The International Journal of Oral & Maxillofacial Implants, 03/2025

Purpose: To assess the impact of magnesium on osseointegration by examining various aspects of implant stability, correlating them with serum bone markers, and establishing a foundation for future research on its potential as a potent analgesic. Materials and Methods: A total of 54 patients were recruited. Immediate implant placement was performed after the extraction of the indicated mandibular molar teeth, and the patients were divided into two groups of 27 patients each: (1) placebo-lactose (control group) and (2) magnesium citrate (intervention group). Bone growth in the peri-implant area was assessed radiographically immediately after the operation, at 6 weeks, and at 12 weeks. Implant stability was measured immediately after the operation, at 4 weeks, and at 12 weeks. Serum parameters were procured preoperatively and postoperatively for serum calcium, serum alkaline phosphatase (ALP), and serum parathyroid hormone at 8 weeks, and serum vitamin D3 levels were also recorded preoperatively. Results: A total of 54 immediate implants were placed, and the demographics and baseline serum, clinical, and radiographic parameters were comparable in both groups. Analysis of implant stability quotient (ISQ) at 12 weeks showed a statistically significant difference in the intervention group based on both intergroup and intragroup analysis. Radiodensity measurements showed a statistically significant difference on both intragroup and intergroup analysis in the intervention group at weeks 6 and 12. The bone gap analysis revealed that the difference in mean change in the horizontal bone gap (HBG) at 6 weeks was not significant, whereas the difference in the HBG at 12 weeks was significant in the intervention group. Regarding the intragroup analysis, mean change in the HBG at 6 weeks and 12 weeks were both significant only in the intervention group. Intergroup analysis of the vertical bone gap (VBG) at 12 weeks and the mean difference in the VBG from week 12 to day 0 (VBG 12-0) showed a statistically significant difference in the intervention group. In the intragroup analysis, VBG 12 was significantly better in the intervention group. During the serum analysis, ALP postoperatively was found to be significantly raised (P = .013) in the intervention group. Numerical rating scale (NRS) analysis showed a significant decrease postoperatively and at days 5 (P = .017) and 7 (P = .002). Conclusions: The oral magnesium citrate supplementation after immediate implant placement helped to enhance the stability of immediate implants and improve the radiodensity around them, which was found to be statistically significant. It also helped to reduce the HBG and VBG around the implant and has significant analgesic potential. Schlagwörter: analgesia, immediate implant, implant stability quotient, magnesium citrate, osseointegration

Purpose: To evaluate the esthetic outcomes and the patient-reported outcome measures (PROMs) of immediately placed implants with a convergent transmucosal profile. Materials and Methods: This single-cohort, monocentric, and retrospective clinical study was conducted on patients treated with immediately placed implants in the esthetic zone (from premolar to premolar in both arches). All the eligible patients were recalled for a clinical and radiographic follow-up visit. Results: This study included 20 patients (20 implants; 8 males and 12 females) with an average age of 55.5 ± 6.8 years and a mean follow-up of 46.5 ± 15.3 months. At the time of follow-up, immediately placed implants showed a mean marginal bone loss of 0.42 ± 0.49 mm. A statistically significant improvement of the esthetic parameters from the immediate implant placement (baseline) to the last available follow-up was found for the pink and white esthetic scores (PES/WES) (P =.001) and the papilla index (PI) at the mesial and distal sites (P < .001). All the patients reported a high satisfaction (visual analog scale [VAS] > 9) both from an esthetic and functional point of view. Conclusions: Immediately placed implants with a convergent transmucosal profile in the esthetic zone showed good clinical and esthetic outcomes, with stable results over time. Schlagwörter: cohort study, immediate placement, prostheses, tissue-level

Purpose: To evaluate the efficacy of vertical guided bone regeneration (GBR) in the mandible using a nonresorbable membrane and a bone graft combination of autogenous bone chips and high-temperature processed (HTP) xenograft via CT scans and micro-CT analysis. Materials and Methods: Patients underwent vertical ridge augmentation procedures prior to implant placement. The surgical procedure included flap elevation and placement of a bone graft comprising a 1:1 combination of autogenous posterior mandible–derived bone chips and HTP xenograft graft particles covered with a dense polytetrafluoroethylene (d-PTFE) membrane trimmed to suit the 3D shape of the bone defect. This was fastened securely with titanium (Ti) screws and pins as well as a layer of native collagen membrane. Postoperative complications and ridge measurements were assessed. Before bone augmentation and implant placement, the bone parameters were obtained from CT scans. Biopsy samples were. harvested during implantation and were examined via micro-CT. Results: All 13 study procedures were successful without any complications. The results revealed average vertical and horizontal bone gains of 3.35 mm and 5.15 mm, respectively. A total of 33 implants were successfully placed in the augmented areas, without the need for further bone augmentation. Micro-CT analysis revealed 48% bone, 15% filler material, and 37% noncalcified tissue in the augmented region compared to 65% bone, 3% filler material, and 32% noncalcified tissue in the pristine bone. Conclusions: A mixture of autogenous bone and HTP xenograft, covered with a d-PTFE membrane and a layer of native collagen membrane, was effective for vertical GBR.  Schlagwörter: d-PTFE, GBR, micro-CT, vertical guided bone regeneration, xenograft

Purpose: To evaluate glycated hemoglobin (HbA1c) levels in patients who have not been diagnosed with diabetes mellitus (DM) but exhibit oral DM symptoms prior to dental implant surgery. Materials and Methods: This study was designed as a retrospective cohort. It was conducted on patients who previously presented to the Department of Oral and Maxillofacial Surgery for dental implant surgery and had not been diagnosed with DM. The inclusion criteria were as follows: patients with the need for dental implants and augmentation, presence of oral DM symptoms, and access to blood test results that included HbA1c. Patients with a prior diagnosis of DM were excluded from the study. Results: A retrospective analysis was conducted on data from 253 patients who applied for dental implant surgery. Among them, 72 patients underwent HbA1c level assessments via blood tests. Patients with previously uncontrolled DM (n = 21) and those whose blood tests were performed at different institutions (n = 8) were excluded from the study. Consequently, the study encompassed a cohort of 43 patients. Among the participants, 55% of them were female and 45% of them were male. The HbA1c values of the patients ranged from 5.1 to 10.9, with an average value of 6.57 ± 1.44. Of the patients, 41.8% were diagnosed with DM, 30.2% were prediabetic (preDM), and 27.9% did not receive any diagnosis. There was no statistically significant relationship between the combinations of xerostomia, delayed wound healing, oral infection, burning sensation in the mouth, periodontitis, and dental caries with HbA1c levels (P > .05). In this study, patients presenting to the clinic for dental implant surgery were directed based on oral symptom findings, and the rates of diagnosed DM and preDM were determined to be 7.11% and 5.14%, respectively. Conclusions: Considering the negative effects and prevalence of uncontrolled DM, it may be recommended to assess the HbA1c levels in patients with oral symptoms before dental implant surgery.  Schlagwörter: diabetes, HbA1c, oral symptoms, undiagnosed diabetes mellitus

Purpose: To evaluate the fracture load of monolithic zirconia (Zr) crowns with implant screw holes, focusing on variations in occlusal and axial thicknesses, and to assess the interaction between these variables. Materials and Methods: Six different prostheses were designed using CAD software, all of which varied in occlusal thickness (0.5 mm, 1.0 mm) and axial thickness (0.4 mm, 0.8 mm, 1.2 mm) based on the height and thickness differences of the titanium (Ti) implant abutment. A total of 12 specimens per design were created by milling Zr blocks and Ti abutments. These specimens were cemented with resin and subjected to thermomechanical aging (50 N; 200,000 cycles; 5°C to 55°C; 30-second dwell time) using a chewing simulator. Static loading was applied using a universal testing machine at a rate of 0.5 mm per minute until fracture occurred, and the load value (N) at the moment of the initial fracture was recorded. Fracture pattern and surface analyses were performed. Statistical analyses included two-way analysis of variance (ANOVA), Tukey HSD test, multiple regression analysis, and Fisher’s exact test. Results: Both occlusal and axial thicknesses significantly influenced the fracture load (P < .05), and a significant interaction was found between them (P < .05). An occlusal thickness of 1.0 mm exhibited a significantly higher fracture load compared to 0.5 mm (P < .05). An axial thickness of 1.2 mm showed a significantly higher fracture load compared to 0.4 and 0.8 mm (P < .05). The difference in axial thickness between 0.8 and 1.2 mm had a more substantial impact on fracture load than the difference in occlusal thickness between 0.5 and 1.0 mm (P < .05). Fractographic analysis showed that the thin axial wall exhibited twist hackles without involvement of the crown margin, whereas the thick axial wall exhibited no hackles and a more catastrophic failure involving the crown margin. Conclusions: For monolithic Zr crowns with implant screw holes, when sufficient occlusal thickness cannot be achieved, an axial thickness of at least 1.2 mm is recommended to ensure higher fracture resistance. Schlagwörter: axial thickness, fracture load, implant-supported fixed dental prosthesis, occlusal thickness, screw hole, zirconia crown

Purpose: To compare the insertion torque (IT) and removal torque (RT) of Neodent Zi zirconia (Zr) implants (Straumann) and Neodent Alvim titanium (Ti) implants (Straumann) while measuring both the maximum torque (MT) supported by the Zr implant and the MT sustained by the assembler of the implants until fracture. Materials and Methods: In this in vitro study, 24 implants with the same microgeometry were split into two groups—12 Zr implants and 12 Ti implants—and compared. Implant bed preparations were completed in bovine ribs following a standardized drilling protocol. Then the IT, RT, MT to fracture, and MT to fracture of the assembler were completed using a calibrated torque meter. Data was presented using descriptive statistics including means, SDs, medians, and quartiles. The Shapiro-Wilk test was used to verify data normality and the Wilcoxon test was used to evaluate differences between groups. Statistical significance was established as P < .05. Results: Zr implants showed an IT of 89.33 ± 31.18 Ncm and an RT of 84.89 ± 32.92 Ncm. Ti implants showed an IT of 77.58 ± 28.96 Ncm and an RT of 76.75 ± 31.29 Ncm without significant differences (P > .05). In relation to fracture under rotational force, the Zr implants. fractured at 106.17 ± 22.54 Ncm, and the implant assembly fractured at 84.00 ± 13.14 Ncm. Conclusions: Neodent Zi implants showed stability but a lower fracture torque than the Alvim Ti implants. As the fracture values of the assembler were significantly lower than the fracture values of the Zr implants, it can be stated that, as recommended by the manufacturer, they act as a safety measure during placement. Schlagwörter: biomechanical phenomena, fracture strength, Y-TZP ceramic

Purpose: To examine how saline and acidic environments affect the mechanical integrity of narrow single-body titanium (Ti) implants for oral rehabilitation. Materials and Methods: A total of 30 Ti-base alloy implants (2.5-mm diameter) were placed into a polyacetal holder and coupled to a stainless steel prosthetic cap for fatigue testing in the three different environments as follows: (1) dry air, (2) saline solution (pH at 7.6), and (3) lactic acid solution (pH at 3.4). The fracture surfaces were analyzed using a scanning electron microscope (SEM). Also, finite element analysis (FEA) was carried out to estimate the maximum von Mises stresses. Results: The fatigue resistance was higher in the group tested in dry air (60%), followed by saline solution (30%) and lactic acid (10%). Regardless of the environment, the FEA showed that fractures occurred at the same areas with highest stress concentration. SEM analyses revealed two distinct failure regions that both had fatigue streaks: fatigue and overload. A high incidence of secondary cracks was also noticed on the specimens exposed to the solutions. Conclusions: Both saline and acidic solutions significantly affect the fatigue resistance of narrow dental implants. Critical regions of the narrow implants were also susceptible to cracks and plastic deformation, which should be taken into consideration when planning for an oral rehabilitation.   Schlagwörter: corrosion, extra-narrow implants, fatigue, failure analysis, saline solution

Purpose: To explore the comparative efficacy of two different drilling protocols that use burs with different designs to help prepare implant sites through the evaluation of radiographic, clinical, and patient-reported outcomes. Materials and Methods: The present randomized controlled clinical trial, with an allocation ratio of 1:1, was carried out at the University of Milan and at the IRCCS Ospedale Galeazzi Sant’Ambrogio Hospital in Milan by two experienced surgeons and researchers (S.C. and S.T.). In the control group, surgeons followed a protocol with standard straight burs, and in the test group they used step burs. In both groups the patients received the same type of implants and prostheses. The primary outcome was marginal bone resorption 1 year after prosthetic placement. Results: The study included and treated a total of 60 patients (86 implants). At the 1-year follow-up, 54 patients (74 implants) were screened, and 50 patients were screened at the 2-year follow-up (69 implants). This study showed no evidence of a difference in bone resorption, which increased significantly over time, between the control and test groups. Conclusions: Bot clinical parameters and patient-centered outcomes revealed no differences between the two protocols for implant site preparation with two different drill shapes. Schlagwörter: bone surgery, dental implant, implant bur design, marginal bone resorption, osteotomy, success rate, quality of life

Purpose: To evaluate the causes and risk factors associated with implant removal as observed in a hospital setting over a 20-year timespan to find the most common causes leading to implant removal. Materials and Methods: In the present retrospective study, implants removed between 2000 and 2022 were registered and the cause of removal established. All implants were removed by a single operator (P.P.M.) in the Department of Oral Surgery of the George Eastman Dental Hospital in Rome, Italy. Characteristics of removed implants such as implant surface, morphology (bone- versus tissue-level implants), type of restoration (fixed versus removable), mode of retention in the case of fixed restorations (cement- versus screw-retained), and location of the implant (maxillary versus mandibular) were recorded. Patient-level characteristics were also recorded, including patients’ systemic health conditions, the medications they were currently taking or had taken, smoking habits, and if they had a previous history of periodontitis. Results: In total, 381 implants in 381 patients were removed in the 20-year timespan. The most frequent cause of removal was peri-implantitis (82.4% of implants), followed by implant malposition and loss of osseointegration. Conclusions: The survival time was not affected by the cause of removal, while bone-level implants had a longer survival time versus tissue-level implants. Maxillary implants had a higher prevalence of peri-implantitis compared to mandibular implants. Schlagwörter: failure analysis, implant removal , peri-implantitis, retrospective cohort

Purpose: To investigate the associations between the concentrations of bone turnover markers and maxillary and mandibular cancellous Hounsfield units (HUs) to determine whether bone turnover marker (BTM) assessments are effective for preoperative examinations for implant treatment. Materials and Methods: The study included 94 patients (37 males and 57 females) with a mean age of 62.0 ± 11.9 years. Spearman’s rank correlation and multivariate linear regression coefficients were used to determine the associations between the BTMs and maxillary and mandibular cancellous HUs. Results: Multivariate bias correction showed that the concentrations of bone-specific alkaline phosphatase, procollagen type 1 N-terminal propeptide, and deoxypyridinoline were negatively associated with the maxillary HUs. The concentration of undercarboxylated osteocalcin tended to be negatively associated with the maxillary HUs but was not significant. The concentrations of deoxypyridinoline and tartrate-resistant acid phosphatase 5b were significantly negatively associated, and the concentrations of bone-specific alkaline phosphatase and procollagen type 1 N-terminal propeptide only tended to be negatively associated, with the mandibular HUs. Conclusions: Several bone formation and resorption markers were negatively correlated with the maxillary and mandibular HUs. The BTM measurement was effective for preoperative examination for implant treatment Schlagwörter: bone mineral density, bone turnover marker, Hounsfield units, implant

Purpose: To examine and compare the mechanical success of customized CAD/CAM and prefabricated abutments and screws before and after cyclic loading by measuring removal torque values. Materials and Methods: A total of 28 dental implants with identical characteristics were divided into two equal groups. The control group comprised prefabricated abutments and screws, and the study group comprised customized CAD/CAM abutments and screws. Removal torque values (RTVs) were measured before and after 50,000 and 1 million cycles of loading in both groups. Additionally, to evaluate the screw fatigue performance, they were retightened to 30 Ncm torque and RTV measurements were repeated. The data were analyzed using a one-way analysis of variance (ANOVA), a Newman Keuls test, and a paired t-test. Results: No significant difference was observed in RTVs before cyclic loading within each group. However, the RTVs measured before cyclic loading were found to be significantly lower in the study group compared to the control group. Both groups exhibited a significant decrease in RTV after cyclic loading. The RTV of the study group was significantly lower than the control group, especially after 1 million cycles. No significant difference was found in the screw fatigue performance of both groups. Conclusions: The significantly lower RTVs of customized CAD/CAM abutments and screws before and after cyclic loading have raised questions about their effectiveness and widespread use. This study underscores the necessity for further clinical investigations comparing the mechanical success of custom and prefabricated abutments and screws. Schlagwörter: CAD/CAM, custom abutment, cyclic loading, removal torque value

Purpose: To evaluate the influence of using polyetheretherketone (PEEK) copings and/or three different dental restorative materials for the success of tooth-and-implant-supported fixed partial dentures (TISFPDs) in the maxillary posterior region under static loading via 3D finite element analysis (3D FEA). Materials and Methods: Six 3D FEA models were designed for the extraction of maxillary first and second molars. The following elements were modeled: bone, implant, abutment, PEEK copings, second premolar, periodontal ligament (PDL), and six three-unit TISFPDs with different restorative materials (porcelain-fused-to metal [PFM], PEEK-composite [PC], monolithic zirconia [MZ]). Then PEEK copings were modeled to be cemented onto the implants as a double-crown system for the first three groups (PFMPEEK, PCPEEK, and MZPEEK), whereas the next three groups (PFM, PC, and MZ) excluded a PEEK coping in their designs. The prostheses were loaded twice—once vertically and once obliquely. From the determined points, 250 N for vertical loading (0 degrees to the long axis) and 200 N for the oblique loading (30 degrees to the long axis) were applied. Von Mises stresses and maximum and minimum principal stress values were analyzed. Results: Regardless of the material used for the suprastructure, the maximum average stress was reduced by the use of PEEK copings. Considering the maximum stress distribution, PC appeared to have the highest stresses on the cortical bone, implant, and screw. Additionally, the von Mises stresses formed in the PDL model were lower when a PEEK coping was included in the design of the TISFPD, reducing the risk of intrusion. Conclusions: The stress distribution was positively affected by the PEEK coping in the TISFPD design, reducing bone resorption and failure. This elastic material generated lower stresses at the bone and implant, and no significant effect was found on stresses around natural teeth.  Schlagwörter: finite element analysis, PEEK, stress distribution, static loading