed, and a sterile paper cone collected material inside implant bodies. This material was transferred to new tubes with BHI to verify the presence of cloudy broths within 24 to 48 hours.

RESULTS

There were no statistically significant differences between the two materials for each time period (Fisher exact test; P >0.05). Group E showed the least level of sealing ability (six implants contaminated), whereas group T showed the highest level (only two implants).

CONCLUSIONS

1) Materials tested were not able to prevent contamination over 63 days. 2) Bacterial contamination was verified after 14 and 35 days in the control and experimental groups, respectively. 3) Although materials tested had demonstrated similar sealing capacities, dental implants showed bacterial contamination regardless of their external or internal hexagonal configurations.

Comparison of bacterial plaque samples from titanium implant and tooth surfaces by different methods

Studies have shown similarities in the microflora between titanium implants or tooth sites when samples are taken by gingival crevicular fluid (GCF) sampling methods. The purpose of the present study was to study the microflora from curette and GCF samples using the checkerboard DNA-DNA hybridization method to assess the microflora of patients who had at least one oral osseo-integrated implant and who were otherwise dentate. Plaque samples were taken from tooth/implant surfaces and from sulcular gingival surfaces with curettes, and from gingival fluid using filter papers. A total of 28 subjects (11 females) were enrolled in the study. The mean age of the subjects was 64.1 years (SD+/-4.7). On average, the implants studied had been in function for 3.7 years (SD+/-2.9). The proportion of Streptococcus oralis (P<0.02) and Fusobacterium periodonticum (P<0.02) was significantly higher at tooth sites (curette samples). The GCF samples yielded higher proportions for 28/40 species studies (P-values varying between 0.05 and 0.001). The proportions of Tannerella forsythia (T. forsythensis), and Treponema denticola were both higher in GCF samples (P<0.02 and P<0.05, respectively) than in curette samples (implant sites). The microbial composition in gingival fluid from samples taken at implant sites differed partly from that of curette samples taken from implant surfaces or from sulcular soft tissues, providing higher counts for most bacteria studied at implant surfaces, but with the exception of Porphyromonas gingivalis. A combination of GCF and curette sampling methods might be the most representative sample method.

Early colonization of non-submerged dental implants in patients with a history of advanced aggressive periodontitis

The aim of the study was to evaluate the early colonization of non-submerged implants over a 6-month period in partially edentulous patients treated for advanced aggressive periodontal disease. In 22 patients treated for advanced aggressive periodontitis and in a supportive maintenance program for a period between 12 and 240 months at implant surgery, a total of 68 non-submerged dental implants were installed. Patients had a plaque score below 20%, and less than 20% of the pockets around the teeth were bleeding on probing (BOP). Using DNA-probes (micro-IDent), the presence and concentration of five periodontal pathogens (Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf) and Treponema denticola (Td)) were determined in the five deepest pockets of the rest dentition pre-operatively and after 6 months as well as five places around each implant 10 days, 1 month, 3 months and 6 months after surgery. In each patient, a test to determine the genotype interleukin-1 (IL-1) was performed (PST - micro-IDent). After 6 months, no difference in microbial composition as compared with baseline was found around the teeth in five patients, in 12 minute differences and in five patients important differences were observed. Ten days after surgery, three patients had a complete similar bacterial composition between teeth and implants. In 14 patients, the composition was fairly similar, while large differences in composition and concentration occurred in five patients. This microbiota around the implants remained almost unchanged over a 6-month period and did not hamper the clinical and radiographic osseointegration and did not lead to peri-implantitis, mucositis or initiation of bone destruction.

Microbiological and clinical effects of chlorhexidine enclosed in fixtures of 3I-Titamed®implants

This double-blind study used a split-mouth design to investigate the microbiological and clinical effects of 0.2% chlorhexidine enclosed in fixtures. Twelve patients had 46 fixtures implanted. At second-stage surgery, a microbiological sample (baseline sample) of the inner parts of the fixtures was taken. Then, a 0.2% chlorhexidine solution was applied into the inner space of 23 fixtures (test group), and in 23 fixtures saline was applied (control group). Abutments were installed and gingival index, plaque index and crevicular fluid flow were monitored weekly. After 6 weeks, a second microbiological sample of the inner part of the fixtures was taken. At baseline, viable bacteria were detected within 46% of the fixtures. After weeks, bacteria were found in 87% of the fixtures. The numbers of bacteria in the control group were significantly higher than those in the test group. The results indicate that, after first-stage surgery, contamination of the inner spaces of the fixtures is commonplace. Application of a 0.2% chlorhexidine solution at second-stage surgery inhibits growth or acquisition of bacteria in the fixtures. In both test and control groups, the crevicular fluid flow as well as the gingival index decreased during the experimental period. At 4, 5, and 6 weeks after chlorhexidine application, these values in the test group appeared lower, but did not attain statistical significance.

Deformation at the implant interface to prosthetic superstructure: an interferometric approach

Dental implants are deformed by masticatory forces. These deformations may affect the implant, the prosthetic superstructure or, in particular, the interfaces between the implant and the superstructure. The resulting changes in the geometrical relationships may lead to gap formation in this region. The objective of the present pilot study was to present an interferometric method for the direct recording and quantitative three-dimensional analysis of load-induced dynamic implant deformation. Three implant screws of 4.1 mm diameter were loaded using a piezoelectric device. The results showed that the screws itself exhibited a homogeneous deformation pattern, whereas implants with screw-retained superstructures demonstrated dislocations of the crown and resulting gap formations (0.27 +/- 0.37 microm--mean +/- SD; max: 0.82 microm). The results supported the hypothesis that the high precision of prefabricated abutments is adversely affected by dynamic deformations under functional loading.