Short communication: Cemented implant reconstructions are associated with less marginal bone loss than screw-retained reconstructions at 3 and 5 years of loading

OBJECTIVES To analyse whether there is a difference in marginal bone levels (MBL) and the respective changes between cemented and screw-retained reconstructions at 3 and 5 years of loading. METHODS Radiographic data from 14 prospective multicentre clinical trials following implant loading with fixed cemented (CEM) or screw-retained (SCREW) reconstructions with a 3- to 5-year follow-up were retrieved from a database. MBL and MBL changes were assessed at initiation of implant loading (BL), at 3 (FU-3) and 5 years (FU-5) thereafter. The presence of peri-implantitis was also determined. RESULTS Data from 1,672 implants at BL, 1,565 implants at FU-3 and 1,109 implants at FU-5 were available. The mean MBL amounted to 0.57 mm (SD 0.87) at BL, 0.55 mm (SD 0.86) at FU-3 and 0.65 mm (SD 1.18) at FU-5. At FU-3, the mean MBL was 0.44 mm (SD 0.65) in group CEM and 0.63 mm (SD 0.99) in group SCREW showing a significant difference between the groups (intergroup <0.05). At FU-5, the mean MBL was 0.42 mm (SD 0.77) in CEM and 0.80 mm (SD 1.37) in SCREW, again with significant differences between both groups (p < .05). MBL changes between BL and FU-3 amounted to 0.11 mm (SD 1.02) (bone loss) in SCREW and -0.17 mm (SD 1.03) (bone gain) in CEM. Similarly, mean MBL changes from BL to FU-5 amounted to 0.23 mm (SD 1.31) (bone loss) in SCREW and -0.26 mm (SD 1.27) (bone gain) in CEM. The prevalence of peri-implantitis amounted to 6.9% in CEM and 5.6% in group SCREW (intergroup p = .29063) at FU-3. At FU-5, peri-implantitis amounted to 4.6% in CEM and 6.2% in group SCREW (intergroup p = .28242). CONCLUSION Cemented implant reconstructions compared with screw-retained reconstructions revealed higher marginal bone levels and similar rates of peri-implantitis during 5 years. The difference in MBL and the respective changes between the two groups, however, appear to be clinically negligible

Outcome measures and methods of assessment of soft-tissue augmentation interventions in the context of dental implant therapy: A systematic review of clinical studies published in the last 10 years.

AIM The aim of the study was to identify and report outcome measures and methods of assessment on soft-tissue augmentation interventions in the context of dental implant therapy reported in clinical studies published in the last 10 years. MATERIAL AND METHODS The protocol of this PRISMA 2020-compliant systematic review was registered in PROSPERO (CRD42021252214). A literature search was conducted to identify articles that met the pre-established eligibility criteria. Data of interest, with an emphasis on outcome measures, were extracted. For each outcome, specific methods and timing of assessment were described in detail. Following a critical qualitative analysis of the data, outcome measures were categorized. Primary outcomes were identified and the frequency of reporting in the selected articles was calculated. Additionally, risk of bias assessments were performed for individual articles and primary outcomes. RESULTS Ninety-two articles, of which 39 reported randomized controlled trials (RCTs), 20 reported non-RCTs, and 33 reported case series studies, were selected. Outcome measures were categorized into either investigator-evaluated outcome measures (i.e., clinical, digital imaging, esthetic, histologic, biomarker, and safety) or patient-reported outcome measures (PROMs). Clinical outcomes were the most frequently reported type of outcome. Considering all categories, the most frequently reported primary outcomes were facial mucosa thickness assessed with clinical methods (22.83%), facial keratinized mucosa width assessed with clinical methods (19.57%), facial mucosal margin position/recession assessed with clinical methods (18.48%), facial mucosa thickness assessed with digital imaging methods (11.96%), facial soft-tissue volume assessed with digital imaging methods (9.78%), and supracrestal tissue height assessed with clinical methods (9.78%). No distinguishable patterns of association between specific types or quality (level of bias) of clinical studies and the choice of primary outcomes were observed. CONCLUSION Clinical research on peri-implant soft-tissue augmentation has progressively increased in the last 10 years. Although clinical outcome measures were the most frequently reported outcomes in the selected literature, trends in the field are indicative of a shift from traditional clinical assessment methods to the use of digital technologies. PROMs were generally underreported but should be considered an integral methodological component in future clinical studies

The 3D emergence profile on implant-supported restorations: A method for evaluating restorative angles

STATEMENT OF PROBLEM: Emerging evidence indicates that the emergence profile and subsequent restorative angle play a crucial role in clinical outcomes and can potentially affect the development and progression of peri-implant diseases. However, the traditional evaluation of the emergence profile and angle has been limited to mesial and distal sites using periapical x-rays, without considering the buccal sites. PURPOSE: To describe a novel 3D method to estimate the emergence profile and restorative angles around single implant-supported crowns including buccal sites. MATERIALS AND METHODS: A total of 30 implant-supported crowns (11 molars, 8 premolars, 8 central incisors and 1 canine) were extra-orally scanned using an intraoral scanner and the STL files produced were imported into a 3D software. The crown/abutment interface of each crown was delineated, and apico-coronal lines were automatically drawn following the shape of the crown. Three reference points were defined on the apico-coronal lines at the transition edge of the biological (BC) and the esthetic zone (EC) and the resulting angles were then calculated. The reliability of the measurements (2D and 3D) were assessed using the intraclass correlation coefficient (ICC). RESULTS: In anterior restorations, the mean angle of the esthetic zone amounted to 162 ± 14° at mesial sites, to 140 ± 10° at buccal sites and to 163 ± 11° at distal sites. The corresponding angles at the biological zones, amounted to 155 ± 13° at mesial sites, 139 ± 15° at buccal sites and 157 ± 5° at distal sites. In posterior restorations, the mean angle of the esthetic zone amounted to 162 ± 12° at mesial sites, to 157 ± 13 at buccal sites and to 162 ± 11 at distal sites. The corresponding angles at the biological zone, amounted to 158 ± 8 at mesial sites, 150 ± 15° at buccal sites and 156 ± 10 at distal sites. The ICC for all measurements ranged between 0.77 and 0.99 indicating a good intra-examiner reliability. CONCLUSION: Within the limitations of the present study, the 3D analysis seems to be a reliable and applicable method for the quantitative evaluation of the emergence profile in daily practice. Future randomized clinical trials are needed to assess whether a 3D analysis with the ensuing the emergence profile serves as a predictor for clinical outcomes. CLINICAL SIGNIFICANCE: The development and implementation of a 3D workflow will provide technicians and dentists with the ability to assess the restorative angle of implant-supported restorations during the provisional phase and the final restoration. This approach may help achieve an aesthetically pleasing restoration while minimizing potential clinical complications

Outcome measures and methods of assessment of soft tissue augmentation interventions in the context of dental implant therapy: A systematic review of clinical studies published in the last 10 years.

AIM To identify and report outcome measures and methods of assessment on soft tissue augmentation interventions in the context of dental implant therapy reported in clinical studies published in the last 10 years. MATERIALS AND METHODS The protocol of this Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) 2020-compliant systematic review was registered in PROSPERO (CRD42021252214). A literature search was conducted to identify articles that met the pre-established eligibility criteria. Data of interest, with an emphasis on outcome measures, were extracted. For each outcome, specific methods and timing of assessment were described in detail. Following a critical qualitative analysis of the data, outcome measures were categorized. Primary outcomes were identified, and the frequency of reporting in the selected articles was calculated. Additionally, risk-of-bias assessments were performed for individual articles and primary outcomes. RESULTS Ninety-two articles, of which 39 reported randomized controlled trials (RCTs), 20 non-RCTs, and 33 case series studies, were selected. Outcome measures were categorized into either investigator-evaluated outcome measures (i.e., clinical, digital imaging, aesthetic, histological, biomarker, and safety) or patient-reported outcome measures (PROMs). Clinical outcomes were the most frequently reported type of outcome. Considering all categories, the most frequently reported primary outcomes were facial mucosa thickness assessed with clinical methods (22.83%), facial keratinized mucosa width assessed with clinical methods (19.57%), facial mucosal margin position/recession assessed with clinical methods (18.48%), facial mucosa thickness assessed with digital imaging methods (11.96%), facial soft tissue volume assessed with digital imaging methods (9.78%), and supracrestal tissue height assessed with clinical methods (9.78%). No distinguishable patterns of association between specific types or quality (level of bias) of clinical studies and the choice of primary outcomes were observed. CONCLUSIONS Clinical research on peri-implant soft tissue augmentation has progressively increased in the last 10 years. Although clinical outcome measures were the most frequently reported outcomes in the selected literature, trends in the field are indicative of a shift from traditional clinical assessment methods to the use of digital technologies. PROMs were generally under-reported but should be considered an integral methodological component in future clinical studies

Cemented vs screw-retained zirconia-based single implant reconstructions: A 3-year prospective randomized controlled clinical trial

OBJECTIVES The objective of the present randomized clinical trial was to test whether or not the use of screw-retained all ceramic implant-borne reconstructions results in clinical, technical, and biologic outcomes similar to those obtained with cemented all ceramic reconstructions. The hypothesis was that there is no difference in clinical, technical, and biological parameters between the two types of retention. MATERIALS AND METHODS Forty-four patients randomly received 20 cemented reconstruction (CR) and 24 screw-retained (SR) all ceramic single crowns on two-piece dental implants with nonmatching implant-abutment junctions. All patients were recalled after crown insertion, at 6 months, 1 year, as well as at 3 years. At these visits, biological and radiographic evaluations were performed. Technical outcomes were assessed using modified USPHS (United States Public Health Service) criteria. Data were statistically analyzed with Wilcoxon-Mann-Whitney, Wilcoxon and Fisher exact tests. RESULTS During 3 years of follow-up, eight patients (18.2%) lost the reconstruction due to technical (6 patients, 13.6%, 2 CR and 4 SR group) or biological complications (2 patients, 4.5%, only CR group). Thirty-two subjects with 18 SR and 14 CR reconstructions attended the FU-3Y, whereas four patients (9.1%, 2 SR, 2 CR) were not available (drop-outs). Biological, technical, and radiographic outcomes did not differ significantly between the groups (P > 0.05). One implant (2.3%) was lost in the CR group. One more cemented crown (2.3%) had to be removed because of peri-implant disease. Six patients (13.6%) lost the reconstructions due to a fracture of the zirconia abutment (4 SR, 2 CR). The mean marginal bone level at 3 years was -0.4 mm (-0.5; -0.3) in group SR and - 0.4 mm (-0.6; -0.3) group CR (P = 0.864). CONCLUSIONS At 3 years, CR and SR exhibited similar survival technical, biological and radiographic outcomes. The rate of technical complications was high in both groups

Survival and complication rates of two dental implant systems supporting fixed restorations: 10-year data of a randomized controlled clinical study

OBJECTIVES To compare clinical, radiographic, biological and technical long-term outcomes of two types of dental implants over a period of 10 years. MATERIALS AND METHODS Ninety-eight implants were placed in 64 patients, randomly allocated to one of two manufacturers (AST and STM). All implants were loaded with fixed restorations. Outcome measures were assessed at implant insertion (T$_{i}$), at baseline examination (T$_{L}$), at 1, 3, 5, 8 and 10 (T$_{10}$) years. Data analysis included survival, bone level changes, complications and clinical measures. RESULTS Re-examination was performed in 43 patients (23 AST and 20 STM) at 10 years. The implant level analysis was based on 37 (AST) and 32 (STM) implants. Survival rates of 100% were obtained for both groups. The median changes of the marginal bone levels between baseline and T$_{10}$ (the primary endpoint) amounted to a loss of 0.07 mm for group AST and a gain of 0.37 mm for group STM (intergroup p = 0.008). Technical complications occurred in 27.0% of the implants in group AST and in 15.6% in group STM. The prevalence of peri-implant mucositis was 29.7% (AST) and 50.1% (STM). The prevalence of peri-implantitis amounted to 0% (AST) and 6.3% (STM). CONCLUSIONS Irrespective of the implant system used, the survival rates after 10 years were high. Minimal bone level changes were observed, statistically significant but clinically negligible in favor of STM. Technical complications were more frequently encountered in group AST, while group STM had a higher prevalence of peri-implant mucositis

Precision of digital implant models compared to conventional implant models for posterior single implant crowns: A within-subject comparison

OBJECTIVE To calculate the precision of the implant analog position in digital models generated from different computer-assisted design and computer-assisted manufacturing (CAD-CAM) systems compared to gypsum models acquired from conventional implant impressions. MATERIALS AND METHODS In five patients in need of a single implant crown, a within-subject comparison was performed applying four different manufacturing processes for the implant model. Each implant was scanned with three different intraoral scanners: iTero Cadent (ITE), Lava True Definition (LTD), and Trios 3Shape (TRI). All digital implant models were fabricated using the corresponding certified CAD-CAM workflow. In addition, a conventional impression was taken (CON) and a gypsum model fabricated. Three consecutive impressions were acquired with each impression system. Following fabrication, all implant models were scanned. The datasets were aligned by a repeated best-fit algorithm and the precision for the implant analog and the adjacent teeth was measured. The precision served as a measure for reproducibility. RESULTS Mean precision values of the implant analog in the digital models were 57.2 ± 32.6 µm (ITE), 88.6 ± 46.0 µm (TRI), and 176.7 ± 120.4 µm (LTD). Group CON (32.7 ± 11.6 µm) demonstrated a statistically significantly lower mean precision value for the implant position in the implant model as compared to all other groups representing a high reproducibility. The mean precision values for the reference ranged between 31.4 ± 3.5 µm (TRI) and 39.5 ± 16.5 µm (ITE). No statistical significant difference was calculated between the four treatment groups. CONCLUSIONS The conventional implant model represented the greatest reproducibility of the implant position. Digital implant models demonstrated less precision compared to the conventional workflow

Histologic analyses of flapless ridge preservation in sockets with buccal dehiscence defects using two alloplastic bone graft substitutes

OBJECTIVES To investigate whether one of two synthetic bone substitute materials used for ridge preservation in the extraction sockets with buccal dehiscence defects was superior regarding new bone formation and ridge preservation and to compare it to sites left for spontaneous healing. MATERIALS AND METHODS In sixteen dogs, P3 and P4 were hemi-sectioned and the respective distal roots were extracted. Following the preparation of a mucoperiosteal flap without vertical releasing incisions, 50% of the buccal bone was carefully removed. The extraction sites were randomly assigned either to a ridge preservation procedure (alloplastic bone substitute material (two test groups)) or to spontaneous healing (control group). Descriptive histology and histomorphometric analyses were performed at healing times of 4, 8, and 16 weeks. In case of homogeneous variances, the results were analyzed by one-way ANOVA, followed by Tukey's post-hoc test. If inhomogeneous, the data was analyzed using Welch-type ANOVA, followed by the Games-Howell post-hoc test. RESULTS The use of bone substitute material led to significantly greater horizontal dimensions amounting to 3.3 mm (SD = 0.67; test 1) and 3.5 mm (SD = 0.72; test 2) compared to spontaneous healing (1.7 mm, SD = 0.23) at 16 weeks of healing (p  0.05). The final ridge profile was more favorable after ridge preservation (p < 0.001) as demonstrated by a loss of 28.8% (spontaneous healing) and an increase in both test groups at 16 weeks (test 1 = 60.5% and test 2 = 31.2%). CONCLUSIONS The use of alloplastic materials rendered greater horizontal dimensions and a more favorable maintenance of the ridge profile. CLINICAL RELEVANCE Alloplastic bone substitute materials can successfully be used for ridge preservation procedures

Clinical and patient-reported outcomes of implants placed in autogenous bone grafts and implants placed in native bone: A case-control study with a follow-up of 5-16 years

AIMS To compare the radiographic marginal bone levels of implants placed in sites previously augmented with autogenous bone grafts and implants placed in native bone. Secondary outcomes included: implant survival, periodontal/peri-implant parameters as well as short- and long-term patient-reported outcome measures. MATERIALS AND METHODS The study was designed as a case-control study including 38 patients equally distributed into two groups (previously augmented with autogenous bone blocks [AB] and implants placed in native bone [NB]). In total, 67 implants were placed. Clinical, radiographic and patient-reported outcome measures (PROMs), and complication rates were assessed based on a chart review and at a follow-up examination (≧5 years after implant placement). Nonparametric mixed models were applied for the comparison of the two groups because of the clustered data. The data were analyzed descriptively, and p-values were calculated using nonparametric mixed models to account for the clustered data. RESULTS The mean follow-up time was 10.2 years (range 6-13 years; AB) and 8.3 years (range 5-16 years; NB). One implant was lost in group NB (97.5% survival rate) and none in group AB (100%). Following primary augmentation, six major complications (wound dehiscences, acute pulpitis, intra- and extraoral sensitivity disturbances) were observed at the donor sites. At time of implant placement, only minimal complications occurred and only in group NB. Median marginal bone levels at the follow-up were significantly higher in group NB (1.15; Q1: 0.50 mm/Q3: 1.83 mm) than in group AB (1.58; Q1: 1.01 mm/Q3: 2.40 mm; p = 0.0411). Probing depth, bleeding on probing and recession values were similar in both groups. PROMs revealed high visual analog scale values (i.e., high satisfaction) for both procedures. CONCLUSIONS Dental implants placed in sites augmented with autogenous bone or in native bone revealed healthy peri-implant tissues after 5-16 years. Marginal bone levels were significantly higher for implant placed in native bone. Complications following primary augmentation encompassed every third patient but were mostly transient