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Surface contaminants on customized implant abutments could trigger an inflammatory response in the peri-implant tissues. The aim of this randomized controlled study was to assess the radiographic bone changes around implants restored with customized, platform-switched abutments, with and without autoclave treatment, 12 months after definitive restoration. Dental implants were placed 1 mm subcrestally in 64 systemically healthy patients (mean age: 63.3 ± 10.0 years; 31 patients had a history of periodontitis) to replace single or multiple missing teeth. According to a randomization list, abutments were subjected to steam and autoclave sterilization (43 implants, test group) or steam cleaning alone (44 implants, control group). Periapical standardized radiographs were taken at implant placement, prosthetic abutment connection, and 12 months after definitive cement-retained restoration. All implants were clinically stable without any sign of infection at the 12-month follow-up. An average marginal bone loss of 0.25 ± 0.19 mm was found in the test group compared to 0.35 ± 0.23 mm in the control group (no statistically significant difference), while the percentage of bleeding sites was significantly higher in the control group (8.7% ± 13.1% vs 19.1% ± 19.8%; P = .035). Autoclave treatment of customized abutments seems to reduce the inflammatory response around subcrestally placed implants. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the bone level changes in a new implant design (fully tapered with platform switching) with the one-abutment one-time protocol after 1 year of loading. Materials and Methods: Thirty patients received 1 or 2 implants (6-, 8-, or 10-mm length and 3.5-, 3.75-, or 4.5-mm diameter, bone-level design) to replace one or multiple edentulous sites. Only the mesial implant was assessed. Radiographic, clinical, and esthetic results and the survival and success rates were evaluated 1 year after final loading. Results: At 1 year, no peri-implant bone loss was seen in any of the cases. Mean marginal crestal bone loss between surgery and crown placement was 0.19 ± 0.17 mm (P < .0001). Between surgery and the 1-year follow-up, the mean marginal crestal bone loss was 0.25 ± 0.24 mm (P < .0001). The difference in the modified Plaque Index between 1 year of follow-up and crown placement was significant for in the mesial (0.33 ± 0.54 mm; P = .003) and distal surfaces (0.5 ± 0.73 mm; P = .001). The probing pocket depth was statistically significantly deeper at 1 year than at crown placement at the mesial and distal aspects (average depth = 0.75 mm; P < .0005). No statistically significant differences were found for any other clinical or esthetic parameters. The overall survival and success rates after 1 year were 100%. Conclusions: The fully tapered, deep-thread, platform-switched implant design placed with the one-abutment one-time protocol demonstrated minimal marginal crestal bone loss and crestal bone stability at 1 year of follow-up. [ABSTRACT FROM AUTHOR]

AbstractAs large-language-model (LLM) AI chatbots create new pathways for problem-solving, they pose a challenge to the dominance of traditional search engines and knowledge sharing platforms. Utilizing theories of Status Quo Bias and Symbolic Consumption, this study investigates how user inertia and the perceived prestige of LLM AI chatbots influence the transition between platforms. A national survey comprising participants who have used LLM AI chatbots, knowledge sharing forums, and search engines (N = 800) within China was conducted. The findings obtained from structural equation modeling reveal that user inertia, rooted in habits and sunk costs, inhibits platform transition; however, the prestige of LLM AI chatbots can promote adoption and mitigate inertia; and entrenched media habits could, surprisingly, facilitate openness to new technologies. Implications on platform migration behavior amid technological advancements are discussed. [ABSTRACT FROM AUTHOR]

While the online learning industry has a positive growth rate, the completion rate has remained low in recent years. Previous studies have examined the influence of the push-pull-mooring effect on individuals' intentions to switch to non-formal educational platforms. Since financial and usability factors had been overlooked, this study added perceived price and perceived usefulness factors. Based on the push-pull-mooring framework, the study aimed to explore the drivers of users' intentions to switch for performance on nonformal education platforms. Data were gathered through an online survey of 370 respondents. Covariance-based structural equation modeling (CB-SEM) was used to analyze the data. The study's results showed an indirect influence of perceived price and perceived usefulness factors on individuals' switching intentions. By understanding the driving reasons behind the intention to switch to non-formal education platforms, the research was expected to assist education platform providers in developing platform services aligned with user needs. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the influence on peri‐implant crestal bone loss exerted by the vertical mucosal thickness and the abutment height over 12 months after placement of the restoration on subcrestal implants with change of platform, using a restoration abutment platform smaller than the implant platform. Materials and Methods: A total of 99 implants were rehabilitated in the maxillary and mandibular posterior regions. A total of 22 implants were rehabilitated in the maxilla and 77 implants in the mandible, using digitally designed customized abutments with Atlantis weborder software, from the commercial house Dentsply Sirona (Dentsply Sirona S.A., Barcelona, Spain), version 4.6.5, adapting the height to the vertical thickness of the mucosa. Clinical and radiographic monitoring begins during the surgical procedure of placement of the implant and ends 12 months afterwards. Crestal bone loss was evaluated through the Carestream® CS8100 3D radiographic equipment. Results: In all cases, the greatest loss of marginal bone occurred between the day of surgery (Tx) and placement of the rehabilitation (To). The average bone loss between both times was greater when the abutment height and vertical mucosal thickness did not exceed 3 mm. Subsequently, bone loss slowed and stabilized at 12 months. Conclusions: The minimum abutment height and the vertical mucosal thickness are factors to take into account when minimizing peri‐implant marginal bone loss, the abutment height having the greatest importance according to the clinical data obtained. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the long‐term (5 years) clinical efficacy of the one‐abutment one‐time protocol (test) versus the standard of care by placing the definitive abutment on the day of the prosthetic delivery (control). Materials and Methods: In this study, 39 subjects with 60 implants were randomly allocated to either the test or the control group. Changes in the radiographic interproximal bone levels (DIB), modified sulcus bleeding index, probing depth, modified plaque index, papilla fill (Jemt score), incidence of peri‐implantitis and peri‐implant mucositis as well as patient‐reported outcomes measures (PROMs) were collected and compared at 1, 3 and 5 years. Results: At 5 years, the control group showed a greater, although not statistically significant, change in mean DIB values (0.97 mm vs. 0.53 mm). Regarding the other clinical parameters evaluated, no statistically significant differences were observed between groups at any time point. At 5 years, 51% of the implants presented peri‐implant mucositis (25.5% in the control and 23.5% in the test), and only one implant in the test group developed peri‐implantitis. Conclusions: The connection and disconnection of healing abutments during the healing period was not associated with higher long‐term bone loss. Clinical outcomes and PROMs were similar between groups. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate studies with a minimum follow-up of 3 years to find the peri-implant marginal bone loss (MBL) and rate of implant failure with platform-switching (PS) and platform-matching (PM) implant-abutment connections. Materials and Methods: A systematic review and meta-analysis was done based on the preferred reporting items for systematic reviews and meta-analyses guidelines, with a focused question on population, intervention, comparison, and outcome. The Cochrane Collaboration's Risk of Bias tool was used to assess bias. Randomized controlled trials (RCTs) comparing peri-implant MBL and implant failure in patients receiving PS implants and PM implants only were included. The risk ratio (RR) of the implant-abutment connection and implant failure was calculated, and peri-implant MBL was expressed in mean differences (MD) at 95% confidence intervals (CIs). Results: Three hundred eighty-one articles were obtained after an initial literature search. Finally, nine articles were included in the study that fulfilled the inclusion criteria. Four hundred twenty-six PS and 411 PM implants were placed with 16 implant failures (8 PS and 8 PM). The implant survival rate was 98.12% for the PS group, and 98.05% for the PM group, with no statistically significant difference (P = .97). The mean peri-implant MBL with the PS implant was lower (0.33 ± 0.41 mm) compared with the PM implant (0.66 ± 0.42 mm). A significant effect of PS implants was found in reducing peri-implant MBL (MD: -0.70, 95% CI: -1.25,-0.15; P = .01) compared with PM implants. The MD of peri-implant MBL between the PS and PM implants decreases with increased follow-up: MD of 0.69 (P = .15) with follow-up of = 3 years but < 5 years, and MD of 0.62 (P = .04) with follow-up of = 5 years. Conclusion: Reduced peri-implant MBL was found with the PS concept. The peri-implant MBL decreases with an increased mismatch between the abutment and implant platform. The difference in peri-implant MBL in PS and PM implants in the maxilla was greater and favored the PS concept. Bone-level implants with single crowns or splinted prostheses better preserved the peri-implant marginal bone with the PS concept. [ABSTRACT FROM AUTHOR]

Purpose: This clinical study was conducted to compare the influence of a platform-switched bone-level implant and a platform-matched tissue-level implant on marginal bone loss during the first year after loading. Materials and Methods: Edentulous subjects who applied for two-implant-retained mandibular overdentures and showing sufficient bone volume for implants with 4.3-mm diameter and 12-mm length were enrolled. For standardization reasons, all subjects received a platform-matched tissue-level implant and a platform-switched bone-level implant in the anterior mandible. Since implants from the same manufacturer were used, both implants had identical implant thread designs and surface properties. All subjects received two-implant-retained mandibular overdentures with opposing maxillary complete dentures, and the implants were loaded after 6 weeks. Marginal bone loss was monitored via panoramic radiographs obtained immediately after loading and at the 6- and 12-month recalls after implant loading, and periodontal parameters, such as pocket probing depths, Plaque Index scores, and bleeding on probing, were also measured and recorded. Results: Twenty-six patients received 26 bone-level and 26 tissue-level implants. No statistically significant differences were detected between the bone loss of the two groups for all the measurements (P > .05). Additionally, no significant difference was detected between the measured periodontal parameters of the two groups (P > .05). Conclusion: Within the limitations of this prospective clinical study with a follow-up time of 12 months, it can be concluded that the platformswitching bone-level design and the platform-matching tissue-level design show similar bone loss in the anterior edentulous mandible. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to evaluate the peri‐implant soft tissue and marginal bone loss (MBL) around implants with platform‐switching and internal conical connection placed at crestal and subcrestal levels in posterior areas. Materials and methods: Nineteen partially edentulous patients with at least two adjacent missing teeth in posterior areas unilaterally or bilaterally were included. Forty‐two implants were placed randomly at the crestal or subcrestal (1 mm) level in a split‐mouth design. Implant‐supported fixed dental prostheses with screw retention were delivered after 4 months of healing. Clinical and radiological measurements were performed at implant placement (T0), restoration delivery (T1), and 1‐year follow‐up after loading (T2). MBL was calculated as the change in distance from the implant‐abutment interface to the first radiographically visible bone‐implant contact. A repeated‐measures mixed ANOVA followed by a paired Student's t‐test with the Bonferroni correction was used for statistical analysis. p < 0.05 was considered statistically significant. Results: Eighteen patients with thirty‐eight implants completed the study at T2. The MBL was lower in the subcrestal group than in the crestal group (0.04 ± 0.08 vs. 0.17 ± 0.17 mm, p = 0.004). The peri‐implant probing depth (PD) was 2.31 ± 0.48 mm in the subcrestal group and 1.92 ± 0.43 mm in the crestal group; this difference was statistically significant (p = 0.002). Intragroup comparison showed no significant differences in MBL, or PD around the crestal group and subcrestal group from T1 to T2. Conclusion: After 1 year of functional loading, subcrestal placement of implants with platform‐switching and internal conical connection showed lower MBL and was associated with greater PD and peri‐implant soft tissue height than implants placed at the crestal level. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this retrospective study was to evaluate the effect of vertical soft tissue thickness (STT) on crestal bone loss (CBL) of early loaded implants after 1 and 5 years. Method and materials: Forty-four tapered implants with platform switching and conical connection were placed in the posterior mandible and maxilla to rehabilitate edentulous sites. STT at implant sites was divided into two groups: thin (n = 21, mean STT = 2.0 ± 0.3 mm) and thick (n = 23, mean STT = 3.0 ± 0.8 mm). The implants were loaded after 6 to 8 weeks. Survival and success rates and CBL were measured after 1 and 5 years. Results: The survival and success rates at 1 and 5 years were 100% and 97.8%, respectively. At the 1-year follow-up, the CBL of the thin and thick gingival groups was 0.96 ± 0.49 and 0.55 ± 0.41 mm, respectively; the difference was statistically significant (P = .004). At 5 years, the CBL of the thin and thick gingiva groups increased to 1.12 ± 0.84 and 0.65 ± 0.69 mm, respectively; the difference was not statistically significant (P = .052). Conclusion: At 1 year, the CBL was more pronounced at sites with a thin gingiva; at 5 years the difference between the groups was not statisically significantly different. Within the limitations of this study, early loading of implants with platform switched and conical connection was safe. [ABSTRACT FROM AUTHOR]

Short dental implants with platform matching connection have been used for the rehabilitation of atrophic jaws whenever standard-length dental implants cannot be placed without prior bone augmentation. Yet, there remains a lack of data regarding the risk of technical failures when the all-on-4 configuration is performed in atrophic jaws with platform-switching distal short dental implants. Thus, the current study used the finite element method to evaluate the mechanical behavior at the level of the prosthetic components of the all-on-4 concept performed in atrophic mandible using short-length distal implants with platform switching (PSW) connection. Three models of the all-on-4 configuration were generated in human atrophic mandibles. The geometric models consisted of PSW connection tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) and straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants. A resultant force of 300 N was performed obliquely in the left side and posterior region of the prosthetic bar. The von Mises equivalent stress (σvm) and maximum and minimum principal stresses (σmax and σmin) were performed at level of the prosthetic components/implants and peri-implant bone crest, respectively. The general displacement of the models was also evaluated. The stress analysis was performed on the side of load application. The AO4S configuration showed the lowest values of σvm in the mesial left (ML) and distal left (DL) abutments (37.53 MPa and 232.77 MPa, respectively) and dental implants (91.53 MPa and 231.21 MPa, respectively). The AO4Sh configuration showed the highest values of σvm in the bar screw (102.36 MPa), abutment (117.56 MPa), and dental implant (293.73 MPa) of the ML area. Among the models, the highest values of σmax and σmin were noticed in the peri-implant bone crest of the AO4T design (131.48 MPa and 195.31 MPa, respectively). All models showed similar values of general displacements, which were concentrated in the mandible symphysis. The all-on-4 configurations designed with PSW connection and tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) or straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants were not associated with higher odds of technical failures. The AO4Sh design may be a promising option for the prosthetic rehabilitation of atrophic jaws. [ABSTRACT FROM AUTHOR]

Neveen S Abd El Rahim,1,2 Asmaa A Ashour1 1Department of Removable Prosthodontics, Faculty of Dental Medicine for Girls, Al-Azhar University, Cairo, Egypt; 2Department of Removable Prosthodontics, College of Dentistry, Taibah University, Medina, Saudi ArabiaCorrespondence: Asmaa A Ashour, Department of Removable Prosthodontics, Faculty of Dental Medicine for Girls, Al-Azhar University, Nasr, Cairo, Egypt, Tel +20 1284048535, Email aasmaa@azhar.edu.egPurpose: To evaluate the impact of the platform-switched implant on marginal bone loss (MBL) and the probing pocket depth (PPD) in patients wearing mandibular overdenture.Patients and Methods: This longitudinal study included 40 completely edentulous patients aged 51– 64 years. All patients received complete dentures and were distributed into two groups randomly; 20 patients each. The first group GI received two platform switched implants; however, the 2nd group GII received two platform matched implants (3.6 × 11.5 mm) in the canine region of the mandible. The radiographic evaluations were carried out every year for six years, whereas probing pocket depth was evaluated every six months for 72 months for both groups. The data were analyzed by repeated ANOVA, Friedman’s, and Student’s t-test.Results: This study included 36 patients; 56 ± 3.6 years was the mean age; 17 females (47%) and 19 males (53%) completed the study. Statistically significant differences were observed in MBL and PPD in each of GI and GII after 6 years, p ≤ 0.05. Between GI and GII after 6 years, a statistically insignificant difference was detected in MBL or PPD, p ≥ 0.05, except in PPD at loading, 2 and 6 years, p ≤ 0.05.Conclusion: Time positively affected MBL and PPD in platform switched and matched implants retained mandibular overdentures. Platform switching influences probing pocket depth in implants retained mandibular overdentures.Keywords: dental implant, platform switching, overdenture, supporting structures, COVID-19

Dental trauma is a serious and highly prevalent health issue across the globe. Most of the frequent dental injuries result in the loss of teeth and affects the overall quality of life. The loss of a tooth is usually compensated by a dental implant. The common methods adopted while placing the implant tooth are platform switching and platform matching. A plethora of works has studied the qualitative performance of these methods across different situations clinically. However, a detailed comparative work studying in-depth the mechanical parameters has not been attempted yet. In this computational work, two commonly available different platform-switched and one platform-matched implant-abutment configurations were compared. A 3D model of an implant (5.5 × 9.5 mm) was designed and inserted into a human mandibular bone block using computer-aided design (CAD) and extracting the clinical imaging data. Three separate models of implant-abutment configurations such as Platform Switched (PS)-I, a 5.5 mm implant with a 3.8 mm wide abutment, Platform Switched (PS)-II, a 5.5 mm implant with a 4.5 mm wide abutment, and Platform Matched (PM), a 5.5-mm implant with a 5.5 mm wide abutment were analyzed. Clinically relevant vertical-, horizontal-, and oblique-type of occlusal loadings were applied to each model to characterize the mechanical response. Mechanical parameters such as von Mises stresses, deformations, and strain energies were obtained using finite element modeling (FEM). These parameters showed lower values for platform switching within the peri-implant bone and that may help to limit marginal bone loss. However, the same parameters were increasing more in the abutment, implant, and screw for the platform-switched implant configuration than that of platform-matched configuration. The computational framework, along with the results, are anticipated to guide the clinicians and medical practitioners in making better decisions while selecting the commonly available methods. [ABSTRACT FROM AUTHOR]

Purpose: This randomized, controlled, split-mouth trial with a 3-year follow-up was carried out to compare radiologic changes of crestal bone level (CBL) between splinted tissue-level implants restored by platform matching and bone-level implants restored by platform switching. Materials and Methods: Periapical radiographs were taken to evaluate the peri-implant crestal bone changes at baseline (implant restoration), at 1 year, and at 3 years after the definitive restoration. Results: Thirty-five patients requiring a partial fixed dental prosthesis supported by two implants had their sites randomized according to receiving both implant types. Fifty tissue-level implants restored by platform matching, as control implants, and 50 bone-level implants restored by platform switching, as test implants, were placed. For baseline to 3 years, crestal bone changes were 0.18 ± 0.46 mm (P = .043) in the control group and 0.14 ± 0.35 mm (P = .514) in the test group. The mean differences between groups were as follows: baseline to 1 year, 0.07 ± 0.23 mm (95% CI: -0.034, 0.185); 1 to 3 years, 0.01 ± 0.01 mm (95% CI: -0.055, 0.074); baseline to 3 years, 0.04 ± 0.11 mm (95% CI: -0.080, 0.150). No statistically significant differences in CBL at baseline to 1 year (P = .269), 1 year to 3 years (P = .811), and baseline to 3 years (P = .513) were observed. Conclusion: In this trial, CBL changes in the tissue-level control group were statistically significant only between the baseline and 3-year follow-up. Meanwhile, CBL changes in the bone-level test group were not statistically significant in the different times studied. No statistically significant difference in CBL between two implant types was observed. [ABSTRACT FROM AUTHOR]

Abstract Background The combination of a prosthetic index with Morse taper connection was developed, with the purpose of making prosthetic procedures more precise. However, the presence of the index may compromise the mechanical performance of the abutment. The aim of this study is to evaluate the effect of prosthetic index on stress distribution in implant–abutment-screw system and peri-implant bone by using the 3D finite element methodology. Methods Two commercial dental implant systems with different implant–abutment connections were used: the Morse taper connection with platform switching (MT-PS) implant system and the internal hex connection with platform matching (IH-PM) implant system. Meanwhile, there are two different designs of Morse taper connection abutment, namely, abutments with or without index. Consequently, three different models were developed and evaluated: (1) MT-PS indexed, (2) MT-PS non-indexed, and (3) IH-PM. These models were inserted into a bone block. Vertical and oblique forces of 100 N were applied to each abutment to simulate occlusal loadings. Results For the MT-PS implant system, the maximum stress was always concentrated in the abutment neck under both vertical and oblique loading. Moreover, the maximum von Mises stress in the neck of the MT-PS abutment with index even exceed the yield strength of titanium alloy under the oblique loading. For the IH-PM implant system, however, the maximum stress was always located at the implant. Additionally, the MT-PS implant system has a significantly higher stress level in the abutment neck and a lower stress level around the peri-implant bone compared to the IH-PM implant system. The combined average maximum stress from vertical and oblique loads is 2.04 times higher in the MT-PS indexed model, and 1.82 times for the MT-PS non-indexed model than that of the IH-PM model. Conclusions MT-PS with index will cause higher stress concentration on the abutment neck than that of without index, which is more prone to mechanical complications. Nevertheless, MT-PS decreases stress within cancellous bone and may contribute to limiting crestal bone resorption.

Purpose: This retrospective study quantitatively analyzed the minimum prosthetic abutment height to eliminate bone loss after 4.7-mm-diameter implant placement in maxillary bone and how grafting techniques can affect the marginal bone loss in implants placed in maxillary areas. Materials and Methods: Two different implant types with a similar neck design were singularly placed in two groups of patients: the test group, with platformswitched implants, and the control group, with conventional (non-platform-switched) implants. Patients requiring bone augmentation underwent unilateral sinus augmentation using a transcrestal technique with mineralized xenograft. Radiographs were taken immediately after implant placement, after delivery of the prosthetic restoration, and after 12 months of loading. Results: The average mesial and distal marginal bone loss of the control group (25 patients) was significantly more than twice that of the test group (26 patients), while their average abutment height was similar. Linear regression analysis highlighted a statistically significant inverse relationship between marginal bone loss and abutment height in both groups; however, the intercept of the regression line, both mesially and distally, was 50% lower for the test group than for the control group. The marginal bone loss was annulled with an abutment height of 2.5 mm for the test group and 3.0 mm for the control group. No statistically significant differences were found regarding marginal bone loss of implants placed in native maxillary bone compared with those placed in the grafted areas. Conclusion: The results suggest that the shorter the abutment height, the greater the marginal bone loss in cement-retained prostheses. Abutment height showed a greater influence in platform-switched than in non-platform-switched implants on the limitation of marginal bone loss. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this randomized clinical trial with a 5-year follow-up was to assess the differences in radiographic levels of peri-implant bone crest between tissue-level implants restored with platform matching (control group) and bone-level implants restored with platform switching (test group) in the posterior region. Materials and Methods: To assess marginal bone level changes, periapical radiographs were taken at the moment of prosthesis delivery (baseline), at 1 year, and at 5 years after the definitive restoration. Results: One hundred subjects, partially edentulous in the posterior region, were selected for this study. There were 54 men and 46 women between the ages of 25 and 70 years (mean = 50.5 years). A total of 202 implants were assigned to both groups using a randomized procedure (100 implants in the control group and 102 in the test group). The mean marginal bone level (MBL) changes for tissue-level implants restored with platform matching were 0.26 ± 0.55 mm at baseline to 1 year, 0.34 ± 0.54 mm at 1 year to 5 years, and 0.61 ± 0.73 mm at baseline to 5 years. The mean MBL changes for bone-level implants restored with platform switching were -0.03 ± 0.74 mm at baseline to 1 year, -0.17 ± 0.67 mm at 1 year to 5 years, and -0.20 ± 0.75 mm at baseline to 5 years. The mean difference between the two groups was 0.31 mm at baseline to 1 year, 0.53 mm at 1 year to 5 years, and 0.85 mm at baseline to 5 years. There was a statistically significant difference in MBL (P < .001). Both implant systems showed good and similar survival rates (98% for tissue-level implants restored with platform matching and 96.1% for bone-level implants restored with platform switching). Conclusion: In this randomized controlled trial, the following observations were made. Radiographic levels of peri-implant bone crest in tissue-level implants restored by platform matching were statistically significant in the three interval times. Meanwhile, MBL changes for bone-level implants restored with platform switching were not statistically significant in the different times studied. Nevertheless, the mean difference between the two groups was statistically significant. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the impact of the platform-switched implant on marginal bone loss (MBL) and the probing pocket depth (PPD) in patients wearing mandibular overdenture. Patients and Methods: This longitudinal study included 40 completely edentulous patients aged 51– 64 years. All patients received complete dentures and were distributed into two groups randomly; 20 patients each. The first group GI received two platform switched implants; however, the 2nd group GII received two platform matched implants (3.6 × 11.5 mm) in the canine region of the mandible. The radiographic evaluations were carried out every year for six years, whereas probing pocket depth was evaluated every six months for 72 months for both groups. The data were analyzed by repeated ANOVA, Friedman's, and Student's t-test. Results: This study included 36 patients; 56 ± 3.6 years was the mean age; 17 females (47%) and 19 males (53%) completed the study. Statistically significant differences were observed in MBL and PPD in each of GI and GII after 6 years, p ≤ 0.05. Between GI and GII after 6 years, a statistically insignificant difference was detected in MBL or PPD, p ≥ 0.05, except in PPD at loading, 2 and 6 years, p ≤ 0.05. Conclusion: Time positively affected MBL and PPD in platform switched and matched implants retained mandibular overdentures. Platform switching influences probing pocket depth in implants retained mandibular overdentures. [ABSTRACT FROM AUTHOR]

Background: The combination of a prosthetic index with Morse taper connection was developed, with the purpose of making prosthetic procedures more precise. However, the presence of the index may compromise the mechanical performance of the abutment. The aim of this study is to evaluate the effect of prosthetic index on stress distribution in implant–abutment-screw system and peri-implant bone by using the 3D finite element methodology. Methods: Two commercial dental implant systems with different implant–abutment connections were used: the Morse taper connection with platform switching (MT-PS) implant system and the internal hex connection with platform matching (IH-PM) implant system. Meanwhile, there are two different designs of Morse taper connection abutment, namely, abutments with or without index. Consequently, three different models were developed and evaluated: (1) MT-PS indexed, (2) MT-PS non-indexed, and (3) IH-PM. These models were inserted into a bone block. Vertical and oblique forces of 100 N were applied to each abutment to simulate occlusal loadings. Results: For the MT-PS implant system, the maximum stress was always concentrated in the abutment neck under both vertical and oblique loading. Moreover, the maximum von Mises stress in the neck of the MT-PS abutment with index even exceed the yield strength of titanium alloy under the oblique loading. For the IH-PM implant system, however, the maximum stress was always located at the implant. Additionally, the MT-PS implant system has a significantly higher stress level in the abutment neck and a lower stress level around the peri-implant bone compared to the IH-PM implant system. The combined average maximum stress from vertical and oblique loads is 2.04 times higher in the MT-PS indexed model, and 1.82 times for the MT-PS non-indexed model than that of the IH-PM model. Conclusions: MT-PS with index will cause higher stress concentration on the abutment neck than that of without index, which is more prone to mechanical complications. Nevertheless, MT-PS decreases stress within cancellous bone and may contribute to limiting crestal bone resorption. [ABSTRACT FROM AUTHOR]

Clinicians very often have seen marginal bone loss around dental implants at the crest level early on after implant placement and uncovering. Early clinical publications had suggested that this bone loss occurred during the first year of loading. Thus, numerous attempts have been made to minimize or eliminate such bone loss. However, the timing and reason for this bone loss are not always apparent. The objective of this study was to review the evidence regarding marginal bone loss around dental implants from the standpoint of biologic consequences to help understand marginal bone changes around dental implants. One hypothesis for the bone loss around these implants was related to the presence of bacteria in the interfaces between the implant and abutment connections. The literature was reviewed regarding the three major types of implant-abutment crestal connections, including butt-joint, platform-switched and no interface (tissue-level or one-body). This review article revealed that 1.5 to 2.0 mm of bone loss occurred around bone-level, butt-joint connections when the interface was created because the microgap was wide enough for penetration and colonization of bacteria, and that this bone loss was not observed around implants with no interface because they did not have a contaminated interface at the bone crest. Many studies have shown an advantage in the amount of marginal bone resorption for implants with a platform-switched connection and there appears to be a significantly different biologic reaction. Recent publications indicate that such contaminated implant-abutment connections might have an effect on peri-implantitis and failure over time. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this prospective study was to evaluate radiographic levels of peri-implant bone crest as well as soft tissue response, papilla height, and buccal mucosa recession, in bone-level implants restored with platform switching after 1-year and 5-year follow-ups. Materials and Methods: This prospective study called for the placement of 59 implants to obtain a target of 90% power. To compensate for possible dropouts, the sample size was adjusted to 67 implants. To assess marginal bone level changes, periapical radiographs were taken at baseline, 1 year, and 5 years after the definitive restorations. Peri-implant soft tissue modifications were evaluated by performing a photographic sequence at 15 days, 1 year, and 5 years after implant restoration. Parameters measured were: (1) distance from the tip of the papilla to the contact point and (2) apicocoronal crown length. Results: A one-way analysis of variance (ANOVA rank test) was used to compare quantitative data among the three time points studied. Mean marginal bone level changes were as follows: -0.06 ± 0.32 mm from baseline to 1 year, -0.23 ± 0.38 mm from 1 to 5 years, and -0.28 ± 0.45 mm from baseline to 5 years. In bone-level outcomes, no statistically significant differences were found between baseline and 1 year, while the mean differences between 1 and 5 years and baseline and 5 years showed statistically significant differences. In the soft tissue analysis, the distance from the tip of the papilla to the contact point showed the following values: baseline, 2.08 mm; 1 year, 1.54 mm; 5 years, 1.31 mm. No statistically significant differences were found between baseline and 1 year, whereas statistically significant differences between 1 and 5 years and baseline and 5 years were found. Apicocoronal crown length measurements showed the following values: baseline, 9.44 mm; 1 year, 9.28 mm; 5 years, 9.81 mm. No significant differences were found between times studied. Conclusion: This prospective clinical study of 67 bone-level implants restored according to the platform-switching concept reported that radiographic levels of peri-implant bone crest were statistically significant between 1 and 5 years and baseline and 5 years. For the soft tissue response, the greatest reduction in the distance from the papilla to the contact point from 1 to 5 years and baseline to 5 years was observed. No significant differences were shown in the buccal margin. [ABSTRACT FROM AUTHOR]

Purpose: To correlate soft tissue thickness and peri-implant bone remodeling of platform-switching implants. Materials and Methods: This comparative prospective trial evaluated, for up to 3 years after implant loading, the influence of soft tissue thickness on changes in peri-implant marginal hard tissue levels. Any patient who was partially edentate in the mandible and required at least two adjacent implant-supported restorations was recruited at the University of Valencia in Spain. A 3-mm tissue punch biopsy, which corresponded to a diameter slightly smaller than the coronal diameter of the implants, was performed using a circular mucotome. Afterward, implants with a length of 10 to 13 mm and a diameter of 3.8 mm were inserted. Outcome measures were implant and prosthesis survival rates, marginal hard tissue changes, any complications, and results of morphologic and histomorphometric analyses. Correlation between mucosa width components (epithelium, connective tissue, and epithelium and connective tissue) and radiographic bone loss at 1 and 3 years after loading was performed at the patient level. Statistical significance was set at P ≤ .05. Results: A total of 26 samples in 26 patients with 68 implants were analyzed. The specimens were divided into two groups: group 1 (16 patients, 40 implants), with thin mucosa (≤ 2 mm), and group 2 (10 patients, 28 implants), with thick mucosa (> 2 mm). Two dropouts (two specimens) were recorded at the 3-year follow-up. None of the implants or definitive prostheses failed during the healing period, resulting in an overall implant and prosthesis cumulative survival rate of 100%. No major biologic or mechanical complications were recorded. The mean (standard deviation, SD) epithelium thickness was 430.33 (250.21) μm; the mean (SD) connective tissue thickness was 1,324.31 (653.46) μm, and the mean (SD) mucosa thickness was 1,751.29 (759.53) μm. Comparisons of radiographic bone loss between group 1 and group 2 failed to show any statistically significant differences at the 1-year (P = .290) or 3-year (P = .090) follow-up examinations. Conclusion: The initial mucosa thickness surrounding a bone-level platform-switching implant seems not to influence the pattern of physiologic marginal bone loss. [ABSTRACT FROM AUTHOR]

Purpose: This systematic review and meta-analysis was aimed at evaluating the longitudinal effect of platform switching on implant survival rates as well as on soft and hard tissue outcomes. Materials and Methods: An electronic search of the databases of the National Center for Biotechnology Information, PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Collaboration Library was conducted in February 2015. Studies published in English with at least 10 human participants and a 12-month postloading follow-up were included. Random effects meta-analyses of selected studies were applied to compare the primary and secondary outcomes of platform-switched (PS) and regular-platform (RP) implants, as well as the experimental designs and clinical outcomes. Results: A total of 26 studies involving 1,511 PS implants and 1,123 RP implants were evaluated. Compared to RP implants, PS implants showed a slight increase in vertical marginal bone loss (VMBL) and pocket depth reduction (weighted mean differences were –0.23 mm and –0.20 mm, respectively). The PS implants had a mean VMBL of 0.36 ± 0.15 mm within the first year of service. The meta-regression suggested a trend of decreased bone resorption at sites with thick soft tissues at baseline. Conclusion: This study suggested that platform switching may have an indirect protective effect on implant hard tissue outcomes. [ABSTRACT FROM AUTHOR]

Dental trauma is a serious and highly prevalent health issue across the globe. Most of the frequent dental injuries result in the loss of teeth and affects the overall quality of life. The loss of a tooth is usually compensated by a dental implant. The common methods adopted while placing the implant tooth are platform switching and platform matching. A plethora of works has studied the qualitative performance of these methods across different situations clinically. However, a detailed comparative work studying in-depth the mechanical parameters has not been attempted yet. In this computational work, two commonly available different platform-switched and one platform-matched implant-abutment configurations were compared. A 3D model of an implant (5.5 × 9.5 mm) was designed and inserted into a human mandibular bone block using computer-aided design (CAD) and extracting the clinical imaging data. Three separate models of implant-abutment configurations such as Platform Switched (PS)-I, a 5.5 mm implant with a 3.8 mm wide abutment, Platform Switched (PS)-II, a 5.5 mm implant with a 4.5 mm wide abutment, and Platform Matched (PM), a 5.5-mm implant with a 5.5 mm wide abutment were analyzed. Clinically relevant vertical-, horizontal-, and oblique-type of occlusal loadings were applied to each model to characterize the mechanical response. Mechanical parameters such as von Mises stresses, deformations, and strain energies were obtained using finite element modeling (FEM). These parameters showed lower values for platform switching within the peri-implant bone and that may help to limit marginal bone loss. However, the same parameters were increasing more in the abutment, implant, and screw for the platform-switched implant configuration than that of platform-matched configuration. The computational framework, along with the results, are anticipated to guide the clinicians and medical practitioners in making better decisions while selecting the commonly available methods.

Abstract Background Many factors play a role in the long-term survival of osseointegrated dental implants. Among these, the preservation of crestal bone remains to be the key principal. The aim of this comparative study was to assess crestal bone loss (CBL) between tissue-level implants restored with platform matching abutments and bone-level implants restored with conical/platform switched hybrid abutments in the posterior molar region. Results All implants in both groups showed a 100% survival and success rate at 1 year. Mean CBL for group I was 0.8 mm (SD 0.85), and mean CBL for group II was 0.18 mm (SD 0.48). There was a statistically significant difference between the CBL in both groups (p

Abstract Background The interpretation of the results of randomized clinical trials is often questioned in relation with daily circumstances in practices. This prospective observational multicenter study was instigated to reflect the need for information in real-life situations with dental implants with internal conical implant-abutment connection (Conelog implant system). The implants were followed up at least 5-year post-loading; survival analysis (Kaplan-Meier), changes of soft tissue, and bone level over time, as well as patient satisfaction were evaluated. Results In total, 130 dental implants were placed in 94 patients (64 female, 30 male). Mean age of patients was 50.4 ± 13.7. At 5-year post-loading, 104 implants in 76 patients were available for evaluation. The cumulative implant survival rate was 96.6%. After an initial bone remodeling process post-surgery (bone loss of − 0.52 ± 0.55 mm), the bone level change remained clinically stable from loading to 5-year post-loading (− 0.09 ± 0.43 mm). Patient satisfaction surveyed by questionnaire (comfort, ability to chew and taste, esthetics, general satisfaction) steadily increased towards the end. At the last study follow-up, all the patients rated their general satisfaction as either very satisfied (87.5%) or satisfied (12.5%). Conclusion The study implants have shown to be highly effective with reliable peri-implant tissue stability over the 5 to 7 years of observation for both single tooth restorations and fixed partial dentures while used in standard conditions in daily dental practice. The results obtained are comparable with those obtained in controlled clinical trials.

Abstract Background To compare tissue response to two implant systems, featuring internal hexed connections with different designs. Methods Patients enrolled in this randomized controlled trial were assigned to two groups. In Group 1, patients were treated with implants with a 5° conical internal hexed connection (Anyridge®, MegaGen, South Korea). In Group 2, patients were treated with implants with an internal hexed connection (Core®, Kristal, Italy). After implant placement and a provisionalisation period of 12 months, impressions were taken, stone casts were poured and digitised with a desktop scanner (D700®, 3Shape, Copenhagen, Denmark). In a digital environment, for each fixture, two values were collected at the buccal zenith: the height of the peri-implant mucosa (mucosal height; MH), calculated from the vestibular shoulder of the implant analogue to the upper gingival margin of the supra-implant tissue; and the width of the peri-implant mucosa (mucosal thickness; MT), calculated from the vestibular shoulder of the analogue to the external mucosa point perpendicular to the implant major axis. The mean and standard deviation for MH and MT, as well as their ratios, were calculated for each group; the sectors in which the implants were placed were also considered. Finally, correlation between MH, MT, connection type and sector was assessed by Pearson’s correlation coefficient, with significance level set at 0.05, and a confidence interval (CI) set at 95%. Results Data deriving from 188 implants placed in 104 patients were evaluated. The mean MH values were 3.32 (± 0.12) and 2.70 (± 0.16) mm for Groups 1 and 2, respectively. The mean MT values were 4.37 (± 0.16) and 3.93 (± 0.18) mm for Groups 1 and 2, respectively. Group 1 showed higher MH and MT values and a better ratio (1.50 ± 0.88) than Group 2 (1.81 ± 1.20). The MH, MT and MH/MT ratio were significantly influenced both by sector (p = 0.015) and group (p = 0.047). Conclusions Within the limits of this study, the 5° connection implants supported a more extended tissue height and thickness at the buccal zenith, and a better ratio between them. Trial registration This study was retrospectively registered in Clinicaltrials.gov, with number NCT04160689, dated 13/11/2019.

Purpose: To test the hypothesis that platform switching and regular platform implants would have different outcomes in single-tooth replacement against the alternative hypothesis of no difference. Material and methods: This study was designed as a randomised controlled split-mouth trial. Eighteen patients with bilaterally missing single premolars or molars to be restored with implantsupported single crowns, were consecutively enrolled. Implant sites were randomly assigned to be treated according to the platform switching concept (PS group), or with matching implant–abutment diameters (RP group). A total of 36 Nobel Replace Tapered Groovy implants were installed. All the implants were inserted in healed bone, with an insertion torque between 35 and 45 Ncm, according to a one-stage protocol. Both implant types were loaded with a screw-retained temporary crown 3 months after implant insertion. Definitive screw-retained single crowns were delivered 2 months later. Outcome measures were implant and prosthetic survival rates, biological and prosthetic complications, radiographic marginal bone level (MBL) changes, pocket probing depth (PPD) and bleeding on probing (BOP). Clinical data was collected at implant placement (baseline), and at 3, 9 and 36 months after loading. Results: No patients dropped out and no implant failed. No prosthetic complications were recorded. One patient experienced mucosal inflammation with positive BOP (RP group) after 3 months, three patients had bilateral peri-implant mucosal inflammation with positive BOP at 6, 24 and 30 months after loading, respectively. There were no statistically significant differences between groups for complications (3/18 versus 4/18; P = 1.0; Odds Ratio = 1.333; 95% CI: 0.3467 to 5.1272). Nine months after loading, the mean MBL was 0.93 ± 0.26 mm in the RP group and 0.84 ± 0.23 mm in the PS group, with no statistically significant differences between groups (mean difference = 0.09 mm, 95% CI: -0.22 to 0.04, P = 0.18). Three years after loading, mean MBL was 1.09 ± 0.31 mm in the RP group and 1.06 ± 0.24 mm in the PS group, with no statistically significant differences between groups (mean difference = 0.02 mm, 95% CI: -0.06 to 0.10, P = 0.70). Marginal bone level changes between 3 years and baseline were 0.72 ± 0.28 mm in the RP group and 0.71 ± 0.27 mm in the PS group, with no statistically significant differences between the groups (mean difference = -0.00 mm, 95% CI: -0.07 to 0.07, P = 0.89). Mean PPD was 2.70 ± 0.52 mm in the RP group and 2.46 ± 0.69 mm in the PS group at 36 months after loading, with no statistically significant differences between the groups (mean difference = 0.23 mm, 95% CI: -0.05 to 0.35, P = 0.43). Mean BOP was 0.83 ± 0.96 mm in the RP group and 0.89 ± 0.99 mm in the PS group at 36 months after loading, with no statistically significant differences between the groups (mean difference = 0.07 mm, 95% CI: -0.03 to 0.17, P = 0.77). Conclusions: The clinical and radiographic outcomes of implants restored according to the platformswitching concept versus implants restored with the matching implant-abutment diameters are comparable, 3 years after loading. [ABSTRACT FROM AUTHOR]

Objective: The aim of this retrospective study was to evaluate medium-term marginal peri-implant bone loss following placement of root-form implants featuring a micro-threaded rough-surfaced neck and a platform-switched implant-abutment connection. Method and Materials: Records were identified of patients treated with such implants over a 3-year period at three Italian dental centers. Patient radiographs were digitized and subjected to computerized analysis of peri-implant bone resorption. Results: Records of 112 patients who received 257 implants were analyzed. Although implant diameters and lengths varied, all had a 0.3-mm platform-switching width and a 2.5-mm high micro-threaded neck. All patients healed uneventfully, and no peri-implant infection, implant mobility, or radiolucency around the implant were detected at any follow-up control. At the 72-month control (average 71 ± 5 months) all implants were successful according to Albrektsson and Zarb's criteria. At implant level, average peri-implant bone resorption was 0.18 ± 0.12 mm at 6 months, 0.22 ± 0.15 mm at 12 months, 0.23 ± 0.16 mm at 24 months, 0.25 ± 0.17 mm at 36 months, 0.26 ± 0.15 mm at 48 months, and stable at subsequent controls, regardless of the implant diameter and length. At patient level, a similar trend was observed, with crestal bone loss stabilizing from 48 months onward. Conclusion: The surface, geometry, and platform-switching features of the implant under investigation allowed effective bone preservation on a medium-term basis. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate and compare the clinical and radiographic outcomes of single implants with a platform-switched rough collar (PSRC) and a platform-matched smooth collar (PMSC). Materials and Methods: Twenty-six patients missing a tooth in the anterior maxilla (through the premolars) were randomly assigned to the PSRC or the PMSC group. All implants were placed in a flapless approach and restored with an early loading protocol. Clinical measurements were performed at surgery, loading, and at 3, 6, and 12 months after loading. In addition, radiographic evaluations were carried out using standardized periapical radiographs and cone beam computed tomography. Patient satisfaction surveys were completed, and microbial analysis with DNA probes was performed. Results: The implant survival rate was 100% for both groups. The mean marginal bone level (MBL) was significantly higher in the PSRC group compared to the PMSC group at all time points. From the 2-week postoperative visit to 1 year postloading, the mean MBL change in the PSRC group was 0.21 ± 0.56 mm and in the PMSC group it was 0.74 ± 0.47 mm. Soft tissue profiles were stable over time, with no significant differences between groups. There were no significant differences between groups in the number of microbial species seen. Patients in both groups were highly satisfied with postoperative and postprosthetic experiences. Conclusion: In this study, the PSRC method preserved marginal bone by a mean of 0.53 mm more than the standard PMSC protocol. Within the limitations of the present study, it can be concluded that the PSRC protocol may be beneficial in marginal bone preservation. Longitudinal studies are needed to verify the long-term effects of this approach. [ABSTRACT FROM AUTHOR]

Purpose: To report the up-to-2-year outcomes of the immediately loaded novel variable-thread tapered implant with an internal conical connection and built-in platform shifting. Materials and Methods: Sixty-four partially and completely edentulous patients were referred to two private centers for implant treatments between December 2010 and June 2012. Clinical and radiographic parameters were assessed retrospectively; the outcomes were implant and prosthetic failure, marginal bone remodeling, and complications. Results: One hundred forty-eight NobelReplace Conical Connection implants were placed in both postextraction sockets (n = 67) and healed sites (n = 81). One maxillary postextractive implant failed before the definitive prosthesis delivery, accounting for a cumulative success rate of 99.3%. No definitive prostheses failed. A mean marginal bone loss (MBL) of 0.42 ± 1.16 mm and 0.71 ± 1.53 mm was observed between implant placement and the 1-year (n = 147) and 2-year (n = 74) follow-up periods, respectively. In the postextraction sites, the mean MBL was 0.28 ± 0.39 mm and 0.69 ± 0.75 mm at the 1-year (n = 66) and 2-year (n = 50) follow-up periods; in the healed sites, the mean MBL was 0.51 ± 0.88 mm (n = 81) and 0.62 ± 0.80 mm (n = 24), respectively. At the 2-year follow-up session (n = 74), bleeding on probing was 8.3%, and the plaque score was 15.7%. No technical complications were observed. One biologic complication (0.8%) was reported. Conclusion: Within the limitations of this study and the relatively short follow-up, the immediately loaded NobelReplace Conical Connection implants demonstrated good treatment outcomes with regard to implant and prosthetic survival rate, MBL, and soft tissue conditions, in both postextraction and healed sites. [ABSTRACT FROM AUTHOR]

Purpose: This prospective, longitudinal study evaluated the survival, marginal bone levels, and soft tissue conditions for immediately loaded, straight-walled, platform-switched, titanium-alloy implants with an internal connection and nanosurface topography. Materials and Methods: Patients were enrolled at a single center. The immediate loading protocol required a final insertion torque ≥ 25 Ncm, an implant stability quotient (ISQ) > 55, and placement of the provisional prosthesis on the same day as implant placement. Posttreatment follow-up examinations were scheduled at 3, 6, and 12 months and annually thereafter. Soft tissue evaluation consisted of assessment of the implant sites for signs of peri-implant infection including mucosal inflammation, bleeding on probing or suppuration, and progressive bone loss. Oral hygiene was evaluated, and radiographic marginal bone levels were analyzed and compared to baseline at the time of provisional loading. Results: Forty-eight consecutively treated patients received 122 implants; 112 qualified for immediate loading and were included. ISQ scores ranged from 51 to 87, with a mean value of 75.1 (SD = 6.8). One implant failed (after 3 months). After an average follow-up period of 6.2 years (SD = 0.37; range, 5.4 to 6.9), no further losses occurred, leading to an overall cumulative survival rate of 99.1%. Average bone loss for the 111 implants after 6 years was 0.35 mm (SD = 0.45; range: -0.35 to 2.20). Four implants (3.6%) in two patients showed concomitant peri-implant infections associated with bleeding on probing and/ or purulence after 2 years in function. Exploratory surgery revealed residual submucosal cement. After its removal, the progressive bone loss stopped, and peri-implant tissue in both patients returned to a healthy condition. Conclusion: This study based on 40 patients treated with 112 straight-walled, platform-switched, titanium-alloy implants with nanosurface topography yielded a 99.1% survival rate after a mean follow-up time of 6.2 years. Additionally, mean crestal bone loss was limited to 0.26 mm (SD = 0.38) after 1 year and 0.35 mm (SD = 0.45) after 6 years. Peri-implant infection associated with excessive bone loss above 2 mm was only encountered in one implant, and residual cement was shown to be responsible. [ABSTRACT FROM AUTHOR]

Aim: To evaluate 1‐year bone‐level changes around subcrestal platform‐switching implants with 1 or 3 mm definitive abutments. The influence of mucosal thickness on bone‐level alterations was further analysed. Materials and methods: Implants were placed in the posterior sextants and positioned 1.5 mm subcrestally with an abutment of 1 or 3 mm height. Final restorations were delivered after 16 weeks. Radiographic measurements of inter‐proximal bone level were the primary outcome and were adjusted by vertical mucosal thickness. Peri‐implant clinical conditions and resonance frequency analysis were also compared. Results: A total of 65 subjects with 99 implants were analysed. The overall 1‐year implant survival rate between the 1‐ and 3‐mm groups was 96.4% and 94.4%, respectively. Statistically significant lower inter‐proximal marginal bone‐level changes were observed in the 3‐mm group (1 mm: −0.17 ± 0.02 mm at mesial and −0.21 ± 0.02 mm distal; 3 mm: −0.03 ± 0.02 mm at mesial and −0.03 ± 0.02 mm and distal; mesial: p =.001; distal: p <.001). Initial vertical mucosal thickness was not correlated with inter‐proximal marginal bone loss. Conclusions: Subcrestal implants with 3‐mm abutment were associated with minimal inter‐proximal bone loss. Independent of the abutment height, crestal mucosal thickness was not correlated with bone loss. [ABSTRACT FROM AUTHOR]

PurposeTo evaluate the clinical and radiological performance of an immediately loaded novel implant design over a 3-year period.Materials and methodsThis prospective study includes 54 consecutive partially edentulous patients treated between December 2010 and October 2011. Outcome measures were: implant and prosthetic failures; biological and mechanical complications; marginal bone loss (MBL); sulcus bleeding index (SBI); and plaque score (PS).ResultsA total of 118 (29 narrow platform, 70 regular platform and 19 wide platform) NobelReplace Conical Connection implants were placed in both post-extraction sockets and healed sites and immediately loaded. The mean insertion torque was 63.4 ± 7.1 Ncm. One hundred out of 118 implants (84.7%) were inserted with a torque ranging between 55 and 70 Ncm. Each patient received a single prosthesis. At the 3-year follow-up, no patient dropped out and only two post-extractive implants failed (1.7%) in two patients (3.7%). The only complication (1.9%) observed was an event of periimplantitis, consisting of a mean mesiodistal peri-implant bone loss of 3.2 mm reported in a healed site of a smoker patient at the 2-year follow-up examination. No prosthesis failures were detected. The cumulative mean MBL between implant placements at the 3-year follow-up was 0.68 mm (95% CI: 0.44, 0.92). At the 3-year follow-up session, the SBI and PS were 5.7% and 15.4%, respectively.ConclusionsThe NobelReplace Conical Connection implant can be considered as a valuable treatment option for immediate implant placement and loading in the partially edentulous patients over a 3-year period. Insertion torques ranging between 55 and 70 Ncm are not detrimental to osseointegration.

Purpose: To evaluate crestal bone changes around implants with platform-switched abutments placed 1 mm subcrestally in a prospective clinical investigation. Materials and Methods: Forty consecutive systemically healthy patients (mean age ± standard deviation [SD], 55.2 ± 8.7 years) with one or more missing teeth were consecutively treated with 1-mm subcrestally positioned, platform-switched, tapered, full treated implants restored with coded abutments. A total of 58 implants were placed. Final restorations were delivered 4 to 8 months after implant insertion. Digital standardized periapical radiographs using customized film holders were obtained at the time of implant insertion, and at 12 and 24 months after final prosthesis placement. Marginal peri-implant bone levels were measured at the mesial and distal surfaces of each implant using digital image software. Results: All implants osseointegrated and were clinically stable at the 2-year follow-up. The cumulative survival rate was 100%. From implant insertion to the 2-year follow-up, the mean bone loss was 0.32 ± 0.37 mm. No significant differences related to sex, implant site, and bone density were observed. The mean midbuccal and interproximal soft tissue margin positions were 1.13 ± 0.5 mm and 1.15 ± 0.6 mm coronal to the prosthetic finish line, respectively. Conclusion: There is limited clinical information regarding the amount of marginal bone loss around two-piece platform-switched implants placed at subcrestal positions. Results of this study suggest that platform switching and subcrestal location of the implant-abutment interface may be effective in reducing bone loss and in preserving esthetics around dental implants. [ABSTRACT FROM AUTHOR]

Purpose: To assess the methodologic quality of systematic reviews on the effect of platform switching upon peri-implant marginal bone loss. Materials and Methods: An electronic literature search of several databases was conducted by two reviewers. Articles were considered for quality assessment if they met the following inclusion criterion: systematic reviews that aimed at investigating the effect of platform switching/mismatch on marginal bone levels around dental implants. Two independent examiners evaluated the review publications using two quality-ranking scales (assessment of multiple systematic reviews [AMSTAR] and Glenny checklist). Descriptive statistics were used to summarize the results, and Cohen's kappa coefficients were calculated to appraise interrater agreement of each checklist. Results: Overall, five systematic reviews (including three of them with meta-analysis) were evaluated. The mean AMSTAR score ± standard deviation was 8.4 ± 2.6 (range, 4 to 11), and the mean Glenny score was 10.8 ± 2 .9 (range, 6 to 14), showing high statistical correlation (rs = 0.98, P = .005). Cohen interexaminer test yielded values of κ = 0.88 and κ = 0.86 for the AMSTAR and Glenny checklist, respectively. The AMSTAR items rated positive in 78%, whereas 18% met the criteria for "no" and 4% were "not applicable." Only one review article met all criteria. Items of the Glenny checklist rated positive in 73% and negative in 27%. All but one study with the lowest quality scores (finding no difference) demonstrated a clinical benefit of implant platform switching in preserving the peri-implant marginal bone loss. Conclusion: According to the quality-ranking scales appraised, substantial methodologic variability was found in systematic assessment of benefits with the platform switching concept to preserve peri-implant bone level. High-quality systematic reviews, however, generally favored platform switching over platform matching. [ABSTRACT FROM AUTHOR]

Objective: The aim of this cross-sectional study was to estimate bone loss of implants with platform-switching design and analyze possible risk indicators after 5 years of loading in a multi-centered private practice network. Method and Materials: Peri-implant bone loss was measured radiographically as the distance from the implant shoulder to the mesial and distal alveolar crest, respectively. Risk factor analysis for marginal bone loss included type of implant prosthetic treatment concept and dental status of the opposite arch. Results: A total of 316 implants in 98 study patients after 5 years of loading were examined. The overall mean value for radiographic bone loss was 1.02 mm (SD ± 1.25 mm, 95% CI 0.90– 1.14). Correlation analyses indicated a strong association of peri-implant bone loss > 2 mm for removable implant-retained prostheses with an odds ratio of 53.8. Conclusion: The 5-year-results of the study show clinically acceptable values of mean bone loss after 5 years of loading. Implant-supported removable prostheses seem to be a strong co-factor for extensive bone level changes compared to fixed reconstructions. However, these results have to be considered for evaluation of the included special cohort under private dental office conditions. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of the different dental implant neck designs, diameters, and inclinations, on the stress distributions at the mandibular crestal bone and implant-abutment complex, using three-dimensional (3D) finite element stress analysis (FEA) method. Finite element models of three-unit fixed partial dentures supported with two same length implants (10 mm), placed on the second premolar and second molar regions, were designed. Eight different models were designed according to the implants' neck designs (platform switching/traditional), diameters (4.1 mm/4.8 mm) and the tilting angles of the posterior implants (0°/15°). The anterior implants' widths were 4.1 mm and the neck design of the anterior implants matched the posterior implants. Two types of 100-N loads in vertical and 30° oblique directions were applied separately onto each central fossae and functional cusps of the fixed partial dentures crowns. Algor Fempro Software was used for the simulation and evaluation of the stress levels at the implant-abutment complex and the crestal bone. Stress levels measured at the crestal bone were found to be lower for the platform switching models. However, the platform switching design generated higher stress magnitudes within the implant-abutment complex. Inclined placement of posterior implants increased the amount of stress at the crestal bone around both implants. Biomechanically, selection of the largest diameter possible when using tilted platform switched implants may be recommended at the posterior mandible. [ABSTRACT FROM AUTHOR]

Background: The overall success of dental implants depends on the crestal bone support around the implants. During the initial years, the bone loss around the implants determines the success rate of treatment. Platform switching (PLS) preserves the crestal bone loss, and this approach must be applied clinically. Aim: The purpose of this study was to determine the changes in vertical and horizontal marginal bone levels in platform-switched and platform-matched dental implants. Materials and Methods: One fifty patients received one fifty dental implants in the present study over a 1-year period. Measurement was performed between the implant shoulder and the most apical and horizontal marginal defect by periapical radiographs to examine the changes of peri-implant alveolar bone before and 12 months after prosthodontic restoration delivery. Results: These marginal bone measurements showed a bone gain of 1.56 ± 2.4 mm in the vertical gap and 1.49 ± 2.24 mm in the horizontal gap of the platform matching, while in the PLS, a bone gain of 2.67 ± 2.0 mm in the vertical gap (P < 0.05) and 2.89 ± 1.67 mm in the horizontal gap was found. Only a statistically significant difference was found comparing bone gains in the vertical gap between the two groups (P < 0.05). Conclusion: PLS helps preserve crestal bone around the implants, and this concept should be followed when clinical situations in implant placement permit.

Objectives: The aim was to evaluate the rate of bone loss progression during experimentally induced peri-implantitis using two different implant-abutment connections in implants with identical surface topography. Material and methods: Forty-eight Regular Neck tissue-level SLA implants with a matching implant to abutment connection (TL) and 36 bone-level SLA implants with a switching platform implant to abutment connection (BL) were subjected to experimental peri-implantitis in two independent in vivo pre-clinical investigations. Experimental peri-implantitis was induced by means of silk ligatures during 3 months (induction phase), and followed for one extra month without ligatures (progression phase). Radiographic and clinical outcomes were evaluated longitudinally along both studies and subsequently compared between experiments. Results: During the induction phase, radiographic bone loss was significantly higher in implants with matched abutments compared with those with platform switching connections (2.65 ± 0.66 mm vs 0.84 ± 0.16 mm, respectively, p = 0.001). During the progression phase, both types of implant-abutment connection exhibited similar rates of radiographic bone loss. Similar outcomes were observed clinically. Conclusions: A platform switching connection resulted in a more benign development of peri-implantitis during the experimental induction phase of the disease. These differences, however, disappeared once the ligatures were removed (progression phase). Clinical relevance: Influence of the implant-abutment connection in peri-implantitis progression may be relevant when considering implant selection in the moment of placement. In this sense, platform switching abutment demonstrated less peri-implantitis development when compared to implant matching connection. [ABSTRACT FROM AUTHOR]

Minimising marginal bone loss around dental implants is of paramount importance. The success of methods such as platform switching (PS) and laser-micro-texturing (LM) are well documented. Whether or not a combination of these designs will further improve outcomes has not been studied previously. Hence, this prospective, randomized controlled single-centre pilot study compared the clinical and microbiological outcomes of implants with both PS and LM (test) to implants with only LM (control). A test and control implant were placed in thirteen patients totalling 26 implants. The primary investigated outcome was marginal bone level (MBL); secondary outcomes were peri-implant probing depths (PPD), bleeding on probing (BOP) and marginal tissue height (MTH). Additionally, the presence of five putative periodontal pathogens were assessed using real-time polymerized chain reaction. At 12 months the overall implant survival rate was 95.8%. MBL change was not found to be different between test and control at any time points, but a significant change was detected within the test implants at 6 months compared to baseline (p = 0.006). No differences were found in the secondary outcomes. Average PPD at 12 months was 2.68 ± 0.73 mm and 2.30 ± 0.46 mm and average change in MTH was 0.05 ± 0.72 mm and −0.24 ± 0.59 mm at tests and controls. No differences were reported in BOP frequency. Total periodontal pathogens count revealed no significant difference among control, test implants and adjacent tooth sites. Within the limitations of this study, it can be concluded that the addition of PS to LM implants does not significantly alter either short-term clinical outcomes or the vulnerability to pathogenic microflora colonization. [ABSTRACT FROM AUTHOR]

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: The aim of this study was to evaluate the effect of tooth-implant proximity using an implant system with a double platform shift that was designed to load bone coronal to the implant-abutment interface. Materials and Methods: A retrospective cohort study was conducted between January 2008 and December 2009. The sample was composed of patients who had received at least one 5-mm–wide hydroxyapatite-coated single-tooth Bicon implant that had been placed adjacent to at least one natural tooth. Descriptive statistics and univariate and multivariate linear mixed-effects regression models, adjusted for multiple implants in the same patient, were utilized. The primary predictor variable was the horizontal distance between implant and adjacent tooth, and the primary outcome variable was the change in peri-implant bone levels over time. Results: Two hundred six subjects who received 235 plateau root-form implants were followed for an average of 42 months. Tooth-implant distance ranged between 0 and 14.6 mm. Out of 235 implants, 43 implants were placed < 1 mm to an adjacent natural tooth on mesial and/ or distal sides. The proximity of a plateau root-form implant was not associated with complications on the adjacent tooth such as bone loss, root resorption, endodontic treatment, pain, or extraction. The proximity of an adjacent tooth was not a risk factor for the failure of a plateau root-form implant. After adjusting for other covariates in a multivariate model, the proximity of a natural tooth did not have a statistically significant effect on peri-implant bone levels (P = .13). The extraction of an adjacent tooth was associated with a significant increase in peri-implant bone loss (P = .008). Conclusion: The placement of a plateau root-form implant with a sloping shoulder in close proximity to an adjacent tooth did not cause damage to that tooth or lead to bone loss or the failure of the implant. [ABSTRACT FROM AUTHOR]

Purpose: To compare the clinical outcome of platform switching (PS) and regular platform (RP) implants in bilateral single molar replacements. Material and methods: This study was designed as a randomised, controlled, split-mouth trial. Eighteen patients, with bilaterally missing single molars had one site randomly assigned to a PS implant or a RP implant. A total of 36 implants were bilaterally installed. Both implants were loaded with screw retained temporary crowns 3 months after implant insertion and with screw retained definitive crowns 3 months later. Outcome measures were implant/crown failure, complications, radiographic marginal bone-level changes, pocket probing depth (PPD) and bleeding on probing (BOP). Clinical data were collected at baseline 6 and 12 months after implant placement. Results: No patients dropped out and no implant failed. No prosthetic or major biological complications were observed. One year after implant placement, mean marginal bone level was 0.93 ± 0.26 mm (95% CI 0.81 to 1.05) in RP group and 0.84 ± 0.23 mm (95% CI 0.73 to 0.95) in the PS group and no statistically significant differences between the two groups were observed (P = 0.18). Mean PPD and BOP values were, 6 and 12 months after implant placement, 2.74 ± 0.49 mm (95% CI 2.51 to 2.97) and 1.28 ± 0.75 (95% CI 0.93 to 1.63) in the RP group, and 2.70 ± 0.38 mm (95% CI 2.53 to 2.88) and 1.39 ± 0.78 (95% CI 1.03 to 1.75) in the PS group respectively, with no statistical differences between groups (P = 0.81 and P = 0.16, respectively). Conclusions: No statistically significant difference was observed between platform switched and non-platform switched implants. [ABSTRACT FROM AUTHOR]