Ridge Width Research Articles

Alveolar Bone Reconstruction Simultaneous to Implant Removal due to Advanced Peri-Implantitis Defects: A Proof of Concept.

To evaluate the safety and effectiveness of alveolar bone reconstruction simultaneous to implant removal due to peri-implantitis. Partial or fully dentulous patients subjected to implant removal due to advanced peri-implantitis (≥ 50% of bone loss) lesions and seeking to have the failed implant replaced for esthetic or functional reasons were consecutively included. Guided bone regeneration was performed by means of a mixture of xenograft and autogenous bone and a ribose cross-linked barrier membrane. Re-entry for implant placement was performed at 4-month follow-up. Overall, six radiographic variables were assessed before (T0) and after (T1) alveolar bone reconstruction at four levels in ridge width (RW) and height (RH). Peri-implant conditions were evaluated at latest follow-up. Simple and multiple binary logistic regression models were calculated using generalized estimation equations to evaluate the effect of baseline upon reconstructive outcomes. In total, 20 patients (nimplant = 39) met the inclusion criteria. Alveolar RW and RH were augmented from T0 to T1 at all levels. All implants achieved primary stability. Only ~13% were subjected to ancillary bone regeneration simultaneous to implant placement. After a mean follow-up period after loading of ~2.2 years, ~70% implants demonstrated peri-implant health, while mucositis was diagnosed in the remaining implants. The performance of alveolar bone reconstruction in residual partially contained defects simultaneous to implant removal due to peri-implantitis lesions demonstrates being safe and effective for implant site development.

Effect of Local Zoledronic Acid Application in Alveolar Bone Healing: An Experimental Study.

This experimental study aimed to assess the three-dimensional and histological changes of the alveolar socket with local application of ZA. Nine male New Zealand white rabbits were randomly allocated into 4-, 8-, and 12-week groups after the extraction of 4 incisor teeth. The upper and lower right sockets were filled with ZA + collagen sponge (ZA-CS group), while the left sockets were filled with collagen sponge alone (CS group) postoperatively. At 4, 8, and 12 weeks (T1, T2, and T3) after the extraction, radiographic and histomorphometric evaluations were conducted for both groups. The increase in alveolar bone density of the ZA-CS group at T2 and T3 was significantly higher than the CS group (P＜0.01). Three-dimensional evaluations demonstrated no statistically significant differences in ridge height and width between the 2 groups at T2 and T3. On histological evaluation, the ZA-CS group included significantly fewer TRAP-positive cells than the CS group at T1 (P＜0.05). In ALP staining, all cases in both groups were classified as positive at each time point. Masson trichrome staining showed significantly higher mean red collagen volume fraction in the ZA-CS group (76.09%, 79.64%) than in the CS group (66.17%, 69.22%) at T2 and T3, respectively (P＜0.05 and ＜0.01). Although local ZA application with collagen sponge did not reduce alveolar ridge contraction, it improved the bone density and maturity of newly formed bone after tooth extraction.

Does Injectable Platelet-Rich Fibrin Combined With Autogenous Demineralized Dentine Enhance Alveolar Ridge Preservation? A Randomized Controlled Trial.

The present trial evaluated the first-time application of autogenous demineralized dentin graft with injectable platelet-rich fibrin (ADDG + i-PRF) versus autogenous demineralized dentin graft (ADDG), in alveolar ridge preservation (ARP) in the maxillary aesthetic zone. Twenty-two maxillary (n = 22) non-molar teeth indicated for extraction were randomized into two groups (n = 11/group). Extracted teeth were prepared into ADDG, implanted into extraction sockets with or without i-PRF amalgamation and covered by collagen sponge. Cone-beam computed tomography scans at baseline and 6 months were compared to assess ridge-dimensional changes. Keratinized tissue width, patient satisfaction, pain score and chair time were recorded. In the course of dental implant placements at 6 months, bone core biopsies of engrafted sites were obtained and analysed histomorphometrically. Reduction in ridge width was 1.71 ± 1.08 and 1.8 ± 1.35 mm, while reduction in ridge height was 1.11 ± 0.76 and 1.8 ± 0.96 mm for ADDG + i-PRF and ADDG, respectively (p > 0.05). Significant differences in keratinized tissue width reduction were notable between ADDG + i-PRF and ADDG (0.12 ± 0.34 and 0.58 ± 0.34 mm respectively; p = 0.008). Postoperative pain scores were significantly lower in ADDG + i-PRF (p = 0.012). All patients in the two groups were satisfied with no differences in chair time (p > 0.05). No differences in total percentage area of newly formed bone, soft tissue or graft particles were observed between the groups (p > 0.05). ADDG alone or in combination with i-PRF yields similar results regarding ARP clinically, quality of the formed osseous tissues, as well as patients' satisfaction. Yet, the addition of i-PRF to ADDG tends to preserve the keratinized tissue and lessen postoperative pain.

Soft Tissue Contours at Pontic Sites With or Without Soft Tissue Grafting-A 15-Year Follow-Up of a Controlled Clinical Study.

To report on soft tissue contour changes at pontic sites with or without soft tissue grafting over an observation period of 15 years. Fourteen patients received a fixed dental prosthesis (FDP) in the posterior zone in a controlled clinical study and were available at the 15-year follow-up. Eight patients received a subepithelial connective tissue graft in the pontic area (test) while six received the FDP without soft tissue grafting (control). Impressions were taken after FDP cementation and at 15 years. Casts were digitized and a profilometric analysis was performed (mean distance) and the pontic height (PH) and ridge width (RW) were analyzed at the mid-buccal area. A descriptive analysis and Wilcoxon-Mann-Whitney test was performed (level of significance: 5%). Profilometric changes (mean distance) from baseline to 15 years amounted to -0.68 mm (test) and to -0.33 mm (control) (p = 0.208), 95% CI for group difference (0.290; -0.750). PH measured -0.47 mm (test) and 0.0 mm (control) (p = 0.079) and RW amounted to -1.05 mm (test) and -0.38 mm (control) (p = 0.138). Remodeling of the soft tissue contour at pontic sites of FDPs was evident in both groups, but slightly more accentuated following soft tissue grafting. This study is the first to report on soft tissue changes at pontic sites over more than 10 years. It investigates whether tissue contour changes with and without soft tissue grafting before the insertion of FDPs. Remodeling of the soft tissue contour at pontic sites was observed over 15 years, with more pronounced changes when soft tissues were augmented with SCTGs before FDP insertion. The volume loss at the augmented site must be considered in relation to the overall tissue changes over long periods. Connective tissue grafts reliably improve shape and esthetics around the pontic unit. Further long-term studies with more patients are needed to evaluate the initial gains and long-term performance of these augmentations.

Investigating mechanoreceptor variability and morphometric proxies in Rhesus Macaques: Implications for primate precision touch studies.

The origin of primates has long been associated with an increased emphasis on manual grasping and touch. Precision touch, facilitated by specialized mechanoreceptors in glabrous skin, provides critical sensory feedback for grasping-related tasks and perception of ecologically-relevant stimuli. Despite its importance, studies of mechanoreceptors in primate hands are limited, in part due to challenges of sample availability and histological methods. Dermatoglyphs have been proposed as alternative proxies of mechanoreceptor density. We investigated the relationships between mechanoreceptors (Meissner and Pacinian corpuscles), dermatoglyphs, and demography in the apical finger pads of 15 juvenile to adult rhesus macaques (Macaca mulatta) from a free-ranging population at Cayo Santiago Primate Field Station (Puerto Rico). Our results indicate substantial interindividual variation in mechanoreceptor density (Meissner corpuscles: 11.9-43.3 corpuscles/mm2; Pacinian corpuscles: 0-4.5 corpuscles/mm2). While sex and digit were generally not associated with variation, there was strong evidence of a developmental effect. Specifically, apical pad length, Meissner corpuscle size, and Pacinian corpuscle depth increased while mechanoreceptor densities decreased throughout juvenescence, suggesting that primate mechanoreceptors change as fingers grow during adolescence and then stabilize at physical maturity. We also found Meissner corpuscle density was significantly associated with dermatoglyph ridge width and spacing, such that density predicted by a dermatoglyph model was strongly correlated with observed values. Dermatoglyphs thus offer a useful proxy of relative Meissner corpuscle density in primates, which opens exciting avenues of noninvasive research. Finally, our results underscore the importance of considering demographic factors and methodology in comparative studies of primate touch.

Demineralized, Freeze-Dried Allogeneic Bone Blocks With Suture Fixation Technique for Reconstruction of Maxillary Alveolar Bone Deficiency: A Case Series.

This study aims to evaluate the clinical outcomes of using demineralized, freeze-dried allogeneic bone blocks (DFDABB) combined with the periosteal vertical mattress suture (PVMS) technique for the reconstruction of severe horizontal alveolar bone deficiencies in the maxilla. In continuous horizontal maxillary defects cases, bone augmentation was performed using DFDABB and deproteinized bovine bone matrix (DBBM) filling the interstice. Subsequently, a resorbable collagen membrane was carefully placed over the graft surface, and both the membrane and bone graft were firmly secured using the PVMS technique. Linear changes were assessed through superimposed cone-beam computerized tomography scans obtained before the operation and after a healing period of 6-10 months. A total of 7 female patients with 10 bone blocks and 13 implants were included in this study. One of the wounds was slightly ruptured postoperatively without infection, and all implants showed successful osseointegration. The average alveolar ridge width at a point 5 mm below the crest was 4.52 ± 2.03 mm before bone graft and 9.79 ± 1.57 mm after implantation with an average increase of 5.26 ± 1.97 mm. Similarly, at a point 10 mm below the crest, the pregraft alveolar ridge width measured 7.23 ± 3.60 mm, and postimplantation, it expanded to 11.81 ± 2.90 mm, showing an average gain of 4.58 ± 2.01 mm. This case series demonstrates the successful application of DFDABB combined with the PVMS technique to achieve adequate bone width for implantation at severe continuous horizontal bone deficiency of the maxilla. DFDABB with the PVMS technique resulted in superior horizontal bone gain during maxillary bone augmentation with horizontal continuity deficiency. However, further studies are necessary to validate these findings.

Rotor proliferation promotes high-brightness AIE of iridium emitter accomplishing high-contrast luminous imaging of latent fingerprints to level 3 details

Luminous imaging of latent fingerprints (LFPs) necessitates the possession of high-brightness aggregation-state luminescence by developers to ensure sufficient imaging contrast and resolution. A novel strategy involving incremental rotor modification is presented for AIE activation of the iridium developer. The rotor proliferation prominently improves the rotational activity of groups and facilitates high-efficiency RIM, thereby prompting the AIE activation of iridium developer with high luminous efficiency. Subsequently, a prompt, high-contrast, and robust LFP imaging protocol is developed utilizing the high-brightness AIE-active iridium developer. This innovative protocol realizes the luminous imaging and quantification of microscopic features in fingerprint ridges and furrows, including ridge widths, edge morphology of ridges, included angles, pores, and pore pitches with exceptional imaging contrast and refined detail resolution. Moreover, it allows for accurate identification of individual traits across diverse substrates without any pre-/post-processing to LFPs. The high-brightness AIE-active iridium developer provides outstanding aging resistance to developed fingerprints, thereby strongly supporting the acquisition, transfer, and preservation of fingerprint evidence. The luminous imaging protocol of LFPs based on high-brightness AIE exhibits robust adaptability to actual scenes and offers a premium scheme for facilitating forensic investigation.

Design and Experiment of an Independent Leg-Type Chassis Vehicle Attitude Adjustment System

In response to the current low work efficiency of soil ridge-working machinery, as well as its poor stability, passability, and adaptability, this paper designs an independent leg-type working platform that can autonomously adjust its vehicle attitude through LiDAR scanning in a soil ridge-working environment. The platform, in terms of its mechanism and structural design, adopts dual parallelogram mechanisms, dual lead screw mechanisms, and independent column leg mechanisms, with a maximum adjustable ground clearance of 107 mm and a maximum wheelbase adjustment of 150 mm. A gyroscope is mounted at the center of the platform for attitude adjustment, ensuring the accurate data collection of the ultrasonic ranging module. Moreover, the platform adopts an adaptive adjustment method based on vehicle attitude and soil ridge shape parameters, obtaining soil ridge parameters through LiDAR and combining ultrasonic ranging module data with stepper motor pulse signals to obtain the absolute vehicle attitude parameters, using first and second linear regression methods to adjust the vehicle attitude and other working parameters. A prototype was also created, and the test data from the soil obtained through experiments show that, after leveling with the gyroscope leveling algorithm, the average value of the pitch angle is up to 0.6154°, and the average value of the roll angle is up to 0.9989°, with the maximum variance of the pitch angle being 0.0474° and the maximum variance of the tilt angle being 0.1320°. After the ultrasonic ranging module data are filtered by the Kalman filter, the maximum variance is 0.0304, and after applying the final fusion algorithm, the maximum variance is only 0.0085. The LiDAR measurement width value deviates from the actual width value by no more than 1.0 cm, and the LiDAR measurement height value deviates from the actual height value by no more than 1.0 cm. The platform’s actual adjusted width deviates from the actual soil ridge width by no more than 2.0 cm, and the platform’s actual adjusted height deviates from the actual soil ridge height by no more than 1.2 cm. This platform can improve the passability, adaptability, and stability of agricultural machinery in soil ridge work and provide technical references for subsequent related research.

Effectiveness of using implant fixture as a ridge expander.

Adequate bone thickness around dental implants is vital for their stability and to reduce resorption. This study evaluated the ability of implant fixtures to serve as ridge expanders by measuring width changes pre- and post-implantation. Measurements including initial alveolar bone width, post-osteotomy width, post-expansion width, and buccal bone thickness were recorded for patients undergoing implant placement. Bone quality was assessed using established criteria. Of the 102 subjects (52% male, 48% female), significant ridge width increases at 0mm and 2mm levels were noted (p < 0.05). Larger implant diameters resulted in greater ridge expansion. Absence of prior augmentation was linked to higher bone quality (B = -1.684, p = 0.001), explaining 15% of bone quality variance. Ridge expansion effects also correlated with the site, implant diameter, and design. Dental implant fixtures can effectively expand the ridge, with expansion influenced by implant diameter, anatomical location, prior augmentation, and implant design. These factors must be considered for tailored treatment planning in implant dentistry. This study's clinical relevance lies in its exploration of the potential benefits of dental implant fixtures can effectively to expand the ridge taking into consideration implant diameter, anatomical location, prior augmentation, and implant design.

Lateral Alveolar Ridge Augmentation with Autogenous Tooth Roots and Staged Implant Placement-5-Year Follow-Up Case Series.

Background/Objectives: Alveolar bone augmentation before implant placement is a safe and effective treatment option for the reconstruction of a deficient alveolar ridge. According to recent research, permanent teeth have been used as bone graft materials, with studies confirming their clinical and histological results. This study aimed to evaluate the efficacy of alveolar ridge augmentation with autogenous tooth roots and staged implant placement, and peri-implant tissue stability in augmented sites. Methods: A total of 20 augmentations with autogenous tooth roots on mandibular alveolar ridges in 15 patients were performed. After 6 months, the ridge width (RWa) and ridge width gain (RWg) were measured. Titanium dental implants were placed in grafted sites and loaded 10 weeks after placement. Clinical parameters (bleeding on probing-BOP; probing depth-PD; mucosal recession-MR; and clinical attachment level-CAL) were assessed 2 months (T1), 3 years (T2), and 5 years (T3) after implant loading. Results: The mean RWa was 6.71 ± 0.74 mm, and the RWg was 3.15 ± 0.54 mm, respectively. No statistically significant differences were observed for clinical parameters (BOP, PD, MR, and CAL) among different time points (p > 0.05). Conclusions: Autogenous tooth roots represent a viable solution for alveolar ridge augmentation and implant placement, providing a stable environment for peri implant tissues.

Local delivery of pamidronate with collagen matrix mitigates buccal bone resorption following immediate implant placement - An experimental invivo study.

The aim of this experimental invivo pilot study was to evaluate the effect of the local delivery of pamidronate within a collagen membrane on the changes in the buccal soft and hard tissue dimensions at the time of immediate implant placement and whether this effect was influenced by the placement of bone substitutes. In six beagle dogs, the distal roots of the third and fourth premolars were extracted, and immediate implants were placed. Treatment groups were randomly allocated to each socket: (i) covering the buccal bone with pamidronate-soaked collagen membrane (BP group), (ii) filling the gap defect with synthetic bone substitute (BS group), (iii) filling the gap defect with synthetic bone substitute and covering the buccal bone with pamidronate soaked collagen membrane (BP/BS group), (iv) no treatment (control group). Intraoral scanning was performed immediately after the surgery and at 20 weeks. Histomorphometric and micro-computed tomography (CT) outcomes were evaluated at 20 weeks. The micro CT analysis demonstrated that the BP group showed no apparent difference in vertical bone level with residual mesial root area, while control group showed significant buccal bone resorption at the implant site. The histomorphometric analysis demonstrated that the vertical bone level of buccal plate was significantly differed between the BP and control group (0.34 ± 0.93 and 1.27 ± 0.56 mm, respectively; p = .041). There was no statistically significant difference in the horizontal ridge width (HRW 1, 2, 3) among the groups. Also, the thickness, height and buccal contours of the soft tissue did not reveal significant changes among the groups. The local delivery of pamidronate to the outer surface of the buccal wall at the time of immediate implant placement effectively limits buccal bone resorption. The results from the present investigation should be interpreted with caution, as well as its clinical translatability. Further investigation is needed to understand the pamidronate binding and releasing kinetic, as well as the ideal carrier of this drug for its topical application.

Investigation of pollen morphology and viability of sweet and sour cherry genotypes by multivariate analysis.

The aim of this study was to examine the dimensions and surface morphology of pollen grains of some sweet and sour cherry genotypes through scanning electron microscopy (SEM) as an additional alternative identification tool. In vitro pollen germination and pollen tube length as indicators of their viability were determined as well. Observations were carried on 10 sweet cherry (Prunus avium L.) and 7 sour cherry (Prunus cerasus L.) genotypes. All genotypes had prolate, tricolpate pollen grains, and striate exine ornamentation, with more parallel longitudinal ridges. Significant differences among genotypes within species and between species were found for most pollen grain characteristics and exine ornamentation. In both sweet and sour cherry the largest variability was recorded for colpus length (CV = 15.0% and 12.9%, respectively). For sweet cherry genotypes, in vitro pollen germination and pollen tube length ranged between 1.4% to 51.5% and 360.4 to 669.3 μm respectively, while for sour cherries they ranged from 15.5% to 37.0% and 96.3 to 960.2 μm, respectively. The results of the correlation analysis showed that in vitro pollen germination correlated positively with pollen length/pollen width (L/W) ratio (r = .640) and furrow width (r = .588), and negatively with the number of ridges (r = -.517), while pollen tube length was not significantly correlated with any of the studied characteristics. Principal component analysis (PCA) revealed that pollen length, pollen width, L/W ratio, colpus length, mesocolpium width, and ridge width are relevant tools to discriminate among the studied genotypes. The measurements made on pollen grains did not reveal individually big differences, but when all features were considered together, the pollen of each genotype exhibited a unique pattern. The distribution on the scatter plot showed considerable variation among sweet and sour cherry genotypes based on pollen morphological characteristics, which led to their distribution into two separate groups. This demonstrates the ability to distinguish cherry species based on pollen morphological characteristics determined by SEM. To improve discriminative ability for genotypes within species combination between pollen ultrastructural analysis, morphological and molecular markers is desirable, in subsequent work. RESEARCH HIGHLIGHTS: Significant differences in pollen characteristics between sweet and sour cherry. Significance of pollen morphology in taxonomic differentiation. Significance of SEM studies for the taxonomic identification.

Evaluation and comparison of autologous particulate dentin with demineralized freeze dried bone allograft in ridge preservation procedures - a prospective clinical study.

To compare effectiveness of Autologous Particulate Dentin (APD) with Demineralized Freeze-Dried Bone Allograft (DFDBA) in ridge preservation, using radiographic and clinical parameters. Thirty subjects with indication of mandibular posterior teeth extraction were randomly assigned to either test or control group. After atraumatic extraction, ridge preservation was performed using APD or DFDBA mixed with i-PRF in test and control groups respectively. Both groups had sockets sealed with A-PRF membrane. Clinical parameters (plaque, gingival and healing indices) and radiographic parameters (vertical ridge height, horizontal ridge width) were assessed at baseline and 6 months using CBCT. Statistical analysis was performed using an independent t-test to compare clinical and radiographic parameters between the groups. Both groups had significant decreases in ridge dimensions over 6 months (p < 0.001). The test group showed less reduction in ridge dimensions than control group at 6 months (p < 0.001). Mean change in vertical height was not significant (1.37 ± 1.32, 1.7311 ± 0.563), but in horizontal ridge width (1.3120 ± 1.13, 1.8093 ± 1.16) was significantly different between test and control groups respectively. There was no statistical difference in clinical parameters between the groups at 6 months (p > 0.001). APD grafts resulted in significant improvements in radiographic parameters, specifically in vertical ridge height and horizontal ridge width, compared to DFDBA group. Autologous particulate dentin is a promising, versatile substitute for regenerative procedures. While more research on its long-term efficacy and application is needed, current evidence suggests it could significantly improve patient care and outcomes.

Study on 1550 nm Human Eye-Safe High-Power Tunnel Junction Quantum Well Laser.

Falling within the safe bands for human eyes, 1550 nm semiconductor lasers have a wide range of applications in the fields of LIDAR, fast-ranging long-distance optical communication, and gas sensing. The 1550 nm human eye-safe high-power tunnel junction quantum well laser developed in this paper uses three quantum well structures connected by two tunnel junctions as the active region; photolithography and etching were performed to form two trenches perpendicular to the direction of the epitaxial layer growth with a depth exceeding the tunnel junction, and the trenches were finally filled with oxides to reduce the extension current. Finally, a 1550 nm InGaAlAs quantum well laser with a pulsed peak power of 31 W at 30 A (10 KHz, 100 ns) was realized for a single-emitter laser device with an injection strip width of 190 μm, a ridge width of 300 μm, and a cavity length of 2 mm, with a final slope efficiency of 1.03 W/A, and with a horizontal divergence angle of about 13° and a vertical divergence angle of no more than 30°. The device has good slope efficiency, and this 100 ns pulse width can be effectively applied in the fields of fog-transparent imaging sensors and fast headroom ranging radar areas.

Radiographic changes after alveolar ridge preservation using autogenous raw tooth particles versus xenograft: A prospective controlled clinical trial.

The use of extracted teeth has been introduced as an option for bone grafting. However, the current method requires special machines and solutions, posing significant time and cost. The aim of this study was to evaluate the clinical performance of autogenous raw tooth particles (RTP), a grafting material made from a ground tooth using basic equipment, for alveolar ridge preservation. Twenty-three patients (12 study/11 control), having 14 and 13 sites were included for the study and control groups (commercially available xenograft), respectively. Radiographic measurements were taken at the baseline and the 4-month follow-up appointment. Furthermore, a questionnaire survey concerning the general preference of the type of graft to receive (if needed), before and after knowing the price, was distributed at the completion of the procedure for patients to answer. Alveolar ridge width change was -1.03 ± 0.64 and -0.84 ± 0.35 for the study and the control groups, respectively. Regarding the height, the study group showed a buccal and lingual change of -0.66 ± 0.48 and -0.78 ± 0.81, respectively, while this was -0.78 ± 0.56 and -0.9 ± 0.41 for the xenograft group. There was no statistically significant difference between the groups. Patients preferred the raw tooth particles over other grafting materials (p = .01). No core biopsies were taken to evaluate bone formation, which should be done in future studies. Within its limitations, the current study demonstrated that RTP graft could be an alternative graft for bone augmentation, offering a new cost-effective option for clinicians when available.

Novel Technique for Alveolar Ridge Expansion: A Comparative Clinical Study

Background: Piezosurgery improved the split approach by making it safer, easier, and less prone to complications when treating extremely atrophic crests. Densah drills, with their unique design, expand the ridge by densifying bone in a reverse, non-cutting mode. Objective: To assess the effectiveness of sagittal piezosurgery, which involves cutting bone to the full implant depth and then expanding it using osseodensification drills. We use this technique to expand narrow alveolar bones and simultaneously place dental implants in the maxillary and mandibular arches. Methods: Fourteen patients received 31 dental implants. The maxillary arch received 19, and the mandible received 12 dental implants. This study will include patients who have narrow alveolar bone ridges (2.5–4 mm). After marking the implant sites with a pilot drill, we used a piezoelectric surgery tip to cut the alveolar crest to the depth of the planned dental implant. We then sequentially used Versah Drills, accompanied by extensive irrigation using cooled, sterile normal saline, and finally inserted the implant into the subcrestal level. Results: This study revealed a significant difference in alveolar ridge width immediately after the procedure, and the significant change in the mandible was slightly higher than that in the maxillary arch. However, all implants in both jaws achieved successful osseointegration. Conclusions: The alveolar ridge width changed a lot more in the mandible than in the maxillary arch after the procedure. These two strategies work well together to properly and simply expand severely atrophied alveolar ridges without affecting bone healing or the osseointegration process.

Study on ultra-precision diamond cutting of polymers: Factors affecting dimensional accuracy and material removal mechanism

Polymers with surface microstructure have promising prospects for applications in the domains of aerospace, integrated circuits, and optical engineering. Ultra-precision cutting has unique advantages in the preparation of microstructure with high precision and complex shape. However, the inherent characteristics of polymers such as high elasticity, strong toughness, and poor thermal conductivity bring ultra-precision cutting a great challenge. In this study, the rectangular groove microstructures on polymers were fabricated by ultra-precision diamond cutting, and the influence of matrix material, feedrate and cutting depth on cutting performance and dimensional accuracy was quantitatively evaluated. The results indicate that the polyimide (PI) exhibits a good machinability compared with polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE). In addition, the feedrate have a negligible influence on the morphologies and dimensional accuracy of groove structure, while the groove width decreases and the ridge width increases as the cutting depth increases from 10 μm to 100 μm. The groove structure has the best dimensional accuracy when the cutting depth is 10 μm. Furthermore, the material removal mechanism of PI was discussed detailedly based on the results of numerical simulation and experiment.

Horizontal ridge augmentation through ridge expansion via osseodensification, guided bone regeneration and ridge‑split: Systematic review and meta‑analysis of clinical trials.

The aim of the present systematic review was to compare three ridge augmentation procedures in order to assist clinicians in finding the ideal surgical method relative to the horizontal bone gain needed and the width of the alveolar ridge available. An electronic and hand literature search was performed in the online databases PubMed-Medline, Cochrane Central Register of Controlled Trials, EMBASE, Cochrane Oral Health Group Trials Register and Web of Science, and various specialized journals, between January 2017 and December 2022. The included studies were evaluated using the Methodological Index for Non-randomized Studies score and Cochrane's RoB tool. The primary variable studied in the meta-analysis was the final bone gain. The implant survival rate and initial ridge width were the secondary variables. Then four studies on ridge expansion via osseodensification (OD), seven on guided bone regeneration (GBR) and seven on the ridge-split technique (RS) were included in the review; 17 out of 18 were selected for meta-analysis. The mean horizontal bone gain for OD was 2.151 mm [1.327-2.975 mm; 95% confidence interval (CI)], for GBR was 4.036 mm (3.351-4.772 mm 95%CI) and for RS was 3.661 mm (2.991-4.399 mm 95%CI). The results were statistically significant (P=0.002). GBR reported the most bone gain horizontally, followed closely by RS and then OD. OD is a recent technique that should be taken into account when discussing the protocols of horizontally atrophied ridge rehabilitation.

Alveolar ridge bone changes in patients treated with the split-crest technique with simultaneous implant placement: Aretrospective longitudinal observational study.

To investigate long-term alveolar ridge bone changes in patients treated with the split-crest technique (SCT) with simultaneous implant placement. Alveolar ridge width (ARW) was measured with a caliper immediately before (ARW1) and after SCT (ARW2) with a caliper. Existing CBCT scans taken at least 5 years postoperatively were used to assess the healed ARW (ARWF), buccal bone thickness (BBT), and lingual/palatal bone thickness (L/PBT) at 0, 3, and 5 mm apically from implant platform level (IPL). The distance between IPL and buccal bone crest (IPL-BBC) was also measured. Findings were compared with Wilcoxon and Student's t tests (p < .05). Records of thirty patients with 85 implants were included. Eleven patients (31 implants) presented CBCT scans taken in two separate occasions, resulting in 116 measurements. Tomographic follow-up ranged from 5 to 18 years (11.5 ± 4.18 years). Mean ARW increased from 3.2 ± 0.6 to 6.6 ± 0.48 mm after SCT, but significantly reduced overtime to 4.46 ± 0.83 mm (ARWF) (p < .0001). Mean BBT was 0.5 ± 0.9, 1.3 ± 0.9, and 2.0 ± 1.2 mm, while mean L/PBT was 0.9 ± 0.7, 1.6 ± 0.9, and 2.1 ± 1.0 mm at 0, 3, and 5 mm from IPL, respectively. IPL-BBC distance varied up to 8.7 mm (1.4 ± 2.0 mm), with 56/116 measurements (51/85 implants) showing IPL-BBC = 0 mm. Although SCT with simultaneous implant placement can predictably increase ARW postoperatively, ARW tended to significantly reduce over time, due to reductions in BBT and L/PBT, especially coronally. Nonetheless, 60% of the implants still presented some buccal bone at IPL.

Optimization of Heat-Dissipation Structure of High-Power Diode Laser in Space Environments.

The high-power laser diode (HPLD) has witnessed increasing application in space, as the aerospace industry is developing rapidly. To cope with the space environment, optimizing the heat-dissipation structure and improving the heat-dissipation ability via heat conduction have become key to researching the thermal reliability of the HPLD in space environments. Based on a theoretical analysis of the HPLD, a simulation model of the HPLD was constructed for numerical simulation, and it was found that the maximum temperature and thermal resistance of lasers were efficaciously decreased by changing the packaging position of laser bars. The packaging position of the bars and the cutting angle of the microchannel heat sink (MCHS) were determined based on the light-emitting angle of the light-emitting unit and the internal structure of the MCHS. The internal structure of the MCHS was optimized through a single-factor experiment, an orthogonal experiment, and the combination of neural networks and genetic algorithms (GAs), using three key structural parameters, namely the MCHS ridge width, W1, the channel width, W2, and the channel length, L1. After optimization, the performance of the MCHS was obviously improved. Finally, an analysis was carried out on the applicability of the optimized MCHS to bars with a higher power.