The International Journal of Oral & Maxillofacial Implants, 01/2025

Principal component analysis (PCA) is a statistical tool that condenses the information contained in a large group of independent variables to a more manageable number of variables. This is useful when performing an analysis on data sets with a large number of variables. PCA restructures the original independent variables into new variables called principal components that maximize the information present in the data. The principal components then act as a substitute for the independent variables in an analysis. The purpose of this article is to present PCA in an understandable way for researchers without advanced statistical and mathematical backgrounds. To solidify the comprehension of the process and provide a template for researchers, we present an extended step-by-step example of PCA in use on a fictitious peri-implantitis data set. Schlagwörter: big data, principal component analysis, statistical methods, tutorial, variable reduction

Purpose: To evaluate the real-life clinical results of monolithic zirconia (Zr) screw-retained crowns without the interposition of a titanium base (Ti-base) on external hex implants fabricated from intraoral scans and a cast-free approach in private practice. Materials and Methods: Single external hex implants were restored with monolithic Zr crowns without the interposition of a Ti-base. The crowns were directly screwed on the external hex implant connections with a cast-free, fully digital workflow. Data were analyzed using descriptive statistics and the Kaplan-Meier test. Between September 2022 and March 2023, the California Dental Association’s modified criteria were adopted for the present clinical evaluation after recalling all patients. Results: A total of 304 single-tooth restorations in the maxillary and mandibular posterior regions were fabricated between July 2014 and July 2022 in 252 patients (120 males and 132 females, mean age: 53.6 years; SD: 23.3). Seven crowns were excluded because of patient dropout. The most common minor technical complications were screw loosening (three crowns) and loss of the screw access hole filling (three crowns). There were four failures, including two implant failures with mobility and two fractured crowns. No screw or implant fractures were recorded. The overall cumulative survival rate was 98.6%, and the average success rate (crowns experiencing no failures or complications) was 96.0%. The mean overall survival time was 101.3 months (standard error: 0.847; 95% CI for the mean, 99.67–102.99). The overall survival probability was 87.9% up to 97 months. Conclusions: With careful case selection and a comprehensive periodontal maintenance program, single crowns that were directly screwed onto an external hex platform showed excellent survival and success rates that were comparable to available data regarding single crowns with a Ti-base prosthetic interface. Schlagwörter: CAD/CAM, digital workflow, prosthodontics, single implant

Purpose: To evaluate the effect of osteotomy preparation techniques and implant diameter on primary stability and the bone-implant interface of short implants (6 mm) when placed in bone with a high degree of cancellous content. Materials and Methods: Overall, 90 short dental implants (6 mm; Astra Tech Implant System EV, Dentsply Sirona) were divided into nine groups based on width (narrow implants [N]: 4.2 mm; regular implants [R]: 4.8 mm; or wide implants [W]: 5.4 mm), and the type of osteotomy preparation used (standard [ST], osteotome [OT], or osseodensification [OD]) to be placed in porcine tibia plateau bone samples. The following groups were created: group N-ST, group N-OT, group N-OD, group R-ST, group R-OT, group R-OD, group W-ST, group W-OT, and group W-OD. The insertion torque and implant stability quotient (ISQ) were measured. Additionally, four implants from groups N-ST, N-OT, and N-OD were evaluated histomorphometrically. Results: The insertion torque was significantly higher for implants in group W-OD compared to group W-ST (50.00 ± 14.14 Ncm vs 28.00 ± 10.85 Ncm; P = .005). Similarly, the insertion torque was significantly higher for implants in group W-OT compared to group W-ST (46.87 ± 17.10 Ncm and 28.00 ± 10.85 Ncm, respectively; P = .026). The insertion torque was also significantly higher for implants in group W-OD compared to group N-OD (50.00 ± 14.14 Ncm and 31.5 ± 15.82 Ncm, respectively; P = .04). No significant differences were observed for the percentage of bone marrow space and connective tissue in contact with the implant surface between studied groups. Conclusions: Osteotomy preparation technique in sites with a high degree of cancellous content was found to influence the implant insertion torque for short and wide implants (5.4 × 6 mm). Implant width was found to influence the insertion torque of short implants placed with the OD technique. Schlagwörter: bone, histology, implants, osseodensification, osteotome, stability

Purpose: To evaluate the occurrence, incidence rate, and esthetic impact of facial growth in adult patients who need a single implant rehabilitation in the central incisor area to assess the influence of time on changes in the incisal level. Materials and Methods: Patients were included if they received a single implant in the maxillary central incisor site, were at least 19 years old at the time of placement, and had natural adjacent teeth. Standardized images were obtained to evaluate the presence and incidence of incisal linear changes. All rehabilitations followed the same standard of reconstruction, while always keeping the mimetics of the homologous and adjacent tooth the same to provide the same incisal level and achieve the best esthetics for all patients. Thus, at implant placement (T0), the incisal-level difference between the crown and the adjacent tooth was zero. Any modifications in the incisal levels from 1.0 mm of difference were registered. This measurement of 1.0 mm was the cutoff mark because it permits easy observation of a difference, either by the dental professional or the patient. The data obtained were analyzed and correlated statistically. Results: A total of 56 patients and 56 implants were included (age range: 23–63 years; average age: 40.79 ± 12.25 years) in this study. Incisal-level alterations between the tooth and implant were found and had an incidence rate of 19.6%. The study had an average follow-up of 10.7 ± 3.37 years. All implants evaluated had stability and healthy peri-implant tissue conditions throughout the followup period, with a 100% survival rate. There was no statistically significant prevalence of incisal-level changes between males (19%) and females (20%) (P = .238); the incidence rate was 41.7% for patients between 20 and 30 years old, 13.3% for patients between 31 and 40 years old, 23.7% for patients between 41 and 50 years old, and 6.3% in the group over 50 years old; note that there were no statistically significant differences (P = .118) among different age groups. Similarly, no statistically significant difference was observed (P = .262) comparing the number of clinical cases in each subgroup with and without change in the incisal level. Conclusions: Changes in the incisal level of maxillary anterior crowns retained by single implants in adult patients were present in 19.6% of the cases evaluated. This prevalence was not influenced by sex or age group; however, it was observed more often in dental implant cases with longer follow-ups. Schlagwörter: anterior single implant, esthetics, facial growth, incisal level

Purpose: To evaluate the extent of crestal bone loss (CBL) at 2, 12, 36, and 60 months in implants placed with the shoulder at the equicrestal level and 2 mm below the alveolar ridge. Materials and Methods: A split-mouth randomized controlled clinical trial was conducted by selecting subjects with a Kennedy Class IV partially edentulous mandible. Two implants of equal length and diameter were inserted, one equicrestal and the other subcrestal, in the lateral incisor sites. Using Rinn centering devices, intraoral periapical radiographs were taken at implant insertion (T0) and at 2 (T1), 12 (T2), 36 (T3), and 60 months (T4). Descriptive statistics and t test were used, with P ≤ .05 considered statistically significant. Twentyfive patients were recruited, with a mean age of 65 ± 9.88 years (range: 42 to 82 years), and none dropped out. A total of 50 implants were inserted, 25 at the crestal level and 25 at the subcrestal level. Results: At the 60-month follow-up, no implant or prosthetic failure was recorded. An average CBL of 0.81 ± 0.40 mm (range: 0.1 to 1.6 mm) was recorded in the crestal implant group, while the subcrestal implants had an average CBL of 0.87 ± 0.41 mm (range: 0.2 to 2 mm); however, the higher CBL in the subcrestal group was not statistically significant (P = .65). Comparing the mean CBL of both groups at the various follow-ups, greater crestal bone resorption was recorded in subcrestal implants between T0 and T1 (0.25 vs 0.1 mm) and between T1 and T2 (0.39 vs 0.23 mm), while in subsequent follow-ups, a greater and statistically significant (P = .01) CBL was recorded in equicrestal implants between T3 and T4 (0.05 vs 0.18 mm). Conclusions: Thus, over time, the extent of CBL seems to be reduced in subcrestal implants, with bone retention above the implant shoulder. Although the position of the implant shoulder relative to the crestal ridge does not affect the CBL, subcrestal placement is recommended in order to reduce the risk of exposing the rough implant surface. Schlagwörter: crestal bone loss, dental implant-abutment design, dental implant platform switching, dental radiography, microthreads, Morse taper connection, sub-bone level

Purpose: To investigate the cumulative survival rate (CSR) and marginal bone loss (MBL) of single implants immediately placed and restored with two-unit cantilevered fixed dental prostheses (FDPs) following the extraction of two adjacent mandibular incisors with a compromised periodontal condition. Materials and Methods: Patients in need of extraction and replacement of two adjacent mandibular incisors due to an advanced periodontal loss of attachment were treated consecutively. Following a flapless procedure, a single implant was placed at the time of extraction in one of the two fresh alveolar sockets and immediately restored with a screw-retained two-unit provisional FDP. The area of extraction was grafted using xenograft particulate material. The following elements were evaluated: the peri-implant soft and hard tissue condition at the last follow-up appointment, MBL at the last follow-up appointment at least 1 year after the delivery of the final prosthesis, and the final esthetic result. Results: A total of 20 patients were recruited between January 2014 and December 2019 in a single private practice. Each of them received a single implant and immediate provisional restoration with a two-unit cantilevered FDP. Patients were followed up for 22 to 94 months (average follow-up = 4 years) and none of the implants failed, resulting in a 100% CSR. The cumulative MBL—measured using the VixWin Platinum software— was 1.08 ± 0.35 mm. A lower MBL was observed in the presence of platform switching (0.63 ± 0.11 mm) compared to the absence of platform switching (1.27 ± 0.20 mm). Conclusions: The preliminary results obtained from this study suggest that patients who need to replace two adjacent periodontally compromised mandibular incisors can be treated with an immediately placed and restored single implant. Schlagwörter: immediate placement, immediate restoration, mandibular incisor, narrow implants, partial edentulism

Purpose: To evaluate multiple risk factors for peri-implant bone loss via a statistical analysis with a multivariate logistic regression model to provide recommendations for clinical treatment. Materials and Methods: This case-control study was conducted on patients who had received dental implant treatment from January 2018 to December 2021. Patients who had implants with bone loss were included in the case group, and patients who had implants with no bone loss were included in the control group. The following risk factors were evaluated: history of periodontitis, abutment connection type, implant surface type, implant diameter, implant location, implant 3D position, opposing dentition, adjacent teeth, prosthetic type, retention type, and the use of custom abutments. A multivariate logistic regression model was used to evaluate these risk factors, providing corresponding odds ratios (ORs) and 95% CIs. Results: A total of 776 implants in 479 patients were included in the analysis. The number of implants in the case group and the control group were 84 and 692, respectively. Cement-retained prostheses (OR = 2.439, 95% CI = 1.241–4.795) and non-platform-switched designs (OR = 2.055, 95% CI = 1.167–3.619) were identified as weak risk factors. Horizontal deviation (OR = 4.177, 95% CI = 2.265–7.703) was demonstrated to be a moderate risk factor. Vertical deviation (OR = 10.107, 95% CI = 5.280–19.347) and implants located in the mandibular molar region (OR = 10.427, 95% CI = 1.176–92.461) were considered high risk factors. Conclusions: Implants in the molar region, cement-retained prostheses, non-platform-switched designs, and poor 3D implant positioning were identified as significant risk factors for peri-implant bone loss. Schlagwörter: abutment design, dental implants, logistic regression, peri-implant bone loss

Purpose: To assess the feasibility and success rate of nasal or transnasal implants placed in patients who were affected by severe maxillary anterior atrophy with residual anatomical features that indicate this surgery. Materials and Methods: In this retrospective multicentric study, 52 nasal or transnasal dental implants were placed in 31 maxillary atrophic anterior sites (Cawood and Howell’s class V/VI). All implants were successful after the healing period; 27 nasal implants reached an insertional torque ≥ 50 Ncm², and the threshold value was estimated to be able to support an immediate load. Results: All 52 implants were successful, so the proportion of success was 100%, with a 97.5% one-sided CI of 88.8% to 100%. The success rate was achieved only when at least two of the following criteria were met: (1) a torque > 50 Ncm as a minimum sufficient condition to plan immediate loading; (2) after a healing period of 16 weeks, no coronal bone resorption (this condition allows for successive prosthetic finalization) observed clinically or radiographically; and (3) a possibility of carrying out a full-arch rehabilitation with minimal anterior spread. Insertion torque was < 50 Ncm in 14 patients (45%) and 50 Ncm in 17 patients (55%). Mechanical loading was delayed in the former group of patients and immediate in the latter group of patients. The proportion of torque that was < 50 Ncm was greater in men (69%) than in women (28%; P = .033). Immediate torque was not significantly affected by age. Conclusions: Although the present sample was not extremely numerically significant, it conveyed a clear and significant clinical and surgical meaning that has never been seen before in the literature: nasal or transnasal implants can be very useful in reducing the anterior cantilever and overcoming the anatomical limitations affecting conventional quad zygoma implants. Schlagwörter: anterior cantilever prostheses, pterygoid implants, severe atrophy, nasal implants, zygomatic implants

Purpose: To measure the association between dental implant failure and obesity. Materials and Methods: A retrospective cohort study was performed to investigate the association between implant failure and obesity. The time to implant failure and other covariates of interest were studied, including sex, history of periodontal disease, and smoking. A consecutive series of implant patients were studied from January 1, 2000, through September 30, 2021, in the Department of Dental Specialties at the Mayo Clinic in Rochester, Minnesota. Obesity was measured through the patient’s body mass index (BMI), which was calculated from their height and weight closest to the date of implant placement (within 12 months). They were then categorized as “not overweight or obese” (BMI ≤ 24.9), “overweight” (BMI 25.0 to 29.9), or “obese” (BMI ≥ 30). Kaplan-Meier models were compared using a log rank test to assess the associations of demographic and systemic conditions with implant failure. Survival curves and hazard ratios (HRs) were calculated at the implant level separately from BMI, sex, and smoking. Results: The sample included 6,241 patients who received 16,921 implants. The mean age was 54.43 years (SD: 17.04), and 42.7% of the patients were male. A total of 5,847 implants were placed in 2,161 patients categorized as “obese,” with 327 implants failing in 171 patients. BMI status was not found to be a risk for implant failure in the population or setting studied (HR: 0.97; 95% CI 0.82–1.15; P value = 0.44). Current smokers (P < .0001) and males (P = .015) were significantly associated with implant failure. Conclusions: Obesity was not shown to be associated with an increased risk of implant failure. Schlagwörter: body mass index, dental implant, failure, obesity, periodontitis, smoking

Purpose: To assess the alteration in keratinized mucosa (KM) dimensions during the early healing period after implant placement and the influence of the variables measured during implant surgery on KM alteration. Materials and Methods: The study participants were consecutively recruited from patients who had received implants following a nonsubmerged surgical protocol. The implant had to be placed in an extraction socket that had healed for more than 6 months without any soft or hard tissue augmentation. Keratinized mucosa width (KMW), keratinized mucosa thickness (KMT), soft tissue level (STL), and probing pocket depth (PPD) were all measured at implant placement as well as at 3 and 6 months after implant surgery. The influence of these variables measured during implant surgery on the 6-month KMW alteration was assessed. Results: A total of 66 implants in 55 patients who completed the follow-up examination after 6 months were included in this study. KMW, KMT, and STL significantly decreased at the 3- and 6-month follow-ups by 0.7 to 1.2 mm. KMW decreased by 24.6%. Mesial PPD significantly increased between the 3- and 6-month follow-ups. In the multivariate generalized estimating equations (GEE) analysis, the implant diameter negatively influenced KMW alteration at the 6-month follow-up, but the KMW at implant surgery was positively influenced at the 6-month KMW alteration follow-up. Conclusions: The KMW decreased significantly at the 3- and 6- month follow-ups after implant placement. If the initial KMW was wider, the KMW decreased more at 6 months after implant placement. Therefore, it is important to carefully monitor KMW alterations during the early healing period to ensure optimal esthetics and peri-implant tissue health. Schlagwörter: dental implants, mucous membrane, prospective studies, wound healing

Purpose: To compare the prosthetic outcomes of screw-retained monolithic zirconia (Zr) single crowns supported by either narrow-diameter (3.3 mm) or standard-diameter (4.1 mm) tissue-level titanium-zirconia (TiZr) implants in posterior sites. Materials and Methods: A total of 18 participants, each with a missing molar or premolar tooth requiring an implantsupported single crown, were randomly assigned to either the test or control group. All participants received screwretained monolithic Zr single crowns supported by single tissue-level TiZr implants. Test group participants received narrow-diameter implants (3.3 mm), whereas control group participants received standard-diameter implants (4.1 mm). A modified version of the United States Public Health Service (USPHS) criteria was used to assess the prosthetic outcome across 12 parameters after 1 year of function. Data were analyzed descriptively, and statistical analysis was performed using a statistical software (SPSS, Version 28.0; IBM) with the level of significance set at P < .05. Results: Of the 18 single crowns delivered, 16 were available for review at the 1-year follow-up, including 7 in the test group and 9 in the control group. Patient characteristics and crown site distribution were similar, with no significant differences observed between the two groups (chi-square test; P < .05). There were no crown failures, meaning a crown survival rate of 100% was achieved after 1 year. The prosthetic outcome based on USPHS criteria was comparable between the two groups with no significant differences observed (chi-square test; P < .05). There were 19 prosthetic events in total (10 in the test group and 9 in the control group), with no significant differences between the groups (chi-square test; P < .05). Loss of proximal contact was the dominant event, with a total of eight events (three in the test group and five in the control group). Patient satisfaction after 1 year was high in both treatment groups, with no significant differences detected. Conclusions: Screw-retained monolithic Zr single crowns supported by either narrow- or standard-diameter tissue-level TiZr implants in posterior sites have comparable prosthetic outcomes after 1 year. Long-term results from well-designed trials are still needed to validate the findings of the present study. Schlagwörter: monolithic zirconia single crowns, narrow-diameter implants, randomized controlled trial, USPHS criteria

Purpose: To compare the morphometric results of immediate implants with a cylindrical (conventional) or triangular neck placed in Type 1C sockets in the anterior maxilla, with 6 months of osseointegration. Materials and Methods: This prospective randomized clinical trial comprised 20 individuals randomly assigned to each group (10 triangular-neck implants and 10 cylindrical-neck implants). Consecutively, direct measurements were performed: before (T-1) and after (T0) tooth extraction, after implant placement (T1), after 1 month of submerged implant healing (T2), when placing the healing abutment (T3), after placing the definitive crown (T3c), and after 6 months of osseointegration (T4). Results: A significant difference in the buccal cortical thickness was identified between T1 and T3 (0.49 ± 0.86 mm). Although there was a significant increase in the buccal cortical thickness in both implants, this increase was greater for the triangularneck implants (0.08 ± 0.59 mm for cylindrical vs 0.90 ± 0.91 mm for triangular). It was also observed that implants placed below the buccal bone crest (≤ –1 mm) promote less vertical buccal bone loss than implants placed ≥ –1 mm, at crest level (–0.65 ± 0.52 mm vs –1.42 ± 0.86 mm, respectively). This observation needs to be further investigated in additional studies. Conclusions: The triangular-neck implants showed an increase in the cortical buccal thickness compared to the cylindrical implants. However, this increase does not fully compensate the remodeling after tooth loss. Schlagwörter: dental implant placement, dental implants, endosseous implant, esthetics, immediate dental implant placement, single tooth

Purpose: To evaluate the effect of titanium base height on torque loss of monolithic zirconia, lithium disilicate, and polymer-infiltrated ceramic hybrid abutment restorations for an offset placed implant. Materials and Methods: A total of 42 hybrid abutment restorations supported by offset implant placement (4.2-mm diameter, 10-mm length) were divided into six groups: short titanium base and zirconia (SZ), long titanium base and zirconia (LZ), short titanium base and lithium disilicate (SE), long titanium base and lithium disilicate (LE), short titanium base and polymer-infiltrated ceramic (SP), and long titanium base and polymer-infiltrated ceramic (LP). An adhesive resin cement was used to bond the restoration to the titanium base. The restoration was secured with a titanium screw, tightened to 30 Ncm using a calibrated torque meter device. The specimens were exposed to thermocycling (5,000 cycles at 5ºC to 55ºC), then cyclic loading (120,000 cycles, 50 N, 1.6 Hz), where the load was placed vertically in the mesial fossa of the restoration. The loosening torque value of the abutment screw was measured by the torque meter device, and then the torque loss and its percentage were calculated. Two-way and one-way ANOVA and post hoc Tukey tests were used for statistical data analysis (α = .05). Results: Two-way ANOVA showed significant differences in loosening torque, torque loss, and percentage of torque loss across the restorative material (P < .001), with no significant difference across the height of the titanium base (P = .213) and no significant interaction (P = .845) between the restorative material and titanium base height. Regarding the restoration type, one-way ANOVA showed a significant difference (F ratio = 15.95, P < .001) in torque loss between groups. The mean torque loss was significantly higher for monolithic zirconia than for lithium disilicate (P = .039) and polymer-infiltrated ceramic (P < .001). A significant difference (P = .013) was also found between the lithium disilicate and polymer-infiltrated ceramic. Conclusions: The restorative material had a major effect on the torque maintenance in hybrid abutment restorations supported by offset implant placement, while the titanium base abutment height had no influence on torque maintenance. Compared to lithium disilicate and polymer-infiltrated ceramic materials, monolithic zirconia induced higher torque loss when used as a hybrid abutment restoration. Schlagwörter: abutment height, ceramic, implant, titanium base, torque loss

Purpose: To examine the variables that influence the stability of secondary orthodontic anchoring miniscrews after the occurrence of initial placement failure. Materials and Methods: A total of 100 miniscrews were reinserted in 71 patients who experienced primary insertion failure. The analysis considered 15 independent variables related to systemic factors and site characteristics. The success rate and risk factors associated with reinsertion were assessed using univariate analyses (chi-square test for categorical variables and Mann-Whitney U test for continuous variables) and a correlation analysis (Spearman correlation analysis to exclude variables that might cause interference in a multivariable model). Significant parameters from the univariate analyses were then integrated into a generalized estimating equation (GEE) model. Results: The success rate of reinsertion was 66.00% (66/100), and the cancellous bone density and the patient’s age had a strong correlation with the stability of reinserted miniscrews. Conclusions: The study indicates that younger patients with miniscrews reinserted in areas with high cancellous bone density are more likely to experience instability. This finding warrants careful consideration by orthodontists when performing miniscrew reinsertion procedures. Schlagwörter: miniscrew, reinsertion, risk factors, stability

Purpose: To compare and quantify the surface changes seen in two of the most commonly used orthodontic miniscrew implants (MSIs) after their clinical use. Materials and Methods: In total, 40 MSIs (20 titanium [Ti] and 20 stainless steel) were retrieved from the maxillary arch of 20 patients (13 females and 7 males) after their intended use. The patients were 18 to 27 years old (mean age = 22.4 ± 3.83 years). As-received MSIs were used as the control. All the MSIs were analyzed under a scanning electron microscope (SEM) (Evo 18, Zeiss) for the characterization of their morphologic condition, including blunting of tip, surface defects, and corrosion. Furthermore, an energy dispersive x-ray (EDX) microanalysis was carried out to study the changes in surface characterization. Results: When captured using the SEM, the new Ti and stainless steel MSIs demonstrated a relatively smooth surface with no surface defects. However, the retrieved Ti and stainless steel implants showed a statistically significant increase in surface defects (both corrosion and cracks). The retrieved Ti MSIs (115.31 ± 24.38 μm) showed four times more blunting compared to the retrieved stainless steel MSIs (29.74 ± 8.56 μm), with the latter showing two to three times more surface corrosion. Conclusions: The clinical usage of MSIs had pronounced effects on both the Ti and stainless steel MSI alloys in terms of changes in the surface characteristics. While stainless steel MSIs are more susceptible to surface corrosion, Ti MSIs exhibit greater alterations in the form of tip blunting and cracks in the screw threads. Schlagwörter: orthodontic miniscrews, stainless steel miniscrews, titanium miniscrews, surface characterization, surface corrosion, tip blunting

Purpose: To assess whether (and to what extent) average torque readings evaluating the bone density of polyurethane foam blocks and bovine ribs are correlated with that of gray values (GVs) measured via CBCT scans, both at the site of reading and at adjacent sites where bone is expected to engage the implant threads. Materials and Methods: Average torque readings were collected on blocks and ribs via CBCT scans that were then analyzed to measure the GVs of purposedly designed regions of interest (ROIs). The ROIs were shaped as concentric hollow cylinders centered on the sites of average torque measurements. The relation between average torque and GVs was investigated through correlation analyses. Results: The correlation between average torque and GVs from blocks was strong (r = 0.94, r² = 0.89, P < .001), which was independent of the ROI size. On the bovine ribs, the correlation was weak but significant (r = 0.23, P = .029); however, it become stronger when denser bone (average torque ≥ 7 Ncm) was tested (r = 0.41, P = .008). This result was independent from the distance of the site where the average torque had been read. Loss of average torque–GV interchangeability observed on bovine ribs was likely caused by intrinsic bone characteristics, such as an abundance of bone marrow and nonmineralized tissue, possibly having a confounding effect on GV measurements, especially at lower bone densities. Conclusions: Within the limitations of the study, average torque values were found to estimate physical bone density just as well as GVs from CBCT scans. In low-density bone, the assessment of mineral bone density was also found to possibly be more informative than GVs. Results of this study suggest that the micromotor may be presently regarded as a complementary tool to CBCT assessment of bone density and quality in the clinical setting. Schlagwörter: average torque, bone quality, bone density, CBCT, gray values, implant micromotor

Purpose: To examine and compare peri-implant bone stress under the occlusal forces of 30% carbon fiber–reinforced polyetheretherketone (Cfr-PEEK), 60% Cfr-PEEK, and titanium (Ti) materials for dental implants through finite element analysis (FEA). Materials and Methods: Single-tooth implants made of 30% Cfr-PEEK, 60% Cfr-PEEK, and Ti were modeled in the maxillary anterior, maxillary posterior, and mandibular posterior regions. As a result of the applied vertical and oblique forces, von Mises stresses—including the maximum principal stress values, minimum principal stress values, and stress distributions in the implant—in the cortical bone and cancellous bone of each model were examined. Results: Overall, 30% Cfr-PEEK implants’ stress in the surrounding bone was higher than that in the Ti and 60% Cfr-PEEK implants. The 60% Cfr-PEEK material displayed a lower stress distribution on both cortical and cancellous peri-implant bone in all models. Conclusions: Ti and 60% Cfr-PEEK implants were found to distribute stresses to bone more homogeneously than the 30% Cfr-PEEK implants. Overall, oblique forces had a more destructive effect than vertical forces, and denser bone structures showed better stress distribution against incoming forces. Schlagwörter: carbon fiber–reinforced PEEK, dental implant, finite element analysis