Tissue-level versus bone-level single implants in the anterior area rehabilitated with feather-edge crowns on conical implant abutments: An up to 5-year retrospective study

Immediate loading full-arch rehabilitation using transmucosal tissue-level implants with different variables associated: a one-year observational study

BACKGROUND

The aim of the present observational study was to investigate the application of transmucosal tissue-level implants in immediate loading full-arch rehabilitation with different variables associated.

METHODS

Patients needing a full-arch implant rehabilitation were recruited and rehabilitated with four transmucosal tissue level implants. Data related to implants' diameters and lengths, jaw distributions, and presence of angulated abutments were collected. The following outcomes were evaluated: survival rate, marginal bone loss (MBL), Plaque Index (PI), bleeding on probing (BoP), probing depth (PD). Descriptive statistical analysis was reported and univariate linear regression models were built to assess a significant correlation between MBL and the different implant related factors.

RESULTS

Twenty patients were rehabilitated for a total implant number of 80; 11 rehabilitations were performed on the maxilla, while 9 were performed on the mandible; 48 implants presented a 3.8 mm diameter and 32 implants presented a 4.25 mm diameter. Implants length varied between 10 to 15 mm; 40 tilted implants were connected to angulated abutment, while 40 straight implants were connected directly to the prostheses (no abutments). At the one year follow-up visit no implants failed resulting in an implant survival rate of 100%. The overall MBL was 1.19±0.30 mm. No statistically significant difference (P>0.05) was highlighted among any of the subgroups analyzed.

CONCLUSIONS

Despite different variables associated, tissue level implants seem to represent a valid option when applied in immediate loading full-arch rehabilitation. Further research and longer observational periods are encouraged to confirm the result.

Clinical Outcomes of Dental Implants with Two Different Internal Connection Configurations—A RCT

Background: The aim of the present study was to highlight clinical and radiographical differences among implants sharing the same macro-geometry but with two different prosthodontic connections. Methods: Patients requiring at least 2 implants in the posterior area of the jaw were randomly divided into two groups (Conical (CS) and Internal Hexagonal (IH) connection). At implant surgery (T0), insertion torque, implant stability quotient (ISQ values recorded by resonance frequency analysis, RFA), and soft tissue thickness (STH) were assessed. A 1-abutment/1-time protocol was applied, and the prosthesis was realized following a fully digital workflow. At the 36-month follow-up periapical x-rays were taken. In order to statistically analyse differences among the two groups and the different variables, paired T-test was used. Linear regression analysis was conducted to analyze how marginal bone loss (MBL) was affected by other independent variables. A neural network created to predict the success (good or not good) of the implant itself was implemented. Results: 30 out of 33 patients (14 males, 16 females, mean age: 68.94 ± 13.01 years) (32 CS and 32 IH) were analyzed. No implants failed. Marginal bone loss at the 3-year time-point was 0.33 ± 0.34 mm and 0.43 ± 0.37 mm respectively for CS and IH with a significant difference between the two groups (p = 0.004). The presence of keratinized gingiva (p = 0.034) significantly influenced MBL. Conclusions: Both the implant connections investigated presented optimal clinical outcomes with minimal marginal bone loss; however, CS implants and implants with the presence of a greater width of keratinized tissue presented significantly lower MBL.

Full-Arch Rehabilitation Using Trans-Mucosal Tissue-Level Implants with and without Implant-Abutment Units: A Case Report

Recently, tissue-level implants with a convergent collar have been introduced. While different studies have investigated the outcomes of this implant design in the rehabilitation of single teeth, its use in full-arch rehabilitation has yet to be investigated. The present case report describes the clinical outcomes of a full-arch immediate loading rehabilitation using tissue-level implants, with and without using implant-abutment units, with 2 years of follow-up. A female patient with mandibular terminal dentition and a high level of bone resorption (distal areas with a few millimeters of residual bone in the vertical dimension and both distal and anterior areas with narrow crestal bone in the horizontal dimension) was seen at the C.I.R Dental School, Turin, Italy. The patient was seeking to be rehabilitated with fixed prosthodontics, and she was found eligible for an immediate loading implant full-arch rehabilitation. Four implants were inserted in the same appointment. The two anterior implants were inserted straight and connected directly to the prosthesis (no abutments); the two distal implants were tilted in order to avoid the alveolar nerve and connected to two 30° angulated abutments. Two years post-implant placement, all of the implants were successfully integrated, resulting in an implant survival rate of 100%. The peri-implant soft tissues were stable at all the implant sites. No differences were highlighted between those implants with and without abutments. Within the limitations of the present clinical report, implant full-arch rehabilitations with tissue-level implants both with and without implant-abutment units showed optimal outcomes after two years of follow-up. Further research is encouraged to confirm whether this implant design may be a valid alternative to traditional implants in this type of rehabilitation, with or without implant-abutment units.

The Characterization of Titanium Particles Released from Bone-Level Titanium Dental Implants: Effect of the Size of Particles on the Ion Release and Cytotoxicity Behaviour

Many studies are being carried out on the particles released during the implantoplasty process in the machining of dental implants to remove bacterial biofilms. However, there are no studies on the release of particles produced by the insertion of bone-level dental implants due to the high compressive frictional loads between the rough titanium implant and the bone tissue. This paper aims to characterize the released particles and determine the release of titanium ions into the physiological environment and their cytocompatibility. For this purpose, 90 dental implants with a neck diameter of 4 mm and a torque of 22 Ncm were placed in 7 fresh cow ribs. The placement was carried out according to the established protocols. The implants had a roughness Ra of 1.92 μm. The arrangement of the particles in the bone tissue was studied by micro-CT, and no particle clusters were observed. The different granulometries of 5, 15, and 30 μm were obtained; the specific surface area was determined by laser diffraction; the topography was determined by scanning electron microcopy; and the particles were chemically analysed by X-ray energy microanalysis. The residual stresses of the particles were obtained by X-ray diffraction using the Bragg-Bentano configuration. The release of titanium ions to the physiological medium was performed using ICP-MS at 1, 3, 7, 14, and 21 days. The cytocompatibility of the particles with HFF-1 fibroblast and SAOS-2 osteoblast cultures was characterized. The results showed that the lowest specific surface area (0.2109 m²/g) corresponds to the particles larger than 30 μm being higher than 0.4969 and 0.4802 m²/g of those that are 5 and 15 μm, respectively, observing in all cases that the particles have irregular morphologies without contamination of the drills used in the surgery. The highest residual stresses were found for the small particles, -395 MPa for the 5 μm particles, and -369 for the 15 μm particles, and the lowest residual stresses were found for the 30 μm particles with values of -267 MPa. In all cases, the residual stresses were compressive. The lowest ion release was for the 30 μm samples, as they have the lowest specific surface area. Cytocompatibility studies showed that the particles are cytocompatible, but it is the smallest ones that are lower and very close to the 70% survival limit in both fibroblasts and osteoblasts.

Analysis of Peri-Implant Bone Loss with a Convergent Transmucosal Morphology: Retrospective Clinical Study

OBJECTIVE

The aim of this study was to analyze the peri-implant bone loss of infracrestal, supracrestal, and crestal implants from the day of placement and up to 1 year of prosthetic loading.

MATERIAL AND METHODS

A retrospective clinical study was carried out. The sample consisted of 30 implants placed on 30 patients. It was divided into three groups: infracrestal (n = 10), crestal (n = 10), and supracrestal (n = 10) implants.

RESULTS

Following the statistical analysis, it was observed that, 4 months after implant placement, the mean values of total peri-implant bone loss were 0.04 mm in infracrestal implants, 0.26 mm in crestal implants, and 0.19 mm in supracrestal implants. At the end of one year of prosthetic loading, the peri-implant bone loss was 0.12 mm in infracrestal implants, 1.04 mm in crestal implants, and 0.27 mm in supracrestal implants. It was determined that peri-implant bone loss in crestal implants was significantly higher than in supracrestal implants, and these in turn were significantly higher than in infracrestal implants.

CONCLUSIONS

The implants that obtained a better biological behavior on peri-implant bone tissue were the infracrestal implants with a converging transmucosal abutment.

Comparison between Early Loaded Single Implants with Internal Conical Connection or Implants with Transmucosal Neck Design: A Non-Randomized Controlled Trial with 1-Year Clinical, Aesthetics, and Radiographic Evaluation

To evaluate the implant and prosthetic of two implants with different surfaces and neck design. Enrolled patients received bone level, 12° conical connection implants (Nobel Parallel, Nobel Biocare; NOBEL group) with anodized surface (TiUnite) and roughness of 1.35 μm, or transmucosal implant system (Prama, Sweden and Martina; PRAMA group) with convergent collar, ZIrTi surface, and roughness 1.4–1.7 μm. Both implants were made of pure grade IV titanium, with similar diameter and length, chosen according to the dentistry department availability and patient’s request. After early prosthesis delivery, patients were filled for at least one year. Outcome measures were: implant and prosthetic survival and success rates, physiological marginal bone remodeling, periodontal parameters and pink esthetic score (PES). Results: Fifteen patients were allocated and treated in each group. At the one-year follow-up, three patients dropped out, one in the NOBEL group and two in the PRAMA group. During the entire time of investigation, all implants survived and the prostheses were successful. No statistically significant differences were found in term of marginal bone loss, periodontal parameters, and aesthetics (p > 0.05). Conclusion: With the limitations of the present study, both implant systems showed successful clinical results. Finally, many other clinical and surgical variables may influenced marginal bone levels, implant survival, and periodontal parameters. More homogenous clinical trials with larger samples are needed to confirm these preliminary conclusions.