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Statement The aim of this systematic review is to analyze literature regarding the relationship between the implant‐abutment emergence angle (EA) and implant emergence profile (EP) and the prevalence of peri‐implantitis. Methods PubMed and the Cochrane Library were searched for studies from initiation up to April 2022. Studies describing the EA and EP in association with peri‐implantitis were considered eligible for this review and selected for inclusion in this review if implant groups with wide and narrow EA and different EP types were described. Results Searches in PubMed and the Cochrane Library led to 1116 unique titles and the inclusion of three studies. These concerned 168–349 implants. Two studies presented the mean prevalence of peri‐implantitis which was 16.7% and 24.8% at the implant level. Both studies showed a significant relationship between peri‐implantitis in bone‐level implant groups with an EA above 30° compared to implants with an EA below 30°. A third study presented marginal bone loss which tended to be smaller when the EA was around 20°–40°. In one of the three included studies, the prevalence of peri‐implantitis was significantly higher if implants had a convex EP compared to a concave or straight EP. Another study showed a significantly higher prevalence of peri‐implantitis in implants with a convex EP compared to other EP types, if combined with an EA above 30°. Conclusions Three eligible studies were found. Reported associations should therefore be considered with caution. Synthesis suggests an association between a larger EA (>30°) and a higher prevalence of peri‐implantitis or marginal bone loss compared to a smaller EA (<30°). A convex EP may also be associated with a higher prevalence of peri‐implantitis. However, causality remains a question.

Underwater acoustic transducers need to expand the coverage of acoustic signals as much as possible in most ocean explorations, and the directivity indicators of transducers are difficult to change after the device is packaged, which makes the emergence angle of the underwater acoustic transducer limited in special operating environments, such as polar regions, submarine volcanoes, and cold springs. Taking advantage of the refractive characteristics of sound waves propagating in different media, the directivity indicators can be controlled by installing an acoustic lens outside the underwater acoustic transducer. To increase the detection range of an underwater acoustic transducer in a specific marine environment, a curvature-determining method for the diverging acoustic lens of an underwater acoustic transducer is proposed based on the acoustic ray tracing theory. The relationship equation between the original directivity indicators of the underwater acoustic transducer and the emergence angle in the specific environment is constructed, and the slope of the acoustic lens at different positions of the underwater acoustic transducer is obtained by a progressive solution. Then, the least squares polynomial fitting of the acoustic lens slope at all the refractive positions is carried out to obtain the optimal curvature of the acoustic lens. Experiments are designed to verify the effectiveness of the curvature determination method for the diverging acoustic lens of an underwater acoustic transducer, and the directivity indicators of acoustic lenses under different materials and different marine environments are analyzed. The experimental results show that the acoustic lens can change the directivity of the underwater acoustic transducer without changing the acoustic unit array, and the curvature of the acoustic lens directly affects the directivity indicators after refraction, so the method proposed in this paper has important reference value for determining the optimal shape of the diverging acoustic lens.

Dental implants have emerged as a dependable solution for replacing missing teeth, boasting high survival rates. Nonetheless, implant placement marks only the initiation of a lifelong maintenance protocol. Ensuring the long-term success of dental implants hinges on the essential preservation of peri-implant tissue health and is dependent on patient compliance, which is considered a critical determinant in supportive care. The purpose of this study is to retrospectively analyze peri-implant mucosal aspects from the time of baseline assessment to a follow-up period of 3.5-4.5 years. This retrospective analysis included follow-ups of 68 patients who received one or multiple dental implants between 2011 and 2016. Baseline assessment took place around 8 weeks after placement of the final restoration to assess the peri-implant condition clinically and radiographically. Peri-implant bleeding on probing (PiBOP), peri-implant probing pocket depth (PiPPD), and gingival recession were recorded during every visit. Implant-level analysis of PiBOP showed an increase from 31% at baseline to 48% at the follow-up appointment ( < 0.001). The average PiPPD at implant level was 3.2 mm at baseline and increased to 3.5 mm ( < 0.001). Male patients presented with significantly higher PiPPD values compared to female patients (implant level: =0.017, patient level: =0.039). There was no apparent difference in PiPPD between the group with a restoration with an emergence angle <30° or ≥30° ( =0.912). Peri-implant conditions remained fairly stable after the follow-up period. More effort needs to be made to improve the adherence of patients to peri-implant maintenance care.

Objectives The aim of this study was to investigate the association of the Mucosal Emergence Angle (MEA) with peri‐implant tissue mucositis. Material and Methods Forty‐seven patients with 103 posterior bone level implants underwent clinical and radiographic examination. Three‐dimensional data from Cone Bean Computer Tomography and Optica Scan were transposed. Three angles were defined: MEA, Deep Angle (DA) and Total Angle (TA) and measured at six sites for each implant. Results There was a significant correlation between MEA and Bleeding on Probing for all sites with an overall odds ratio of odd ratio 1.07 (95% confidence interval [CI] 1.05–1.09, p < 0.001). Sites with MEA ≥ 30°, 40°, 50°, 60°, and 70° had a higher risk for bleeding with an odds ratio of 3.1, 5, 7.5, 11.4 and 33.55, respectively. When all 6 sites of an implant prostheses had MEA ≥ 40°, the risk of having bleeding at all 6 sites was 9.5 times higher (95% CI 1.70–52.97, p = 0.010). Conclusions Maintaining MEA no wider than 30°−40° is advisable, while the aim should be to keep this angle as narrow as clinically feasible. Registered in Thai Clinical Trials Registry: http://www.thaiclinicaltrials.org/show/TCTR20220204002.

Background/Objectives: Prosthodontic restoration design plays a key role in the long-term success of implant-supported treatments and in maintaining peri-implant tissue health. Inadequate emergence angles and profiles can compromise tissue stability and negatively influence clinical outcomes. Generative design, as an algorithm-driven optimization approach, requires the definition of key parameters in advance to guide the process and determine the final shape of the hybrid implant abutment. Methods: A detailed literature review of the PubMed and Scopus databases was performed to find appropriate studies published up to 1 December 2025. Studies that investigated the emergence angle and emergence profile of implant-supported restorations were included. Seventeen studies fulfilled criteria and were included in the final analysis. Results: While the optimal emergence angle is still debatable, the literature suggests that an angle less than 30° may be beneficial. However, a concave emergence profile of implant-supported restoration has a significant role in improving stability and maintaining peri-implant health. Conclusions: Careful characterization and evaluation of the included parameters provide useful insights for generative design workflows, enabling the creation of implant abutment designs that maintain a balance between mechanical performance and biological compatibility.

Background: The aim of the present retrospective study was to assess peri-implant soft tissue health for implants restored with different prosthetic emergence profile angles. Methods: Patients were treated with implants supporting fixed dentures and were followed for 3 years. Buccal emergence angle (EA) measured at 3 years of follow-up visits (t1) were calculated for two different groups: Group 1 (153 implants) for restorations with angle between implant axis and prosthetic emergence angle from ≥30°, and Group 2 (67 implants) for those with angle ≤30°, respectively. Image J software was used for the measurements. Moreover, peri-implant soft tissue parameters such as pocket probing depth (PPD), plaque index (PI) and gingival index (GI) were assessed, respectively. Results: A total of 57 patients were included in the analysis and a total of 220 implants were examined. Mean (±SD) EA in Groups 1 and 2 was 46.4 ± 12.2 and 24.5 ± 4.7 degrees, respectively. After 3 years of follow-up, a PPD difference of 0.062 mm (CI95% −0.041 mm; 0.164 mm) was calculated between the two groups and was not statistically significant (p = 0.238). Similar results were found for PI (OR = 0.78, CI95% 0.31; 1.98, p = 0.599). Furthermore, GI scores of 2 and 3 were found for nine implants (5.9%) in Group 1, and for five implants in Group 2 (7.5%). A non-significant difference (p = 0.76) was found. Conclusions: Peri-implant soft-tissue health does not seem to be influenced by EA itself, when a proper emergence profile is provided for implant-supported reconstructions in anterior areas.

Objectives Recent research has suggested the contour of the prosthesis and the vertical height of the peri‐implant mucosa as important parameters that can influence the long term health and stability of the peri‐implant tissue. In particular, overcontouring of the prosthesis has been correlated with an increased risk for peri‐implantitis, while reduced soft tissue height has been associated with marginal bone loss, recession, and other soft tissue complications. Although these two parameters have been investigated as independent in the current literature, clinical experience points toward a close interrelation between transmucosal tissue height and prosthesis contour angle. It is often found that a reduced vertical height of the implant supracrestal complex is the main reason for overcontouring of the prosthesis. At the same time, achieving a favorable contour of 30o or less is not possible unless the clinician has ensured an adequate vertical height of the soft tissue. The purpose of this short communication is to establish the relation between tissue vertical height and prosthesis contour by utilizing a theoretical geometry equation based on the Pythagorean theorem. In doing so, one can use the dimensions of the implant as well as those of the prosthesis at the mucosal margin to calculate the essential vertical height for achieving a favorable prosthesis contour. Conclusions As the treatment plan of the implant supracrestal complex is “top‐down,” in case of deficient vertical height, subcrestal placement of the implant should be considered to achieve a proper prosthesis contour.

Objectives The primary aim of this cross‐sectional study was to investigate the association between prosthesis design and peri‐implant mucosa dimensions and morphology. The secondary aim was to investigate associations between mucosal dimensions and the presence of mucositis. Materials and Methods Forty‐seven patients with 103 posterior bone level implants underwent clinical and radiographic examination, including cone beam computer tomography and intraoral optical scanning. Three‐dimensional models for each implant and peri‐implant mucosa were constructed. Vertical mucosa height (TH), horizontal mucosa width at implant platform (TW), and 1.5 mm coronal of the platform (TW1.5), as well as mucosal emergence angle (MEA), deep angle (DA), and total contour angle (TA) were measured at six sites for each implant. Results There was a consistent correlation between peri‐implant mucosa width and height (β = 0.217, p < 0.001), with the width consistently surpassing height by a factor of 1.4–2.1. All three angles (MEA, DA, TA) were negatively associated with mucosa height (p < 0.001), while DA was negatively associated with mucosa width (TW1.5) (p < 0.001, β = −0.02, 95% CI: −0.03, −0.01). There was a significant negative association between bleeding on probing (BoP) and mucosa width at platform (OR 0.903, 95% CI: 0.818–0.997, p = 0.043) and 1.5 coronal (OR 0.877, 95% CI: 0.778–0.989, p = 0.033). Implants with less than half sites positive for BoP (0–2/6) had significantly higher mucosa height (OR 3.51, 95% CI: 1.72–7.14, p = 0.001). Conclusions Prosthesis design can influence the dimensions of the peri‐implant mucosa, with wider emergence profile angles associated with reduced peri‐implant mucosa height. In particular, a wider deep angle is associated with reduced mucosa width in posterior sites. Reduced peri‐implant mucosa height and width are associated with more signs of inflammation. Trial Registration Registered in Thai Clinical Trials Registry: http://www.thaiclinicaltrials.org/show/TCTR20220204002.

Objectives This study aims to retrospectively assess to what extent peri‐implant bone level changes occur from exposing the implant to the oral environment at the second stage of surgery (SSS) to the baseline assessment and, additionally, after 1–1.5 years of functional loading. Further, this study aims to examine the role of the emergence angle in marginal bone changes. Material and Methods This retrospective study included 46 patients treated between 2012 and 2019. These patients received 64 bone‐level dental implants. After implant placement, SSS, and baseline assessment, relevant clinical peri‐implant conditions and radiographical data were collected. A radiographic examination of the marginal bone level was performed after SSS, the baseline assessment, and 1–1.5 years of follow‐up. Results The peri‐implant periodontal probing depth increased significantly from 3.08 ± 0.7 mm at the baseline to 3.27 ± 0.81 mm at the 1–1.5‐year follow‐up. The mean marginal bone level at the implant level was 0.12 ± 0.23, 0.35 ± 0.43, and 0.47 ± 0.47 mm at the SSS, baseline, and the 1–1.5‐year follow‐up, respectively. Most changes occurred at the implant's distal site. A significant relationship was found between the emergence angle and the extent of change in the marginal bone level between the SSS and baseline (r = .430, p ≤ .001). Conclusions Most changes in the marginal bone level occurred between SSS and baseline assessments. For diagnostic purposes, it is advised to obtain a standardized radiograph after SSS to monitor peri‐implant bone‐level alterations.

In underwater wireless sensor networks, distance-related localisation technologies rely on acquiring distance information between nodes to complete node location. Currently, ranging algorithms generally have the problems of high energy consumption and low accuracy. Therefore, a new ranging algorithm is proposed. In this algorithm, an information transmission mechanism is designed to transmit ranging information efficiently. Based on this mechanism, when the network clock is asynchronous, the information propagation time between nodes is obtained by a small number of asymmetric information sending and receiving operations. Furthermore, a selection method for the master beacon node is designed to balance the energy consumption of the nodes. To solve the problem of signal propagation path non-linearity caused by stratification effect, a signal emergence angle fast iterative method based on the known sound speed profile information is developed to calculate the distance between nodes. Simulation experiments demonstrate that the proposed algorithm is better than other state of the art algorithms in terms of energy consumption and network lifetime. In addition, the proposed algorithm can quickly solve the signal emergence angle, effectively reduce the impact of seawater sound speed layering and has good ranging accuracy in shallow seas.