Peri-implant Bone Research Articles

Maxillary bone augmentation with calvarial bone graft for immediate full-arch rehabilitation: Insights from a 10-year proof-of-concept retrospective analysis.

Evaluate the long-term outcomes of full-arch rehabilitation using immediate dental implant placement and continuous functional loading with full-fixed dental prostheses (FFDPs). Fifty-six patients received temporary implants (n = 327) at maxillary augmentation with calvarial bone. A provisional acrylic FFDP was immediately loaded onto these implants. After 6 months, the temporary implants were replaced with definitive implants (n = 326) and immediately loaded with a second provisional FFDP (N = 55). Subsequently, a baseline radiograph was taken following a 6-month healing period. The second bridge was then substituted with a definitive FFDP. Primary outcomes included peri-implant marginal bone level (MBL) and definitive implant survival. Secondary outcomes evaluated provisional implant and prostheses survival, complications, and patient satisfaction. The provisional implants had a survival rate of 97.9%. One patient was excluded from further analysis due to loss of temporary implants and first FFDP. The definitive implant survival rate after 10 years was 92.2%, with a moderate but significant decrease in MBL between baseline radiography and 10 years later (-0.08 ± 0.18 vs. -0.24 ± 0.44). However, large individual variations were observed, with 65.8% of implants showing no bone loss and 9.2% showing loss ≥0.5 mm. Sinusitis was experienced by 14.3% of patients upon surgery. Patient satisfaction was high or reported no issues after protocol completion (80%). One patient lost all six definitive implants and definitive FFDP 8.2 years after implant placement. The described protocol can be regarded as a long-term, highly successful method for full-arch rehabilitation of atrophied maxillae while enabling continuous masticatory and speaking functionality.

Influence of Mucosal Tissue Thickness on Peri-Implant Bone Stability: Retrospective Radiological Study

Abstract Gradual bone loss around the implants is an ongoing concern. Mucosal tissue thickness is considered as a contributing factor that influences bone remodelling after implantation. It has been suggested that tissue thickness thinner than 2.5 mm may contribute to more peri-implant bone loss, eventually affecting implant bone stability. Measuring mucosal thickness prior to surgery may be a predictor of the bone changes and could modify the surgical methods. In this study mucosal tissue thickness was measured retrospectively on radiographs before implant insertion, one year and at least three years after implantation. Within the limits of this study, no influence of initial mucosal tissue thickness on long term peri-implant bone stability was found.

A digital technique for cloning the emergence profile of the interim to the definitive implant-supported restoration

The subgingival contour of implant-supported restorations is key to ensuring the long-term health of the peri-implant bone and soft tissues. This report describes a step-by-step technique used to accurately clone the emergence profile of the interim crown for the definitive implant-supported restoration.

ОБОСНОВАНИЕ ИСПОЛЬЗОВАНИЯ ДОРЗАЛЬНО НАКЛОНЕННЫХ ДИСТАЛЬНЫХ ИСКУССТВЕННЫХ ОПОР ПРОТЯЖЕННЫХ ИМПЛАНТАЦИОННЫХ ПРОТЕЗОВ У ПОЖИЛЫХ ПАЦИЕНТОВ

The subject of the research is implant prosthetics.
 The goal is to increase the efficiency of implant prosthetics by optimizing the design of the prosthesis.
 Methodology. 131 patients (57 men and 74 women) aged from 60 to 82 years (mean age 68.3 ± 7.3 years) were examined.
 The patients were divided into 3 groups: group 1 – 36 patients (14 men and 22 women with an average age of 70.1 ± 5.4 years) with vertical distal implants without dorsal weight; group 2 – 44 people (19 men, 25 women with an average age of 69.4 ± 7.2 years) with inclined distal implants without dorsal weight; group 3 – 51 people (24 men and 27 women with an average age of 68.4 ± 6.8 years) with inclined distal implants, which also carried the dorsal body of the prosthesis with unilateral support on them.
 The condition of the peri-implant bone was assessed using 16 criteria obtained using clinical and instrumental research methods. The study of the distributions and magnitude of elastic stresses in the peri-implant bone was carried out using mathematical modeling using finite elements.
 Results. Identical results were obtained for the reaction of the peri-implant bone and mucous membrane of the peri-implant cuff, as well as the levels of preservation of implants and implant prostheses in the long term (2–3 years) in patients with different configurations of the distal parts of extended implant prostheses. Mathematical modeling by the finite element method also showed the non-criticality of the distribution of elastic stresses in the prosthesis, distal implant, compact and cancellous bone with different configurations of the distal parts of the prosthesis.
 Conclusion. Inclined implants, including those with additional load in the form of a dorsal body with unilateral support, can be quite widely used in elderly patients.

Mini Crestal Sinus Lift With Bone Grafting and Simultaneous Insertion of Implants in Severe Maxillary Conditions as an Alternative to Lateral Sinus Lift: Multicase Study Report of Different Techniques.

The present study evaluates the efficacy and clinical outcomes of crestal sinus lift techniques used to elevate the sinus floor simultaneously with bone grafting and implant placement as a possible and reproducible alternative to lateral sinus lift. Patients underwent different crestal sinus elevation techniques. The heterologous biomaterial was used as graft material, and multiple implants were placed simultaneously after sinus augmentation. Radiographic and clinical examinations were performed during follow-up. All procedures were successfully performed without any apparent perforation of the Schneider membrane. The sinus floor was augmented with an average height of 5mm (range: 2.8-7.4mm). The implants healed smoothly with healing screws. Peri-implant marginal bone was stable with a mean follow-up of 50 months (range: 33-71mo). No complications were observed during the follow-up. Based on the limited data collected in this study, the new crestal sinus elevation approach can effectively raise the sinus floor and reduce the incidence of postoperative complications. Other cases with long-term follow-up are needed to confirm and improve this crestal sinus lift technique.

Site-specific radiation dosage and implant survival in oral cancer patients: A cohort study.

We assessed the radiation dosages (Dmean) on implant regions to identify the threshold for implant loss in patients with an intraoral malignancy treated with dental implants to support a mandibular denture during ablative surgery before volumetric-modulated arc therapy (VMAT). Data was collected prospectively from 28 patients treated surgically for an intraoral malignancy, followed by postoperative radiotherapy (VMAT) and analyzed retrospectively. Patients received 2 implants in the native mandible during ablative surgery. Implant-specific Dmean values were retrieved from the patients' files. Radiographic bone loss was measured 1 year after implant placement and during the last follow-up appointment. Implant survival was analyzed with the Kaplan-Meier method. Univariate logistic regression and Cox-regression analyses were performed to investigate the effect of increasing implant-specific radiation dosages on implant loss. Five out of 56 placed implants were lost during follow-up (median 36.0 months, IQR 39.0). Radiographically, peri-implant bone loss occurred in implants with a Dmean > 40 Gy. Implant loss occurred only in implants with a Dmean > 50 Gy. An implant-specific Dmean higher than 50 Gy is related to more peri-implant bone loss and, eventually, implant loss.

Crestal and Subcrestal Placement of Morse Cone Implant-Abutment Connection Implants: An In Vitro Finite Element Analysis (FEA) Study.

The issue of dental implant placement relative to the alveolar crest, whether in supracrestal, equicrestal, or subcrestal positions, remains highly controversial, leading to conflicting data in various studies. Three-dimensional (3D) Finite Element Analysis (FEA) can offer insights into the biomechanical aspects of dental implants and the surrounding bone. A 3D model of the jaw was generated using computed tomography (CT) scans, considering a cortical thickness of 1.5 mm. Subsequently, Morse cone implant-abutment connection implants were virtually positioned at the model's center, at equicrestal (0 mm) and subcrestal levels (-1 mm and -2 mm). The findings indicated the highest stress within the cortical bone around the equicrestally placed implant, the lowest stress in the -2 mm subcrestally placed implant, and intermediate stresses in the -1 mm subcrestally placed implant. In terms of clinical relevance, this study suggested that subcrestal placement of a Morse cone implant-abutment connection (ranging between -1 and -2 mm) could be recommended to reduce peri-implant bone resorption and achieve longer-term implant success.

Peri-Implant Bone Loss in Fixed Full-Arch Implant-Supported Mandibular Rehabilitation: A Retrospective Radiographic Analysis

Background: the aim of the study was to assess, through orthopantomograms (OPGs), the existence of peri-implant bone loss of distal implants in implant-supported full-arch mandibular restorations. A comparison between full-arch implant-supported rehabilitations performed in the inter-foraminal region and full-arch rehabilitations that include implant insertion distal to the mental foramen was conducted. Methods: a retrospective observational analysis of 17,950 OPGs from 2010 to 2020 was conducted. The presence of fixed implant-supported prostheses in a fully edentulous mandible was the inclusion criteria of the study. OPGs were divided according to the number of implants (four, six, and eight), position of the implants (mesial or distal to the mental foramen), and positioning patterns (models 1, 2, 3, 4, and 5). Results: a total of 51 OPGs were included in the study, 19 of which showed peri-implant bone loss. In particular, 16 belonged to the six-implant rehabilitation group and 3 to the eight-implant rehabilitation group; none of the four-implant-supported rehabilitations were affected by peri-implant bone loss. In all rehabilitations affected by peri-implant bone loss, the distal implant was the most involved, in particular the implant in positions 36 and 46. Conclusions: implants distal to the mental foramina are more susceptible than mesial implants to bone resorption in full-arch fixed implant-supported prostheses. This significant difference should be investigated further for the presence and synergy of biomechanical factors that could act predominantly in this area, such as mandibular flexure and occlusal loading.

Forming a Modern Therapeutic Resource for Geriatric Dentistry

Background. The special status and position of older and oldest old in the therapeutic, diagnostic, and preventive activities of a dentist lead to a firm conviction of an urgent necessity and expediency of creating a new medical specialization — geriatric dentistry.Aim. Based on many years of clinical experience and scientific research, including extensive use of high-tech oral prosthetics for older adults, to make the first attempt at creating an optimal therapeutic resource for a new medical specialization — geriatric dentistry.Materials and methods. Examination and prosthetics were performed on 645 patients aged 60 to 85 years old, with various types of implantable prostheses in the period o 3 to 7 years after their implantation. In addition, 903 implantable prostheses and 3287 of their artificial supports (implants) were also examined.Results. The mean age of patients who visited the orthopedic dentistry department for dental prosthetics was 64.72 ± 6.8 years old. As the main method of rehabilitation of older patients’ masticatory and speech apparatus, we have used implant-supported prosthesis with its digital transformation. Most of the patients underwent reasonably radical oral cavity preparation for prosthetics. The original state retention of the tissues of the implant bed ranged from 78.04 to 100%. At the same time, fixed structures of implantable prostheses were characterized by higher indicators. The preservation of the implants was from 96.8 to 100%, depending on the observation period.Conclusion. The high values of implant and prosthesis retention rates, good condition of the peri-implant mucous membrane and bone in remote periods after prosthetics, as well as a high level of patient satisfaction and significantly higher achieved level of their quality of life, along with high medical and economic efficiency of the method, allow us to consider it a promising standard of geriatric dentistry. Thus, a modern therapeutic, or rather, rehabilitation, resource for effective pre-prosthetic preparation and implant prosthesis has been developed and justified, which is the optimal approach in geriatric dentistry.

Long-term evaluation of combined prosthetic-surgical approach and soft tissue augmentation in the esthetic zone.

There is no standard protocol for immediate implant placement and subsequent loading in the smile zone. We aimed to evaluate the long-term outcomes of simultaneous implant placement, soft tissue grafting, and immediate prosthetic loading in the esthetic zone. Thirty-five implants were placed in the maxillary aesthetic zone. Twenty-two patients were evaluated using the Pink Esthetic Score (PES) and White Esthetic Score (WES). Also, the degree of peri-implant bone resorption and patient survey were applied for the esthetic and functional outcomes. The esthetic and harmonizing outcomes were achieved according to the mean total PES/WES value (17.9±2.0). The mean overall PES was 8.5±1.66. The papilla level had the highest mean score (1.8±0.36). Furthermore, the combination of root convexity/color and soft tissue color and texture was one of the key values in evaluating the effectiveness of this method (the mean value was 1.5±0.5). The mesial and distal papillae were 1.6±0.5 and 1.8±0.4, respectively. None of the 35 implants reached below 6 points (which is considered an esthetically unsatisfactory result). The mean WES score was 9.5±0.57. The average degree of total peri-implant bone resorption was 1.05±0.3 mm after 12 months. According to the questionnaire, all the patients smiled without hesitation and were satisfied with the treatment (100%). This study showed that restoring one or more teeth in the smile zone using the concept of one-stage implant placement, soft tissue flap augmentation, and loading with provisional crowns was an esthetically successful and predictable method.

Osseodensification: An Alternative to Conventional Osteotomy in Implant Site Preparation: A Systematic Review.

Osseodensification is an innovative method of preparing the implant osteotomy using drills that promote bone self-compaction. The main objective of this technique is to promote peri-implant bone densification and compaction of autologous bone and to increase the primary stability of the implant due to the viscoelastic characteristics of the alveolar bone using Densah® burs in a counterclockwise direction at a speed of 800 to 1500 rpm. The objective of this review is the analysis of the scientific literature regarding the applicability of the osseodensification technique in oral implantology. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were used and registered at PROSPERO. The search strategy included electronic databases from 2016 to 2023 and was performed by two independent reviewers. The results demonstrate the advantage of the osseodensification technique in relation to conventional drilling, allowing an increase in the bone density and primary stability of the implant, bone density, and bone-implant contact. The osseodensification technique can be applied in different clinical situations: sub-antral bone grafts, narrow alveolar bone crests, low-density bone areas, and immediate implant placement in post-extraction sockets.

A cross-sectional study for prevalence and risk factors of peri-implant marginal bone loss

Progressive peri-implant marginal bone loss and peri-implantitis have become a growing problem, but cross-sectional studies on their prevalence and risk factors are sparse. The purpose of this cross-sectional clinical study was to investigate the prevalence of peri-implant marginal bone loss (MBL) and to identify systemic and local risk factors. All adult patients who had received dental implants at the National Taiwan University Hospital (NTUH) during 2009 or 2010 were included. Their medical records were collected from the NTUH-integrative Medical Database. Consecutive follow-up radiographs were accessed for severity of MBL. The influence of each factor on MBL was estimated by using generalized estimating equations (GEEs). A total of 732 participants with 1873 implants were analyzed (mean follow-up: 5.30 years). The prevalence of MBL was 59.15% at the individual level and 49.55% at the implant level. The risk indicators identified for the presence of MBL were follow-up period of more than 2 years, diagnosis of diabetes within 12 months, radiation therapy (2 years after implant placement), implant location at maxillary canine (compared with mandibular molar), and implants from the Nobel Biocare brands (Brånemark System and NobelActive). A second multivariate GEE model confirmed the association of progressive MBL with implant location at the maxillary canine and mandibular incisor and implant brand or design. The identified risk indicators for MBL were longer follow-up period, diagnosis of diabetes, radiation therapy, implant location at maxillary canine, and implant brand or design.

Biomechanical performance of dental implants inserted in different mandible locations and at different angles: A finite element study

Accurate implant placement is essential for the success of dental implants. This placement influences osseointegration and occlusal forces. The freehand technique, despite its cost-effectiveness and time efficiency, may result in significant angular deviations compared with guided implantation, but the effect of angular deviations on the stress-strain state of peri-implant bone is unclear. The purpose of this finite element analysis (FEA) study was to examine the effects of angular deviations on stress-strain states in peri-implant bone. Computational modeling was used to investigate 4 different configurations of dental implant positions, each with 3 angles of insertion. The model was developed using computed tomography images, and typical mastication forces were considered. Strains were analyzed using the mechanostat hypothesis. The location of the implant had a significant impact on bone strain intensity. An angular deviation of ±5 degrees from the planned inclination did not significantly affect cancellous bone strains, which primarily support the implant. However, it had a substantial effect on strains in the cortical bone near the implant. Such deviations also significantly influenced implant stresses, especially when the support from the cortical bone was uneven or poorly localized. In extreme situations, angular deviations can lead to overstraining the cortical bone, risking implant failure from unfavorable interaction with the implant. Accurate implant placement is essential to mitigate these risks.

Effect of customized abutment taper configuration on bone remodeling and peri-implant tissue around implant-supported single crown: A 3D nonlinear finite element study.

The optimal configuration of a customized implant abutment plays a crucial role in promoting bone remodeling and maintaining the peri-implant gingival contour. However, the biomechanical effects of abutment configuration on bone remodeling and peri-implant tissue remain unclear. This study aimed to evaluate the influence of abutment taper configurations on bone remodeling and peri-implant tissue. Five models with different abutment taper configurations (10°, 20°, 30°, 40°, and 50°) were analyzed using finite element analysis (FEA) to evaluate the biomechanical responses in peri-implant bone and the hydrostatic pressure in peri-implant tissue. The results demonstrated that the rate of increase in bone density was similar in all models. On the other hand, the hydrostatic pressure in peri-implant gingiva revealed significantly different results. Model 10° showed the highest maximum and volume-averaged hydrostatic pressures (69.31 and 4.5mmHg), whereas Model 30° demonstrated the lowest values (57.83 and 3.88mmHg) with the lowest excessive pressure area. The area of excessive hydrostatic pressure decreased in all models as the degree of abutment taper increased from 10° to 30°. In contrast, Models 40° and 50° exhibited greater hydrostatic pressure concentration at the cervical region. In conclusion, the abutment taper configuration had a slight effect on bone remodeling but exerted a significant effect on the peri-implant gingiva above the implant platform via hydrostatic pressure. Significant decreases in greatest and average hydrostatic pressures were observed in the peri-implant tissues of Model 30°. However, the results indicate that implant abutment tapering wider than 40° could result in a larger area of excessive hydrostatic pressure in peri-implant tissue, which could induce gingival recession.

Emerging factors affecting peri-implant bone metabolism.

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

Usage of xenogeneic bone intentionally left exposed to the oral environment after immediate implant placement: a case report with six-year follow-up

Objective: This clinical case report aims to demonstrate a successful treatment using an alternative technique for flapless immediate implant placement by letting the xenogeneic bone graft exposed to the oral environment. Case report: A flapless immediate implant placement into the fresh mandibular first molar socket was done. The alveolar gap was filled by deproteinized bovine bone mineral (DBBM) up to the level of the gingival margin, and the biomaterial was intentionally left exposed and maintained only by the cover screw. A definitive restoration was placed six months after the implant insertion. This patient exhibited no clinical or radiologic complications throughout the six-year follow-up period. Conclusion: The DBBM exposed to the oral environment showed stability and caused no sign of infection and clinical complications. Throughout the follow-up time, the patient presented a favorable peri-implant phenotype, with a wide keratinized mucosa width, stable peri-implant buccal bone, as well as the maintenance of crestal bone. Although the exposed biomaterial may be more susceptible to displacement, this approach showed satisfactory performance regarding uneventful healing, esthetics, and function, in a six-year follow-up. However, randomized clinical trials to evaluate the clinical predictability and soft and hard tissues healing profile are needed.

Long-term clinical performance of short 6-mm implants supporting single crowns in the posterior region: A 10-year cohort study.

Long-term clinical success of non-splinted, posterior, and short implants still is unclear. This prospective cohort study reports the 10-year follow-up of 6-mm implants supporting single crowns in the posterior region, and patient-reported outcomes. Baseline sample comprised 20 patients treated with 46 screw-retained crowns supported by 6-mm implants with moderately rough implant surface. Participants were recalled for a 10-year clinical follow-up to assess survival rates, biologic and mechanic conditions, quality of life (OHIP-14), and treatment satisfaction. Data were collected with clinical-radiographic exams and analyzed using descriptive and inferential statistics. Fourteen patients with 35 implant-crown units were examined after 127.6 ± 11.8 months. For the entire cohort period, 7/46 implants were lost (survival estimate: 77.7% at 133 months), and mechanic complications occurred in 14/46 units (survival estimate: 66.4% at 116 months). In the Cox models, "maximum occlusal force" had a significant effect for implant loss (p = 0.038) and for prosthetic screw loosening (p = 0.038); "arch" and "bruxism" were not significant. Peri-implant bone loss was 0.4 ± 0.6 mm at 10 years. For peri-implant bone level, "crown-to-implant ratio" (p < 0.001) and "time" (p = 0.001) were significant. Bone levels differed from baseline to 12, 48, and 120 months. Satisfaction VAS was 94.0 ± 7.9 mm and OHIP-14 was 2.3 ± 2.2. Single screw-retained crowns supported by 6-mm implants have an acceptable long-term clinical performance, with stable peri-implant bone levels after 10 years of function.

Evidence of bisphosphonate-conjugated sitafloxacin eradication of established methicillin-resistant S. aureus infection with osseointegration in murine models of implant-associated osteomyelitis

Eradication of MRSA osteomyelitis requires elimination of distinct biofilms. To overcome this, we developed bisphosphonate-conjugated sitafloxacin (BCS, BV600072) and hydroxybisphosphonate-conjugate sitafloxacin (HBCS, BV63072), which achieve “target-and-release” drug delivery proximal to the bone infection and have prophylactic efficacy against MRSA static biofilm in vitro and in vivo. Here we evaluated their therapeutic efficacy in a murine 1-stage exchange femoral plate model with bioluminescent MRSA (USA300LAC::lux). Osteomyelitis was confirmed by CFU on the explants and longitudinal bioluminescent imaging (BLI) after debridement and implant exchange surgery on day 7, and mice were randomized into seven groups: 1) Baseline (harvested at day 7, no treatment); 2) HPBP (bisphosphonate control for BCS) + vancomycin; 3) HPHBP (hydroxybisphosphonate control for HBCS) + vancomycin; 4) vancomycin; 5) sitafloxacin; 6) BCS + vancomycin; and 7) HBCS + vancomycin. BLI confirmed infection persisted in all groups except for mice treated with BCS or HBCS + vancomycin. Radiology revealed catastrophic femur fractures in all groups except mice treated with BCS or HBCS + vancomycin, which also displayed decreases in peri-implant bone loss, osteoclast numbers, and biofilm. To confirm this, we assessed the efficacy of vancomycin, sitafloxacin, and HBCS monotherapy in a transtibial implant model. The results showed complete lack of vancomycin efficacy while all mice treated with HBCS had evidence of infection control, and some had evidence of osseous integrated septic implants, suggestive of biofilm eradication. Taken together these studies demonstrate that HBCS adjuvant with standard of care debridement and vancomycin therapy has the potential to eradicate MRSA osteomyelitis.

Effect of Novel Low-intensity Pulsed Ultrasound Stimulation on Accelerated Implant Osteointegration in Canine.

To evaluate the effect of low-intensity pulsed ultrasound (LIPU) application on dental implant accelerated osseointegration in the two-stage implant protocol. A total of 20 implants were placed in 10 mature mongrel dogs, two implants for each dog replacing the lower 3rd premolars bilaterally. After 3 months of extraction, implants were placed. After 24 hours of implantation, the right sides received LIPU for 20 mins/day, continuously for 20 days. The left sides didn't receive LIPU (control). Standardized radiographs were taken before LIPU and after 10 and 20 days for both sides. After 20 days of LIPU application, second-stage surgery was performed and provisional crowns were placed on each implant. Implants were subjected to functional occlusal loading for 4 weeks. Standardized radiographs were taken after 2 and 4 weeks of loading and analyzed to assess the peri-implant bone density changes. All data were collected, tabulated, and statistically analyzed. All tissues appeared clinically normal, with the absence of inflammation and peri-implant radiolucency. The survival rate was 100%. The LIPU group showed a statistically significantly higher percentage increase in mean bone density after 10 LIPU sessions, 20 LIPU sessions, and 2 and 4 weeks of loading, than a control group. The LIPU stimulation radiographically increased the bone density around implant area and accelerated osseointegration in the two-stage implant protocol. Low-intensity pulsed ultrasound stimulation could be beneficial in accelerating osseointegration and thus shortening the waiting period for final prosthetic delivery.

Stress distribution of four implant supported overdentures with tilted standard-sized implants and mini implants.

The goal of the current study is to evaluate the stress distribution when tilted implants and mini-implants are used to support a mandibular overdenture. Three-dimensional (3D) finite element models of mandibular overdentures were established using four, axial, standard-sized implants (SA model), four standard-sized implants with the mesial ones axial and the distal ones tilted (ST model) and four mini-implants (MA model) with Locator attachments. On each model, a 100 N load was applied to the overdenture in four different directions; bilateral vertical, unilateral vertical and oblique load on the posterior region, and a vertical load on the incisors. The stresses distributed at the peri-implant bone, implants, the prosthetic components, and the overdentures were evaluated. Non-axial posterior loading caused higher stress values in the implant and the prosthetic component than axial posterior loading. Lower stress values of the implant and the prosthetic component were observed in the ST model than SA model. The stress distribution in the overdenture at posterior loads were mostly observed around the implants. Less prosthetic complications may be expected when the treatment option in the ST model is used. Fatigue fractures may occur around the implants in the overdentures, precautions are advised.