Ridge Width Research Articles

Quasi-Guided Modes Supported by a Composite Grating Structure with Alternating Element Widths

The efficiency of many optical processes is significantly dependent on the magnitude of the electric field. In this context, many artificially made resonating structures have been investigated to enhance light–matter interactions and facilitate the creation of practical applications. While metal–based terahertz metamaterials have been extensively investigated for this purpose, their performances are mainly limited by the poor confinement of terahertz waves on metal surfaces, exhibiting low resonance quality factors. In this work, we propose and investigate a simple yet novel scheme of enhancing wave–matter interactions in the terahertz region by exploiting the phenomenon of quasi–guided modes. The quasi-guided modes with ultra–high quality factors and huge local field enhancement can be achieved by manipulating the guided modes supported by a slab waveguide. The guided modes with the dispersion lines below the light line have infinite Q factors and can not be accessed from external space. By using a new type of composite grating composed of two ridge grating arrays with alternating ridge widths, the grating period is doubled, leading to a folding of the first Brillouin Zone and the flipping of the dispersion lines to be above the light line. Then, the guided modes will be transitioned into new quasi–guided modes with the possibility of free–space excitation while the Q factors are determined by the level of period–doubling perturbation. The presented results of realizing quasi–guided modes can be extended to other structures, providing a novel means of manipulating light–matter interactions.

Extreme temperature operation for broad bandwidth quantum-dot based superluminescent diodes

The high-temperature resilience of quantum-dot (QD) laser materials is exploited to realize a broad spectral bandwidth emitter in the near infrared. For an InAs/GaAs-based QD-superluminescent light emitting diode (SLEDs), we introduced a 2000 μm long, 5 μm width ridge waveguide that is tilted by 7° and composed of eight multi-sections. With increased temperature operation over 160 °C, the spectral bandwidth is dramatically increased by thermally excited carrier transition in ES1 and ES2. Additionally, the positive net-modal gain is demonstrated at the high operating temperatures, and this is exploited in the QD-SLEDs operating at 180 °C, which exhibit a −3 dB linewidth of 270 nm and a power of 0.34 mW. The simplicity of this approach, utilizing heat alone, is contrasted with other approaches for the extremely broad spectral bandwidth emitter.

Numerical Investigation on Hydrodynamic Processes of Extreme Wave Groups on Fringing Reef

The low-lying reef islands distributed in the tropical and subtropical coastal regions are highly vulnerable to the devastating damages of surges and waves during the severe weather events. Over the past two decades, extreme waves have caused tremendous loss and damages to the tropical and subtropical coastal regions. Previous research has focused on the wave hydrodynamics of tsunami waves, as well as regular and irregular waves on the fringing reefs. The complex wave hydrodynamics of extreme waves on the fringing reefs are rarely studied. By applying the nonhydrostatic numerical flow solver (NHWAVE), transformation and breaking process of the crest- and trough-focused wave groups on the fringing reef are analyzed in this study. Influences of the major factors, i.e., water depth, significant wave height, peak wave period, forereef slope and backreef slope, and ridge width, are discussed in detail. The results show that there are complex interactions between the fringing reef and the focused wave group. Breaking waves of high intensity can form at the reef crest. Meanwhile, due to the wave breakings at the reef crest and bottom friction of the reef flat, the local wave height can be effectively reduced. Within the complex wave hydrodynamics of focused waves on the fringing reef, most of the wave energy can be dissipated. In addition, hydrodynamic difference between the crest- and trough-focused waves on the fringing reef is very limited. The research results of this study will further help researchers to better understand the wave hydrodynamics of extreme waves over the fringing reefs.

Design of motor-driven precision seed-metering device with improved fuzzy PID controller for small peanut planters

Traditional passive ground wheel drive of peanut planters has displayed poor high-speed seeding performance and the slippage caused in case of sticky and wet soil. Given this, an integrated electric-driven precision seed metering device and controller were designed, which features the application of improved fuzzy PID algorithm. Based on a small peanut planter with one ridge width and duplicate rows, the servo motor drive is used to replace the traditional passive ground wheel. In addition, the satellite speed measurement is employed to complete the electric driving and controlling modification of the seed meter and precise seeding control. A working process mathematical model for the peanut metering device was established to conduct motor speed and field tests which aim at comparing performances between the conventional and the improved fuzzy PID controls. The motor speed trial shows that the average error of the actual speed of the improved fuzzy PID motor was ±1 rad/min, and the coefficient of variation was less than 1%. Against the conventional one, it can better suppress overshoot and improve the response speed. The stable output speed can still be obtained even in case of step changes. Field tests show that when working at medium and low speeds, the qualified rate of plant spacing was greater than 98%, and the rate of missed sowing is <2%; while working at high speed, the qualified rate was greater than 94%, and the rate of missed sowing was less than 4%. The average plant spacing qualification rate of the seed device increased by 6.72%; compared with other electric-driven peanut seed meters, the plant spacing qualification rate increased by 4% during high-speed sowing. In summary, this study has provided an effective technical reference for high-speed precision planting of peanuts. Keywords: peanut planter, precision seeding, control system, improved fuzzy PID DOI: 10.25165/j.ijabe.20231601.7859 Citation: Yu Y, Hu Y R, Shang S Q, Diao L S, Ge R C, Zhang X. Design of motor-driven precision seed-metering device with improved fuzzy PID controller for small peanut planters. Int J Agric & Biol Eng, 2023; 16(1): 136–144.

Split crest technique - an effective method in dental implantology for narrow ridges: A case report

Introduction. Implant placement with simultaneous bone augmentation presents procedure with high risk of complications. In those situations, one of the surgical procedures with promising outcomes is the split crest technique. Case report. A 69-year-old edentulous patient was referred to the Clinic of Oral Surgery, at the Faculty of Dentistry in Pancevo. The width of the mandibular alveolar ridge in the inter-canine region was 2 mm. For the ridge splitting and expansion, a special split and expansion kit was used (Esset KitR, Osstem, South Korea). The procedure started with crestal remover carbide cylindrical bur of 7 mm diameter for flattening of the alveolar ridge to the width of 4 mm. Then, a sharp lance drill was used to mark the places for implant osteotomies and placement. After that, 1.8 mm twist drill was used to prepare a bed of 10 mm depth, and a 13 mm saw was directed vertically. Set of expansion drills were used to expand the alveolar ridge gradually. Two implants 3.5x10 mm each (TSIII SAR, Osstem, South Korea) were inserted in the region of lower canines and the space between split buccal and lingual bone lamellae remained empty. Initial stability of inserted implants was assessed by implant stability quotient (ISQ). The values for implant stability were high for both inserted implants (98 and 93). After the surgical procedure, a control CBCT was done. The wound healed uneventfully. Conclusion. Split crest technique seems to be a predictable alternative for implant placement in narrow alveolar ridges.

Maxillary Ridge Split with Simultaneous Implant Placement – A Case Report

Inadequate alveolar ridge width often poses difficulty in implant placement. Such ridges require a combination of techniques in placing implants. One such technique is the ridge split technique which helps the expansion of the ridge with or without greenstick fracture of cortical plates. Before placing implants the width of the alveolar ridge can be effectively restored utilising the modified ridge splitting approach employing autologous bone grafts. This case report describes the ridge splitting and placement of a dental implant in the left maxillary central region followed by guided bone regeneration. Ridge expansion was done in relation to 21 and osteotomy was prepared to the desired depth. After proper treatment planning implant measuring 3.5 mm in diameter and 11.5 mm in length was placed. Four months later final cementation was done with PFM crown. The ridge split technique with the immediate implant placement resulted in minimal resorption of alveolar bone along with maximum expansion of the bone. The sequential surgical and restorative techniques were combined into one successful protocol whose steps are well elaborated in this case report.

Study on backward stimulated Brillouin scattering of chalcogenide inverted-ridge optical waveguide with air slot

The stimulated Brillouin scattering (SBS) effect has the advantage of narrow spectral line width, frequency stability, and sensitivity to gain direction, which is commonly used in the field of integrated photonic devices, such as lasers, slow light generation and microwave photonic filters. In practical applications, due to the low gain coefficient of SBS in traditional chalcogenide waveguides, there are high threshold of pumping power and long waveguide length. In this paper, a inverted-ridge waveguide structure with air slot is designed by adopting As&lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;3&lt;/sub&gt; and SiO&lt;sub&gt;2&lt;/sub&gt; materials, which presents high backward stimulated Brillouin scattering (BSBS) gain coefficient. This chalcogenide inverted-ridge optical waveguide with air slot can better confine the optical and acoustic fields within the ridge region for improving the coupling efficiency between optical and acoustic fields. More significantly, adding an air slot in the ridge region of this chalcogenide waveguide will produce powerful radiation pressure at the boundary between the air slot and As&lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;3&lt;/sub&gt;. Owing to the fact that the acoustic field is mainly distributed near the air slot in the ridge region, the coupling effect of the radiation pressure and acoustic field is significantly enhanced, leading to a significant increase in BSBS gain coefficient. In this paper, the optical fundamental mode as optical mode due to the chalcogenide waveguide with submicron size structure and the six lowest order acoustic modes that meet the matching vector conditions as acoustic mode are calculated, and it is found that the fifth order acoustic mode achieves the maximum BSBS gain coefficient among the six acoustic modes. On this basis, by scanning the waveguide structural parameters of the air slot width, waveguide ridge width &amp; height, and waveguide thickness, the BSBS gain coefficient is as high as 8.22×10&lt;sup&gt;4&lt;/sup&gt; W&lt;sup&gt;-1&lt;/sup&gt;·m&lt;sup&gt;-1&lt;/sup&gt;, which is more than three times the currently reported chalcogenide waveguide with non-suspended structure. Additionally, the calculation results also indicate that this chalcogenide waveguide with a smaller effective mode field area has a higher BSBS gain coefficient in the same optical and acoustic mode, providing a new idea for further improving the BSBS gain coefficient in the design of waveguide structures. At the same time, the impact of optical loss on BSBS gain is also analyzed, and it is found that when the waveguide length exceeds the optimal value, the lost energy caused by the optical loss will be beyond the input energy of the pump optical wave, causing the power of the stokes optical wave to begin to decrease; However, the improvement of the power of pump optical wave not only increases the maximum power of the stokes optical wave, but also rises the optimal value of the waveguide length; The results of simulation calculation have shown that when the input power of pump optical wave is about 20 mW, this chalcogenide waveguide with the only 2 cm waveguide length has the BSBS gain of 100 dB, which has advantage of low pumping power and short waveguide length in the current reported on-chip integration of chalcogenide waveguides.

Changes in Alveolar Bone Width Following Immediate Implant and Fresh Socket Preservation with Xenogeneic Gap-Filling Material Versus Guided Tissue Healing with Anatomical Tooth-Shaped Caps: A 3-Year Retrospective Case-Control Study.

This study aimed to calculate the 3-year dimensional change in crestal bone width when dental implants placed in postextraction sockets underwent two alternative techniques for alveolar preservation. Fresh sockets that had undergone immediate implant placement were categorized into one of two groups depending on the procedure type. For the xenogeneic biomaterial grafted (BG) group, the gaps between the metallic implant surfaces and the bony walls were filled with corticocancellous porcine bone; in the anatomical cap group, in which patients were treated with guided tissue healing (GTH), cross-linkable acrylic resin caps were immediately screwed on the implants. Absolute measurements of the alveolar width were performed on 3D images acquired before tooth extraction (thereby ensuring correct surgical treatment) and 3 years after surgery. Nonparametric statistics were performed, with the level of significance set at 1%. The results of 46 implants (placed in 36 patients) were analyzed, and 100% survival rates were reported for both groups at 3 years postsurgery. Minor swelling of treated areas was observed the first few days of healing, but neither mucositides, dehiscence events, nor suppurations occurred. At 3 years postsurgery, loss in alveolar ridge width was higher for the BG group (-1.1 ± 0.6 mm) than for the GTH group (0.0 ± 0.3 mm); moreover, these changes were significantly different (P < .0001). This clinical and radiographic data analysis suggests that the implant sites that received a xenogeneic filling material were less effective in maintaining the preoperative alveolar bone width than sites that underwent GTH with immediate implants and anatomical tooth-shaped caps.

Preoperative CBCT Guided Bone Regeneration Combined with Concentrated Growth Factor Applied in the Implantation of Maxillary Teeth with Insufficient Bone Mass.

It was to explore the application effect of cone beam computed tomography (CBCT) guided bone regeneration (GBR) combined with concentrated growth factor (CGF) in the implantation of maxillary teeth with insufficient bone mass. 78 patients with single maxillary anterior tooth loss and labial alveolar defects in Dazhong Stomatological Hospital were retrospectively analyzed and randomly divided into groups A and B. Both groups were treated with surgical methods of GBR at the same time of implantation. Group A: CGF fibrin fluid and Bio-Oss bone powder, covered with CGF membrane on the surface to guide bone regeneration. Group B: Bio-Oss bone powder was implanted and covered with Heal All collagen biofilm. The horizontal bone width, keratinized gingival width, bone plate thickness, implant margin results, and alveolar ridge width were analyzed at 3 and 6 months before and after the operation in both groups. 6 months after the operation, the difference in the indexes between the two groups was evident; and in group A, the indexes had an obvious difference in contrast with those before operation; the healing rate of soft tissue was 100% in group A and 80% in group B, which was significantly different (P < 0.05). Preoperative CBCT GBR combined with CGF can promote the bone formation content of guided regeneration of bone defects in the maxillary teeth region.

Alveolar ridge preservation: Complications and cost-effectiveness.

Alveolar ridge preservation is routinely indicated in clinical practice with the purpose of attenuating postextraction ridge atrophy. Over the past two decades numerous clinical studies and reviews on this topic have populated the literature. In recent years the focus has primarily been on analyzing efficacy outcomes pertaining to postextraction dimensional changes, whereas other relevant facets of alveolar ridge preservation therapy have remained unexplored. With this premise, we carried out a comprehensive evidence-based assessment of the complications associated with different modalities of alveolar ridge preservation and modeled the cost-effectiveness of different therapeutic modalities as a function of changes in ridge width and height. We conclude that, among allogeneic and xenogeneic bone graft materials, increased expenditure does not translate into increased effectiveness of alveolar ridge preservation therapy. On the other hand, a significant association between expenditure on a barrier membrane and reduced horizontal and vertical ridge resorption was observed, though only to a certain degree, beyond which the return on investment was significantly diminished.

Effect of Mechanized Ridge Tillage with Rice-Rape Rotation on Paddy Soil Structure

Ridge tillage is one of the essential tillage methods in China. It affects the soil structure by altering the soil-water environment. With the rapid development of agricultural mechanization, the mechanized ridge tillage technology that combines modern mechanized agriculture with conservation tillage has become a pertinent agricultural production technology in the hilly regions. However, to date, the effects of mechanized ridge tillage on soil structure have garnered little attention. In this study, a field plot experiment involving the following four treatments: conventional tillage with rice and winter fallow (CK1), conventional tillage with rice-rape rotation (CK2), wide ridge tillage with rice-rape rotation (BT), and narrow ridge tillage with rice-rape rotation (RT) was conducted to study the effects of mechanized ridge tillage with rice-rape rotation on soil aggregate stability and soil porosity. The results indicated that mechanized ridge tillage could reduce the porosity of pores &gt; 30 μm in diameter and increase the porosity of pores &lt; 0.5 μm. Furthermore, mechanized ridge tillage could increase soil aggregate stability; the order of average mass diameter and geometric average diameter was RT &gt; BT &gt; CK2 &gt; CK1. The BT and RT treatments could increase the agglomeration degree of the soil particles, which followed the order of RT &gt; BT &gt; CK2 &gt; CK1. Therefore, mechanized ridge tillage with rice-rape rotation is effective in enhancing soil structure.

Promotion of Specific Single-Transverse-Mode Beam Characteristics for GaSb-Based Narrow Ridge Waveguide Lasers via Customized Parameter Design

GaSb-based single-transverse-mode narrow ridge waveguide (RW) lasers with high power and simultaneous good beam quality have broad application prospects in the mid-infrared wavelength region. Yet its design and formation have not been investigated systematically, while the beam characteristics that affect their suitability for specific applications remain rarely analyzed and optimized. The present work addresses these issues by theoretically establishing a waveguide parameter domain that generalizes the overall possible combinations of ridge widths and etch depths that support single-transverse-mode operation for GaSb-based RW lasers. These results are applied to develop two distinct and representative waveguide designs derived from two proposed major optimization routes of model gain expansion and index-guiding enhancement. The designs were evaluated experimentally based on prototype 1-mm cavity-length RW lasers in the 1950 nm wavelength range, which were fabricated with waveguides having perpendicular ridge and smooth side-walls realized through optimized dry etching conditions. The model gain expanded RW laser design with a relatively shallow-etched (i.e., 1.55 upmum) and wide ridge (i.e., 7 upmum) yielded the highest single-transverse-mode power to date of 258 mW with a narrow lateral divergence angle of 11.1^circ full width at half maximum at 800 mA under room-temperature continuous-wave operation, which offers promising prospects in pumping and coupling applications. Meanwhile, the index-guiding enhanced RW laser design with a relatively deeply etched (i.e., 2.05 upmum) and narrow ridge (i.e., 4 upmum) provided a highly stable and nearly astigmatism-free fundamental mode emission with an excellent beam quality of M^2 factor around 1.5 over the entire operating current range, which is preferable for seeding external cavity applications and complex optical systems.

Modified Periosteal Inhibition (MPI) Technique for Extraction Sockets: A Case Series Report

Several Alveolar Ridge Preservation (ARP) procedures have been proposed over the years. The purpose of this study was to describe the new Modified Periosteal Inhibition (MPI) technique for ARP. Seven patients were enrolled (age range: 28–72 years old; 5 males, 2 females). In total, nine hopeless teeth were treated. Following the elevation of a full-thickness flap, atraumatic tooth extraction was conducted, preserving the buccal bone of the alveolar socket. OsteoBiol® Lamina Soft (Tecnoss®, Giaveno, Italy), 0.5 mm thick, was suitably shaped (8–10 mm in height, extending from the mesial and to the distal corners of the socket). The lamina was gently positioned between the buccal periosteum and the buccal bone plate. Tisseel® (Baxter Healthcare Corporation, Deerfield, IL, USA) was applied to seal the cortical membrane. The flaps were sutured with PTFE 4-0 (Omnia, Fidenza, Italy). Postoperative instructions were provided. Patients were strictly monitored during the follow-up. No early or late biological complications were experienced. Cone Beam Computed Tomography (CBCT) exams were performed at baseline and 4 months later. The thickness of the buccal cortical bone at baseline was 1.18 ± 0.57 mm. The pre-operative and post-operative ridge widths were 10.74 ± 1.54 mm and 11.16 ± 1.57 mm, respectively. A horizontal ridge increase of 0.41 ± 0.21 mm was observed during the healing period. At 4 months of healing, the bone volume was adequate for implant placement and no additional bone regeneration procedures were required. MPI technique was effective in preventing the horizontal contraction of the post-extraction socket. Further studies will be needed in the future to confirm our positive results.

Visualization and dermatoglyphics of latent fingerprints (sweat pores): Security ink for anticounterfeiting labels and case studies

In this report, 1,8-naphthalimide (NG)-based blue emitters non-covalently doped on silica was used for visualization of latent fingerprints and anticounterfeiting applications. The NG possess CIE coordinate value x = 0.2, y = 0.32 with blue-green emission in solid state and possess low cytotoxicity with IC50 value 85 µM. The excellent performance of NG@SiO2 was demonstrated by visualization of LFPs up to levels 1–3 on a variety of substrates including porous and nonporous surfaces using powder dusting method without any post treatment. The details of level 1 (classification); level 2 (19 minutiae points such as bifurcations, hook, eye, delta, bridge, crossover, lake, island, ridge incipient, scar and speciality features) and level 3 (size, shape, number and position of sweat pores, width of the fingerprint ridge) are clear. A detailed case studies have been carried out by collecting fingerprints from 14 subjects aged between 19 and 29 years. Each collected LFPs were screened and differentiated from each other to establish the individuality of subjects using information of levels 1–3, The NG was further used for developing invisible security ink for use in pen, stamp pad for writing/stamping on paper and silica-coated TLC plates. These results may find applications in forensic science and data security.

Splitting for good: A case report

: The bone split procedure is a unique technique used to increase the width of narrow ridge for possible simultaneous implant placement. : We would present a case of horizontal ridge augmentation in this article, using an alveolar ridge expansion approach and simultaneous implant placement. : In this report, we have described a ridge split technique and immediate implant placement for a 40-year-old male patient with missing teeth in maxillary anterior tooth region who reported to us for implant treatment: A successful prosthetic rehabilitation was obtained following the healing phase. This approach leads to restoration of aesthetics, function and speech with a predictable outcome.

Reconstruction of vertical alveolar ridge deficiencies utilizing a high-density polytetrafluoroethylene membrane /clinical impact of flap dehiscence on treatment outcomes: case series/

ObjectivesThe aim of this study was to evaluate the effects of membrane exposure during vertical ridge augmentation (VRA) utilizing guided bone regeneration with a dense polytetrafluoroethylene (d-PTFE) membrane and a tent-pole space maintaining approach by registering radiographic volumetric, linear and morphological changes.MethodsIn 8 cases alveolar ridge defects were accessed utilizing a split-thickness flap design. Following flap elevation VRA was performed with tent-pole space maintaining approach utilizing the combination of a non-reinforced d-PTFE membrane and a composite graft (1:1 ratio of autogenous bone chips and bovine derived xenografts). Three-dimensional radiographic evaluation of hard tissue changes was carried out with the sequence of cone-beam computed tomography (CBCT) image segmentation, spatial registration and 3D subtraction analysis.ResultsClass I or class II membrane exposure was observed in four cases. Average hard tissue gain was found to be 0.70 cm3 ± 0.31 cm3 and 0.82 cm3 ± 0.40 cm3 with and without membrane exposure resulting in a 17% difference. Vertical hard tissue gain averaged 4.06 mm ± 0.56 mm and 3.55 mm ± 0.43 mm in case of submerged and open healing, respectively. Difference in this regard was 14% between the two groups. Horizontal ridge width at 9-month follow-up was 5.89 mm ± 0.51 mm and 5.61 mm ± 1.21 mm with and without a membrane exposure respectively, resulting in a 5% difference.ConclusionsWith the help of the currently reported 3D radiographic evaluation method, it can be concluded that exposure of the new-generation d-PTFE membrane had less negative impact on clinical results compared to literature data reporting on expanded polytetrafluoroethylene membranes.

Can Platelet Rich Fibrin enhance the role of alloplastic bone graft in socket preservation: A Randomized Clinical Trial

Socket preservation aims at limiting the resorptive events that occurs as a consequence of tooth extraction. Besides the use of autologous and commercially available graft materials, there has been an increasing shift towards the utilization of biological substitutes like Platelet Rich Fibrin for socket preservation. : A randomized clinical trial was conducted in fourteen extraction sites, out of which seven were filled with alloplastic bone graft material alone (control group) and rest were filled with alloplastic bone graft material along with PRF (test group). The sites were assessed clinically and radiographically at baseline and six months post treatment. The mean +/- SD was calculated for alveolar ridge width and height. Although alveolar ridge width and height reduced significantly in the span of six months in both test and control groups, there was no statistically significant intergroup difference in both groups at six months post treatment in these parameters. Wound healing was comparatively better in the test group compared to the control group initially, but at the end of the study period both groups attained same level of healing. Even though alveolar socket preservation has a clinically significant effect on preserving the residual ridge dimensions, use of PRF as an adjunct to alloplastic bone graft in socket preservation procedure has no additional benefit over alloplastic bone graft material alone.

An Appendage to Alveolar Ridge Augmentation Using Allograft Bone Block – A Case Report

Patients with insufficient width of ridge for implant rehabilitation can go for block grafting prior to implant placement. Block grafting gives volume for Guided bone regeneration along the ridge.

On-Chip Design of a Broadband 850 nm TM-Pass/TE-Stop Polarizer with Tilted Subwavelength Gratings

An integrated TM-pass/TE-stop polarizer centered at 850 nm is designed in this paper. The proposed polarizer is designed on a Si3N4 on insulator platform with tilted subwavelength gratings (SWG). Since the tilted SWGs have much more of an impact on the effective index of the TE polarization state than that of the TM polarization state, they help to achieve high TM and low TE transmission simultaneously. After geometries optimization, the polarizer’s working bandwidth, which is defined as the wavelength region with an extinction ratio higher than 20 dB, is determined to be 185 nm under a SWG tilting angle of 30 degrees. At the same time, the insertion loss is always less than 0.45 dB over the entire working wavelength band. Finally, the results of fabrication tolerance analysis show that the SWG ridge width jitter only degrades the polarizer’s working bandwidth by 16 nm.

Comparing Dual-Zone Immediate Implant Placement and Socket Shield Technique for Ridge Width Changes in the Maxilla: A Prospective Cohort Study.

The aim of this prospective cohort study was to assess the facial-palatal ridge dimensional changes that occurred at 8-10 months following flapless dual-zone (DZ) immediate implant placement and socket-shield (SS) immediate placement in the maxilla. A total of 19 patients who received 20 implants were included, with 10 implants (MegaGen AnyRidge) placed for each treatment, DZ and SS. Cast models were made at 8-10 months after implant placement to assess the dimensional ridge changes by measuring the facial-palatal ridge width on implant sites (T) at six designated points starting from the gingival margin (0, 1, 2, 3, 5 and 7) and comparing it with the corresponding measurement on the contralateral tooth site (C). All 20 implants demonstrated successful osseointegration at 8-10 months follow-up (survival rate 100%). Two out of ten cases of SS group presented with minor manageable complications of external shield exposure. DZ group showed an average of 0.3 mm facial-palatal ridge width reduction, while SS group revealed a mean gain in ridge width of approximately 0.2 mm at 8-10 months follow-up. When comparing between two treatments, there was a significant difference in ridge width change at 8-10 months following implant placement, indicating better preservation of the ridge contour for socket shield technique.