Evaluation of the Peri-Implant Tissues of Patients with Severe Bone Atrophy Treated with a New Short and Extra-Short Implant System-A Pilot Study.

This study aimed to assess clinical and radiographic outcomes, including implant survival, marginal bone loss, and patient satisfaction, in individuals with severe bone atrophy treated using a newly developed system of short and extra-short implants. A total of 44 implants (37 short and 7 extra-short) were placed with immediate loading in 11 patients. The patients were followed up at between 6 and 24 months. Bone changes, keratinized mucosa, bleeding on probing, probing depth, crown-to-implant ratio, and patient satisfaction were evaluated. An implant survival and success rate of 100% was observed. The peri-implant bone condition showed no significant associations between marginal bone loss (MBL) and gingival recession. In extra-short implants, the crown-to-implant ratio did not affect MBL in the evaluated times. However, short implants showed a statistically significant inverse correlation between mesial measurement and crown-to-implant ratio (p = 0.006) and between distal measurement and crown-to-implant ratio (p = 0.004) over six months. Plaque was present in the mesiobuccal regions in 38.64% of the implants, with extra-short implants having the highest relative frequency (71.4%). Bleeding was observed in 18.9% of the short implants in the mesiolingual region and 14.3% of the extra-short implants. There was a statistically significant association between bleeding on probing in the mesiobuccal region and the type of implant (p = 0.026). The analysis of probing depth showed no difference between the types of implants. Within the limits of this study, short and extra-short implants presented similar clinical and radiographic behavior of soft and hard tissues in the evaluated times.

Prosthetic rehabilitation of segmental mandibulectomy patient using a free fibula flap and Corticobasal implant supported prosthesis: A Case report.

INTRODUCTION: Segmental mandibular reconstruction using free fibula flaps and implants is challenging for maxillofacial surgeons and prosthodontists. This case report describes the successful use of Corticobasal implant reconstructive prostheses after a free fibula flap with five years of follow-up. CLINICAL CASE PRESENTATION: A 24-year-old female presented to the clinic following segmental defect reconstruction using fibula reconstruction, owing to squamous cell carcinoma resection and seeking prosthetic treatment. An intraoral examination revealed a complete healing of the soft tissue. A panoramic radiograph showed a fibula bone graft rehabilitating the left side of the mandible supporting with a reconstructive plate. A multidisciplinary team was formed. A treatment plan included a mandibular reconstructive fixed Corticobasal implant prosthesis supported by eight basal cortical screw implants (BCS®, Dr. Ihde Dental AG, Switzerland) and a follow-up schedule was formulated. After 5-years of function, the implant demonstrated a 100 % survival rate, with no implant loss or fracture, excellent peri-implant soft tissue health, complete union of the bone graft, and a very stable prosthesis. The patient reported significant improvements in aesthetics, mastication, phonation, and self-satisfaction. DISCUSSION: The multidisciplinary team has significantly improved the treatment outcomes. The prescribed treatment modality provides the patient with a fixed treatment modality, immediate loading, reduces the risk of biological and biomechanical complications, and hence improves the patient's functions and satisfaction. CONCLUSION: A Corticobasal implant-supported prosthesis can be used in combination with a free fibula flap to reconstruct segmental mandibulectomy patients with a high survival rate and satisfactory aesthetic and functional outcomes.

Assessment of Patient Satisfaction and Oral Health-Related Quality of Life Following Full Mouth Rehabilitation with Implant-Supported Prostheses.

Background: The concept of success is typically established by the researcher or the practitioner rather than the patient, who has the greatest stake in the outcome of the prosthodontics therapy. Aim: To assess patient satisfaction and oral health-related quality of life (OHRQoL) in following full mouth rehabilitation with implant-supported prostheses (ISP). Methods and Materials: Thirty-two patients who underwent full mouth rehabilitation with ISP were included in this study. The Oral Health Impact Profile-14 (OHIP-14) questionnaire was used for the assessment of patient satisfaction and OHRQoL following full mouth rehabilitation with ISP. Results: The functional limitation among study participants before, 1 month, and 3 months after ISP was 2.1 ± 1.3, 1.5 ± 0.8, and 1.4 ± 0.9, respectively. There was a significant reduction in functional limitation, psychological disability, and social disability before and 3 months after ISP. Conclusion: There is a significant improvement in patient satisfaction and OHRQoL in following full mouth rehabilitation with ISP.

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.

Bacterial adhesion and microleakage of restorative materials for sealing accessory canals in implant prosthesis.

The level of bacterial adhesion and bacterial microleakage in four different materials utilised to seal the access passage of screw retained implant supported prosthesis (SRIP) is of interest to dentists. Four distinct categories were created from the samples on the basis of restorative materials used for sealing access passage in SRIP. Guttapercha and light cured acrylic resin were found to have comparatively low bacterial adhesion and bacterial microleakage in sealing accessory canals in screw retained implant supported prosthesis.

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 conducted following 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).

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 (2271µÎµ). 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.

Rehabilitation of Edentulous Arch Using All-on-Four Treatment Protocol: A Case Report.

In edentulous arches, alveolar ridge atrophy after tooth extraction is a common problem that affects patient comfort and quality of life. Implant-supported fixed restorations are a well-proven treatment option for edentulism. The concepts of implant dentistry have developed over time to produce better aesthetics and functional results. To reduce cantilever length and enable prostheses with 12 teeth, the all-on-four technique entails inserting two anterior implants axially and distally orienting two posterior implants. Compared to conventional loading, immediate loading offers various benefits without compromising quality. An instantaneous fixed provisional allows patients immediate function and preserves their quality of life while also promoting a high degree of patient satisfaction in terms of aesthetics, phonetics, mastication, and psychological comfort.

Conventional and digital maxillary occlusal record for the manufacture of complete-arch implant-supported fixed prostheses: randomized controlled clinical trial.

OBJECTIVES: To evaluate the trueness of the digital maxillary occlusal records in comparison with the conventional records for the fabrication of complete-arch implant-supported fixed prostheses. MATERIALS AND METHODS: This randomized controlled clinical trial followed the recommendations of the CONSORT statement. Twenty participants who used a mandibular interim complete-arch fixed prosthesis and conventional complete maxillary dentures were included in the study. The participants were randomized into two types of maxillary occlusal records: conventional (COR) and digital (DOR) (TRIOS; Shape A/S). After fabricating the prostheses, the distribution and number of occlusal contact points, and the time taken to obtain the maxillary occlusal record and work model were evaluated. Descriptive analysis was used to evaluate the distribution of occlusal contact points. The Wilcoxon test was employed for assessing the number of occlusal contact points, while the Mann-Whitney U test was used for the time taken to obtain the working casts and the maxillary occlusal record and occlusal adjustment times (p < 0.05). RESULTS: There was a similarity in the jaw relation recording methods regarding the distribution of occlusal contact points. There was no difference in the number of occlusal contact points between the anterior (p = 0.439) and posterior (p = 0.227) teeth. No relationship was observed between the distribution and number of occlusal contact points (COR, p = 0.288; DOR, p = 0.183). DOR required less occlusal and clinical adjustment time, on the other hand more laboratory and total workflow time than COR (p < 0.001). CONCLUSION: The DOR may be an option for obtaining the functional space necessary for the assembly of teeth in complete-arch implant-supported fixed prostheses; however, it requires more working time. CLINICAL RELEVANCE: The digital occlusal recording method can be used to assess the interocclusal space for the virtual tooth setup of a complete-arch implant-supported fixed prosthesis.

The Scalloped Surgical Guide as an Alternative to Flat Bone Reduction Guide in Full-Arch Implant Restoration.

The goal of this clinical report was to present an alternative to traditional flat bone reduction guides, using a custom-designed 3-dimensional (3D)-printed guide according to the future gingival margin of the planned dentition. A 61-year-old woman with concerns regarding her smile appearance was presented. The initial examination revealed excessive gingival show accompanied by excessive overjet. The dentition was in a failing situation. The proposed treatment plan, relying on the sufficient amount of bone and keratinized tissue, consisted of recontouring of the alveolar ridge and gingiva and placement of 6 implants and an FP-1 prosthesis after extraction of all remaining maxillary teeth. Digital smile design was completed, and a fully digitally guided surgery was planned. This consisted of using 3 surgical guides, starting with the fixation pin guide, continuing with the scalloped hard- and soft-tissue reduction guide, and finally the implant placement template. Following the surgery, the patient received a temporary restoration, and on the 4-month follow-up, a new polymethyl meta-acrylate temporary prosthesis was delivered. The patient's 7-month follow-up is presented in the article. The report of this triple-template guided surgery indicated that digital 3D planning is a considerably predictable tool to properly establish and evaluate future occlusal plane, smile line, and lip support. Scalloped guides seem to be an excellent alternative to conventional bone reduction guides since they require less bone removal and improve patient comfort during surgery.

Evaluation and assessment of the survival of tooth implant supported prosthesis in tooth and implant supported rehabilitation cases with metal frameworks.

INTRODUCTION: Over the years, implant therapy has been a commonly used treatment option for individuals who are partially or totally edentulous, with a long-term success rate of over 90%. With significant advancements in biomaterials and technology, implant dentistry can now conduct prosthetic rehabilitations in the majority of patients catering to all types of needs. However, in order to meet the demands of a patient base that is always growing, new trends in implantology are emerging in recent years that are focused on minimally invasive surgery and financial sustainability. In certain clinical scenarios, connecting teeth and implants to support fixed partial prosthesis (FPPs) may be a predictable and workable course of treatment. MATERIALS AND METHODS: 22 patients were selected for this study who had tooth and implant supported prosthesis placed as a final restoration. Out of these 22 patients; 12 were male and 10 were female patients. Implants were placed following proper protocol and if grafting procedures were required they were carried out. A second stage surgical procedure was carried out and delayed loading protocols were followed. The statistical analysis was done using the IBM SPSS 24.0, Chicago, USA. The survival of the implants and teeth were measured by the Kaplan Meier survival scale. Bone loss was assessed at baseline(upon loading), 12 months and 24 months. RESULTS: The implant survival rate was measured at 6 months, 12 months, 18 months and 24 months. At 24 months, one implant showed failure, so the survival rate of the implants were 95.4%. Bone loss of 1 mm was seen around one implant at 12 months. Bone loss of 1 and 2 mm was present around two implants and one implant respectively at 24 months. CONCLUSION: From the results of this study, we can conclude that tooth implant supported prosthesis show very good survival when used in rehabilitation cases.

Awareness and oral health related quality of life (OHRQoL) in patients with dental implants compared to tooth supported FPD: A questionnaire study.

Background: Recently researches in the field of dental implantology have increased, in spite of that very limited knowledge is available to the patients about dental implants as an option for replacement of missing teeth. Goal of replacement of missing teeth is not only functional rehabilitation but overall improvement in quality of life of the patient. Aim: To assess the awareness of dental implants and to compare oral health related quality of life (OHRQoL) in patients treated with implant supported fixed prosthesis (ISPs) and teeth supported fixed prosthesis (FPDs). Methods: & Material: General implant awareness questionnaire was used to assess the awareness of dental implants in 500 participants. Oral health impact profile (OHIP) questionnaire was used to compare OHRQoL between 300 patients treated with ISPs and 300 patients treated with FPDs. Statistical analysis: Sample size was taken to estimate difference between groups at 30 % & 80% power and 5% risk. IBM SPSS 20 (SPSS Inc., Chicago, IL) was used for statistical analysis. Chi square test and independent t- test was used to find statistical difference between variables. Results: 27.2% participants were aware about dental implants. 74.4% participants agreed that missing teeth should be replaced with prosthetic options. Dentists were primary source of knowledge (66%) of dental implants for patients. Parameters like functional limitations, psychological discomfort and pain during mastication were significantly (p < 0.05) higher in FPDs compared to implant supported prosthesis. Conclusions: Awareness of dental implants in general population needs to be increased. Functional and psychological comfort was significantly higher in ISPs compared to teeth supported FPDs.

The Influence on Osseointegration of Immediate Functional Loading on Single Crowns: A Randomized, Double-Blind, Split-Mouth Controlled Clinical Trial with Histomorphometric Evaluation.

PURPOSE: To evaluate the influence of immediate loading on the osseointegration and bone density of implants placed in a healed alveolar bone crest and supporting single crowns. MATERIALS AND METHODS: Two solid titanium transmucosal miniimplants were placed in the distal regions of the mandible in 14 patients. One mini-implant was immediately functionally loaded, whereas the other was left unloaded. After 2 months of healing, biopsy samples were retrieved and the levels of new bone, old bone, and total bone (new + old) were assessed. RESULTS: Histologic examination was performed on biopsies from 12 patients (n = 12). The new bone-to-implant contact percentage (BIC%) was 40.3% ± 16.8% and 55.1% ± 19.1% (P = .043) at the unloaded and loaded sites, respectively; in addition, the total BIC% was 44.9% ± 17.0% and 59.5% ± 18.8%, respectively (P = .034). The new bone density was 45.9% ± 11.6% for the unloaded implants and 45.9% ± 16.7% for the loaded implants (P = .622). CONCLUSIONS: Immediate loading had a positive effect on bone apposition at the implant surface, but no effect on bone density was observed after 2 months of healing.

Occlusal equilibration and muscle activity in fixed versus removable mandibular implant supported overdenture.

OBJECTIVES: Single denture rehabilitated patients have negative appraisals regarding oral function, mostly associated by stability and retention issues regarding mandibular prosthetics. Therefore, this study assessed patients' occlusal equilibration, muscle activity, and oral health-related quality of life (OHRQoL) receiving milled removable or fixed mandibular implant retained prostheses. MATERIALS AND METHODS: Twenty-two edentulous mandibular ridges patients were randomly distributed into two groups based on the definitive prosthesis received. Group I: Removable mandibular implant-supported overdenture, Group II: Implant retained fixed prosthesis. Occlusal equilibration was evaluated utilizing Occlusense, muscle activity via Electromyograph (EMG) at delivery, after one, and three months. The OHRQoL was evaluated by Oral Health Impact Profile questionnaire (OHIP-19) before delivery and after follow-ups. Data were collected, tabulated, and analyzed, utilizing independent t-test and One-way ANOVA followed Tukey`s post-hoc test. Significance level set at P ≤ 0.05. RESULTS: Groups I &II showed significant improvement in occlusal equilibration, muscle activity and OHRQoL. Group II demonstrated significantly higher improvement than group I in occlusal equilibration associated with muscle activity after 1 month, and in functional limitations domain in OHRQoL questionnaire after 3 months. CONCLUSION: Implant retained mandibular prosthesis showed improvement in occlusal equilibration, muscle activity, and OHRQoL regardless of prosthesis type employed. Fixed implant-supported prosthesis revealed better outcomes than removable mandibular implant-supported overdenture concerning occlusal equilibration, muscle activity, and OHRQoL regarding functional limitations. CLINICAL RELEVANCE: Implant retained mandibular prosthesis is one of best treatment options for single mandibular completely edentulous patients, as dental implants improved occlusal equilibration, muscle activity, and OHRQoL.

Prosthetic Rehabilitation of All-on-Six Implant-Supported Prosthesis: A Case Report.

This clinical report explores the effectiveness of dental implants for rehabilitating fully edentulous arches, with a focus on the all-on-six treatment approach. Implant-supported fixed restorations, particularly using six implants, are presented as an expected and cost-effective solution for the rapid repair of the edentulous patient, avoiding the need for bone grafting. This report details the successful rehabilitation of a patient's completely edentulous arches using the all-on-six concept, highlighting the meticulous planning and execution involved. It concludes that precise diagnostic and implant planning, along with thorough attention to all the features, is crucial for successful implant-supported fixed prostheses, with the all-on-six concept offering improved clinical and radiological outcomes for atrophied maxillae.

Analysis of soft tissue integration-supportive cell functions in gingival fibroblasts cultured on 3D printed biomaterials for oral implant-supported prostheses.

To date, it is unknown whether 3D printed fixed oral implant-supported prostheses can achieve comparable soft tissue integration (STI) to clinically established subtractively manufactured counterparts. STI is mediated among others by gingival fibroblasts (GFs) and is modulated by biomaterial surface characteristics. Therefore, the aim of the present work was to investigate the GF response of a 3D printed methacrylate photopolymer and a hybrid ceramic-filled methacrylate photopolymer for fixed implant-supported prostheses in the sense of supporting an STI. Subtractively manufactured samples made from methacrylate polymer and hybrid ceramic were evaluated for comparison and samples from yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP), comprising well documented biocompatibility, served as control. Surface topography was analyzed by scanning electron microscopy and interferometry, elemental composition by energy-dispersive x-ray spectroscopy, and wettability by contact angle measurement. The response of GFs obtained from five donors was examined in terms of membrane integrity, adhesion, morphogenesis, metabolic activity, and proliferation behavior by a lactate-dehydrogenase assay, fluorescent staining, a resazurin-based assay, and DNA quantification. The results revealed all surfaces were smooth and hydrophilic. GF adhesion, metabolic activity and proliferation were impaired by 3D printed biomaterials compared to subtractively manufactured comparison surfaces and the 3Y-TZP control, whereas membrane integrity was comparable. Within the limits of the present investigation, it was concluded that subtractively manufactured surfaces are superior compared to 3D printed surfaces to support STI. For the development of biologically optimized 3D printable biomaterials, consecutive studies will focus on the improvement of cytocompatibility and the synthesis of STI-relevant extracellular matrix constituents.

Rehabilitation of a Full-Arch Patient with Cemented Metal-Ceramic Multiple Prostheses on Implants: A Case Report / Reabilitação de paciente de arco completo com Próteses Múltiplas Metalocerâmicas Cimentadas sobre Implantes ­ relato de caso

Objective: To report a clinical case of a female patient rehabilitated with Cemented Metal-Ceramic Multiple Prostheses on Implants in the upper arch. Materials and Methods: A multidisciplinary approach was employed, utilizing various clinical skills to achieve satisfactory outcomes in the rehabilitation of a fully edentulous patient. The treatment plan involved the use of cemented metal-ceramic prostheses, with a focus on optimizing the positioning of the crown margins to ensure periodontal health. Results: The use of cemented metal-ceramic multiple prostheses effectively addressed the patient's aesthetic concerns by eliminating screw access holes and ensuring the continuity of the ceramic material. The supragingival positioning of the crown margins prevented excess cement in the peri-implant sulcus, promoting periodontal health. The final prostheses provided excellent aesthetics and functionality, leading to enhanced patient satisfaction. Conclusion: The choice of cemented implant-supported prostheses represents a highly effective approach for treating edentulism. This method offers clinical benefits, such as increased retention and improved esthetic outcomes, while also positively impacting the patient's quality of life (AU)

Objetivo: Relatar um caso clínico de uma paciente feminina reabilitada com Próteses Metálicas-Cerâmicas Cimentadas em Implantes na arcada superior. Materiais e Métodos: Foi empregada uma abordagem multidisciplinar, utilizando várias habilidades clínicas para alcançar resultados satisfatórios na reabilitação de um paciente totalmente edêntulo. O plano de tratamento envolveu o uso de próteses metálicas-cerâmicas cimentadas, com foco na otimização do posicionamento das margens das coroas para garantir a saúde periodontal. Resultados: O uso de próteses metálicas-cerâmicas cimentadas abordou efetivamente as preocupações estéticas da paciente ao eliminar os orifícios de acesso para parafusos e garantir a continuidade do material cerâmico. O posicionamento supragengival das margens das coroas preveniu o excesso de cimento no sulco peri-implantar, promovendo a saúde periodontal. As próteses finais proporcionaram excelente estética e funcionalidade, resultando em maior satisfação do paciente. Conclusão: A escolha de próteses suportadas por implantes cimentadas representa uma abordagem altamente eficaz para o tratamento da edentulismo. Este método oferece benefícios clínicos, como maior retenção e melhores resultados estéticos, além de impactar positivamente a qualidade de vida do paciente(AU)

Evaluation of Prosthetic Outcomes and Patient Satisfaction With 3D-Printed Implant-Supported Fixed Prosthesis.

OBJECTIVES: The objectives of this study were to quantify the number and type of prosthetic complications associated with 3D-printed implant-supported fixed prostheses (3DISFP) and to evaluate patient satisfaction and oral health-related quality of life over a four-month period. METHODS:  Fifteen edentulous patients who underwent implant therapy were included in the study. Each patient received a 3D-printed prosthesis using OnX dental resin. Prosthetic complications were documented, and data from the 14-item Oral Health Impact Profile (OHIP) questionnaire were collected at two time points: at enrollment and during a four-month recall. RESULTS: During the four-month evaluation period, a total of nine complications were recorded, with three classified as catastrophic failures. Statistical analysis revealed statistically significant differences in OHIP scores between the preoperative and postoperative assessments (p<0.001). CONCLUSION: Within the limitations of this study, it can be concluded that utilizing 3D-printed prostheses with OnX resin represents a viable alternative for long-term implant-supported temporaries. The patients experienced a significant improvement in their oral health-related quality of life. These results suggest that 3D printing technology, combined with the use of OnX resin, holds promise in providing satisfactory clinical outcomes and enhanced patient satisfaction. However, it is important to acknowledge the limitations of this study, and further research is warranted to validate these findings and explore the long-term performance and durability of 3D-printed implant-supported fixed prostheses. This study contributes to the growing body of evidence supporting the effectiveness of 3D printing technology in implant dentistry. The results highlight the potential of 3DISFP with OnX resin to improve oral health-related quality of life in edentulous patients. Continued advancements in 3D printing materials and techniques will likely expand the utilization of these prostheses, ultimately benefiting patients in need of implant-supported restorations.

Analysis of implant-supported cantilever fixed partial denture: An in vitro comparative study on vertical misfit, stress distribution, and cantilever fracture strength.

PURPOSE: To evaluate the vertical misfit, stress distribution around dental implants, and cantilever fracture strength of 3-unit implant-supported cantilever fixed partial dentures (FPDs) using frameworks made from different materials and manufacturing techniques. MATERIALS AND METHODS: Forty FPDs were fabricated and divided into 5 groups (n = 8) based on the framework material used: LAS Co-Cr (Conventional casting-laser welding); TIG Co-Cr (Conventional casting -TIG welding); OP Co-Cr (Conventional casting-one-piece); CAD Co-Cr (CAD-CAM); and CAD Zr (CAD-CAM ZrO2 ). The vertical misfit was evaluated before porcelain application (T1) and before (T2), and after thermomechanical cycling (T3) by stereomicroscopy. Cantilever fracture strength was tested with a 50 kN (5000 kgf) load cell at a crosshead speed of 0.5 mm/min. Qualitative and quantitative photoelastic analysis was performed to evaluate stress distribution at seven specific points in five FPDs (n = 1/group) subjected to occlusal loading. RESULTS: Only the molar showed interaction among the three factors (G × S × T; F(20.932) = 1.630; p = 0.044). Thermomechanical cycling (T2 vs. T3) had a significant effect on intra-group vertical misfit in molar, especially in LAS Co-Cr (Δ = 5.87; p = 0.018) and OP Co-Cr (Δ = 5.39; p = 0.007), with no significant effect in premolar (p > 0.05). Ceramic application combined with thermomechanical cycling (T1 vs. T3) caused a significant intra-group increase in vertical misfit in all groups, both in the molar and premolar (p < 0.05). OP Co-Cr was associated with greater vertical misfit and stress concentration. Frameworks manufactured by the CAD-CAM system exhibited lower vertical misfit and better stress distribution. FPDs with metal frameworks (>410.83 ± 72.26 N) showed significantly higher fracture strength (p < 0.05) than zirconia (277.47 ± 39.10 N), and the first signs of ceramic veneering fracture were observed around 900 N. CONCLUSIONS: FPDs with frameworks manufactured using a CAD-CAM system appear to be associated with lower vertical misfit and better stress distribution, although the section of the frameworks followed by welding may be a viable alternative. In addition, metal frameworks exhibit high fracture strength.

A comprehensive study on the mechanical effects of implant-supported prostheses under multi-directional loading and different occlusal contact points.

AIMS: To evaluate screw loosening and fracture load and angular deviation of a single implant-supported prosthesis under multi-directional loading condition at three different occlusal contact points. METHODS: A total of 40 metal crowns were cemented to external connection implants and were embedded vertically and obliquely. The occlusal surface of the crown was designed with three flat surfaces, contact a, b, and c, representing outer and inner 20-degree inclination for buccal and lingual cusps. The angular deviations of implant crown under static 50N of loading were measured. And screw removal torque was evaluated before and after 57,600 load cycles. Then, fracture load was measured for each specimen. Data analysis was performed using one-way analysis of variance test of significance followed by Tukey honest significant difference (HSD) test(p < 0.05). RESULTS: Angular deviation results showed statistical significance between all contact points in vertically embedded group compared to obliquely embedded group, which showed similar results between contact A and B compared to C. In the other hand, screw loosening evaluation did not show statistical significance among the tested groups. And for the fracture load evaluation the maximum values reached twice the yield values in all contact areas. CONCLUSIONS: Mechanical effects were different regarding to diverse loading direction and contact points. The results of this study suggest that the stress concentration might increase in unfavorable vector direction.