Conical Connection Implants Research Articles

Effect of scan body designs and internal conical angles on the 3-dimensional accuracy of implant digital scans

Statement of problemAxial displacement is inevitable when connecting scan bodies to implants for digital scans using intraoral scanners, and axial displacement may reduce implant position accuracy in digital casts. However, studies assessing scan body type and accuracy are lacking. PurposeThe purpose of this in vitro study was to assess the linear and angular displacements of implants in digital casts using 2 scan body types with or without a vertical stop to minimize the axial displacement and 2 internal conical connection implants (ICCIs) with different internal conical angles. Material and methodsTwo identical reference casts were fabricated from epoxy resin by duplicating a partially edentulous mandibular dentiform. Each cast received 3 implants in the left first premolar, first molar, and second molar regions. One cast received an ICCI with a 7-degree internal conical angle (7-degree ICCI), and the other received an ICCI with an 11-degree internal conical angle (11-degree ICCI). A 10-mm polyetheretherketone (PEEK) cube was attached to the buccal area of the mandibular second premolar of each reference cast. A vertical stop was used in the experimental scan bodies to minimize the axial displacement, and conventional scan bodies were hand tightened to the implants in the reference casts. An intraoral scanner was used to fabricate 4 digital cast groups (2 implant types and 2 scan body types; each group had 10 casts). A coordinate measuring machine and digital inspection software program were used to measure the implant platform centroids (x, y, z) and projection angles (θXY, θYZ, θZX) of implant long axes in the reference and digital casts, respectively. One-way analysis of variance (ANOVA) and linear mixed model both with Tukey post hoc and 2-way ANOVA tests were performed to assess the significance of linear and angular displacements between groups (α=.05). ResultsSignificant differences were noted in all linear displacement variables among the 4 digital cast groups, except for Δx in the left first premolar implant. For the 7-degree ICCI, the linear displacement was statistically similar in the experimental and conventional scan bodies. However, for the 11-degree ICCIs, the experimental scan body group resulted in significantly smaller Δy, Δz, and Δd (Δd2=Δx2+Δy2+Δz2) than the conventional scan body group (P<.05). Overall, the 11-degree ICCIs demonstrated a significantly greater linear displacement than the 7-degree ICCI, regardless of the scan body type (P<.05). Significant differences between the test groups were observed for 10 of the 12 angular displacement variables (P<.05). ConclusionsThe 11-degree ICCIs demonstrated significantly greater linear displacements in Δy, Δz, and Δr than the 7-degree ICCIs. The experimental scan bodies with a vertical stop demonstrated significantly smaller linear displacements in the 11-degree ICCIs.

Unified conical connection implants.

Unified conical connection implants.

Radiographic evaluation of the distance between the restoration margin and the alveolar bone crest in dental implant patients: A retrospective study

ObjectivesThe recently introduced Implant Disease Risk Assessment (IDRA) identifies a restoration margin-alveolar bone crest (RM-AC) distance of less than 1.5 mm as a key risk factor for peri‑implant disease among eight major risk factors. This study evaluated the impact of the RM-AC distance on marginal bone loss (MBL) through radiographic analysis. MethodsThis retrospective cross-sectional study included 77 partially edentulous patients (39 females and 38 males, aged 22 to 76 years) with 202 platform-switched conical connection implants, cement-retained, implant-supported fixed restorations, and bone-level implants placed between 2016 and 2021. Dental implants were followed for least 6 to 36 months at follow up functional loading. Study participants were categorized into Group A (RM-AC distance ≤ 1.5 mm, n = 69) and Group B (RM-AC distance > 1.5 mm, n = 133). Twelve patients in Group B and five patients in Group A had no history of periodontal disease. The MBL was measured radiographically from the most coronal point of the implant shoulder to the alveolar bone, and the RM-AC distance was measured from the restoration margin to the alveolar crest. Multinomial logistic regression analysis was used for statistical evaluation. ResultsThe incidence of MBL in Group A was statistically significant and 3.42 times higher than that in Group B. The rate of MBL in periodontitis Stage 4 was found to be 26.31 times higher than that in periodontitis Stage 2. The incidence of MBL was 6.097 and 5.02 times higher with increasing implant diameter and length, respectively. ConclusionThis study conclusively demonstrates that RM-AC distance ≤ 1.5 significantly increases the risk of MBL, particularly in patients with a history of periodontal disease. Clinical significanceThis study highlights the critical role of maintaining an RM-AC distance greater than 1.5 mm in the prevention of MBL, particularly in patients with a history of periodontal disease. Since implant diameter and length have a significant impact on the risk of MBL, it emphasizes that implant demographics should also be carefully evaluated.

Clinical Evaluation of Two Distinct Materials for Implant-Supported Interim Fixed Partial Prostheses: An Original Research

ABSTRACT Aim: This study aimed to evaluate the clinical efficacy of posterior resin implant-supported fixed partial dentures (FPDs) made from two different computer-aided design and computer-aided manufacturing (CAD–CAM) materials: polymethylmethacrylate (PMMA) and polyoxymethylene (POM). Materials and Methods: Twenty-one patients received a total of 49 interim implant-supported FPDs. The same participant received PMMA and POM as part of the control and experimental groups, respectively. The restorations were evaluated 1 week, 3 months, and 6 months after placement. In addition, their functional wear and color stability were assessed. Nonparametric statistics (α = 0.05) were used to analyze the data. Results: The study found that PMMA outperformed POM in surface and color parameters, with more fractures occurring with internal conical connection implants. The color stability analysis showed ΔE*ab values of 7.18 for PMMA and 8.8 for POM, with no significant differences. After 6 months of operation, both materials showed a significant increase in wear, but no significant differences were found within the materials. Conclusion: The study found that PMMA interim implant-supported FPDs outperformed POM in surface and color parameters, while polymer posterior implant-supported FPDs with internal conical connection implants were more fracture-prone.

Microbiological analysis of bacterial sealing of internal conical implants with different taper angles.

The present study evaluated the effect of the taper angle of different internal conical connection implants and cyclic loading on the implant-abutment bacterial seal. A total of 96 implant-abutment sets were divided into eight groups. Four groups of different taper degrees with cyclic mechanical loading of 500,000 cycles per sample, with a 120-N load at 2 Hz before analysis [16DC (16-degree, cycled), 11.5DC (11.5-degree, cycled), 3DC (3- degree, cycled) and 4DC (4- degree, cycled)] were compared to four control groups without cyclic loading [16D (16-degree), 11.5D (11.5-degree), 3D (3-degree), and 4D (4-degree)]. Microbiological analysis was performed by immersing all samples in a suspension containing Escherichia coli and incubating them at 37°C. After 14 days, the presence of bacterial seals was evaluated. Fisher-Freeman-Halton exact tests and binomial tests were performed (5% significance level). The groups showed significant differences in bacterial seal, and mechanical load cycling improved the bacterial seal in the 3DC group. In all other groups, no significant differences in bacterial seal were found between cycled and uncycled samples. To conclude, the internal conical connection with a 3-degree taper angle showed better results than the other connection with different angles when subjected to load cycling. However, none of the angles tested were fully effective in sealing the implant-abutment interface.

Histologic and histomorphometric evaluation of minicono abutment on implant surrounding tissue healing and bone resorption on implants placed in healed bone. An experimental study in dogs

&lt;abstract&gt; &lt;p&gt;The objective of this evaluation was to measure the width and length of connective tissue (CT) and crestal bone resorption (CBR) related to minicono® abutment inserted in conical connection dental implants, which were placed crestal and subcrestally in a dog's mandible.&lt;/p&gt; &lt;sec&gt; &lt;title&gt;Materials and Methods&lt;/title&gt; &lt;p&gt;Forty-eight Top DM implants with the same coronal diameter were placed at the crestal level, 1 mm (test 1 group) and 2 mm (test 2 group) positions underneath buccal-lingual bone crests. Dental implants used in the study were separated into three groups of 16 implants each. The implants were randomly inserted into healed bone after two months post-extraction sockets of three lower premolars, and first molar, bilaterally in six male fox hound dogs. One 3 mm minicono height abutment was connected to conical connection implants placed at the crestal level (control), 1 mm (test 1) and 2 mm (test 2) positions under buccal-lingual crests.&lt;/p&gt; &lt;/sec&gt;&lt;sec&gt; &lt;title&gt;Results&lt;/title&gt; &lt;p&gt;All abutments and implants used were clinically and histologically integrated into the bone-soft tissue. Soft tissue behavior was observed at eight and 12 weeks in all test groups, displaying similar quantitative findings with significant differences (p &amp;gt; 0.05). However, crestal bone loss was significantly greater at the buccal side around that control group compared to the test 1 and 2 groups. The difference values between groups at the implant shoulder to the top of the lingual bone crest (IS-LBC) and the implant shoulder to the top of the buccal bone crest (IS-BBC) were significantly greater for the test 2 group in comparison with the other two groups (p &amp;lt; 0.05) at eight weeks. In addition, crestal bone resorption (CBR) increased in the crestal group at twelve weeks, but it was reduced for the test 1 and test 2 groups in implants placed sub-crestally (p &amp;lt; 0.05).&lt;/p&gt; &lt;/sec&gt;&lt;sec&gt; &lt;title&gt;Conclusions&lt;/title&gt; &lt;p&gt;Crestal bone loss could be reduced using a 3 mm high abutment on implants submerged below the bone crest from 1 to 2 mm positions.&lt;/p&gt; &lt;/sec&gt;&lt;/abstract&gt;

Abutment removal torque and implant conical surface morphological changes after standardized artificial aging: An in vitro study

Statement of problemZirconia abutments have become popular as they provide favorable esthetic outcomes. However, studies investigating how abutment material affects abutment screw torque performance and implant conical surface morphological changes in internal conical connection systems are scarce. PurposeThe purpose of this in vitro study was to investigate the influence of abutment material on abutment removal torque and implant conical surface morphological changes in internal conical connection implant–abutment assemblies of 2 diameters after simulated long-term oral use. Material and methodsThirty abutments of 3 materials (1-piece titanium, 1-piece zirconia, zirconia with alloy base) and 2 diameters (regular, narrow) made by the original manufacturer were connected to internal conical connection implants and subjected to a standardized artificial aging process consisting of thermal cycling and mechanical cyclic loading with parameters corresponding to anterior and posterior mastication scenarios simulating long-term oral use. An abutment removal torque test was done before and after aging. Morphological changes in the implant conical contact surface were observed with a scanning electron microscope (SEM). Initial and after-aging torque loss values were calculated and analyzed separately with 1-way ANOVA and Tukey HSD post hoc tests (α=.05). ResultsAll specimens survived artificial aging. For initial and after-aging torque loss, the 1-piece zirconia groups showed significantly greater values (P<.001) for both diameters. In the SEM observation, the 1-piece zirconia groups showed distinct widespread surface damage while the other groups exhibited only minor damages. ConclusionsRegardless of diameter, 1-piece zirconia abutments tend to induce more abutment removal torque loss and implant conical surface morphological changes than those with metal connections, both initially and after simulated long-term oral use. Zirconia abutments with an alloy base performed similarly to 1-piece titanium abutments.

Implant deformation and implant-abutment fracture resistance after standardized artificial aging: An in vitro study.

Zirconia abutments have been widely adopted in clinical implant practice. The unique mechanical properties of zirconia may significantly affect the long-term prognosis of implant treatments. The purpose of this study was to investigate the influence of abutment material on implant deformation and fracture resistance of internal conical connection implant-abutment complexes of two diameters after standardized artificial aging. Thirty original abutments (one-piece titanium, one-piece zirconia, zirconia with alloy base) with two diameters (regular, narrow) were connected to internal conical connection implants and subjected to a standardized artificial aging process consisting of thermal cycling and mechanical cyclic loading. Microcomputed tomography (μCT) scans of implant bodies were performed before and after aging. 3-dimensional images of implant bodies were generated from the μCT scans and aligned for before and after aging to calculate the volumetric deformation amount. Finally, fracture resistance was measured using a mechanical static loading test for the surviving aged and 30 brand-new specimens. All specimens survived artificial aging. No significant difference in implant deformation was found in the regular groups (p=0.095). In narrow groups, the one-piece zirconia group showed significantly less deformation (p < 0.0001). For fracture resistance, no significant decrease was observed after aging in any group (p > 0.05). One-piece zirconia abutments showed significantly lower strength than the other two materials for both diameters (p < 0.0001). In the regular diameter system, abutment material had no significant influence on the tested mechanical property degradation after simulated long-term oral use. The mechanical performance of narrow diameter one-piece zirconia abutments differed from the other two materials. For optimal performance, one-piece zirconia abutments should be adopted only in anterior regions.

Preload evaluation of 2 implant-supported fixed partial denture abutment designs

Statement of problemA hemi-engaging abutment design has been suggested to improve the stability of the implant-to-abutment interface compared with that of a fully nonengaging design to restore implant-supported fixed partial denture. However, controversy persists regarding the benefit of using a hemi-engaging abutment design and prompts the need for specific mechanical testing on the effect of these designs on screw preload under simulated clinical conditions. PurposeThe purpose of this in vitro study was to determine whether significant differences in preload values of the screw before and after cyclic loading exist between hemi-engaging and nonengaging abutment fixed partial denture designs. Material and methodsTwenty-four conical connection implants measuring 4.3×10 mm (Nobel Biocare Replace Conical Connection; Nobel Biocare) were mounted in acrylic resin blocks. Specimens were divided into 2 groups. An experimental group included 12 three-unit fixed partial dentures with a hemi-engaging design; a control group included 12 three-unit fixed partial dentures with the conventional design of 2 nonengaging abutments. A digital screw torque meter was used to measure screw torque values per the manufacturer’s recommendation of 35 Ncm. Reverse torque value was measured before cyclic loading and referred to as initial preload. After cyclic loading, reverse torque value was measured and referred to as final preload. The effect of cyclic loading was evaluated by averaging the reverse torque value across the 2 screws in each specimen and then calculating the changes between the initial preload and final preload. The difference between initial and final preload was referred to as reverse torque difference. An additional reverse torque difference, referred to as reverse torque difference-nonengaging, was calculated for the nonengaging screws in each experimental specimen and for 1 randomly selected screw of the 2 in each control specimen. Preload efficiency before and after cyclic loading was also calculated. All groups went through cyclic loading using a universal testing machine. The specimens went through axial loading first, and then the reverse torque value was measured. Twenty-four new abutment screws were then used, and the specimens then went through lateral loading at 30 degrees. Load was applied to the units (1.0×106 cycles) for each loading axis. The statistical significance of differences between the axial and lateral reverse torque difference and between the 2 groups of reverse torque difference and reverse torque difference-nonengaging were assessed using Mann-Whitney U tests (α=.05). ResultsA comparison of reverse torque difference between loading types revealed no significant difference (P=.773). Therefore, data for the 2 loading types were combined before comparing the reverse torque difference and reverse torque difference-nonengaging values between the 2 groups based on abutment design (12 hemi-engaging designs in the experimental group and 12 fully nonengaging designs in the control group). The experimental group mean reverse torque difference was -0.65 ±1.95 Ncm (range -4.0 to 2.4 Ncm), and the control group mean reverse torque difference was -2.5 ±5.44 Ncm (range -15.3 to 5.3 Ncm). No significant difference was found (P=.340). Furthermore, no significant difference was found between the reverse torque difference for the nonengaging screw in each of the 12 implants with a hemi-engaging design versus 1 randomly selected nonengaging screw in each of the 12 implants with a fully nonengaging design (P=.355). ConclusionsNo significant difference was found in screw preload between a hemi-engaging and a full nonengaging 3-unit fixed partial denture supported by conical connection implant configurations before and after cyclic loading.

Limited marginal bone loss in implant-supported fixed full-arch rehabilitations after 5 years of follow-up.

The aim of the present study was to evaluate the 5-year results in terms of marginal bone level (MBL) around implants supporting fixed full-arch metal-ceramic restorations in a series of cases of patients who had lost their teeth in that dental arch because of severe periodontal disease. A retrospective cohort study was designed to evaluate the 5-year MBL results of OsseoSpeed™ Astra Tech TX implants with internal tapered conical connection. Age, gender, bone substratum, smoking habits, history of periodontitis, and prosthetic features were recorded. Mixed linear model was used to determine the influence of the different variables on MBL. In this series, a total of 160 implants placed in 19 patients were evaluated. No implant failure was reported during the 5 years of follow-up. Only 14 (8.75%) implants had more than 2 mm of MBL. Abutment height, F(3,142)=6.917, p < .001, and implant diameter, F(1,141)=15.059, p < .001, were determined to be statistically associated with MBL. No other effect was significant. Pairwise comparisons showed that MBL was larger for abutment height=1 (MBL=-0.987, SE=0.186) compared with the remaining heights [-0.335 (0.171), -0.169 (0.192) and -0.247 (0.267), 2, 4 and 6 mm, respectively]. MBL was larger for narrow (-0.510, SE=0.169) than for wide implants (-0.364, SE=0.190). The current study demonstrates that the vast majority of internal conical connection implants supporting fixed full-arch metal-ceramic restorations do not suffer from relevant MBL after 5 years in function. Particularly, those implants with transmucosal abutments longer than 2 mm show less than 0.5 mm from the implant shoulder to the marginal bone.

Misfit simulation on implant prostheses with different combinations of engaging and nonengaging titanium bases. Part 2: Screw resistance test

Statement of problemProsthesis fit is 1 of the main factors influencing the success and survival of an implant-supported screw-retained restoration. However, scientific validation of the performance of engaging and nonengaging components in a fixed partial denture (FPD) and the effect of their combinations on the fit of FPDs is lacking. The screw resistance test has been used for the fit assessment of screw-retained FPDs. However, objective assessments by using analog and digital devices are now available. PurposeThe purpose of this in vitro study was to investigate the effect of engaging and nonengaging components on the fit of screw-retained frameworks, supported by 2 conical connection implants with simulated vertical and horizontal misfits, by performing 2 different screw resistance tests (analog and digital). Material and methodsThirty 2-implant-supported bar-shaped zirconia frameworks cemented on two 2-mm titanium bases were fabricated and divided into 3 groups (n=10) according to different abutment combinations: both engaging, engaging and nonengaging, both nonengaging. The fit of each framework was tested on the control cast and on 6 definitive casts simulating 50-, 100-, and 150-μm vertical and 35-, 70-, and 100-μm horizontal misfit levels. The abutment screws were tightened on each implant, and the screw rotation angle was measured both digitally, with a custom-made digital torque wrench and a computer software program, and conventionally, with an analog torque wrench and protractor. Clearly ill-fitting specimens were excluded. The data were statistically analyzed by 1-way analysis of variance (ANOVA) and the Tukey post hoc test (α=.05). ResultsBoth engaging specimens on the 100-μm horizontal misfit group and on all vertical misfit groups were clearly ill-fitting and excluded. Statistically significant differences among groups with different combinations of abutments were found (P<.05). The engaging abutments had a higher angle of rotation than the nonengaging abutments on all casts. In the horizontal misfit group, both engaging specimens had the highest angle of rotation, followed by engaging and nonengaging and both engaging specimens. In the vertical misfit group, the engaging and nonengaging specimens had the highest angle of rotation on the side of the engaging abutment. The angle of rotation increased with the increasing level of misfit. ConclusionsBoth nonengaging frameworks showed superiority in misfit tolerance, as the angle of rotation was lower than that of the engaging and nonengaging and both engaging frameworks. Conventional and digital torque wrenches showed similar results.

Microleakage assessment of CAD-CAM Cobalt-Chrome and Zirconia abutments on a conical connection dental implant: Acomparative in vitro study.

ObjectiveTo assess the marginal and bacterial microleakage in zirconia and CAD‐CAM or cast Co‐Cr implant abutments.MethodsSixty‐four conical connection implants with their respective abutments were divided into four groups (Co‐Cr (milled, laser‐sintered, and cast) and Zirconia (milled)). All specimens were subjected to a chewing simulation and thermocycling. After aging process, specimens were submerged in a 0.2% methylene blue solution with Porphyromonas gingivalis (P.g) for 48 h. The marginal microleakage was measured using a 40× optical microscopy at the internal part of the implant, and when positive microleakage was observed, a DNA isolation with a polymerase chain reaction (PCR) test was used. The microbiological assessment was based on colony forming units (CFUs).ResultsThirty (47%) implant‐abutments presented microleakage and the PCR was performed on those specimens (1 Zirconia, 1 Co‐Cr milled, 14 Co‐Cr laser‐sintered and 14 cast). Seven specimens (1 Co‐Cr laser‐sintered and six cast) presented values below the PCR detection limit (< 100 CFUs). The lowest CFUs count occurred in the Co‐Cr milled group (5.17E+02 CFUs/ml) followed by zirconia (7.70E+03 CFUs/ml). The Co‐Cr cast (9.39E+03 CFUs/ml) and laser‐sintered (2.4E+05 CFUs/ml) groups had higher bacterial count. The CFU count comparison performed between Co‐Cr cast and laser‐sintered resulted in a statistically significant differences in favor of Co‐CrCL (p < .05).ConclusionsThe abutment material and fabrication technique affected the implant‐abutment microleakage. Although the CAD‐CAM abutments presented favorable results, all tested groups presented microleakage.

Evaluation of Immediately Loaded Parallel Conical Connection Implants with Platform Switch in the Maxillary Esthetic Zone: A Prospective Clinical Study

To assess immediately loaded parallel conical connection (Nobel Biocare) implants with platform switch design in the maxillary esthetic zone for soft and hard tissue changes. A total of 20 patients (n = 20) underwent prosthetic replacement of the missing maxillary anterior tooth, with an immediately loaded parallel conical connection implant (Noble Biocare, Sweden) having a platform switch design. The size of the implant was 3.75 mm in width and 13 mm in length for all patients and placement followed a standardized surgical protocol. Postoperatively, acrylic provisionalization was done within 48 hours followed by a definitive zirconia prosthesis in the 3rd month. Clinically and radiographically, the implants were evaluated for hard tissue (bone density, implant stability, crestal bone loss) and soft tissue changes (mucosal thickness-MT, sulcus probing depth-PD, bleeding on probing-BOP, width of keratinized gingiva-KG) at baseline till 36 months with follow-up intervals after loading. All patients showed uneventful healing. The difference in implant stability and density scores was significant (p <0.05*) from baseline to 36 months indicating bone formation and osseointegration of the implant. Bleeding on probing was not observed, and probing depth remained within the acceptable range (≤5 mm) at all time intervals after loading. The marginal bone loss was minimal (≤0.2 mm annually) with the absence of implant mobility and without any peri-implant radiolucency. The thickness of the gingiva (3.47 ± 0.34 mm) and width of keratinized gingiva (2.46 ± 0.39 mm) remained within reasonable limits at the 36th month with acceptable esthetic appearance. In the present study, immediate loading of Nobel parallel conical connection implant in the maxillary anterior region provided adequate primary stability, minimal marginal bone loss, and increased bone density indicating earlier osseointegration. Decreased probing depth, absence of bleeding on probing, and adequate tissue collar at the neck showed better soft tissue emergence in the esthetic zone. The platform switch design demonstrated promising results and therefore can be used as an alternative to the conventional method. The present study results suggest that parallel conical connection implants (Nobel Biocare) with TiUnite surface, built-in platform switch combined with conical connection interface, parallel walled body, tapered apex, and double threads from tip to platform are all designed to provide high primary stability and support immediate function protocol, hence can be used flexibly in different bone densities.

Evaluation of Implant Stability and Trephination Depth for Implant Removal-An In Vitro Study.

Malpositioned and broken implants are usually fully osseointegrated; hence, their removal, especially from the lower arch, can be very challenging. Implant removal techniques include reverse torque and trephination. Trephination is an invasive technique that can jeopardize vital structures, cause mandibular fatigue fractures, or lead to osteomyelitis. In this study, we aimed to assess the relationship between trephination depth and implant stability by recording implant stability quotient (ISQ) readings at varying trephination depths in vitro. Materials and methods: Forty-eight implants were inserted into dense synthetic polyurethane foam blocks as artificial bone. Primary implant stability was measured with a Penguin resonance frequency analysis (RFA) device. Implants of two designs with a diameter of 3.75 mm and a length of 13 or 8 mm were inserted. Twenty-four internal hexagon (IH) (Seven®) and twenty-four conical connection (CC) implants (C1®; MIS® Implants, Ltd., Misgav, Israel) were used. The primary implant stability was measured with the RFA device. Trephination was performed, and implant stability was recorded at depths of 0, 3, and 6 mm for the 8 mm implants and 0, 3, 6, 8, 10, and 11.5 mm for the 13 mm implants. Results: Linear regression revealed a significant relation between the trephination depth and the ISQ (F (1, 213) = 1113.192, p < 0.001, adjusted r2 = 0.839). The trephination depth significantly predicted the ISQ (β = −5.337, p < 0.001), and the ISQ decreased by −5.33 as the trephination depth increased by 1 mm. Conclusion: Implant stability reduction as measured using an RFA device during trephination may be a valuable guide to achieving safe reverse torque for implant removal. Further studies are needed to evaluate these data in clinical settings.

Immediate Loading Guided Surgery Full Arch with 7 anterior Socket Shields

The aim of this case report is to evaluate guided surgery applied to immediate loading of a full arch with conical connection implants and screw-retained prosthesis delivered the same day of the computer-guided and immediate loading implant surgery. The patient with terminal dentition at the upper jaw was scheduled for a full arch rehabilitation with six immediate implants with guided surgery and immediate loading. Because with guided surgery I could save time to pay attention to other aspects during the surgery I could perform socket shield technique at the frontal elements from 1.4 to 2.3 (7 adjacent sites) to maintain the natural and native architecture both of the bone and the soft tissues of the patient. Into the extraction gaps, I've inserted biomaterial (xenograft) mixed with fibrine sealant. Multi-unit abutments with a very tight and performing connection and immediate screw-retained temporary were delivered the same day of the surgery in the afternoon. The surgery was performed 5 months ago and everything is going well. The final prosthesis will be delivered next month. This case report has many topics to evaluate, starting with the possibility to use computer-guided surgery to deliver the temporary prosthesis on the same day of the surgery, according to the prosthetic project and the bone situation from the CBCT. The use of socket shield technique to perform ridge preservation when there are indications to maintain aesthetics and long-term predictability for the implants and pontic areas (6,7,8,9), especially in adjacent post-extraction sites. The possibility to build the same day the temporary prosthesis with a rigid type of resin pre-built into the laboratory (that still has a little elasticity module for shock-absorbing) that can be substituted with a final prosthesis after 3/6 months according to the healing of the soft tissues. Tight and efficient conical connection (TPIS, two pieces implant system) at the implant/abutment ensures a stable interface between the components and screw-retained at the prosthetic interface ensure to evaluate easily the situation underneath the prosthesis during and after the osseointegration.

Marginal Bone Loss in Internal Conical Connection Implants Placed at the Crestal and Subcrestal Levels before Prosthetic Loading: A Randomized Clinical Study.

The vertical position concerning the bone in which the implants are placed has been related as one of the factors causing marginal bone loss. The objective of this study was to evaluate the bone loss that occurs before prosthetic loading around tapered internal connection (CIC) implants placed at the crestal (C) and subcrestal (S) levels. Method: A randomized clinical trial (RCT) was carried out, with a sample size of 62 implants placed in 27 patients who underwent radiological controls on the day of placement, at one month, and at 4 months, and stability was measured by resonance frequency analysis (RFA) on three occasions. Results: Bone loss in implants C and S from the time of placement (T0) and the month after (T1) was not significant (p = 0.54) (C = 0.19 mm and S = 0.15 mm). The difference between one month (T1) and four months (T2) (C = 0.17 mm and S = 0.22 mm) was not significant either (p = 0.26). The difference between the day of placement (T0) and the third and last measurement (T2) was almost null (p = 0.94) (C = 0.35 mm and S = 0.36). The overall success rate of the implants was 97.8%. The stability of the implants measured with RFA went from 70.60 (T0) to 73.16 (T1) and 74.52 (T2). Conclusions: No significant differences were found in the bone loss for implants placed at the C and S levels. The millimeters of bone loss detected in both vertical positions did not have a significant impact on the stability of the implants.

A retrospective study of 12,538 internal conical connection implants focused on the long-term integrity of implant-abutment complexes.

To evaluate the long-term integrity of implant-abutment complexes in implant systems with two internal conical angles. 12,538 bone-level implants of two systems placed between January 2012 and December 2018 were retrospectively analyzed. Cumulative abutment/implant fracture rates in systems with larger (LA, 7.5°) and smaller (SA, 5.7°) internal conical angles were estimated using the Kaplan-Meier analysis and compared between groups. The association between implant systems and jammed abutment retrievability was evaluated by multivariable generalized estimating equation logistic regression modeling. For LA, the 8-year cumulative incident rate was 0.10% (95% confidence interval (CI): 0-0.24%) for implant fracture and 0.26% (95% CI: 0.11%-0.41%) for abutment fracture, demonstrating a significant difference in gender (p=.03), implant diameter (p=.01), jaw (p=.006), and antagonist tooth (p<.001). For SA, the 8-year cumulative incident rate was 0.38% (95% CI: 0-0.79%) for implant fracture and 2.62% (95% CI: 0.05%-5.13%) for abutment fracture, which was influenced by implant diameter (p<.001) and site (p=.03). The cumulative implant/abutment fracture rate was lower for LA implants, particularly for LA implant-supported single crowns (SCs) (p<.05). The abutment-retrieval success rate was 92.9% for LA and 57.1% for SA (p=.055). LA implants exhibited a lower incidence of fracture in abutment-implant complexes and a relatively higher retrievability success rate for jammed abutments.

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

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

Immediately provisionalized tapered conical connection implants for single-tooth restorations in the maxillary esthetic zone: a 5-year prospective single-cohort multicenter analysis

ObjectivesThis open, single-cohort, multicenter, prospective study investigated the efficacy of immediately provisionalized tapered conical connection implant for single-tooth restorations in the anterior and premolar regions of the maxilla after 5 years of function.Materials and methodsAll implants were placed in healed sites and immediately provisionalized. MBLs, soft-tissue parameters, and oral-health impact profile (OHIP) were evaluated at implant insertion, 6, 12, 24, 36, and 60 months. Paired Wilcoxon signed-rank tests and Kaplan–Meier survival analysis was used for statistical and implant survival/success analyses, respectively.ResultsSeventy-seven patients (81 implants) completed the 5-year follow-up. The 5-year cumulative survival and success rates were 97.8%, and the mean MBL change from implant insertion to 5 years was − 0.80 ± 1.13 mm. Optimal papilla index scores were observed at 90.1% of sites at 5 years compared with 32.8% of sites at insertion. Pink esthetic score, modified bleeding and plaque indices, and OHIP showed statistically significant improvement at the 5-year follow-up.ConclusionsImmediately provisionalized tapered conical connection implants promote marginal bone stability and excellent esthetic outcomes after 5 years of function.Clinical relevanceThis treatment is a viable option for patients requiring immediately provisionalized single-tooth restorations in the esthetic zone and shows favorable long-term clinical outcomes, including marginal bone stability and excellent esthetics.

Fracture Resistance of Zirconia Abutments with or without a Titanium Base: An In Vitro Study for Tapered Conical Connection Implants.

Dental implants with tapered conical connections are often combined with zirconia abutments for esthetics; however, the effect of the titanium base on the implant components remains unclear. This study evaluated the effects of a titanium base on the fracture resistance of zirconia abutments and damage to the tapered conical connection implants. Zirconia (Z) and titanium base zirconia (ZT) abutments were fastened to Nobel Biocare (NB) implants and Straumann (ST) implants and subjected to static load testing according to ISO 14801:2016. The experiments were performed with 3 mm of the platform exposed (P3) and no platform exposed (P0). The fracture loads were statistically greater in the titanium base abutments than the zirconia abutments for the NB and ST specimens in the P0 condition. In the P3 condition of the ST specimens, the deformation volume of the ZT group was significantly greater than the Z group. The titanium base increased the fracture resistance of the zirconia abutments. Additionally, the titanium base caused more deformation in the P3 condition. The implant joint design may also affect the amount of damage to the implants when under a load. The mechanical properties of the abutment should be considered when selecting a clinical design.