Platform Switching Research Articles

I hate ads but not the advertised brands: a qualitative study on Internet users' lived experiences with YouTube ads

PurposeThis paper aims to explore Internet users' lived experiences with video ads, both skippable and nonskippable, while watching content on YouTube.Design/methodology/approachIn-depth interviews were conducted with 22 participants.FindingsThe participants unanimously expressed dissatisfaction with YouTube ads. The dissatisfaction was directed to the platform but did not spill over to the advertised brand/product. Ethical concerns related to privacy also emerged. Specifically, with respect to nonskippable ads, the participants expressed dislike for forced viewing and explained how they would engage in extraneous activities during the ads. Nonetheless, they appreciated the flexibility offered by skippable ads. They also elaborated on how, why and when they would skip/not skip skippable ads.Originality/valueThe findings are discussed in light of the literature on not only online advertising but also platform switching versus continuance intention, spillover effect, privacy–personalization paradox and visual attention.

Analysis of Biomarkers and Marginal Bone Loss in Platform-Switched and Nonplatform-Switched Implants: A Randomized Clinical Trial.

Objectives To compare the peri-implant crevicular fluid (PICF) biomarker levels, peri-implant status, and marginal bone level (MBL) differences of implants restored with randomly assigned nonplatform-switched (NPS) or platform-switched (PS) abutments. Methods Ninety-four implants in 27 subjects were included in this study. Receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) levels in PICF, peri-implant health, and the change in the MBL were evaluated at the time of restoration (T1) and after 12 months (T2). Results The IL-1β levels decreased and the RANKL, OPG, and MCP-1 levels increased from T1 to T2 (P < 0.05) in both groups. RANKL/OPG ratio at T1, MCP-1 levels at T2, and the MCP-1 change from T1 to T2 were lower in the PS group than in the NPS group (P < 0.05). MBL change was lower (0.51 ± 0.31 mm) in the PS group than that (0.75 ± 0.29 mm) in the NPS group at T2 (P < 0.001). Peri-implant health status between the study groups was negligible. Conclusion PS was superior to NPS regarding the preservation of MBL. Higher MCP-1 levels, altered RANKL/OPG ratio, and lower OPG levels in the NPS group could be associated with subclinical peri-implant bone remodeling.

Soft Tissue Parameters and Esthetic Index Changes in Platform Switching Implant: A Systematic Review and Meta-Analysis

&lt;p&gt;Purpose: The purpose of this study was to perform a systematic review and meta-analysis to critically evaluate the available literature to statistically analyze the effects of platform matched (PM) and platform switching (PS) implants on the peri-implant soft tissue changes and esthetic outcomes. Materials and methods: Electronic databases of the Cochrane Library, Embase, CINAHL and PubMed were searched for human randomized controlled trials (RCTs) with clearly outcome measurement in comparison between PM and PS implant. Primary outcomes included midfacial keratinized gingiva (KG) thickness, width of KG, marginal gingiva height gain, papilla height, and pink esthetic score. Secondary outcomes included bone level, probing depth, plaque index, and sulcus bleeding index. All the included studies had to follow up for at least 1 year after function. Results: A total of 7 RCTs were included in the meta-analysis. Midfacial KG thickness (weighted mean difference (WMD) = 1.34 mm, P &lt; 0.0001), marginal gingiva height (WMD = 0.30 mm, P = 0.01), papilla height (WMD = 0.18 mm, P = 0.003), bone level (WMD = 0.34 mm, P &lt; 0.00001) and probing depth (WMD = -0.22 mm, P = 0.002) demonstrated statistically difference in comparison of PS and PM implants. The result of width of KG (P = 0.92), PES score (P = 0.73), plaque index (P = 0.97) and sulcus bleeding index (P = 0.78) showed no statistical difference. Conclusion: Meta-analysis showed better performance of midfacial KG thickness, marginal gingiva height and papilla height in PS implant than that in PM implants. No statistically difference was found in width of KG and PES score between PS implants and PM implants.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Forecasting Network Interface Flow Using a Broad Learning System Based on the Sparrow Search Algorithm.

In this paper, we propose a broad learning system based on the sparrow search algorithm. Firstly, in order to avoid the complicated manual parameter tuning process and obtain the best combination of hyperparameters, the sparrow search algorithm is used to optimize the shrinkage coefficient () and regularization coefficient () in the broad learning system to improve the prediction accuracy of the model. Second, using the broad learning system to build a network interface flow forecasting model. The flow values in the time period are used as the characteristic values of the traffic at the moment . The hyperparameters outputted in the previous step are fed into the network to train the broad learning system network traffic prediction model. Finally, to verify the model performance, this paper trains the prediction model on two public network flow datasets and real traffic data of an enterprise cloud platform switch interface and compares the proposed model with the broad learning system, long short-term memory, and other methods. The experiments show that the prediction accuracy of this method is higher than other methods, and the moving average reaches 97%, 98%, and 99% on each dataset, respectively.

Comparative Study by Systematic Review and Meta-Analysis of the Peri-Implant Effect of Two Types of Platforms: Platform-Switching versus Conventional Platforms.

Objective: The aim of the systematic review and meta-analysis carried out was to evaluate the effects of changing the prosthetic platform on peri-implant tissue after 1 year of prosthetic loading. Material and methods: In November 2020, an electronic search was carried out in PubMed, EMBASE, Web of Science, and Scopus databases with the aim of obtaining all the randomized clinical trials that had been published in the preceding 10 years comparing the effects on the peri-implant tissue of implants with a prosthetic platform change and implants with a conventional platform for at least 1 year after prosthetic loading. Randomized model meta-analyses of the selected studies were performed to compare the results of the two implant groups in terms of vertical maintenance of bone level and increased probing depth. Results: Nine studies were included, summing up a total of 475 implants with prosthetic platform exchange and 462 implants with a conventional platform. Implants with prosthetic platform exchange had less peri-implant bone loss than implants with a conventional platform (mean difference of 0.255 mm, statistically significant) but suffered a greater increase in probing depth (mean difference of 0.082 mm, not statistically significant). However, the probing depth from One Study Remove revealed a statistically significant increase of 0.190 mm in the prosthetic platform exchange group compared to the conventional platform group. Conclusion: Implants with platform switching suffer less peri-implant bone loss after 1 year of loading than implants with a conventional platform. Further long-term studies are required to observe how these differences vary over time.

10-Year Evaluation of the First Root Analogue Implant on Humans, Made Using a CT Scan, CAD/CAM and DMLS

Ten years ago, for the first time in humans, thanks to the DLMS (direct metal laser sintering) technique, we designed, built and inserted an immediate post-extraction custom-made root-analogue implant in Ti-6Al-4v with platform switching. The implant was inserted into the post-extraction socket, respecting the biological width. After 10 years, we wanted to evaluate the dimensional stability of the implant and the eventual crestal bone resorption. The evaluation was performed clinically with periodontal parameters and radiographically by means of an intraoral X-ray with the parallel technique measuring the distance between the base of the bone crest and the implant shoulder. It appears that the implant has maintained dimensional stability of the peri-implant soft tissues, and the crestal resorption is 0 mm. This could represent a step forward to make this experimental method a valid alternative to the current immediate post-extraction implant procedures in use.

Effect of Ti-Base Abutment Gingival Height on Maintenance of Crestal Bone in Thick Biotype Patients: A Randomized Clinical Trial with 1-Year Follow-up.

To determine the effect of 0.7- and 2.4-mm transmucosal abutment height titanium bases on the crestal bone stability and peri-implant soft tissue condition of bone-level implants with platform switching in patients with vertically thick soft tissues. Sixty bone-level platform-switched implants were placed in the molar and premolar regions of both arches in 60 patients. All epicrestally inserted nonsubmerged implants had a 4.1-mm diameter and, after osteointegration, were randomly allocated into two groups: (1) the short group, with a titanium base of 0.7-mm transmucosal abutment height, and (2) the high group with a 2.4-mm height. Monolithic zirconia restorations were fabricated for all implants. Parallel intraoral radiographs were obtained after the delivery of restorations (T1) and after 1 year (T2). Crestal bone levels and peri-implant soft tissue conditions were calculated for each implant. The significance level was set at α = .05. After 1 year, 55 patients were evaluated, with a mean bone loss of 0.6 ± 0.51 mm (median: 0.71, range: 0 to 2.09 mm) in the short group (23 patients) and 0.45 ± 0.59 mm (median: 0.65, range: 0 to 2.12 mm) in the high group (22 patients), showing no significant difference between groups (P = .168). A significant increase in marginal bone height was noted between the T1 and T2 time points in the short and high (P = .029 and .001, respectively) groups. The peri-implant soft tissue health parameters did not show statistically significant differences. Crestal bone stability after 1 year of follow-up around epicrestally placed platform-switched implants is not influenced by transmucosal abutment height, if the vertical soft tissue thickness is ≥ 3 mm.

Biomechanical Stress Analysis of Platform Switch Implants of Varying Diameters on Different Densities of Bone.

Purpose The purpose of this study was to evaluate and compare the strain developed in D2 and D3 types of bones on vertical loading by platform switch implants of different diameters. Materials and Methods Implants of diameters 3.25 mm, 4.2 mm, and 5.0 mm and of length 11.5 mm were taken and placed each on D2 and D3 bone models. Strain gauges were attached on the buccal and the lingual sides on each of these samples, and a vertical load of 190N was placed on the samples. The strain was recorded using a data logger. The data obtained was analysed using one-way ANOVA and post hoc Tukey test. Results In D2 and D3 bone models, 3.25 mm significantly showed greater bone strain values. The buccal side strain was higher irrespective of the implant diameter and density of bone. Conclusion Within the limitations of the study, it may be concluded that the narrow diameter implant produces greater strain than 4.2 and 5.0 mm diameter implants, respectively. The buccal side consistently produced higher bone strain values.

“THE EFFECT OF PLATFORM SWITCHING ON ALVEOLAR CRESTAL BONE LEVEL – A SYSTEMATIC REVIEW

Background: Dental implants have become the most common restorative technique for rehabilitation of edentulism. The stability of the crestal bone is believed to be a key factor for maintaining stable soft tissue dimension with direct inuence on aesthetics. The concept of “platform switching” explains the use of a smaller-diameter abutment on a larger-diameter implant collar. This may decrease the risk of bone loss around implants. Aim: To analyze the effect of platform switching on alveolar crestal bone level. Materials and methods: An electronic database search for randomized controlled trials, clinical trials, prospective studies and retrospective studies published in peer-reviewed Journals in English was conducted from the following databases: PubMed, EBSCOhost, EMBASE and Google Scholar. Results: A total 248 articles were identied on electronic database. Eleven studies were included for the qualitative synthesis. Out of the 11 studies, 8 were randomized controlled clinical trials, 1 was a clinical trial, 1 was a prospective study and 1 was a retrospective study. All the included studies suggested that platform switching has signicant effect on alveolar crestal bone level. Conclusion: The platform-switched implants remained stable over the course of 10 years and had an overall survival rate of 97.1%. From the present systematic review, based on the articles that were included in this study, it can be concluded that platform switching technique has signicant reduction in alveolar crestal bone level as compared to platform matched technique.

English

The success of dental implant depends on its integration with the surrounding tissue and this is influenced by various factors, like implant material, amount of bone and its quality and the implant loading condition. The peri-implant tissue is comprised of the soft (mucosa) and hard (bone) tissues. Absolute contact between the peri-implant bone and the implant surface is another factor essential for the success of any implant system. The direct structural and functional connection between ordered living bone and the surface of a load-carrying implant is defined as ''Osseointegration''. The bone undergoes remodelling so as to maintain bone strength and mineral homeostasis. The preservation of biological seal, the anatomy and quality of bone where implant needs to be positioned, implant macrostructure are some of the factors that dictate the integration of the implant to the hard tissue. In addition, the gingival morphology also plays an important role in determining the final aesthetic outcome. Gingival morphology is described in terms of gingival phenotype or gingival biotype. ‘‘Gingival phenotype’’ is a term that addresses to the variations in the thickness and width of the keratinized tissuewhereas ''Gingival biotype'' depicts the thickness of the gingiva in the facio-palatal / faciolingual dimension.Inadequate gingival thickness is a major reason for periodontal attachment loss and marginal tissue recession in a patient, directly contributing to the periodontal disease progression. The peri-implant soft tissue consists of a junctional epithelium (JE) and the connective tissue but owing to the biologic differences between the peri-implant and periodontal tissues, the periimplant tissues are more vulnerable to mucosal inflammation and bone loss. The health of the peri–implant tissues play an important role in the long-term outcome of dental implants. The preservation and reconstruction of soft tissue around dental implants is an important aspect of dental implantology. Restoring the function, aesthetics and harmony of dentition is the primary intention of implantology. This is achieved with a sound crestal bone stability and healthy peri-implant soft tissue. Other factors like abutment material and its connection to the implant, the neck design also affects the peri-implant soft tissue integrity. This review discusses the various factors that directly and indirectly influence the aesthetic outcomes following a dental implant placement. KEY WORDS Aesthetics, Peri-Implant Tissue, Osseointegration, Platform Switching

Platform switching technique

Modern dentistry aims to facilitate the patient to achieve excellent oral health. An ideal implant prosthesis can not only provide normal muscle activity, thereby improving the functions of mastication, but also improve esthetics profoundly. Among the factors involved to attain good esthetic result with implants, the correct positioning of the implant is one of the most important factors, along with preserving the integrity of gingival margins and interdental papillae. Preserving crestal bone is paramount, while planning for implant placement as it accumulates bacteria and leads to secondary peri-implantitis. Hence, the objective of this review article is to highlight the advantages of platform technique as compared to conventional treatment approach.

The Association of the One-Abutment at One-Time Concept with Marginal Bone Loss around the SLA and Platform Switch and Conical Abutment Implants.

Objectives: Repeated abutment disconnection/reconnection may compromise the mucosal barrier and result in crestal bone level changes. The clinical significance of this phenomenon is not yet clear, as most studies on this topic are short-term. Therefore, the aim of the present study was to evaluate the influence of abutment disconnections and reconnections on peri-implant marginal bone loss over a medium-term follow-up period. Material and methods: Twenty-one patients (6 men and 15 women) with a mean age 66.23 ± 9.35 year at the time of implant placement were included. All patients who received two adjacent nonsubmerged implants were randomly assigned into one of the two groups: definitive multiunit abutments (DEFs) connected to the implant that were not removed (test group) or healing abutments (HEAs) placed at surgery, which were disconnected and reconnected 3–5 times during the prosthetic phase (control group). Peri-implant marginal bone levels (MBL) were measured through periapical X-rays images acquired immediately after the surgery (baseline), at 4–7 months immediately after prosthetic delivery, and at 1-year and 3-year follow-up visits. Results: No implant was lost or presented bone loss of more than 1.9 mm during the 3-year follow-up; thus, the survival and success rate was 100%. Peri-implant mucositis was noticed in 38.1% DEFs and 41.9% of HEAs at the 3-year follow-up assessment. At the end of 3 years, the MBL was −0.35 ± 0.69 mm for participants in the DEFs group and −0.57 ± 0.80 mm for the HEAs group, with significant statistical difference between groups. Conclusions: Immediate connection of the multiunit abutments reduced bone loss in comparison with 3–5 disconnections noted in the healing abutments 3 years after prosthetic delivery. However, the difference between the groups was minimal; thus, the clinical relevance of those results is doubtful.

Influence of Platform Switching, Abutment Design and Connection Protocols on the Stability of Peri-Implant Tissues. A Systematic Review.

To appraise the effect of abutment factors namely platform switching, design and connection protocols on the stability of peri-implant tissues. An electronic and hand search were conducted. Randomized control trials and controlled prospective studies of at least one-year follow-up, published in the last 12 years, were included. Initial electronic database search generated 3054 studies, while individual journal and hand searching resulted in 232 articles. Sixty-three publications were selected for full text analysis based on inclusion and exclusion criteria. Nineteen articles investigated platform switching. Fourteen studies reported positive influence of platform switching while five studies did not find a significant difference in bone loss compared to platform matched abutments. Two articles reported on concave abutments and found no advantage over conventional abutments. Seven studies investigated "one-abutment-one-time protocol", two found comparable results to multiple abutment disconnections while five studies suggested better soft and hard tissue maintenance. The risk of bias was unclear or high in most studies. Platform switched abutments may reduce crestal bone loss during the first year. There is insufficient evidence to suggest better clinical outcomes of concave abutment. There is insufficient evidence to indicate the superiority of 'one abutment-one-time protocol'.

Mechanical Performance of Chairside Ceramic CAD/CAM Restorations and Zirconia Abutments with Different Internal Implant Connections: In Vitro Study and Finite Element Analysis.

(computer-aided design-computer-aided manufacturing) CAD/CAM monolithic restorations connected to zirconia abutments manufactured with a chairside workflow are becoming a more common restorative option. However, their mechanical performance is still uncertain. The aim of this study was to evaluate the mechanical behavior of a combination of a zirconia abutment and monolithic all-ceramic zirconia and lithium disilicate crown manufactured with a chairside workflow, connected to titanium implants with two types of internal connection—tube in tube connection and conical connection with platform switching. They were thermally cycled from 5 °C to 55 °C and were subjected to a static and fatigue test following ISO 14801. The fractured specimens from the fatigue test were examined by SEM (scanning electron microscopy). Simulations of the stress distribution over the different parts of the restorative complex during the mechanical tests were evaluated by means of (finite element analysis) FEA. The mechanical performance of the zirconia abutment with an internal conical connection was higher than that of the tube in tube connection. Additionally, the use of disilicate or zirconia all-ceramic chairside CAD/CAM monolithic restorations has similar results in terms of mechanical fracture and fatigue resistance. Stress distribution affects the implant/restoration complex depending on the connection design. Zirconia abutments and monolithic restorations seem to be highly reliable in terms of mechanical resistance.

Platform-Switching Concept in Dental Implants: A Systematic Review and Meta-analysis of Randomized Controlled Trials with a Minimum Follow-up of 3 Years

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. 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). 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. 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.

Crestal bone loss in ultrashort implants: retrospective study on two different type of fixture.

Aim This was to assess variation of mean crestal bone loss (CBL) when two different types of ultrashort implants are placed in the upper or in the lower jaw and to evaluate differences in terms of success and survival rates. Materials and methods 99 ultrashort implants were retrospectively evaluated assessing differences at three different time-points (placement, prosthetic loading, end of follow-up) in terms of CBL in the upper and lower jaw. Correlations between CBL and diameter, platform switching, site of placement (upper or lower), type of implants, clinical crown/implant ratio and anatomical crown/implant ratio were statistically performed and success and survival rate were assessed. Results Statistically significant correlations were found between CBL and implant diameter, kind of screw and anatomical crown/implant ratio at the end of follow up. No correlation was highlighted between CBL and platform switching, and site of placement (upper or lower jaw). Survival and success rates were comparable and were found to be 96.37% in the upper jaw and 94.46% in the mandible. Conclusion CBL in ultrashort implants is an issue deserving great attention, therefore to know features and behaviours of different ultrashort implants in different quality of bone and clinical conditions represents a cut above to obtain and maintaining success in this particular kind of rehabilitation.

Influence of Abutment Design and Platform Switching on Peri-implant Marginal Bone Level: A Randomized Controlled Clinical Trial with 1-Year Results.

The purpose of this randomized clinical study was to evaluate the efficacy of platform-switching (PS) vs platform-matching (PM) implants when paired with a newly designed marginless abutment (MA) vs a conventional abutment (CA) in maintaining peri-implant tissue stability. Marginal bone level (MBL) and probing depth were measured up to 1 year postloading. Eighty implants were inserted in 42 patients and randomly assigned to one of four groups, each with a different implant/abutment configuration: Group 1 (PM+CA), Group 2 (PM+MA), Group 3 (PS+CA), and Group 4 (PS+MA). Data were collected at implant placement (T0), abutment placement (T1), final crown placement (T2), and 1 year postloading (T3). At the 1-year follow-up, MBL was more stable in Groups 3 and 4 compared to Groups 1 and 2. These results suggest that the role played by the implant-abutment connection (PS vs PM) is more important than the type of abutment preparation (MA vs CA).

Behavior of Soft Tissue around Platform-Switched Implants and Non-Platform-Switched Implants: A Comparative Three-Year Clinical Study.

To verify the influence of platform-switching (PS) on soft tissue behavior by comparing the soft tissue stability around implants with and without PS, during three years of follow-up. The study included patients treated with fixed dentures supported by implants with an internal connection. The radiographic distance between the first bone-to-implant contact (FBIC) and the implant shoulder was assessed. Additionally, the presence of keratinized facial mucosa and the prosthetic crown height (TH) were monitored for three years from the delivery of the definitive crown. These parameters were measured for two different groups: platform-switched implants in the PS group and non-platform-switched (NPS) implants in the NPS group. Seventy-seven implants were considered in the statistical analysis. After three years, the overall FBIC mean value was 0.31 ± 1.00 mm. However, the mean FBIC was 0.66 ± 0.97 mm for the NPS group and −0.05 ± 0.91 mm for the PS group. Moreover, a mean recession of 0.54 ± 1.39 mm was measured for the NPS group, whereas a mean coronal migration of 0.17 ± 0.95 mm was measured for the PS group. A significant correlation was also found between the presence of PS and ΔTH (p ≤ 0.01) over the three years of follow-up. The absence or presence of platform-switching would appear to affect the tendency of the gingival buccal margin towards recession or creeping. Additionally, implant-abutment platform-switching seems to help prevent peri-implant soft tissue recession over time when compared to implants without PS.

Biomechanical evaluation of stress distributions at the implant-abutment complex and peri-implant bone around mandibular dental implants with different neck geometries and inclinations.

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.

Evaluating the effect of subcrestal placement on platform switched short dental implants and von mises stress in D3 bone-A 3D FEM study.

To investigate the effect of platform switched short dental implants and subcrestal placement on von Mises stress in the maxillary anterior region (D3 bone) by using three-dimensional finite element model analyses (3D FEM). Biomechanical behaviour of von Mises stress in maxillary anterior region (D3) bone were stimulated with the help of 3D FEM with the help of ANSYS WORKBENCH version 17.5. The bone model had a cortical core of (1 mm) surrounding the inner cancellous core, which represents D3 bone. Two models were designed model 1 (6 x 4.6 mm), (7.5 x 4.6 mm) and model 2 (6 x 5.8 mm), (7.5 x 5.8 mm). Loads of 100, 200 N were applied at an angle of 0°, 15°, 30° along the long axis of the tooth model. In all model's cortical bone exhibited greater stress than cancellous bone. Greater stress was reported in axial direction at 30° then 15° and least at 0° irrespective of load applied. An increase in implant length (7.5 mm) did not exhibit any stress reduction in both the model but implant diameter (5.8 mm) led to reduction in von Mises stress in both the groups. Greater the force applied greater was stress in both bones irrespective of direction of force applied (200N). Lastly subcrestal (0.5 mm) placement has slight reduction in stress compared to equicrestal placement in both the groups. Numerical results from the current study suggest that, for short implants, implant diameter is considered more effective design parameter than implant length. Current findings state that platform switch short subcrestal implants results in conservation of marginal bone loss along with better stress distribution around peri-implant regions in D3 bone. However, all models analyzed in this study showed development of von Mesies stresses within physiological limits for human cortical bone.