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Background: The relation between implant abutment disconnection (AD) and increased crestal bone loss is still debated. Purpose To compare bone changes below implant‐abutment junction of subcrestally placed implants between: (1) implant level restorations, that underwent four ADs and (2) implants with immediate tissue level abutment with no AD, 1 month (T2) and 1‐year (T3) after final restoration delivery. Materials and methods: Sixty‐four patients received 64 bone level implants with platform‐switching and conical connection in edentulous sites of posterior mandible and maxilla. All implants were placed 1.5 mm subcrestally and distributed among: (1) control group, that received a regular healing abutment and (2) test group with immediate tissue level (ITL) abutment, which was torqued to implants during surgery, transforming bone level implant to tissue level type. After 2–3 months of healing and a 1‐month temporization, final zirconia‐based screw‐retained crowns were delivered to both groups. Crestal bone levels were calculated after final crown delivery (T2); after 1‐year follow‐up (T3) and compared using Mann–Whitney U test (p ≤.05). Results: Early bone loss of the test and control groups was 0.14 ± 0.27 mm and 0.64 ± 0.64 mm, respectively; the 0.5 mm difference was statistically significant (p =.0001). Late bone loss was 0.06 ± 0.16 mm and 0.21 ± 0.56 mm for the test and control group, respectively; the 0.15 mm difference between the groups was no more statistically significant (p =.22). Both groups displayed bone gain, 0.08 and 0.43 mm, respectively, and the overall crestal bone loss was reduced. Conclusions: Immediate tissue level abutments can significantly reduce early bone loss when measured 1 month after final prosthesis delivery, however, after 1‐year follow‐up, difference between the groups was no more statistically significant. [ABSTRACT FROM AUTHOR]

Purpose Aims of the study were: (a) to register crestal bone loss around 1.5 mm subcrestally placed implants and epicrestally placed implants with soft tissue tenting technique, (b) to record bone remodeling in subcrestal group, and (c) to determine the increase of vertical soft tissues after tenting. Materials and methods: Thirty‐two patients with vertically thin tissues of 2 mm or less received 40 submerged bone level platform‐switched implants, divided into two groups—(a) 1.5 mm subcrestally placed implants and (b) epicrestally placed implants with soft tissue tenting over 2 mm healing abutments. At the second stage surgery, implants received 4 mm healing abutments, soft tissue thickness was measured in epicrestal group, and later implants were restored with zirconia‐based screw‐retained single restorations. Radiological images were taken at the second stage surgery, restoration delivery and after 2 years of follow‐up. Bone loss was calculated as a distance between implant neck and first radiographically visible bone‐to‐implant contact. Bone remodeling was calculated as a distance between the bone crest and implant neck. Mann‐Whitney U test was used for statistical analysis, significance set to 0.05. Results: After 2 years of follow‐up, Group 1 (subcrestal) had 0.18 ± 0.32 mm of bone loss, Group 2 (epicrestal with 2 mm healing abutment) had 0.51 ± 0.4 mm of bone loss, with statistically significant difference (P =.001). Bone remodeling in Group 1 (subcrestal) was 1.17 ± 0.51 mm. Vertical tissue thickness in epicrestal group before the intervention was 1.85 ± 0.26 and 3.65 ± 0.41 mm after the use of 2 mm healing abutment, with a statistical difference (P =.005). Conclusion: Subcrestal implant placement can significantly reduce crestal bone loss, compared to vertical soft tissue thickening by tenting of epicrestally placed implants, although soft tissue tenting can significantly increase soft tissue thickness. [ABSTRACT FROM AUTHOR]

The cover image is based on the Original Article Influence of new immediate tissue level abutment on crestal bone stability of subcrestally placed implants. A 1‐year randomised controlled clinical trial by Tomas Linkevicius et al., https://doi.org/10.1111/cid.12979. [ABSTRACT FROM AUTHOR]

Background: Custom CAD CAM zirconia abutments must undergo various technical procedures including polishing which results in contamination of the abutment. Organic contaminants on the transmucosal abutment area may influence the inflammatory response of periimplant tissues. Conventionally steaming process is used for decontamination of abutments after technical stages. However, evidence suggests that steaming does not allow complete surface cleaning and additional decontamination protocols should be adopted Aim/Hypothesis: To evaluate the efficacy of different cleaning protocols employed to decontaminate organic compounds from zirconium oxide samples. Material and Methods: 18 rectangular specimens of predetermined size (10 × 10 × 3 mm) were sintered from zirconium oxide (Lava Classic 3M ESPE). All samples were polished with NTI CeraGlaze (Kerr) polishers and Zirkopol (Feguramed) diamond polishing paste. Then all specimens were blasted with steam. Samples were randomly assigned to one of the 3 groups (_I_n_i_ = 6)‐ A, B and C. For A group no additional cleaning was done. Specimens of B group underwent an ultrasonic cleaning procedure with water for 10 minutes. C group specimens were cleaned for 10 minutes in an ultrasonic bath with detergent solution (Siladent). Immediately after cleaning procedures samples were subjected to Energy‐dispersive X‐ray spectroscopy (EDX). In order to detect organic materials, level of carbon atoms was measured in arbitrary units. Mann‐Whitney U test was employed to compare differences between groups, with significance level 0.05. Results: EDX analysis revealed that samples in A group had highest levels of carbon atoms (mean 9.29 SD 3.67) on the surface compared to other cleaning protocols. Following B cleaning protocol resulted in lower carbon levels (mean 6.69 SD 3.56), yet the difference was not significant from steam blasted ones (_I_P_i_ = 0.439). All specimens of C group had no detectable carbon atoms (mean 0) and differed significantly from A group (_I_P_i_ = 0.018) and B group (_I_P_i_ = 0.037) Conclusions and Clinical Implications: Only following C group cleaning protocol total decontamination of the abutment surface from organic compounds can be expected. Therefore, it is advised to employ ultrasonic bath with detergent solution for cleaning procedures of the custom‐made abutments before delivery. Decontaminated surface of the abutment might be beneficial for the periimplant soft tissues. However, such statement has to be clinically demonstrated and a standardized cleaning protocol still has to be implemented.

Background: Custom‐made CAD‐CAM abutments made from zirconium oxide must undergo certain processing of the surface in a dental laboratory. However, the end point of polishing is defined subjectively 'until mirror‐like surface' by a dental technician and the actual surface roughness remains unknown. For comparison, stock abutments are manufactured to have surface roughness Ra of around 200 nm. Moreover, scientific material on achieving predetermined surface roughness of zirconium abutments is scarce. Aim/Hypothesis: To evaluate the surface roughness of zirconium oxide samples that undergo gradual polishing using commercially available polishing system and polishing paste. Furthermore, it was aimed to confine scientific based practical implications for zirconia polishing. Material and Methods: Fifty rectangular specimens of predetermined size (10 × 10 × 3 mm) were sintered from zirconium oxide (Lava Classic 3M ESPE) according to manufacturer's instructions. Samples were randomly assigned to one of the 5 groups (_I_n_i_ = 10)‐ Ctrl (control), Co (coarse), F (fine), SF (superfine) and PP (polishing paste). In the Ctrl group no polishing was done. Other specimens were processed using NTI CeraGlaze (Kerr) polisher system consisting of coarse green polisher (P301) for pre‐polishing, fine blue polisher (P3001) for refining and superfine yellow polisher (P30001) for reglaze‐high shine. Green CeraGlaze was used for group Co. Specimens of F group underwent processing with green CeraGlaze plus blue CeraGlaze. Yellow CeraGlaze in addition was used for samples in SF group. Finally, besides CeraGlaze instruments, Zirkopol (Feguramed) diamond polishing paste were used for PP group. Optical profilometer (Sensofar PLu 2300) was used to evaluate surface roughness Ra in nanometers (nm). Results: Surface roughness gradually decreased with further polishing through the groups‐ Ctrl – 525 (SD 99) nm, Co 252 (SD 38) nm, F – 196 (SD 35) nm, SF – 114 (SD 31) nm, PP – 54 (SD 20) nm. Statistically significant differences were detected between all groups (_I_P_i_ < 0.05). Conclusions and Clinical Implications: Zirconium oxide can be polished to various surface roughness using commercially available polishing products. Surface roughness of zirconium abutments similar to stock abutments (200 nm) can be achieved following Fine polishing protocol. Burnishing with diamond polishing paste (PP protocol) will result in surface roughness around 50 nm. The possibility to control surface roughness in a dental laboratory is an important advantage of custom‐made zirconium abutments. [ABSTRACT FROM AUTHOR]