One Piece CAD/CAM Abutment for Screw-Retained Single-Tooth Restorations: A 5-Year Prospective Cohort Study.

BACKGROUND: The use of ceramic-coated patient-specific CAD/CAM titanium abutments represents a therapeutic option for the rehabilitation of single tooth. The utilization of highly customized abutments enables the accurate three-dimensional positioning of the prosthetic emergence. This study evaluates the clinical performance of implant-prosthetic rehabilitations carried out using ceramic-coated CAD/CAM titanium abutments. MATERIALS AND METHODS: Thirty implants were placed in thirty patients and rehabilitated with thirty single crowns attached to CAD/CAM titanium abutments. A conventional procedure was applied, with implant placement after post-extraction socket healing and prosthetic restoration after implant healing. Implants of lengths ranging from 6-15 mm and widths of 3.6, 4.2, and 4.8 mm were used in this study. At the time of prosthesis delivery (T0), after two years (T1), and after five years (T2), plaque (PI) and bleeding (BoP) indices, probing depths (PPD), marginal bone levels (MBL), and PES/WES were evaluated for each implant. RESULTS: No patient dropped out of the study during the follow-up period. All thirty implants were clinically successful at five years post-prosthesis delivery (survival rate: 100%) and showed no signs of peri-implant infection. Peri-implant soft tissues were in good health (BoP at T2: 0% in 73% of patients; 25% in 13% of patients; 50% in 10% of patients; and 75% in 3% of patients). The mean PPD was 2.05±0.56 mm at T0, 1.992±0.6 mm at T1, and 1.867±0.439 mm at T2. The mean MBL at T0 was 0.413±0.440 mm, at T1 was 0.306±0.388 mm, and at T2 was 0.263±0.368 mm. The mean PES, WES, and PES/WES indices, 7.43±1.04, 7.57±0.82, and 15.00±1.17, respectively, indicate good integration of soft tissues, satisfactory aesthetics, and an overall positive outcome. CONCLUSIONS: The success rates, maintenance of marginal bone levels, and periodontal and aesthetic indices suggest the validity of implant-prosthetic rehabilitations with CAD/CAM abutments in cases of single crowns.

Clinical outcomes of implant- versus abutment-level connection in screw-retained fixed dental prostheses: A 5-year randomized controlled trial.

AIM: The aim of the study was to evaluate the 5 years clinical outcomes associated with implant-level connection (IL) versus abutment-level connection (AL) for implants with an internal conical connection (ICC) supporting a screw-retained fixed partial denture. MATERIALS AND METHODS: Fifty patients with 119 implants were randomly allocated to either the AL or IL group. Radiographic (Marginal bone loss) and clinical outcomes (Bleeding on Probing, probing pocket depth, plaque accumulation, incidence of peri-implantitis and peri-implant mucositis as well as prosthetic complications) were collected and compared at 1, 2, 3, and 5 years. A linear mixed model was used to evaluate the differences between groups. RESULTS: Five years after treatment, the MBL change was not significantly different between the groups at any point. The MBL was 0.23 ± 0.64 mm (AL) and 0.23 ± 0.29 mm (IL). The bleeding on Probing was 44% (AL) and 45% (IL) (p = .89). The mean probing depth was 2.91 ± 1.01 mm (AL) and 3.51 ± 0.67 mm (IL). This difference between the groups was statistically significant but clinical insignificant. Presence of plaque was slightly higher (p = .06) in the IL group (34.4%) compared with the AL group (26.3%). The overall technical, biological, and prosthetic complication rates were similar between groups. None of the implants developed peri-implantitis during the entire follow-up period. CONCLUSION: The results of this clinical trial indicated that all clinical and radiographical parameters were clinically comparable between the study groups.

Fully digital workflow for implant-supported fixed restorations consisting of a titanium primary structure and a zirconia secondary structure.

PURPOSE: To describe a fully digital workflow for an implant-supported fixed hybrid restoration that involves a double CAD/CAM structure and to highlight the benefits of this type of restoration. MATERIALS AND METHODS: Using a fully digital workflow, starting from intraoral scans, the necessary steps for producing the final hybrid prosthesis are described. The prosthesis consists of a titanium primary structure and a zirconia secondary structure that is cemented onto the primary structure in the laboratory. A clinical case is presented to illustrate the steps required for prosthetic rehabilitation. RESULTS: This technique enables the fabrication of clinically valid and passive prostheses using a fully digital workflow. CONCLUSION: In just three clinical sessions, a fully digital workflow makes it possible to produce robust implant-supported fixed hybrid prostheses, comprising a titanium primary structure and an outer secondary structure made of zirconia. This procedure can be applied to a wide range of cases from simple to extended, including full-arch restorations.

CAD/CAM Implant Abutments: Peri-implant Hard and Soft Tissue Response with Up to 4 Years of Follow-up- A Retrospective Cohort Study Evaluation.

This retrospective study evaluated hard and soft tissue response and reported mechanical and technical complications around computer-aided design/computer-assisted manufactured (CAD/CAM) abutments. A total of 123 patients restored with titanium, gold-hue titanium, and zirconia CAD/CAM abutments were included (N = 291). Each patient was followed up for at least 2 years. Clinical and radiographic parameters were assessed annually and complications were recorded. No implant or reconstruction failures were reported. One fracture of a zirconia abutment occurred. The prosthetic survival rate after 4 years of function for restorations and abutments was 100% and 99.66%, respectively. No significant differences in biologic and radiographic indices were found. The bleeding on probing index was positive at 42% of implant sites, and it had no significant correlation with the overall change in marginal bone level (0.02 mm) of bone gain. The short-term survival of CAD/CAM abutments was reliable, no matter of the material used for manufacturing.

Interproximal Papilla Stability Around CAD/CAM and Stock Abutments in Anterior Regions: A 2-Year Prospective Multicenter Cohort Study.

The aim of this study was to compare the interproximal papilla stability of restorations supported by computer-aided design/computer-assisted manufacture (CAD/CAM) abutments to those supported by prefabricated stock abutments in anterior areas over a 2-year follow-up. Abutments were selected depending on implant inclination and thickness of buccal peri-implant soft tissues from the following: zirconia stock, titanium stock, zirconia CAD/CAM and titanium CAD/CAM. Differences between the height of the papilla tip were measured (REC). RESULTS: REC values of titanium and zirconia CAD/CAM abutments were significantly lower than those of titanium and zirconia stock. The use of titanium and zirconia CAD/CAM abutments is related to better interproximal papillae stability.

Soft tissues stability of cad-cam and stock abutments in anterior regions: 2-year prospective multicentric cohort study.

AIM: Aim of this study was to verify if the type of implant abutment manufacturing, stock or cad-cam, could influence the maintenance of stable gingival margins around single restorations in anterior areas. METHODS: After 16 weeks of healing, implants (Osseospeed, Astra Tech Dental Implant) were positioned. Depending on the different fixture inclination and the thickness of buccal peri-implant soft tissue, abutment selection resulted in four groups: Group 1 (patients with zirconia ZirDesign(®) stock abutments), Group 2 (titanium stock TiDesign(®) abutments), Group 3 (zirconia cad-cam abutments), and Group 4 (titanium cad-cam abutments). The following parameters were assessed: buccal gingival margin modification (BGM). The modification of the implant gingival margin was followed at 1 and 2 years of follow-up. A computerized analysis was performed for measurements. Differences between soft tissue margin at baseline and after 2 years measured the gingival margin recession. A general linear model was used to evaluate each group in relation to gingival recession after two years. Tukey's post hoc test was used to compare the mean REC indexes of each group of abutments. RESULTS: Seventy-two healthy patients (39 males and 33 females; mean age of 46 years) scheduled for single gap rehabilitation in anterior areas were enrolled. A 100% of implant survival rate was observed after 24 months of function. One failure occurred due to fracture of a Zirconia cad-cam abutment. Moreover, two abutment screw unscrewing were observed. Both for zirconia and titanium stock abutments (Group 1 and 2), the mean recession of implant buccal soft tissue was of 0.3 mm (SD of 0.3 and 0.4 mm, respectively). Soft tissue mean recession of zirconia and titanium cad-cam abutments (Group 3 and 4) was of 0.1 and -0.3 mm, respectively (SD of 0.3 and 0.4 mm, respectively). REC values of cad-cam titanium abutments (Group 4) were significantly lower than that of Group 1 (-0.57 mm), Group 2 (-0.61 mm), and Group 3 (-0.40 mm), respectively (Table 4). CONCLUSION: In the anterior area, the use of cad-cam abutments is related to a better soft tissue stability. Such a relationship is significant if cad-cam titanium abutments are compared to both titanium and zirconia stock abutments.

Dimensions of the healthy gingiva and peri-implant mucosa.

OBJECTIVE: To determine the dimensions of the soft tissue cuff present at various aspects of teeth and to compare these dimensions to those of the mucosa surrounding single implants. MATERIAL AND METHODS: Fifty volunteers were recruited that were ≥25 years of age and exhibited no signs of (i) untreated caries; (ii) loss of periodontal tissue support in the incisor, canine, and premolar regions; (iii) systemic or local disease. Furthermore, among the 50 patients recruited (iV), 27 had one single implant in the maxilla with teeth present mesial and/or distal to the implant. Probing pocket depth (PPD) and transmucosal sounding depth (TS) were assessed by five experienced, carefully calibrated examiners and with the use of a periodontal probe at the proximal (mesial, distal) and flat (facial, buccal and palatal/lingual) surfaces of all teeth/implants. The width of the keratinized mucosa (KM) was also determined. RESULTS: It was demonstrated that (i) PPD and TS were greater at proximal than at flat surfaces at both tooth and implant sites. In addition, both PPD and TS were deeper at implant than at tooth sites. The TS values documented that the cuff of healthy soft tissue that surrounded a tooth varied between 2 mm at flat surfaces and 4 mm at proximal surfaces, while at implant sites, the mucosa at proximal as well as flat surfaces was 1-1.5 mm greater. CONCLUSION: The probing pocket depth (PPD) and the transmucosal sounding depth (TS) values were greater at proximal than at flat, that is, facial/palatal (lingual) surfaces at tooth sites and frequently also at implant sites. Furthermore, the PPD and the TS dimensions were greater at implant than at adjacent tooth sites.

Mucosal inflammation and incidence of crestal bone loss among implant patients: a 10-year study.

OBJECTIVE: The objective of this prospective study was to determine the prevalence and incidence of marginal bone loss and, in addition, peri-implantitis in subjects and implant sites after 10 years in function. MATERIAL AND METHODS: One hundred and thirty-three subjects with a total of 407 implants that had been in function for about 5 years attended a follow-up visit in 2007 (visit 2; V2). 100 of the 133 subjects returned for a new clinical and radiographic examination in 2012 (visit 3; V3). The clinical examination included assessment of "bleeding on probing" (BoP+) and "probing pocket depth." Subjects with implant sites that in the radiograph exhibited crater-shaped marginal bone loss of >0.5 mm were identified as losers. RESULTS: During the interval between V2 and V3 (about 5 years), 13 implants in 7 subjects exhibited progressive bone loss and were removed. The overall amount of crestal bone loss that had occurred at the remaining implants between visit 1 (V1; ≥1 year of loading) and V3 (10 years) was small (0.36 ± 1.4 mm). The bone-level reduction was twice as great between V2 and V3 as between V1 and V2. Forty subjects and 75 (26%) implant sites exhibited marginal bone loss of >0.5 mm between V1 and V3. In the interval between V2 and V3, 37 new implant sites lost significant amounts of bone. During the entire 10-year period (V1-V3), 12% of patients and 5% of implants displayed signs of peri-implantitis (bone loss >0.5 mm, BoP+, PPD ≥6 mm), while in the V2-V3 interval, the corresponding numbers were 10% (patients) and 4% (implant sites). CONCLUSION: Sites with marginal bone loss of ≥1 mm were not common among implant patients. Peri-implantitis occurred in about 10% of patients and 4% of implant sites.

Managing the peri-implant mucosa: a clinically reliable method for optimizing soft tissue contours and emergence profile.

STATE OF THE PROBLEM: The proper representation of soft tissue contours for a natural aspect of the peri-implant mucosa and its mimesis with the adjacent teeth is a crucial aspect of the esthetic area restoration. PURPOSE: This paper describes a method for the easy transfer of the peri-implant tissue morphology onto impression material with a view to achieving an accurate, custom implant restoration. The procedure described is suitable both for single and multi-unit implant-supported prostheses. CLINICAL PROCEDURES: Once the peri-implant mucosa is sculpted by the provisional restoration, the emergence profile is duplicated. The implant analog is embedded into laboratory stone or plaster in a mixing cup and allowed to set. The provisional restoration is removed from the oral cavity and screwed to the implant analog; then, a polyether material is placed in the mixing cup so that the provisional restoration is put into impression material at the level of the prosthetic emergence profile. After the polyether polymerizing, the provisional prosthesis is unscrewed and replaced with the stock hexed transfer for the final impression. Next, cold self-curing resin is poured into this gap and left to set. A custom transfer for this single implant site is thus obtained. This modified transfer is then removed and screwed onto the implant in the oral cavity for the definitive impression. CONCLUSIONS: The technique described enables a faithful reproduction of the peri-implant soft tissues and emergence profile. CLINICAL SIGNIFICANCE: An emergence profile that mimics the natural tooth should be obtained by successful esthetic implant restoration. Moreover, it allows proper hygiene, which is fundamental for implant maintenance. The best way to achieve the correct emergence profile is to sculpture the peri-implant mucosa by means of a provisional prosthesis. Prefabricated provisional crowns cannot mimic the complexity and the variations of human soft tissue. Therefore, only a chair-side modification of the provisional restoration can accomplish the optimal result. Such a requirement can be satisfied by the clinical method described in the present report.

Virtual abutment design: a concept for delivery of CAD/CAM customized abutments-- report of a retrospective cohort.

This report presents early clinical experiences with the treatment of a consecutive cohort of 89 patients who received 125 prostheses supported by 205 milled abutments. Abutments were fabricated using unique computer-aided design software to deliver both titanium and zirconia abutments based on idealized values for tooth dimensions and emergence profiles as well as on a scan of the proposed definitive prosthesis.

A cross-sectional study on the prevalence of marginal bone loss among implant patients.

OBJECTIVE: The aim of the present cross-sectional retrospective study was to determine bone loss in a sample of subjects restored with implant-supported prostheses and the prevalence and severity of peri-implantitis in a sub-sample. MATERIAL AND METHODS: A total of 139 patients who had attended a follow-up visit in 2007 were considered for inclusion. Subjects with implants that had been in function for less than 3 years or had poor quality radiographs were excluded. The final study population comprised 133 subjects with a total of 407 implants. Radiographic measurements identified subjects who had ≥1 implant site exhibiting marginal bone loss of >0.5 mm; 40 subjects met this criterion and were recalled for a clinical examination. Of the 40 subjects that were recalled for the clinical examination, 30 attended. The following parameters were recorded at mesial, distal, buccal, and lingual/palatal aspects of all implants: oral hygiene standard (plaque), bleeding on probing, probing pocket depth (PPD). RESULTS: The mean interval between the baseline (1-year post-loading) and the follow-up radiographs was 4.8 ± 2.3 years. In the total subject sample (133 subjects and 407 implants), the mean amount of marginal bone loss that had occurred was 0.2 ± 1.2 mm. Ninety-three subjects with 246 implant sites exhibited no bone level alteration (group A), whereas 40 subjects with 161 implant sites (group B) displayed marginal bone loss of >0.5 mm at ≥1 implant (loser site). Sixty-eight implant sites in group B exhibited bone loss of >0.5 mm. However, only 20% of subjects and 11% of sites had lost >1 mm marginal bone, and 8% of subjects and 4% of sites had lost >2 mm bone. The total amount of bone loss that had occurred in group B was (i) 0.88 ± 1.5 mm and (ii) among the loser sites 2.1 ± 1.4 mm. Thirty subjects from group B were exposed to a clinical examination; out of 37 sites with bone loss >0.5 mm in this subgroup, 29 sites had a PPD value of ≥4 mm. CONCLUSION: Marginal bone loss (>0.5 mm) at implants was observed in 30% of subjects and 16% of implant sites. More advanced loss of marginal bone occurred in much fewer subjects and sites. Sites with marginal bone loss was in the sub-sample characterized by bleeding on probing, but only occasionally with deep (≥6 mm) pockets.