Implant-supported Prostheses Research Articles

Five years of radiographic evaluation for the peri-implant bone changes of all-on-four implant prostheses constructed from different framework materials using different digital construction techniques

BackgroundThere is insufficient evidence recommending a framework material and a CAD/CAM manufacturing technique for mandibular implant-supported prostheses. The study objective was to evaluate the clinical application of different materials and construction techniques used for mandibular All-on-4 prosthesis on circumferential peri-implant bony changes after 5 years.MethodsThirty-six male patients with all-on-4 mandibular implant-supported prostheses were recalled and divided into three groups. Group PK (patients with frameworks milled from PEEK blocks), Group PSM (patients with frameworks milled from soft metal blocks), and Group SLM (patients with frameworks constructed with additive manufacturing; selective laser melting). The circumferential bone level on all implant faces was assessed with a CBCT. Two-way repeated measures ANOVA was used to compare vertical bone loss (VBL) and horizontal bone loss (HBL) between different groups, implant positions, and observation times followed by Tukey’s multiple comparisons.ResultsFor all observation times, there was a significant difference in VBL between groups for both anterior and posterior implants (P < .001). For anterior implants, group PSM showed the lowest VBL while group PK showed the highest for anterior and posterior implants. For all groups, HBL significantly increased after 5 years for both anterior and posterior implants (P < .001). For anterior implants, group PSM showed the highest HBL. For posterior implants, group PK and SLM showed the highest.ConclusionWithin the study’s limitations, mandibular implant-supported fixed frameworks fabricated with either milling from PEEK or soft metal blocks, or additive manufacturing (laser melting technology) exhibited significant vertical and horizontal bone height changes after 5 years.Clinical Trial Registry Number(NCT06071689) (11/10/2023).

Retrospective assessment of patients' risk for peri-implant diseases using the implant disease risk assessment (IDRA) tool: A cohort study.

The implant disease risk assessment (IDRA) tool was designed to assess an individual's risk of developing peri-implant diseases by evaluating and integrating multiple risk factors. This study aimed to evaluate the IDRA tool to determine the risk of developing peri-implant disease in patients rehabilitated with dental implants. A retrospective observational cross-sectional study was conducted, collecting data from 92 patients with 92 selected dental implants. Data included the history of periodontitis, sites with bleeding on probing (BoP), teeth and/or implants with probing depths (PDs) ≥ 5 mm, alveolar bone loss relative to the patient's age, susceptibility to periodontitis, the frequency of supportive periodontal therapy (SPT), the distance from the restorative margin (RM) of the implant-supported prosthesis to the marginal bone crest (MBC), and factors related to the prosthesis itself. Additionally, the validated instrument periodontal risk assessment (PRA) was employed for comparison. Statistical analyses utilized Chi-square, Mann-Whitney, and ROC curve. Outcomes indicated that 62 implants (67.4%) were classified as high-risk. Among the IDRA parameters, history of periodontitis was the primary factor contributing to an increased risk (p < 0.001). IDRA revealed high sensitivity (100%) and low specificity (63%) (AUC = 0.685; 95% CI: 0.554-0.816; p = 0.047), and there was a low agreement between the IDRA and PRA tools (Kappa = 0.123; p = 0.014). The peri-implant disease developed in 16 implants with 5.44 (±2.50) years of follow-up, however, no significant association was observed between the high- and low-medium risk groups and the occurrence of peri-implant diseases. Most of the evaluated implants presented high IDRA risk. The IDRA tool exhibited high sensitivity and low specificity; no significant association was observed between the risk profile and the development of peri-implant diseases.

Immediate rehabilitation of a palatal defected edentulous patient by implant-supported overdenture: a case report

BackgroundImmediate rehabilitation is a considerable therapeutic challenge but is necessary for edentulous patients with oronasal fistulas, especially those with inadequate residual bone and a history of radiotherapy.Case presentationWe report a rare case of a 63-year-old patient who was missing the majority of his maxillary teeth and who had a defect due to palatal mucoepidermoid carcinoma resection. The patient also received radiotherapy twice within one year postoperatively. An implant-supported prosthesis with an obturator was fabricated immediately.ConclusionThis technique improved patients’ oral function, enhanced the aesthetic effect, and increased their confidence.

Regenerative approaches for rehabilitation with single implant-supported prosthesis in the maxilla: a comprehensive clinical description

Regenerative approaches for rehabilitation with single implant-supported prosthesis in the maxilla: a comprehensive clinical description

Long-term follow-up of a patient with Parkinson’s disease under nursing care after replacement of fixed implant-supported prostheses with an implant overdenture: a case report

BackgroundIn older patients with progressive neurodegeneration, replacing fixed implant-supported prostheses (FIP) with implant overdentures (IOD) has been proposed to prevent future mucosal injury and create an oral environment that is easier for caregivers to clean. However, there have been no reports on the progress after replacing FIP with IOD. In this report, we present the progress of an older patient with Parkinson’s disease in whom FIP was replaced with IOD.Case presentationAn 81-year-old male patient with Parkinson’s disease presented to our outpatient clinic with bruxism and crossbites. FIPs, with five Brånemark system implants, were placed in the bilateral lower molars. The FIP was replaced with an IOD with two locator attachments to create an oral environment that was easier for caregivers to clean and allow easy recovery of masticatory function if residual teeth were fractured in the care environment. As his systemic condition deteriorated, treatment was changed from outpatient to in-home visits. During dental care visits, professional oral cleaning and denture repair were continued, and good nutritional status was maintained. However, the patient developed cholecystitis and was hospitalized. During hospitalization, gastrostomy was performed because he developed aspiration pneumonia. After discharge from the hospital, the patient remained in bed all day and could not wear an IOD, resulting in buccal mucosa ulceration due to abrasion of the locator abutment. We decided to replace the abutment with cover screws; however, not all the implants could sleep submucosally. Although regular oral cleaning was resumed, new ulcers developed even when cover screws were installed. Additionally, swelling and drainage were observed at the peri-implant mucosal site where peri-implantitis had once occurred during an outpatient visit. The patient was readmitted to the hospital for a urinary tract infection, and subsequent visits were abandoned.ConclusionsBy replacing FIP with IOD in an older patient with Parkinson’s disease, we addressed a barrier to caregiver-provided oral management. The removable prosthesis facilitated smooth oral care by caregivers and functional recovery in the event of trouble with residual teeth. However, it could not completely avoid the recurrence of buccal mucosal ulcers or peri-implantitis.

Comparison of Aesthetic, Mechanical Outcome, and Bone Loss in Angulated Screw Channels (ASCs) and Cement-Retained Implant-Supported Prosthesis: A Case-Control Study.

Angulated-screw channels (ASCs) allow the clinician to employ screw-retained restorations in almost all cases, as the access hole can be moved away from the vestibular portion of the crown, where it would jeopardize the final esthetic result. The objective of this study was to compare screw-retained restorations employing ASCs with restorations cemented on angled abutments. In this study, 30 subjects, equally divided into two groups: group 1 (cemented restorations on angulated abutments) and group 2 (screw-retained restorations adopting ASCs), were treated and retrospectively compared after 2 years using the pink esthetic score (PES) and the white esthetic score (WES). All restorations were in use at the last follow-up, with a survival rate of 100%. Three mechanical complications were observed (2 chippings and 1 crown came loose), with a success rate of 93% in group 1 and 87% in group 2 (p > 0.05). No statistically significant differences were reported regarding the esthetic outcome; the marginal bone loss (MBL) showed better results for the screw-retained restorations, both at the distal aspect (group 1 = 0.98 mm ± 0.16; group 2 = 0.45 mm ± 0.06; p = 0.006) and at the mesial aspect (group 1 = 1.04 ± 0.27; group 2 = 0.45 ± 0.005; p < 0.001). From an esthetical perspective, screw-retained restorations with ASCs and cemented restorations on angulated abutments are both effective means of restoring implants; both have excellent esthetic outcomes, but screw-retained restorations have reduced bone loss when compared to cemented ones but are more prone to mechanical complications. Still, our results must be cautiously observed given the reduced dimension of our sample. Larger studies are needed to confirm our findings.

Clinical Effects of Interproximal Contact Loss between Teeth and Implant-Supported Prostheses: Systematic Review and Meta-Analysis

Clinical Effects of Interproximal Contact Loss between Teeth and Implant-Supported Prostheses: Systematic Review and Meta-Analysis

A Study on Materials Used and Longevity of Implant-Supported Prostheses

ABSTRACT Objective: This retrospective research was directed to investigate the longevity and maintenance requirements of implant-supported prostheses in subjects treated at a tertiary care center. Methods: Patient records of individuals who received implant-supported prostheses between January 2018 and December 2020 were retrospectively analyzed. Demographic information, implant type, prosthetic design, and follow-up data were collected. The primary outcomes assessed were prosthetic survival rates and the incidence of complications requiring maintenance interventions. Statistical analysis was performed to identify associations between demographic and clinical variables and the observed outcomes. Results: The research included 150 subjects with an average follow-up duration of 3 years. The overall survival rate of implant-supported prostheses was 90%, with 20% requiring maintenance interventions. Common complications included peri-implantitis (10%), prosthetic fracture (6%), and screw loosening (4%). Significant associations were found between smoking status and peri-implantitis (P &lt; 0.05) and between prosthetic design and prosthetic fracture (P &lt; 0.01). Conclusion: Implant-supported prostheses demonstrated a high overall longevity rate, with a subset of subjects requiring maintenance interventions due to complications. Peri-implantitis, prosthetic fracture, and screw loosening were the most prevalent complications, emphasizing the importance of tailored patient care and risk stratification.

Evaluation of Different Materials used in Prosthetic of Dental Implants: A Comparitive Study

ABSTRACT Background: Implant-supported prostheses have become a cornerstone of restorative dentistry, offering patients an effective solution for missing teeth. However, the choice of material for these prostheses can significantly impact their maintenance requirements and long-term success. Methods: Patient records of individuals who received implant-supported prostheses over a 2-year period were reviewed. Data on maintenance interventions, including adjustments, repairs, and replacements were collected and analyzed for metal alloys, ceramics, and composites. Results: Metal alloys exhibited slightly higher average numbers of adjustments compared to ceramics and composites. Ceramics required a higher mean number of repairs and replacements compared to other materials. Statistical analysis revealed significant differences in adjustment frequency between metal alloys and ceramics (P = 0.047), but no significant differences were observed for repairs or replacements. Conclusion: The outcomes imply that material choice plays a significant role in the maintenance requirements of implant dental prostheses. While metal alloys may require more frequent adjustments, ceramics and composites may necessitate more repairs and replacements over time. Clinicians should consider these factors when selecting materials for implant prostheses and develop tailored maintenance protocols to optimize treatment outcomes.

Evaluating the tightness of proximal contact between natural tooth and adjacent implant supported prosthesis.

The changes in interproximal contact between implant supported prosthesis (ISP) and adjacent natural tooth is of interest to dentists. Hence, we evaluated the tightness of proximal contact (PCT) between adjacent natural tooth and ISP by applying a digital force gauge spanning over a period of 1.5 year with a regular follow-up of 3, 6, and 12 months.80 patients who received ISP were included in this study. In order to measure the PCT, every patient seated in the identical upright position in the dentist chair. The digital force gauge was used to take measurements for mesial PCT and distal PCT. The mesial as well as distal interproximal contacts was more tight as in case of natural tooth adjacent to other natural tooth as compared to interproximal contacts between ISP and adjacent natural tooth. It was also observed that as the time progressed there was decrease in PCT values in both categories. After 12 month follow up 30.6% cases in category 2 while 21.2% cases in category 1 showed complete loss of interproximal contact. There is significant change in proximal contact tightness in interproximal area between implant supported prosthesis and adjacent natural tooth over a period of time and necessary measures should be taken to prevent or reduce it.

TRUENESS AND PRECISION OF DIFFERENT DIGITAL SCAN SYSTEMS IN A TWO IMPLANT COMPLETE ARCH MODEL: AN IN-VITRO STUDY

Background: One of the major concerns in implant-retained prostheses is their accuracy which plays an essential role in implant success and prosthesis adaptation. Although many contemplates stated the indications and merits of different digital scanner systems, little is identified about their trueness and precision in scanning dental implants of implant-retained prostheses. Objectives: This contemplate aimed to evaluate and compare the trueness and precision of two unalike most recent digital scan systems in a mandibular two-implant complete arch model. Materials and Methods: A completely edentulous mandibular cast was utilized into which two conventional dental implant analogs were drilled in its inter-foramina area from which the distance between the analogs was measured by a caliper (Control). The same space was assessed via scanning the whole assembly 13 scans/each digital scanner system. The final distance of each scan attained from both systems was then compared with the control. The accuracy of each system was assessed in terms of trueness and precision. Results: Slight advancement of the Dof Freedom X5 premium digital scanner system than the Medit T300-T500 dental digital scanner regarding trueness although they were still insignificantly different, as P=0.66. The Medit digital scanner system was significantly better than the Dof Freedom one concerning precision, as P=0.001. Conclusion: The two dental laboratory digital scanner systems employed are reliable tools for scanning and reproducing digital dental records accurately for an implant-supported prosthesis. Furthermore, the Medit dental digital scanner system seemed to be more accurate in terms of precision than the Dof Freedom one.

Treatment of total edentulousness by fixed implant-supported prostheses

Total edentulousness presents considerable obstacles to patients in terms of aesthetics, function, and general well-being [1]. Fixed implant-supported prostheses have emerged as a possible treatment option, providing more stability, comfort, and chewing efficiency than typical removable dentures [2]. To obtain predictable and effective outcomes, it is critical to use good case selection, detailed treatment planning, and interdisciplinary teamwork [3]. Considerations for bone quantity and quality, occlusal systems, and maintenance methods are also highlighted in order to maximize long-term prosthetic success and patient happiness [4]. This case report presents the interdisciplinary management of implant-prosthetic treatment and demonstrates the effectiveness of dental implants in the oral rehabilitation of completely edentulous patients, with a focus on the all-on-six treatment approach.

Exploring lived experiences on the usage of removable complete dentures among edentulous patients attending Makerere University Dental Hospital, Kampala, Uganda

BackgroundEdentulism remains a major disability worldwide, especially among the elderly population, although the prevalence of complete edentulism has declined over the last decades. In Uganda, the prevalence of edentulism in people aged 20 years and above is 1.8%. The therapy for edentulous patients can be realized through the use of conventional removable complete dentures, implant-supported prostheses, and computer-aided design and computer-aided manufacturing (CADCAM), however, the provision of removable complete dentures continues to be the predominant rehabilitation for edentulous patients. However, no published study has explored the lived experiences with removable complete dentures among the Ugandan population. The aim of the present study was to explore patients’ lived experiences on the usage of removable complete dentures among Ugandan edentulous patients attending Makerere University Dental Hospital.MethodsThis was a qualitative study approach using purposive sampling. Fifteen (15) respondents were selected across social demographics. Interviews were recorded and transcribed and themes were generated to draw a deeper meaning to the usage of removable complete dentures. A qualitative statistical package, Atlas Ti software was used to generate themes from the interviews followed by an interpretation of the generated data and the results were presented as text and in a table.ResultsThe reported key positive experiences due to removable complete denture rehabilitation were the improvement in speech, eating ability, regaining good facial appearance, better oral hygiene management, self-esteem and confidence to smile in public, and a feeling of completeness. However, respondents complained of pain and discomfort due to the looseness of dentures, inability to eat certain foods, and regular cleaning of dentures. The respondents did not go through proper informed consent processes before getting removable complete dentures.ConclusionThe study found that patients were satisfied with their removable complete dentures rehabilitation due to the positive experiences registered, such as the ability to eat and talk well, and restoration of self-esteem, all of which improved their quality of life. However, they experience pain and discomfort due to the looseness of dentures.

Esthetic analysis of upper lip morphology variation after the cross-arch fixed restoration of maxillary implant-supported prostheses via radiographic methods

Objective: To measure and analyze upper lip morphology variation before and after the cross-arch fixed restoration of the maxillary implant-supported prostheses using cone- beam CT (CBCT) to provide an esthetic objective reference for maxillary edentulous patients. Methods: There were 32 maxillary edentulous patients selected in the Department of Dental Implantology, The Affiliated Stomatological Hospital of Nanjing Medical University from January 2010 to December 2023. The CBCT data of patients with maxillary full-arch implant-supported fixed prostheses were retrospectively collected before implantation (T0), at the time of radio-guide insertion (T1), and after final repair (T2). The length and thickness of the upper lip were measured and analyzed at each time point, and the correlation between the upper lip contour data and facial esthetic parameters was analyzed. Results: After the final prosthodontic treatment, the length of the upper lip was significantly increased from (21.72±2.84) mm to (24.98±2.93) mm (t=-8.13, P<0.001) compared with that before implant treatment. The widths of the middle and vermilion of the upper lip (Sm-Hm/Ls-UP), were reduced from (13.24±1.41), (12.81±1.67) mm to (11.36±1.67), (10.21±1.69) mm, with significant differences (t=7.79, P<0001; t=9.37, P<0.001). The lower face height (Sn-Gn) was increased from (54.52±4.95) mm to (58.70±4.42) mm, with significant differences (t=-11.05, P<0.001). However, the nasolabial angle reduced significantly from 95.35°± 7.70°to 90.53°±7.28°(t=7.68, P<0.001). The width of the middle of the upper lip with a radiation guide was (10.94±1.24) mm, and it increased significantly compared with that after the final prosthesis treatment (t=-0.76, P<0.05). The proportion of straight upper lip profiles accounted for 59% (19/32), and the proportion of concave upper lip profiles accounted for 41% (13/32) after the final prosthesis treatment. In addition, the results of correlation analysis showed that the nasolabial angle variation was weak and negatively correlated with residual bone height (r=-0.37, P=0.490). Conclusions: After the treatment of the maxillary full-arch implant-supported fixed prosthesis, the length of the upper lip increases, and the thickness of the upper lip becomes significantly thin. The maxillary full-arch implant-supported fixed prostheses support upper lips to improve the patients' side appearances.

Analysis of Long-Term Success and Biological Complications in Zygomatic Implant-Supported Prostheses.

Patients with significant maxillary atrophy who are not candidates for standard implants now have an option thanks to zygomatic implants. Long-term statistics on difficulties and success are, however, scarce. A tertiary care center's patient data were retrospectively analyzed. Included were patients who underwent zygomatic implant surgery between 2017 and 2022. This research gathered and examined data on follow-up, surgical techniques, complications, demographics, and implant features. There were 100 patients in all. 92% of the implants were successful, and 92 of them survived. Peri-implantitis (20%), soft tissue dehiscence (15%), sinusitis (10%), prosthesis fracture (8%), and infection (5%), were among the biological consequences. In summary, zygomatic implants have the potential to help individuals with severe maxillary atrophy recover, but close observation and effective management of any problems are necessary to maximize results. To enhance patient care and improve treatment regimens, further research is required.

Clinical Performance of Implant-Supported Prostheses in the Rehabilitation of Patients Previously Treated for Medication-Related Osteonecrosis of the Jaws (MRONJ): A Systematic Review.

There is a lack of consensus on managing resultant bone and soft tissue defects or on restoring oral function and aesthetics following medication-related osteonecrosis of the jaws (MRONJ) lesion healing. This clinical challenge presents a dilemma for practitioners. Removable prostheses pose a recurrence risk if poorly fitted and may inadequately restore function or aesthetics in cases of significant bone defect. Dental implant-supported prostheses could enhance function and quality of life, though their risks and indications are not well-defined. This systematic review examines the clinical outcomes and complications associated with implant-supported rehabilitations post-MRONJ surgery. This study was conductedfollowing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations and it was pre-registered in the Prospective Register of Systematic Reviews (PROSPERO) (CRD42023492539).

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.

Effect of 3D printer, implant analog and angulation on the accuracy of analog position in implant casts

Objectives: To evaluate the accumulative effect of 3D printer, implant analog systems, and implant angulation on the accuracy of analog position in implant casts.Methods: A reference cast, presenting a case of a three-unit implant-supported prosthesis, was scanned with a coordinate measurement machine, producing the first reference data set (CMM, n = 1). The second reference data set (n = 10) was prepared using an intraoral scanner (IOS) (Trios4). Test quadrant casts were produced using three DLP type 3D printers, Max (MAX UV385), Pro (PRO 4K65 UV), and Nex (NextDent 5100), and three implant analog systems, El (Elos), Nt (Nt-trading), and St (Straumann) (n = 90). Stone casts were also produced via analog impressions (Stone, n = 10). After digitization, the accuracy of 3D distance, local angulation (angle between implants) and global angulation (angle between the implant center axis and an axis perpendicular to the global plane) was evaluated by comparing the reference (CMM, IOS), test (3D print), and control (Stone) groups using metrology software. Data were statistically analyzed using three-way ANOVA and Tukey`s tests (α = 0.05).Results: IOS was truer in 3D implant distance and more precise in capturing local angulation than Stone (p ≤ 0.05). Other measurements were similar between both groups (p > 0.05). The amount of error introduced in the workflow by IOS and 3D printing was mostly similar (p > 0.05). 3D printed casts had similar or even higher accuracy than Stone group (p > 0.05). In most cases, higher trueness was achieved when using PRO 4K65 UV 3D printer and Elos implant analog system (p ≤ 0.05).Conclusion: 3D printer, implant analog system, and implant angulation have a significant effect on the accuracy of analog position in implant casts. Limited-span implant-supported cases could be reproduced digitally with similar accuracy as conventional methods.Clinical significance: A fully digital workflow with a carefully selected 3D printer and implant analog system can increase the accuracy of digitally produced implant casts with comparable accuracy to conventional workflow.

The Technique and Material Used to Join Transfers Affect the Accuracy and Final Fit of Implant-Supported Prostheses-In Vitro Study.

This study evaluated the linear dimensional change of polymerization of three materials and two techniques of the union of molding transfers for implant-supported prostheses used in the open-tray technique. A nylon maxilla-shaped matrix was made, two osseous integrated implants were installed, and, over these two, straight conical mini-pillars were installed. Open-tray impression transfers were attached to the mini-pillars, and a silicone guide was made to standardize the connections between the transfers. The samples were divided into six groups (n = 20): PA (Pattern Resin LS, chemically activated acrylic resin in the single step technique); DU (Durallay, chemically activated acrylic resin in the single step technique); BI (Protemp4, bisacrylic resin in the single step technique); PAC (Pattern Resin LS in sectioning and joining of segments technique); DUC (Durallay, in sectioning and joining of segments technique); and BIC (Protemp4, in sectioning and joining of segments technique). The linear dimensional change values that occurred among these transfers were measured in a profile projector (VB300; Starret) coupled to the Quadra Check device, with a resolution of 0.001 mm, performed by a single calibrated operator. Data were submitted to a two-way analysis of variance and Tukey's test (p < 0.01). Statistically significant mean values were found in all comparisons. The PA showed the lowest mean values (µm) of linear dimensional change, both in the single-step technique and in the sectioning and joining technique, in the following order: BI 255.73 (3.81), DU 173.75 (2.30), PA 95.97 (3.20), BIC 23.82 (1.71), DUC 20.85 (2.53), and PAC 13.27 (2.09). The single-step technique showed the worst results, regardless of the material. The sectioning and joining technique reduced the dimensional change in all materials, and the Pattern Resin LS showed the lowest shrinkage mean values, followed by Durallay and Protemp4.

Mechanical and modal analysis of different implant strategies for loss of three teeth with bone atrophy in the maxillary posterior region

Purpose: This study aimed to evaluate the stress distribution and secondary stability involved in five implant strategies, including implant-supported prostheses (ISP) and tooth-implant-supported prostheses (TISP), used for bone atrophy in the maxillary posterior region with teeth loss using finite element analysis, and to explore the more desirable implant methods. Methods: Five implant strategies were made to analyze and compare: M1, implant-supported prosthesis consisting of a short implant with a regular implant; M2, implant-supported prosthesis consisting of a tilted implant with a regular implant; M3, cantilever structure; M4, tooth-implant-supported prosthesis consisting of a short implant with a regular implant; M5, tooth-implant-supported prosthesis consisting of a regular implant, and M6, with only the natural teeth as a control group. Dynamic loading of the above models was performed in finite element analysis software to assess the stress distribution of the bone tissue and implants using the von Mise criterion. Finally, the secondary stability of different models was evaluated by modal analysis. Results: The maximum stress distribution in the cortical bone in M1(60 MPa) was smaller than that in M2(97 MPa) and M3(101 MPa), The first principal strain minimum was obtained in M2 (2271 μ ε ). M4 (33 MPa, 10085 Hz) with the best mechanical properties and highest resonance frequency. But increased the loading on the natural teeth. Conclusions: Short implants and tilted implants are both preferred implant strategies, if cantilever construction is necessary, a tooth-implant-supported prosthesis consisting of a short implant and a regular implant is recommended.