D3 Bone Research Articles

The Influence of Different Pontic Designs on Fracture Resistance of Implant-supported Fixed Partial Dentures Anchored in Polyurethane Simulating Bone-blocks of Two Different Densities: An In Vitro Study.

This study aimed to evaluate the fracture resistance of implant-supported fixed partial prostheses fabricated from monolithic zirconia with different pontic framework designs and anchored in different bone-like simulation models of two different densities. A total of 60 implants were anchored in two different in vitro bone simulation models of two different densities, namely, solid polyurethane foam blocks, 20 and 10 pounds per cubic foot (PCF) to construct implant-supported fixed partial dentures (FPDs), the pontic constructed to replace missing second premolar and first molar. Thirty models were constructed and then divided into two groups according to anchoring material D2 (n = 15) and D3 (n = 15). Each group of models was subdivided into three groups according to pontic design (n = 5). Each model was tested against fracture in a universal testing machine. The data were analyzed with a two-way univariate ANOVA and Tukey HSD test (α = 0.05). The results were statistically analyzed, and the values were considered significant at p≤0.05. The findings showed that neither change in pontic design nor change in bone type has a significant influence on the fracture resistance of the prostheses (p > 0.05). All the tested materials fell within the acceptable range for functioning under mastication, with a slight change in resistance when the pontic design was changed. Zirconia is considered the material of choice when planning implant-supported FPDs because of its high fracture strength values. Within the limitations of this study, the pontic design and synthetic polyurethane bone-simulating model had no effect on the fracture resistance of four-unit implant-supported FPDs. This study postulated that any pontic design could be used in four units of implant-supported FPDs according to functional and aesthetic needs, as long as the histological nature of the alveolar bone falls within the D2 or D3 bone type. How to cite this article: Othman MS, Abu-Eittah MRH. The Influence of Different Pontic Designs on Fracture Resistance of Implant-supported Fixed Partial Dentures Anchored in Polyurethane Simulating Bone-blocks of Two Different Densities: An In Vitro Study. J Contemp Dent Pract 2024;25(7):684-690.

Comparison of Intraosseous Temperature Rise in Different Surgical Guide Systems: An In Vitro Study

Aim: This study proposes to investigate the influence of various surgical guide designs on the generation temperature in the cortical and cancellous regions of the osteotomy site. The working hypothesis was that open guides are more efficacious in controlling excessive heat generation in cortical and cancellous areas. Materials and Methods: Implant osteotomy was performed on specimens simulating D3 bone density using surgical guides produced with three different designs: an open guide, a guide with an external cooling channel, and a closed guide. Temperature increases occurring in the cortical layer from a depth of 2 mm and in the cancellous layer from a depth of 10 mm were measured with type K thermocouples. Results: Temperature averages recorded from a depth of 2 mm during osteotomy show statistically significant differences between groups ( p = .003). The temperature rise in the group using a closed surgical guide was significantly higher than in the groups using an open surgical guide and a surgical guide with an external cooling channel on the cortical layer, while the temperature increase did not show any significant difference in both cortical and cancellous layers between the open guide and guide with external cooling channel. Temperature averages recorded from a depth of 10 mm do not show statistically significant differences between groups ( p = .054). Conclusion: Using open surgical guides or surgical guides with external cooling channels among the guided surgical systems is a more reliable way to keep the thermal increase under control.

Using optimization approach to design dental implant in three types of bone quality - A finite element analysis

Background/PurposeThe use of finite element (FE) analysis in implant biomechanics offers many advantages over other approaches in simulating the complexity of clinical situations. The aim of this study was to perform an optimization analysis of dental implants with different thread designs in three types of bone quality. Materials and methodsThe three-dimensional FE model of a mandibular bone block with a screw-shaped dental implant and superstructure was simulated. In the optimization analysis, the design variables included the thread pitch and the thread depth of the implant. The objective was to minimize the displacement of the implant to the target value. Three FE models with different bone qualities (D2: better bone quality; D3: ordinary bone quality; D4: poor bone quality) were created. ResultsThe FE results showed that the displacement of the implant and the stress of the cortical bone increased, while the Young's modulus of the cancellous bone decreased. In the D2 bone, changing the thread pitch and thread depth had little effect on cortical stress and implant displacement. However, in D3 and D4 bone, increasing thread depth reduced cortical stress by 40 % and implant displacement by at least 9 %. ConclusionAdjusted thread depth for D3 and D4 bone would reduce crestal bone stress and increase implant stability, but only a little alteration on crestal bone stress and implant stability for D2 bone.

Stress distribution by parafunctional loading on tooth–implant, implant–implant, and tooth–tooth-supported prosthesis: A comparative three-dimensional finite element analysis

Aim: The study’s objective was to evaluate the stress distribution in tooth-implant, implant-implant, and tooth-tooth supported prostheses under parafunctional loading in axial and oblique directions employing a 3D finite element analysis in the mandibular posterior region which had D3 bone (porous cortical bone and fine trabecular bone). Setting and Design: In vitro study, Finite element analysis. Meterials and Methods: Cone-beam computed tomography data was used by Mimics software (Materialize Mimics 19) to create a three-dimensional finite element simulation of the jaw. Solid Works 2018 (Dassault Systems) was used to produce a geometric 3D model of the three systems. Each model consisted of a bone, an implant, and teeth (Model I tooth-tooth supported, Model II tooth-implant supported and Model III implant-implant supported). The three models’ geometrical models were transferred to Ansys Workbench (19.2 software) for the analysis portion. A load that mimicked masticatory force was delivered in both axial and oblique directions. Statistical Analysis Used: In the present study, statistical analysis was not required because 3D finite element analysis uses deterministic numerical methods to simulate physical behavior and stress distribution patterns. Result: The results demonstrated that under the parafunctional combined loading process, the implant- implant supported prosthesis showed significantly higher stress concentrations in the bone. It was found that the cortical bone around the crestal region had the highest stresses. Conclusion: Within the constraints of this investigation, we could draw the following conclusion: Of the three models, the tooth-tooth supported prosthesis exhibited the least amount of stress distribution, which was also least when functional loading was applied in the axial direction.

The Effect of Increasing Thread Depth on the Initial Stability of Dental Implants: An In Vitro Study

Background: The long-term success of dental implants largely depends on achieving primary stability, previously described as crucial to obtaining osseointegration and immediate loading protocol requirements. Implant thread depths seem to be one of the key factors influencing primary stability, particularly in low-density bone. Insertion torque (IT) and resonance frequency analysis (RFA) are considered the most reliable tests to assess primary stability. The aim of this work was to evaluate how different thread depths of commercially available dental implants affect primary stability in low-density D3 bone. Materials and Methods: An in vitro study was carried out between February 2024 and March 2024. Twenty-four dental implants were divided into four groups (six implants each) according to their thread depths (Group A: 4 mm, Group B: 4.5 mm, Group C: 5 mm, Group D: 5.5 mm) and were inserted in D3-type artificial bone blocks. The main outcome variables were the IT and the Implant Stability Quotient (ISQ) measured in four different areas of the implant (buccal, lingual, mesial, and distal) with an Osstel® ISQ reader. Descriptive and inferential analyses of the data were performed, and the significance value was set at 5%. Results: A total of 24 implants were analyzed. The highest IT values were obtained in Group D, with a mean of 54.03 Ncm (standard deviation (SD) = 8.99), while the lowest measurements were observed in Group A (mean = 25.12; SD: 2.96 N.cm). The mean ISQ values were consistently higher in Group D for each analyzed area, with a mean of 70.13 N.cm (SD = 1.12). Conclusions: Taking into consideration the limitations of this in vitro study, greater thread depths seem to increase the primary stability of dental implants placed in soft bone. Furthermore, a positive correlation was observed between all IT and ISQ values, regardless of the thread depth.

Comparative Evaluation of Primary Stability in Truncated Cone Implants with Different Macro-Geometries in Low-Density Polyurethane Blocks Simulating Maxillary Sinus Rehabilitations

After tooth loss, particularly in the posterior maxilla, the alveolar ridges undergo bone resorption. Therefore, ensuring the appropriate quantity and quality of alveolar bone is crucial for accurate implant positioning and achieving optimal esthetic and functional results. This study aimed to evaluate biomechanical parameters (insertion torque: IT, removal torque: RT, and implant stability quotient: ISQ) of distinct truncated cone implant designs (Sinus-plant and SLC) on polyurethane blocks simulating type D3 and D4 bone. SLC implants exhibited significantly higher IT, RT, and ISQ values compared to Sinus-plant implants, except in the 10 pounds per cubic foot (PCF) density block with a cortical layer for the IT (24.01 ± 0.91 vs. 23.89 ± 1.66 Ncm). The IT values for SLC implants ranged from 13.95 ± 0.19 Ncm in the lowest density block to 37.94 ± 0.45 Ncm in the highest density block, consistently providing significantly higher primary stability with an ISQ of approximately 70 in the highest density block. Despite lower ISQ in the lowest density block (48.60 ± 0.52 and 48.80 ± 0.42 in buccolingual and mesiodistal directions), it was deemed acceptable considering the inadequate bone densities in the maxillary region. These findings on SLC suggest potential clinical advantages, including reduced procedure duration and costs, improved stability, and the possibility of immediate implant placement following sinus augmentation, thereby streamlining the rehabilitation process.

Correlation Between Implant Stability Quotient and Percussion Sound Frequency.

To determine the correlation between the primary implant stability quotient and the implant percussion sound frequency. A total of 14 pigs' ribs were scanned using a dental cone beam computed tomography (CBCT) scanner to classify the bone specimens into three distinct bone density Hounsfield units (HU) value categories: D1 bone: >1250 HU; D2: 850-1250 HU; D3: <850 HU. Then, 96 implants were inserted: 32 implants in D1 bone, 32 implants in D2 bone, and 32 implants in D3 bone. The primary implant stability quotient (ISQ) was analyzed, and percussion sound was recorded usinga wireless microphone connected and analyzed with frequency analysis software. Statistically significant positive correlations were found between the primary ISQ and the bone density HU value (r = 0.719; p < 0.001), and statistically significant positive correlations between the primary ISQ and the percussion sound frequency (r = 0.606; p < 0.001). Furthermore, significant differences inprimary ISQ values and percussion sound frequency were found between D1 and D2 bone, as well as between D1 and D3 bone. However, no significant differences were found in primary ISQ values and percussion sound frequency between D2 and D3 bone. The primary ISQ value and the percussion sound frequency are positively correlated.

Nano-superhydrophilic and bioactive surface in poor bone environment. Part 1: transition from primary to secondary stability. A controlled clinical trial

ObjectivesBioactive surfaces were designed to increase the interaction between the surface and the cells. This may speed up the biological stability and loading protocols.Materials and methods36 patients with D3-D4 bone density were recruited and allocated into two groups. 30 bioactive (test group) and 30 traditional (control group) surfaced implants were placed. Insertion torque value (Ncm), insertion torque curve integral (cumulative torque, Ncm), torque density (Ncm/sec), implant stability quotient (ISQ) measured at three timepoints (baseline (T0), 30 (T30) and 45 (T45) days after surgery), and marginal bone loss (MBL) at 6 months of loading were assessed.ResultsThe mean ISQ and standard deviation at T0, T30, T45 were respectively 74.57 ± 7.85, 74.78 ± 7.31, 74.97 ± 6.34 in test group, and 77.12 ± 5.83, 73.33 ± 6.13, 73.44 ± 7.89 in control group, respectively. Data analysis showed significant differences between groups in ΔISQ at T0-T30 (p = 0.005) and T30-T45 (p = 0.012). Control group showed a significant decrease in ISQ at T30 (p = 0.01) and T45 (p = 0.03) compared to baseline, while no significant change was observed in test group. Due to the stability of the ISQ value ≥ 70, 26 test group and 23 control group implants were functionally loaded after 45 days. Conversely, due to the ISQ < 70 at T45, four test group implants and one control group implant were loaded after 90 days, and 6 control group implants were loaded after 180 days. Neither insertion torque nor ISQ at baseline were correlated with bone density (in Hounsfield units). There was no significant correlation between cumulative torque and ISQ at baseline. There was a significant positive slope in the correlation between torque density and ISQ at baseline, more accentuated in D3 than D4. This correlation remained significant for the test group in D3 bone at day 30 and 45 (p < 0.01 in both time frames), but not in D4 bone, and it was not significant in CG.ConclusionsThe bioactive surface showed better behavior in terms of implant stability in D3-D4 bone quality in the early stages of bone healing. Clinical relevance This study demonstrated that the transition from primary to secondary stability is improved using bioactive surface, especially in cases of poor bone environment (D3/D4 bone).

An In Vitro Evaluation of Periotest Implant Stability Measurements Taken on Implant Retained Crowns and Healing Abutments.

To assess the reliability of implant stability measurements recorded with the Periotest device and to investigate the differences in values when these measurements were taken on implant retained crowns and healing abutments. Fifty-six implants in eight synthetic bone blocks were used to carry out implant stability measurements using the Periotest device by two different operators. Each block constituted an example of bone of density D1, D2, D3, or D4, and two blocks of each density were used. The healing abutments placed were of a height to allow approximately 6 mm of the implant-abutment complex to be supracrestal and temporary crowns were made to match the dimensions of an average central incisor. Descriptive statistics were used to describe the perio test values (PTVs) at each of the different heights on the implant abutments and implant crowns. Means for each site were calculated and distribution of data assessed using the Kruskal Wallis test. The interclass correlation coefficient (ICC) was used to determine the relationship between the PTVs recorded on the implant abutments and implant crowns. The mean PTV (±standard devidation) recorded across all sites was 5.57 ± 11.643 on the implant abutments, and 12.27 ± 11.735 on the temporary crowns. Excellent/good inter-operator ICCs were recorded for the mid-abutment site in all bone blocks D1-D4 (ICC = 0.814, p < 0.001, ICC = 0.922, p < 0.001, ICC = 0.938, p < 0.001, ICC = 776, p < 0.001). For mid crown sites, ICC between operators was excellent/good only for recordings in D2 bone (ICC = 0.897, p < 0.001). Periotest device seems to be able to reliably measure implant stability across all types of bones when the implant stability is assessed at approximately 3 mm coronal to the implant platform for abutments and 4.5 mm for implant supported single crowns.

A Finite Element Analysis to Study the Stress Distribution on Distal Implants in All-on-Six Treatment Concepts as Affected Tilted and Short Implant.

The number of implants and their respective configurations for implant-supported treatment modalities have been studied for 4 implant-supported prostheses; however, it is not yet clear whether the use of tilting or short implants in rehabilitation would result in substantially improved bone/implant/prosthesis biomechanics in all-on-six concepts. This study compared the biomechanical behavior of tilted long implants and axially short implants to support fixed prostheses in an atrophic maxilla with all-on-six treatment concepts. Three different implant configurations were planned, and six models were obtained with posterior maxilla D3 and D4 bone densities in this study. Implants proper for the all-on-four concept were placed in all models. In models 1 and 2, the short implant was placed; in models 3 and 4, 30°, the mesial-angled implant was placed; and in models 5 and 6, 45°, the mesial-angled implant was placed to the molar region. In the models created, 200 N vertical and 150 N oblique (45° angled buccopalatal direction) forces were implemented to the bilateral tooth regions 4-5-6 on the rigid titanium-supported fixed hybrid prosthesis made on these models. When the stress values in the models were investigated, the oblique forces had higher stress values than the vertical forces did. When the stresses created by oblique forces were assessed, the highest values were observed in the models created with short implants, and the lowest stress values were observed in the models made with 30° angle to mesial. When bone densities were assessed, more stress values were noted in models with D4 bone density. It has been shown that mesial tilted long implants placed in the posterior molar region, in addition to all four implant treatment concepts, create less stress against undesirable oblique forces compared with short implants.

Comparison of the success rate and marginal bone loss of implants placed simultaneously with either bone expansion or ridge splitting in maxillary sites: a prospective non-randomized study

This study was performed to compare the amount of marginal bone loss (MBL) and the success rate of implants placed following maxillary ridge expansion with two surgical techniques. A non-randomized prospective study was designed. The patients underwent either bone expansion or ridge splitting, and simultaneous implant placement. The implants were loaded according to the delayed loading protocol with single crowns. Each study group included 35 implants placed in 31 patients. One year after loading, the implant success rate was 100 % in both groups. The median MBL was 1.00 mm in both groups (interquartile range 0.10 mm in the bone expansion group and 0.30 mm in the ridge splitting group) (no significant difference, P = 0.749). The median MBL around implants placed in sites with D2, D3, and D4 density bone was 1.40 mm, 1.00 mm, and 0.80 mm in the expansion group and 1.50 mm, 1.00 mm, and 0.85 mm in the splitting group, respectively. There was a significant difference in MBL between the different bone density types within both groups (P < 0.001). In conclusion, no significant difference in the amount of MBL or the success rate was observed between implants placed simultaneously with ridge splitting and those placed simultaneously with bone expansion, in the maxilla.

Evaluation of Effect of Different Insertion Speeds and Torques on Implant Placement Condition and Removal Torque in Polyurethane Dense D1 Bone Model.

The aim of this study was to evaluate the effect of two different insertion speeds at eight different insertion torque values ranging from 25 to 60 during implantation in a dense polyurethane (PU) D1 bone model on the placement condition and removal torque of dental implants. In this study, 50 pcf single-layer PU plates were used. In the study, a total of 320 implant sockets were divided into two groups, Group 1 (30 rpm) and Group 2 (50 rpm), in terms of insertion speed. Group 1 and Group 2 were divided into eight subgroups with 25, 30, 35, 40, 45, 50, 55 and 60 torques. There were 20 implant sockets in each subgroup. During the implantations, the implant placement condition and removal torque values were assessed. There was a statistically significant difference between the 30 and 50 rpm groups in terms of overall implant placement condition (p < 0.01). It was found that the removal torque values at 50 rpm were statistically significantly higher than those at 30 rpm (p < 0.01). This study showed that in dense D1 bone, the minimum parameters at which all implants could be placed at the bone level were 50 torque at 30 rpm and 40 torque at 50 rpm.

ISQ for Assessing Implant Stability and Monitoring Healing: A Prospective Observational Comparison between Two Devices

Background: With the growing use of dental implants, there is an urgent need to determine a prosthetic placement protocol by assessing implant stability and monitoring healing. Implant Stability Quotient (ISQ) values are produced using dental non-invasive devices through resonance frequency analysis, considered as indicators for measuring primary stability (i.e., at implant placement), monitoring biological stability (osseointegration), and prosthetic loading. A systematic and detailed comparison of ISQ measurement devices, for a given patient population, is lacking in the literature. This aspect is the subject of the present work, with the devices being two that are widely used in clinical practice (Osstell® and Osseo®100). The aim of this study was to evaluate the reliability of ISQ measurement using two standard devices most commonly used in clinical practice and to highlight any differences when comparing measurements at undefined time intervals. Methods: We enrolled 50 patients (16 males and 34 females) with a mean age of 55.4 years, who indicated dental implant placement and met the inclusion criteria. The sample was divided into two equal groups based on bone density: A (D1–D2 bone density) and B (D3–D4 bone density); each had 25 patients with 40 implants. ISQ was measured using two devices: Osstell® and Osseo 100®, at different time points (A: three and B: four follow-ups). Results: All enrolled patients completed the study without adverse events; all implants placed were successful, with no implant failure. In each of the study groups, ISQ values increased gradually with increasing follow-up time, and there was no significant difference between Osstell and Osseo 100 values at follow-up times except for the T1 follow-up in group A. Temporal comparisons for the two devices revealed significant differences in T0 vs. T2 in group A, whereas significant differences existed in T0 vs. T1, T2, and T3 in group B. Our findings indicated that the overall effect significantly depended on bone density rather than on the device used to measure ISQ. Conclusion: Regardless of the devices used, the ISQ measurement effectively monitors healing after implant insertion and allows prosthetic load to be modulated according to the ISQ value, especially when prosthetizing implants placed in fine trabecular bone (D4 or regenerated bone).

Biomechanical Evaluation of Zygomatic Implant Versus Pterygoid Implant in Atrophic Maxilla: An In vitro Finite Element Study.

Dental implants are considered to be one of several treatment options that can be used to replace missing teeth. The objective of the study is to examine and compare the biomechanics of zygomatic and pterygoid implants planned on the atrophic maxilla with three different bone types. An in vitro finite element study was conducted on a three-dimensional model of zygomatic and pterygoid implants. In a total of 24 implants, two bilateral zygomatic and pterygoid implants with two anterior dental implants were inserted in models. 150 N vertical occlusal and 300 N load on masseter and medial pterygoid were simulated on the modeled prosthesis. The data were processed with ANSYS software. The stress on and deformations of the bones and implants were observed and compared. When comparing the D4, D3, and D2 bones in subgroup I with zygomatic implants, the D2 bone was subjected to less stress compared to D3 and D4. The smallest displacement (0.125784mm) was seen in D4 followed by the largest displacement (0.74073mm) in D2. Similarly, when comparing the D2, D3, and D4 bone in subgroup II with pterygoid implants, the D2 bone in the atrophic maxilla received the least amount of stress from the pterygoid implants compared to D3 and D4. Furthermore, the smallest displacement (0.030934mm) was seen in D2, and the largest (0.046319mm) in D4. Results suggest firstly, that the overall stress was better distributed in D2 bone and secondly, the pterygoid implant showed higher stress concentration than the zygomatic implant.

A comparative finite element analysis of titanium, poly-ether-etherketone, and zirconia abutment on stress distribution around maxillary anterior implants

Background: The aim of this study was to investigate the influence of abutment material, alveolar bone density, and occlusal forces on stress distribution around maxillary anterior implants. Materials and Methods: An in-vitro study was conducted. The maxillary anterior implant was modeled using a three-dimensional finite element model in D2 and D3 bones with three different abutment materials: titanium, zirconia, and poly-ether-ether ketone (PEEK). Von Mises stress was evaluated after the application of vertical and oblique loads of 100 N, 175 N, and 250 N. Statistical analysis was done by Friedman-Wilcoxon signed-rank test, Mann-Whitney U test, and Kruskal-Wallis test. The probability value &lt;0.05 is considered a significant level. Results: Stress distribution around D3 bone was higher than D2 bone in all the abutment materials with greater values seen in oblique load than vertical load with insignificant difference ( P &gt; 0.05). Statistically insignificant stress values were seen greater in PEEK than titanium or zirconia abutment ( P &gt; 0.05). A statistically significant difference was observed between 100 N and 175 N of load ( P &lt; 0.05). Conclusion: PEEK, zirconia, and titanium as abutment material in the anterior region showed similar properties. The stress on the bone was proportionately increased during the vertical and oblique loads suggesting the influence of mechanical load in crestal bone loss rather than the type of abutment material.

Investigating the Influence of All-Ceramic Prosthetic Materials on Implants and Their Effect on the Surrounding Bone: A Finite Element Analysis

This study aims to assess and compare the impact of Monolithic Zirconia (MZ) and In-Ceram Zirconia (ZP) superstructures on stress distribution within implants and D2/D4 bone densities under 200 N vertical and oblique occlusal loads using three-dimensional finite element analysis via ANSYS WORKBENCH R2. The analysis employed maximum and minimum von Mises stress values. Modeling an implant (4.2 mm diameter, 10 mm length) and abutment (0.47 mm diameter), with an 8 mm diameter and 6 mm length single crown, the research identified lower von Mises stresses in D2 cancellous bone with the MZ model under vertical loading. Conversely, under oblique loading, the ZP model exhibited maximum von Mises stresses in D4 bone around the implant. This underscores the critical need to consider physical and mechanical properties, beyond mere aesthetics, for sustained implant success. The findings highlight the effect of material composition and stress distribution, emphasizing the necessity of durable and effective implant treatments.

ETIOLOGY AND DENTAL STATUS IN PATIENTS WITH DENTITION DEFECTS IN THE RESIDENTS OF THE TRANSCARPATHIA

The aim of the study. To evaluate the dental status of patients with dentition defects, residents of the Transcarpathia, and to establish the causes of their occurrence. Materials and methods. The dental status was determined in 450 middle-aged people, residents of the Transcarpathia. The etiology of dentition defects was established, and an index assessment of hygiene, inflammatory and destructive changes in the periodontium, resorption of alveolar processes, and bone type was performed. The mathematical analysis and verification of the results, as well as the calculation of the arithmetic mean and standard errors were performed using the Statistica 6.0 software. Results and discussion. In the case of bounded edentulous spaces of 1–2 adjacent teeth, complicated caries prevailed in the etiology in 57.0 %; in the case of bounded edentulous spaces of 3 or more adjacent teeth, periodontal tissue diseases prevailed in 58.0 % (25.8 % – 16 in the upper jaw, 32.2 % – 20 in the lower jaw). In free-end edentulous spaces, periodontal tissue diseases prevailed among the etiologic factors: unilateral – in 75.0 %, bilateral – in 79.4 %. The hygiene was not satisfactory, the presence of moderate and severe gingivitis and periodontitis was observed with the prevalence of D2 bone type in 53.3 % of patients with bounded edentulous spaces, and 54.5 % of patients with free-end edentulous spaces. Conclusions. In the middle-aged adult population of the Transcarpathia, bounded edentulous spaces account for 26.6 %, and free-end edentulous spaces account for 73.4 %.

BIOMECHANICAL ANALYSIS OF AN OPTIMIZED PATIENT-SPECIFIC DENTAL-IMPLANT SCREW IN THE POSTERIOR MANDIBLE

Implant design developed considerably with the advancement of restorative dentistry. Examining the stress distribution in the cancellous and cortical bones around custom-made implants with different thread-profile models is the study’s objective. The newly designed implants were made with a diameter and length of 4.5 mm and 11.5 mm. The implants were designed the same, but had different thread profiles. Model A is designed with a standard V-shape thread design, and it was compared with the remaining three dental implants (models B, C, and D) having different customized thread-profile designs. The biomechanical characteristics of the four implant models were compared with the use of biomechanical profiling to predict the mechanical performance of various dental-screw models, including the influence of physiological factors. The stress distribution in the D4 bone area of implants with different thread-profile designs under a vertical load of 100 N at 0° and an oblique load of 223.6 N at 25° was examined using ANSYS Workbench. The trabecular and cortical bones comprise the structure of the D4 bone area. Deformation and stress (von Mises) findings were found for the dental implants and bone. While implant models C and D showed less stress distribution in the cortical and cancellous bone, they nonetheless produced outcomes superior to those of the conventional model A underloading. According to the findings, the unique dental implant design lessens the stress concentration in the cortical bone’s neck area. The suggested model C increases the implant’s stability in that region by distributing a low stress over the D4 bone.

Evaluation of Stress Distribution in Platform Switch Short Dental Placed at Different Depths in D1 bone – An in Vitro 3D FEM Study

Context: FEA has been extensively used in implant dentistry to predict the biomechanical behavior of various dental implant designs, as well as the effect of clinical factors for predicting clinical success. Stress patterns in implant components and surrounding bone are well studied. Objective: To investigate the pattern of stress distribution in terms of equicrestal and subcrestal implant placement at various depths using short platform switching dental implants. Materials and Methods: 3D FEM of the mandibular anterior area was modelled with a uniformly cortical bone of 0.5 mm with an inner core of cancellous bone (FEM) using ANYSIS soft wear. Four implant modes were used with the following dimensions. Model 1. (6x4.6x3.5mm), models 2 (7.5x4.6x3.5mm), 3 (6x5.8x4.5mm), and 4 (7.5x5.8x4.5mm). For a realistic simulation, 100N and 200N of force were applied in axial and oblique directions (0°, 15°, and 30°, respectively). At different depths, both cancellous and cortical bone is evaluated for von Mises stress. Ten-noded tetrahedron components with three degrees of freedom per node are used to interpret translations on the x, y, and z axes. Results: Based on bone shape, force direction, and depth of implant placement, each of the five positions of platform-switched short osseointegrated implants examined by FEM simulations had a unique stress-based biomechanical behavior. Conclusions: Axial forces were less harmful than oblique forces. The cortical and cancellous bone experienced less stress because of the implantation of subcrestal implants. According to recent research, platform-switched short subcrestal implant models result in improved stress distribution around peri implant areas in D1 bone and the conservation of marginal bone loss.

An In Vivo Comparative Study between Primary Stability of Dental Implant in D3 and D4 Bone with different Implant Designs

Purpose: The purpose of the study is to assess the difference in primary stability and insertional torque in D3 and D4 bone densities in relation to conical and tapered cylindrical conical implant designs. Implant designs, commonly available as conical tapered thread design presented a similar survival rate in D1 and D2 bone but questionable results were there in D3 and D4 bone. But while placing tapered cylindrical conical implants in D3, D4 bone presented better primary stability and insertional torque upto 40+ N with excellent stability