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Background: The T-scan system has been used previously to analyse occlusion, but the quantitative analysis of occlusal contact by T-Scan system has yet to be reported., Objectives: To evaluate the reliability and validity of T-Scan system for quantitatively measuring occlusal contact area and occlusal contact number., Methods: Twenty-two individuals with normal occlusion, 11 men and 11 women, were recruited for the study. Two occlusal analysis methods, including silicone transmission analysis method (STA) and T-Scan occlusion analysis method (TSO), were used to make quantitative analysis to measure occlusal contact area (OCA) and occlusal contact number (OCN). A test-retest check was performed with an interval of 2 weeks. The values of intraclass correlation coefficients (ICC) between test-retest of each method were calculated for reliability evaluation. Pearson correlations analysis, paired t-tests, regression analysis and Bland-Altman analysis were performed for validity evaluation., Results: The ICC values of STA were greater than those of TSO for OCA while for OCN, ICC values of TSO were greater than STA. The higher OCA and OCN values were found in TSO compared with STA. Pearson's correlation coefficient indicated strong relations between TSO and STA (0.730-0.812) for OCA, while good relations between then (0.569-0.583) for OCN. Paired t-test showed a significant difference between the OCA and OCN values between TSO and STA. Bland-Altman analysis showed good agreement between OCA and OCN values of TSO and STA both in men and women. Regression analysis identified a linear correlation between OCA values obtained from these two methods., Conclusions: T-Scan method showed strong reliability for measuring OCA and OCN quantitatively. Strong correlations were found between OCA values from TSO and STA method, but the validity of TSO for measuring OCN needs to be promoted., Clinical Significance: T-Scan system demonstrates good potential in quantitative analysis of occlusion, which will expand its clinical application., (© 2024 John Wiley & Sons Ltd.)

Purpose: Reference values of occlusal characteristics are needed to interpret the data obtained using the T-Scan System. This study aimed to establish reference values for and to assess the reliability of, occlusal force distribution in the maximal intercuspal position and the occlusion time in young adults with healthy dentition., Materials and Methods: In total 178 adults with natural dentition participated in this retrospective cross-sectional study, of whom 76 performed a retest session. Several occlusal recordings were obtained from each participant using the T-Scan system while asking them to bite two or three consecutive times (multi-bite) or only once (single-bite) at the maximal intercuspal position. The lateral and anteroposterior occlusal force distribution were determined as percentages in the right and posterior teeth . Occlusion time was measured in seconds. After the occlusal force distribution and occlusion time percentiles were calculated, reliability was assessed by the intraclass correlation coefficient., Results: The 5th-95th percentiles for occlusal force distribution were 34%-67% on the right teeth and 55%-94% on the posterior teeth. The 90th percentile for multi-bite occlusion time was 0.17 s and for single-bite occlusion time was 0.27 s. The intraclass correlation coefficients for lateral occlusal force distribution, anteroposterior occlusal force distribution, multi-bite occlusion time, and single-bite occlusion time were 0.70, 0.68, 0.58, and 0.67, respectively., Conclusions: This study generated reference values for key occlusal characteristics (occlusal force distribution and occlusion time) when using the T-Scan system. These values showed moderate reliability., (© 2024 The Authors. Journal of Prosthodontics published by Wiley Periodicals LLC on behalf of American College of Prosthodontists.)

Purpose: Aim of the present study was to assess the relative distribution of occlusal forces after orthodontic treatment and during the first 3 months of the retention phase using a computerized occlusal analysis system (T-Scan, Tekscan Inc., Norwood, MA, USA)., Materials and Methods: A total of 52 patients were included in this prospective cohort study and underwent analysis of occlusal forces on the level of tooth, jaw-half, and -quadrant during a 3-month period. Furthermore, differences between three retention protocols (group I: removable appliances in both jaws; group II: fixed 3-3 lingual retainers in both jaws; group III: removable appliance in the maxilla and fixed 3-3 lingual retainer in mandible) were assessed with Wilcoxon signed-rank tests at 5%., Results: Directly after debonding, measured forces distribution were similar to published references for untreated samples. In the following, no significant difference was found between retention protocols II and III with regard to the asymmetry of the anterior occlusal forces. Both groups maintained an asymmetric force distribution in the anterior segment during the study period. There was also no difference between groups II and III in the distribution of occlusal forces for the posterior segments. Both retention concepts kept the symmetrical distribution of occlusal forces stable over the observation period. The retention concept of group I demonstrated a symmetrical distribution of occlusal forces in the anterior segment after debonding and this remained stable during the 3‑month period. In the posterior segment, no improvement of the initially asymmetric masticatory force distribution could be observed., Conclusions: All three studied retention protocols showed stability in retaining their original symmetrical or asymmetrical occlusal force distribution posteriorly/anteriorly during the 3‑month observation period. Therefore, an even distribution of occlusal forces should be the aim of the finishing phase, as no relative benefit of any single retention scheme in terms of post-debond improvement during the retention phase was seen., (© 2023. The Author(s).)

Cement mediated peri-implantitis accounts for 1.9–75% of dental implant failures associated with peri-implant diseases. This study evaluated the biological impact of dental cements on osseointegrated implants using Lewis rats. Twenty-two rats were distributed into 6 groups: negative control (NC) soft diet (SD), and hard diet (HD); positive control SD and HD (n = 3); Implant + bio-ceramic Cement (BC) SD and HD which included contralateral Sham sites (n = 5). Titanium implants were placed on either side of the maxillae and allowed to heal for 14 days. Later, both sides of experimental groups underwent a re-entry surgery to simulate clinical cementation. The right side received 0.60 mg of BC. At 14 days post cement application, maxillae were harvested for clinical, microtomographic, and histological evaluations. Clinical and microtomographic evaluations indicated evidence of extensive inflammation and circumferential bone resorption around BC implants in comparison to NC. Histology revealed cement particles surrounded by inflammatory infiltrate in the implant area accompanied by biofilm for SD groups. Both sides of BC indicated intensive bone resorption accompanied by signs of osteolysis when compared to NC. Cemented groups depicted significantly lower bone to implant contact when compared to NC. In conclusion, residual cement extravasation negatively impacted osseointegrated implants after re-entry surgeries. [ABSTRACT FROM AUTHOR]

Introduction: The phases of orthodontic treatment include Initial Leveling and aligning, space closure, finishing detailing, settling, and retention. The phase of finishing and detailing in orthodontic treatment has a crucial role in refining the occlusion and ensuring long-term stability. However, the effectiveness of orthodontic treatment is not solely assessed by the alignment of teeth and jaws but also by achieving stable occlusion posttreatment. Hence, the study aims to evaluate postorthodontic occlusion in patients who meet the set criteria of finishing and detailing compared to those who have not, using a digital occlusal analyzer. Materials and methods: The posttreatment records of 42 patients who had undergone debonding after fixed mechanotherapy were evaluated for categorizing the patients based on the inclusion criteria into Groups A and B. The occlusal parameters of the patients were evaluated at time intervals—T1 (30 min after debonding), T2 (3 months after debonding), and T3 (6 months after debonding). The occlusal parameters evaluated were—force distribution in the right and left sides and anterior–posterior force %. Results: In a comparative evaluation between Groups A and B, it was seen that occlusion time, force distribution between the right and left sides, and the anteroposterior force distribution in the anterior and the posterior aspect were higher in Group B as compared to A. Conclusion: The results of our study indicated that in patients who had met the goals of finishing and detailing, the occlusal parameters showed near-ideal values as compared to the patients who had not met the goals of finishing and detailing. Digital analysis obtained using T-Scan is essential during the process of finishing and detailing to obtain a stable and well-balanced occlusion by the end of the orthodontic treatment. [ABSTRACT FROM AUTHOR]

Background and objectives: This study analyzed and compared the distribution patterns of occlusal forces using T-Scan III before and after the hydrostatic temporary oral splint (Aqualizer Ultra) therapy in healthy subjects and subjects with temporomandibular disorders (TMDs). Materials and Methods: Fifty-one subjects were divided into groups based on anamnesis and responses to the Fonseca questionnaire. The first group, non-TMDs group (n = 19), and the second group, TMDs group (n = 32), had mild-to-severe TMDs, as identified by the Fonseca questionnaire. The non-TMDs group had an average age of 25.4 years (SD = 4.8, range 20–38) with 15 females (78.95%) and 4 males (21.05%). The TMDs group had an average age of 27.4 years (SD = 7.0, range 22–53) with 25 females (78.125%) and 7 males (21.875%). T-Scan III device was used for occlusal analysis before and after hydrostatic splint usage. Results: Significant differences were observed in the TMDs group for anterior and posterior right percentages of forces before and after hydrostatic splint usage. The analysis of force distribution per sector before and after hydrostatic splint therapy showed no significant differences in the non-TMDs group. Analysis of force distributions in the entire study population before and after hydrostatic splint therapy showed significant differences in the anterior and posterior right regions. Occlusal force increased by 32–56% in the front region and decreased in the posterior area after hydrostatic splint usage. Conclusions: Hydrostatic splint therapy is recommended as a part of full-mouth rehabilitation treatment for all patients regardless of the severity of TMDs. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Kunming Medical University / Kunming Yike Daxue Xuebao is the property of Kunming Medical Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: This review aimed to reveal the influence of implant guides on surgical accuracy with regard to supporting types, manufacturing methods and design (including fixation screws and sleeves). Methods: A literature search related to accuracy of surgical guides for dental implantation was performed in Web of Science and PubMed. Studies with in vivo or in vitro deviation data published in recent 5 years (2018–2022) were included and assessed by Newcastle–Ottawa Scale with regard to risk of bias and reliability degree of clinical studies. Accuracy-related deviation data were summarized as forest plots and normal distributions. Results: Forty-one articles were included with high degree of credibility. Data showed that implant surgery accuracy can be achieved with mean distance deviation < 2 mm (most < 1 mm) and angular deviation < 8° (most < 5°). Conclusions: Bilateral tooth-supported guides exhibited highest in vitro accuracy and similar in vivo accuracy to unilateral tooth-supported guides; mucosa-supported guides exhibit lowest in vivo accuracy, while its in vitro data showed low credibility due to mechanical complexity of living mucosa tissue. Milling exhibited higher in vivo accuracy of guides than 3d-printing, though further data support was needed. Design of fixation screws and sleeves of implant guides affected the surgical accuracy and might remain a research focus in near future. However, lack of universal evaluation standards for implantation accuracy remained a major problem in this field. The influence of implant guides on surgical accuracy revealed in this review might shed light on future development of dental implantology. [ABSTRACT FROM AUTHOR]

In this study, we developed an osteoplastic material based on collagen–fibronectin hydrogel impregnated with siRNA molecules targeting glycogen synthase kinase 3β (GSK3β), which inhibits the osteogenic differentiation of mesenchymal stem cells. The hydrogel impregnated with polyplexes containing siRNA GSK3β and polyethylenimine has been shown to have no cytotoxic effect: there was no statistically significant change in the cell's viability after 7 days of incubation in its presence compared to the control group. On days 2 and 7, an increase in the level of expression of markers of osteogenic differentiation was observed, which confirms the osteoinductive qualities of the material. It has been demonstrated that the hydrogel maintains cell adhesion. Our results obtained in vitro indicate cytocompatibility and osteoinductive properties of collagen–fibronectin hydrogel impregnated with siRNA GSK3β molecules. [ABSTRACT FROM AUTHOR]

Objectives: This study was conducted to detect the overall performance of both static and dynamic occlusion in post-orthodontic patients using quantified methods, and to ascertain the correlation between the two states of occlusion. Materials and methods: A total of 112 consecutive patients evaluated by ABO-OGS were included in this study. Based on the pre-treatment Angle's classification of the malocclusion, samples were divided into four groups. After removing orthodontic appliances, each patients underwent the American Board of Orthodontic objective grading system (ABO-OGS) and T-Scan evaluations. All the scores were compared within these groups. Statistical evaluation included reliability tests, multivariate ANOVA, and correlation analyses (p < 0.05 was considered significant). Results: The mean ABO-OGS score was satisfactory and did not differ by Angle classifications. The indices making substantial contributions to ABO-OGS were occlusal contacts, occlusal relationships, overjet, and alignment. Disocclusion time in post-orthodontic patients was longer than normal. Occlusion time, disocclusion time, and force distribution during dynamic motions were considerably influenced by static ABO-OGS measurements, especially occlusal contacts, buccolingual inclination, and alignment. Conclusion: Post-orthodontic cases that passed the static evaluation of clinicians and ABO-OGS may nevertheless be left with dental casts interference in dynamic motions. Both static and dynamic occlusion should be extensively evaluated before ending orthodontic treatment. Further research is needed on dynamic occlusal guidelines and standards. [ABSTRACT FROM AUTHOR]

Background: Although jaw asymmetry is commonly seen in skeletal Class III patients, its correlation with occlusal function and masticatory muscle activity has not been fully elucidated. Objectives: The purpose of this study was to investigate the occlusal function and masticatory muscle activity in skeletal Class III patients with various patterns of mandibular asymmetry. Methods: Forty‐two patients and 10 normal participants were examined. The patients were categorised into three groups. Groups 1 and 2 exhibited menton and ramus deviation to the same side. Menton deviation was larger than ramus deviation in Group 1, whereas Group 2 showed the inverse relation. Group 3 patients showed menton and ramus deviation in opposite directions. Occlusal contact area (OCA), relative bite force (RBF), and temporalis anterior (TA) and masseter muscle (MM) activity at maximum clenching were measured using T‐Scan Novus system and Bio‐EMG‐III. Statistical analysis was performed using the t‐test, one‐way analysis of variance with Bonferroni correction and Spearman correlation (α =.05). Results: Compared with normal participants, the patients had smaller OCA and greater asymmetry in the distribution of masticatory muscle activity. Greater ramus deviation was associated with smaller OCA in Group 1 but with larger OCA in Group 3. In Group 1, greater menton deviation was related to stronger TA activity on the non‐deviation side. In Group 2, greater ramus deviation was related to stronger MM activity on the deviation side. Conclusion: Deviation of the menton and ramus was individually related to OCA and masticatory muscle activity, and this relationship varied according to the pattern of mandibular asymmetry. [ABSTRACT FROM AUTHOR]

Digital technology is becoming increasingly popular in dentistry. The aim of this article is to demonstrate and compare the capabilities of two different digital approaches, namely, intraoral scanning and digital examination of occlusion, in the final analysis of occlusion after orthodontic treatment. The capabilities and limitations of both systems are emphasized to help clinicians determine which system to use in specific cases. Materials and methods: The study included 32 patients (15 males and 17 females) in the retention phase after orthodontic treatment. Patients were aged 15 to 28 years with a mean age of 18.62 years (±4.17), and 62.2% were aged under 18 years. At the beginning of the orthodontic treatment, 18 patients had Angle Class I and 14 had Angle Class II. Overall, 18 patients were treated without extractions and 14 with extractions, while 12 had impacted teeth. All patients wore an Essix retainer in the upper jaw and a fixed canine-to-canine retainer in the lower jaw. Intraoral scanning was performed using Trios color (3Shape, Copenhagen, Denmark, 2014), and digital occlusion imaging was performed using T-Scan Novus (Tekscan, Norwood, MA, USA, 2018). SPSS 23.0 was used to perform descriptive statistical analysis. Result and Conclusion: With the 3Shape system, the contacts are marked based on the proximity between dentitions. The T-Scan system measures the strength of the contacts, regardless of their area. Despite its many advantages, intraoral scanning is not a reliable method for recording occlusions. The results obtained are not incorrect, but they include limited parameters for analysis. The T-Scan system provides comprehensive results and allows analysis and treatment of occlusal dysfunctions. The T-Scan system can provide information on the first contact, strength of the contacts, contact distribution on each tooth, sequence of contacts, maximum bite force and maximum intercuspation, path of the lower jaw movement, and occlusion and disocclusion times as well as record videos with active sequences and distributions of the contacts. There is a good collaboration between intraoral scanning and digital occlusion determination. [ABSTRACT FROM AUTHOR]

Introduction: T-scan III is used in clinical practice for a digital assessment of occlusal force distribution and other occlusal parameters. The present study was proposed to do an assessment of occlusal contacts and forces using T-scan III in subjects with class II division II malocclusion and compare it to subjects with class I malocclusion requiring fixed orthodontic treatment. Materials and Methods: This prospective study included 70 subjects - 33 in group A (Angle's class II division II malocclusion) and 37 in group B (Angle's class I malocclusion). Occlusal analysis was done with T-scan III, and parameters like occlusal force distribution (OFD), occlusion time (OT), and disocclusion time (DT) were recorded. Statistical analysis was done with SPSS software. Independent t-test for intergroup comparisons and paired t-tests for intra group comparisons were done. Results: A Significant intergroup difference in OFD between left/right, posterior/anterior regions (P < 0.05) was noted between groups. OT and DT (left lateral excursive) were also significantly higher (P < 0.05) in group A. On intergroup comparison, the L/R bite force ratio was higher in group B males (P < 0.05) and the P/A bite force ratio was higher in group B females (P < 0.05). Conclusion: In subjects with class II division II malocclusion, anterior teeth were subjected to greater occlusal loading when compared to class I subjects and had higher occlusion and disocclusion times. [ABSTRACT FROM AUTHOR]

Purpose: Metal sleeves are commonly used in implant guides for guided surgery. Cost and sleeve specification limit the applications. This in vitro study examined the differences in the implant position deviations produced by a digitally designed surgical guide with no metal sleeve in comparison to a conventional one with a metal sleeve. Materials and Methods: The experiment was conducted in two steps for each step: n = 20 casts total, 10 casts each group; Step 1 to examine one guide from each group with ten implant placements in a dental cast, and Step 2 to examine one guide to one cast. Implant placement was performed using a guided surgical protocol. Postoperative cone‐beam computed tomography images were made and were superimposed onto the treatment‐planning images. The implant horizontal and angulation deviations from the planned position were measured and analyzed using t‐test and F‐test (p = 0.05). Results: For Step 1 and 2, respectively, implant deviations for the surgical guide with sleeve were –0.3 ±0.17 mm and 0.15 ±0.23 mm mesially, 0.60 ±1.69 mm, and –1.50 ±0.99 mm buccolingual at the apex, 0.20 ±0.47 mm and –0.60 ±0.27 mm buccolingual at the cervical, and 2.73° ±4.80° and –1.49° ±2.91° in the buccolingual angulation. For Step 1 and 2, respectively, the implant deviations for the surgical guide without sleeve were –0.17 ±0.14 mm and –0.06 ±0.07 mm mesially, 0.35 ±1.04 mm and –1.619 ±1.03 mm buccolingual at the apex, 0.10 ±0.27 mm and –0.62 ±0.27 mm buccolingual at the cervical, and 1.73° ±3.66° and –1.64° ±2.26° in the buccolingual angulation. No statistically significant differences were found in any group except for mesial deviation of the Step 2 group (F‐test, p < 0.001). Conclusions: A digitally designed surgical guide with no metal sleeve demonstrates similar accuracy but higher precision compared to a surgical guide with a metal sleeve. Metal sleeves may not be required for guided surgery. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to assess the accuracy of virtual planning of computer-guided surgery based on the actual outcomes of clinical dental implant placement. Methods: This retrospective study enrolled patients among whom implant treatment was planned using computer-guided surgery with cone beam computed tomography (CBCT). The patients who received implant according to the guide with the flapless and flapped approach were classified as group 1 and 2, respectively, and the others who could not be placed according to the guide were allocated to the drop-out group. The accuracy of implant placement was evaluated with the superimposition of CBCT. Results: We analyzed differences in the deviated distance of the entrance point and deviated angulation of the insertion of implant fixtures. With regard to the surgical approach, group 2 exhibited greater accuracy compared to group 1 in deviation distance (2.22 ± 0.88 and 3.18 ± 0.89 mm, respectively, P < 0.001) and angulation (4.27 ± 2.30 and 6.82 ± 2.71°, respectively, P = 0.001). The limitations of guided surgery were discussed while considering the findings from the drop-out group. Conclusions: Computer-guided surgery demonstrates greater accuracy in implant placement with the flapless approach. Further research should be conducted to enhance the availability of guides for cases with unfavorable residual bone conditions. [ABSTRACT FROM AUTHOR]

Background: Speaking depends on refined control of jaw opening and closing movements. The medial pterygoid muscle (MPT), involved in jaw closing, and the lateral pterygoid muscle (LPT), involved in jaw opening, are two key mandibular muscles in mastication and are likely to be recruited for controlled movements in speech. Objectives: Three hypotheses were investigated, that during speech the MPT and LPT: (1) were both active, (2) but exhibited different patterns of activity, (3) which fluctuated with the vowels and consonants in speech. Methods: Intramuscular EMG recordings were made from the right inferior head of the LPT and/or the right MPT in five participants during production of 40 target nonsense words (NWs) consisting of three syllables in the form /V1C1V2 C2ə/ (V = vowel; C = consonant; ə = unstressed, reduced vowel), spoken by each participant 10 times per NW; analysis focussed on the target syllable, C1V2. Results: Both MPT and LPT exhibited robust increases in EMG activity during utterance of most NWs, relative to rest. Peak LPT activation was time‐locked to the final part of the target consonant (C1) interval when the jaw begins opening for the target vowel (V2), whereas peak MPT activation occurred around the temporal midpoint of V2, when the jaw begins closing for C2. EMG amplitude peaks differed in magnitude between "high" vowels, i.e., for which the tongue/jaw are high (e.g., in SEEK), and "low" vowels, i.e., for which the tongue/jaw are low (e.g., in SOCK). Conclusions: These novel findings suggest a key role for the LPT and MPT in the fine control of speech production. They imply that speech may impose major synergistic demands on the activities of the MPT and the LPT, and thereby provide insights into the possible interactions between speech activities and orofacial activities (e.g. mastication) and conditions (e.g. Temporomandibular Disorders) that involve the masticatory muscles. [ABSTRACT FROM AUTHOR]

Introduction and Background: Orthodontic and orthognathic surgical treatment require quantified occlusion finish to rule out any temporomandibular disorders. Hence, the present study was proposed to analyze the occlusal efficiency in patients undergoing fixed orthodontic and combined orthodontic-orthognathic surgery using digital occlusal analysis. Methodology: A randomized multi-arm controlled trial was conducted on 55 patients divided into four groups, that is, group I: class I crowding/proclination required extraction for fixed orthodontic treatment, group II: class II div 1 required orthodontic treatment and/or myofunctional therapy, group III: skeletal class II required combined orthodontic and orthognathic surgical treatment, and group IV: skeletal class III required combined orthodontic and orthognathic surgical treatment. The pre-treatment, before debonding, and 1 year after debonding assessment of occlusion were carried out using T-Scan. The repeated analysis of variance (rANOVA) test along with post-hoc analysis was carried out for intra-group and inter-group assessments using SPSS (version 21, USA). The significance level was set at a 'P' value less than 0.05. Results: rANOVA measurement in groups I, II, and III showed a significant difference with respect to maximum bite force difference between right and left sides, anterior and posterior region, and left lateral disclusion time. However, group IV showed a significant difference with respect to maximum bite force in the anterior and posterior region as well as right and left lateral disclusion time only. Further application of the post-hoc Tukey test found a significant difference between the To value to T1 and T2 among all four groups. Conclusion: Improved bite force was found in all malocclusion groups which was gradual in improvement from pre-treatment to post-treatment and a subsequent retention phase. The study also reported the utility of digital occlusal assessment devices as reliable, repeatable, reproducible, and user-friendly in the determination of dynamic occlusion. [ABSTRACT FROM AUTHOR]

Malpositioned and broken implants are usually fully osseointegrated; hence, their removal, especially from the lower arch, can be very challenging. Implant removal techniques include reverse torque and trephination. Trephination is an invasive technique that can jeopardize vital structures, cause mandibular fatigue fractures, or lead to osteomyelitis. In this study, we aimed to assess the relationship between trephination depth and implant stability by recording implant stability quotient (ISQ) readings at varying trephination depths in vitro. Materials and methods: Forty-eight implants were inserted into dense synthetic polyurethane foam blocks as artificial bone. Primary implant stability was measured with a Penguin resonance frequency analysis (RFA) device. Implants of two designs with a diameter of 3.75 mm and a length of 13 or 8 mm were inserted. Twenty-four internal hexagon (IH) (Seven®) and twenty-four conical connection (CC) implants (C1®; MIS® Implants, Ltd., Misgav, Israel) were used. The primary implant stability was measured with the RFA device. Trephination was performed, and implant stability was recorded at depths of 0, 3, and 6 mm for the 8 mm implants and 0, 3, 6, 8, 10, and 11.5 mm for the 13 mm implants. Results: Linear regression revealed a significant relation between the trephination depth and the ISQ (F (1, 213) = 1113.192, p < 0.001, adjusted r2 = 0.839). The trephination depth significantly predicted the ISQ (β = −5.337, p < 0.001), and the ISQ decreased by −5.33 as the trephination depth increased by 1 mm. Conclusion: Implant stability reduction as measured using an RFA device during trephination may be a valuable guide to achieving safe reverse torque for implant removal. Further studies are needed to evaluate these data in clinical settings. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to analyze the 5-year occlusal change in posterior implant-supported single crowns and the association between the relative occlusal force (ROF) and peri-implant bone level. Materials and methods: Partially edentulous patients who had received implant-supported single crowns in the posterior region were included. Occlusal examinations with a computerized occlusion analysis system were conducted at 0.5, 3, 6, 12, 24, 36, 48, and 60 months after delivery of the implant-supported single crown. The ROFs of implant-supported single crowns, mesial adjacent teeth, and control natural teeth were recorded. Intraoral periapical radiographs were taken at each follow-up time to evaluate marginal bone level (MBL). Ordinary least square regression was used to analyze the association between ROF and MBL. Results: Thirty-seven posterior implant-supported single crowns in 33 participants (23.9 to 70.0 years) were followed up for 0.5 to 60 months [(42.4 ± 26.0) months]. The ROF of implant-supported single crowns increased from 2 weeks to 3 months (P < 0.01) and increased continuously between all two sequential time points from 6 to 36 months, with significant differences (P < 0.05). Then ROFs of implant-supported single crowns were significantly higher than those of control teeth at 48 and 60 months (P < 0.05). Regression analysis showed that ROF was significantly associated with MBL with a coefficient of 0.008 (P < 0.05). Conclusion: The ROFs of posterior implant-supported single crown have significant change during 5 years' follow-up. The association between ROF and MBL has limited clinical significance. Trial registration: Chinese Clinical Trial Registry: ChiCTR-ROC-17012240. Clinical relevance: The occlusion of implant-supported single crowns should be carefully monitored during follow-up examinations, and occlusal adjustment should be considered to prevent overloading. [ABSTRACT FROM AUTHOR]