A nomogram prediction of implant apical non-coverage on bone-added transcrestal sinus floor elevation: A retrospective cohort study.

OBJECTIVES: To identify the risk indicators and develop and validate a nomogram prediction model of implant apical non-coverage by comprehensively analyzing clinical and radiographic factors in bone-added transcrestal sinus floor elevation (TSFE). MATERIAL AND METHODS: A total of 260 implants in 195 patients receiving bone-added TSFE were included in the study. The population was divided into a development (180 implants) and a validation (80 implants) cohort. According to 6 months post-surgery radiographic images, implants were categorized as "apical non-coverage" or "apical covered." The association of risk factors including clinical and radiographic parameters with implant apical non-coverage was assessed using regression analyses. A nomogram prediction model was developed, and its validation and discriminatory ability were analyzed. RESULTS: The nomogram predicting bone-added TSFE's simultaneously placed implant's apex non-coverage after 6 months. This study revealed that sinus angle, endo-sinus bone gain, implant protrusion length, graft contact walls, and distal angle were predictors of implant apical non-coverage. The generated nomogram showed a strong predictive capability (area under the curve [AUC] = 0.845), confirmed by internal validation using 10-fold cross-validation (Median AUC of 0.870) and temporal validation (AUC = 0.854). The calibration curve and decision curve analysis demonstrated good performance and high net benefit of the nomogram, respectively. CONCLUSIONS: The clinical implementation of the present nomogram is suitable for predicting the apex non-coverage of implants placed simultaneously with bone-added TSFE after 6 months.

Effectiveness and complications of transcrestal sinus floor elevation using the cushioned grind-out technique: A retrospective cohort study with up to 7 years of follow-up.

AIM: To evaluate the effectiveness and complications of the cushioned grind-out technique. The primary outcome was endo-sinus bone gain (ESBG), while secondary outcomes included the Schneiderian membrane perforation rate and mid- to long-term implant survival. MATERIALS AND METHODS: In this retrospective study, we compared the cushioned grind-out technique with the classic osteotome technique, establishing statistical models to assess ESBG, membrane perforation rate and implant survival rate. RESULTS: A total of 259 patients and 340 implants were included. The mean ESBG was 5.31 mm for the cushioned grind-out group and 4.64 mm for the osteotome group. Multivariable regression analysis revealed that the cushioned grind-out technique significantly facilitated ESBG (p = .028). Nineteen preparation sites experienced membrane perforation, with rates of 5.5% and 6.4% for the cushioned grind-out and osteotome groups, respectively. However, the difference was not statistically significant (p = .920). Additionally, the cumulative survival rate of the implants for 7 years was 95.2% and 91.4%, respectively, with the surgical technique not significantly influencing the results. CONCLUSIONS: With 6 months to 7 years of post-prosthetic restoration review data, our findings show that the cushioned grind-out technique facilitates a higher ESBG, with no significant difference in membrane perforation or implant failure rate.

Cushioned grind-out technique transcrestal sinus floor elevation for simultaneous implantation in severe atrophic maxilla: A retrospective study with up to 7 years of follow-up.

OBJECTIVES: This study aimed to evaluate the effects of the cushioned grind-out technique transcrestal sinus floor elevation for simultaneous implant placement with ≤4 mm of residual bone height (RBH). MATERIALS AND METHODS: This was a retrospective propensity score matching (PSM) study. Five PSM analyses included the confounding variables of Schneiderian membrane perforation, early and late implant failure, and peri-implant apical and marginal bone resorption. After PSM, we compared the difference in five aspects between the RBH ≤ 4 and >4 mm groups. RESULTS: A total of 214 patients with 306 implants were included in this study. After PSM, the generalized linear mixed model (GLMM) indicated that RBH ≤ 4 mm had no significantly higher risk of Schneiderian membrane perforation and early and late implant failure (p = .897, p = .140, p = .991, respectively). The implant cumulative 7-year survival rate of the RBH ≤ 4 and >4 mm groups was 95.5% and 93.9%, respectively (log-rank test: p = .900). Within at least 40 cases per group after PSM, two multivariate GLMMs indicated that RBH ≤ 4 mm could not be identified as the promotive factor of bone resorption of either endo-sinus bone gain or crest bone level (RBH × time interaction p = .850, p = .698, respectively). CONCLUSIONS: Within the limitations, 3 months to 7 years of post-prosthetic restoration review data indicated an acceptable mid-term survival and success rate of applying the cushioned grind-out technique in RBH ≤ 4 mm cases.

Effect of the implant apical exposure and coverage < or ≥ 2 mm bone graft on transcrestal sinus floor elevation: a 1- to 7-year retrospective cohort study.

OBJECTIVES: This study aimed to analyze the effect of the apex coverage by the bone graft, including exposure and coverage less than or greater than 2 mm on implant survival rate and peri-implant bone and soft tissue remodeling. MATERIALS AND METHODS: A total of 264 implants in 180 patients who had undergone transcrestal sinus floor elevation (TSFE) with simultaneous implant placement were included in this retrospective cohort study. Radiographic assessment was used to categorize the implants into three groups based on apical implant bone height (ABH): ≤ 0 mm, < 2 mm, or ≥ 2 mm. The implant survival rate, peri-implant marginal bone loss (MBL) during short-term (1-3 years) and mid- to long-term (4-7 years) follow-up, and clinical parameters were used to evaluate the effect of implant apex coverage after TSFE. RESULTS: Group 1 had 56 implants (ABH ≤ 0 mm), group 2 had 123 implants (ABH > 0 mm, but < 2 mm), and group 3 had 85 implants (ABH ≥ 2 mm). There was no significant difference in the implant survival rate between groups 2 and 3 compared to group 1 (p = 0.646, p = 0.824, respectively). The MBL during short-term and mid- to long-term follow-up indicated that apex coverage could not be considered a risk factor. Furthermore, apex coverage did not have a significant effect on other clinical parameters. CONCLUSIONS: Despite limitations, our study found that implant apex coverage by the bone graft, including exposure and coverage levels less than or greater than 2 mm, did not significantly affect implant survival, short-term or mid- to long-term MBL, or peri-implant soft tissue outcomes. CLINICAL RELEVANCE: Based on 1- to 7-year data, the study suggests that implant apical exposure and coverage levels of less than or greater than 2 mm bone graft are both valid options for TSFE cases.

Horizontal ridge augmentation in the anterior maxilla with in situ onlay bone grafting: a retrospective cohort study.

OBJECTIVES: This study aimed to introduce a digitally guided in situ autogenous onlay grafting technique and compare its effectiveness with the conventional (ex situ) onlay technique in augmenting horizontal bone defects of the anterior maxilla. MATERIALS AND METHODS: This retrospective cohort study included 24 patients who had received autogenous onlay bone grafts combined with guided bone regeneration (GBR) in the anterior maxilla. Fourteen patients were recruited into the in situ onlay grafting group (EG), and 10 were recruited into the ex situ onlay group (CG), defined by the donor sites. The clinical parameters, radiographic changes, micro-CT, and histological processes were evaluated after a mean follow-up period of 1.7 years. RESULTS: The horizontal bone width reflected significant bone modeling over time (p < 0.001) in the first 6 months. Multivariable analysis showed that the treatment modality (grouping) was a critical factor positively associated with vertical bone height alteration. However, neither the alteration rate of horizontal bone width nor the bone volume was associated with the treatment modality. The number of periosteal screws per graft positively affected horizontal contour maintenance (p < 0.05). No significant differences were observed between the groups in the clinical parameters (complications, success rate, and peri-implant parameters). The micro-CT and histological outcomes were similar between the groups. CONCLUSION: Despite the limitations of this study, in situ onlay grafting combined with GBR was an effective and reliable approach for horizontal bone augmentation in the anterior maxilla and appeared to demonstrate better stability in vertical bone remodeling. CLINICAL RELEVANCE: This study introduces a modified and minimally invasive technique of onlay grafting for horizontal bone augmentation. This in situ onlay grafting demonstrates superior stability in vertical bone remodeling. The trial registration number is ChiCTR2100054683.

Radiographic evaluation of a cross-shaped incision technique for thick-gingiva and thin-gingiva patients treated with implant-supported fixed prosthesis.

BACKGROUND: To evaluate a cross-shaped incision technique for thick-gingiva and thin-gingiva patients treated with implant-supported fixed prosthesis. METHODS: Total 55 patients receiving cross-shaped incision were assigned into thick-gingiva group (29 cases) and thin-gingiva group (26 cases). Follow-up was performed at 3 and 12-month after final restoration. RESULTS: Mesial and distal papilla height was significantly greater in thick-gingiva group than thin-gingiva group at 3 and 12 months, while periodontal depth and crestal marginal bone level around implant had no significant difference between the two groups during follow-up. No case of recession of buccal marginal gingiva was observed in thick-gingiva group. However, the recession of marginal gingiva of buccal aspect of the crown was found in 5 patients (19.2%) with thin-gingiva. CONCLUSIONS: The cross-shaped incision may be applied to reconstruct gingival papillae and avoid the gingival recession in patients with thick-gingiva phenotype. Trial registration This study was registered at ClinicalTrials.gov (registration number NCT04706078, date 12 January 2021, Retrospectively registered).

Early Healing of Immediate Implants Connected With Two Types of Healing Abutments: A Prospective Cohort Study.

PURPOSE: To compare hard- and soft-tissue changes around immediate implants connected with 2 types of healing abutments during the early phases of healing. MATERIALS AND METHODS: Twenty-eight immediate implants were placed into molar/premolar sockets through a modified osteotomy method. The gaps around implants were grafted with deproteinized bovine bone mineral. According to the size of the alveoli, the implants were connected with titanium healing abutments (traditional group) or customized healing abutments (CA group). Radiographic and intraoral examinations were performed before surgery, postoperatively, and at the 6-month recall. RESULTS: Buccal (P = 0.717) and lingual (P = 0.087) vertical bone loss was comparable between groups. More significant incomplete defect fill was found at the distal aspect of the CA group (P = 0.000). The buccal bone thickness alterations were similar between the 2 groups (P = 0.902 at the implant platform). The mid-facial soft-tissue level was well maintained in both groups. CONCLUSIONS: Within the limitations of this study, for immediate implants placed into posterior sockets, customized healing abutments can facilitate closure of large sockets. Despite more pronounced incomplete defect fill, healing abutments consisting of polyether ether ketone and resin did not render an increased risk for periimplant bone loss or soft-tissue recession during the early healing period.

The Wnt Inhibitor Sclerostin Is Up-regulated by Mechanical Unloading in Osteocytes in Vitro.

Although bone responds to its mechanical environment, the cellular and molecular mechanisms underlying the response of the skeleton to mechanical unloading are not completely understood. Osteocytes are the most abundant but least understood cells in bones and are thought to be responsible for sensing stresses and strains in bone. Sclerostin, a product of the SOST gene, is produced postnatally primarily by osteocytes and is a negative regulator of bone formation. Recent studies show that SOST is mechanically regulated at both the mRNA and protein levels. During prolonged bed rest and immobilization, circulating sclerostin increases both in humans and in animal models, and its increase is associated with a decrease in parathyroid hormone. To investigate whether SOST/sclerostin up-regulation in mechanical unloading is a cell-autonomous response or a hormonal response to decreased parathyroid hormone levels, we subjected osteocytes to an in vitro unloading environment achieved by the NASA rotating wall vessel system. To perform these studies, we generated a novel osteocytic cell line (Ocy454) that produces high levels of SOST/sclerostin at early time points and in the absence of differentiation factors. Importantly, these osteocytes recapitulated the in vivo response to mechanical unloading with increased expression of SOST (3.4 ± 1.9-fold, p < 0.001), sclerostin (4.7 ± 0.1-fold, p < 0.001), and the receptor activator of nuclear factor κΒ ligand (RANKL)/osteoprotegerin (OPG) (2.5 ± 0.7-fold, p < 0.001) ratio. These data demonstrate for the first time a cell-autonomous increase in SOST/sclerostin and RANKL/OPG ratio in the setting of unloading. Thus, targeted osteocyte therapies could hold promise as novel osteoporosis and disuse-induced bone loss treatments by directly modulating the mechanosensing cells in bone.

Evaluation of the efficacy of keratinized mucosa augmentation techniques around dental implants: a systematic review.

STATEMENT OF PROBLEM: The absence of periimplant keratinized mucosa is considered risky in patients with a predisposition to periodontitis or recession. Although various soft tissue augmentation techniques exist, dentists are seeking for more efficient approaches to augment periimplant keratinized mucosa. PURPOSE: The purpose of this systematic review was to evaluate the efficacy of the various techniques and biomaterials adopted in periimplant keratinized mucosa augmentation and whether one technique or biomaterial is superior. MATERIAL AND METHODS: A search in Medline-PubMed and the Cochrane Central Register of controlled trials was conducted. Randomized clinical trials, prospective cohort studies, clinical control studies, and case series from January 1, 1980, to December 31, 2013, with a follow-up of at least 6 months reporting changes on keratinized mucosa width were included. Several journals were hand-searched for related articles. The bibliographies of all publications selected for inclusion were also scanned. RESULTS: The screening of titles and abstracts resulted in 60 relevant publications. Six of them were finally included. Free gingival graft, connective tissue graft, acellular dermal matrix, and collagen matrix were used for keratinized mucosa augmentation. Because of heterogeneity of the studies, only descriptive analysis was performed. Improvements in keratinized mucosa width were reported in all studies. CONCLUSIONS: A definitive conclusion could not be achieved owing to the lack of well-designed studies and appropriate methods of studying soft tissue. The establishment of universal surgical guidelines and measurement systems is imperative in the future.

Implant over implant: an alternative method for solving malpositioned osseointegrated implants at the sinus floor.

An implant was malpositioned and osseointegrated at the maxillary sinus floor with no complications. However, unexpected bone formation over the implant made the implant nonfunctional. Because the patient rejected the removal of the implant, it was left in place while another short implant was placed into the newly formed bone in approximately the same position as the old implant to restore the posterior maxillary tooth. Within 6 months, the new implant over the old asymptomatic implant was functional. Radiographs revealed osseointegration and stable periimplant marginal bone level with no signs of infection or inflammation.

The three-dimensional stability and accuracy of 3D printing surgical templates: An In Vitro study.

OBJECTIVE: To evaluate the three-dimensional (3D) stability and accuracy of additively manufactured surgical templates fabricated using two different 3D printers and materials. MATERIALS AND METHODS: Forty surgical templates were designed and printed using two different 3D printers: the resin group (n = 20) used a digital light processing (DLP) 3D printer with photopolymer resin, and the metal group (n = 20) employed a selective laser melting (SLM) 3D printer with titanium alloy. All surgical templates were scanned immediately after production and re-digitalized after one month of storage. Similarly, the implant simulations were performed twice. Three-dimensional congruency between the original design and the manufactured surgical templates was quantified using the root mean square (RMS), and the definitive and planned implant positions were determined and compared. RESULTS: At the postproduction stage, the metal templates exhibited higher accuracy than the resin templates (p < 0.001), and these differences persisted after one month of storage (p < 0.001). The resin templates demonstrated a significant decrease in three-dimensional stability after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). No significant differences in implant accuracy were found between the two groups. However, the resin templates showed a significant increase in apical and angular deviations after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). CONCLUSION: Printed metal templates showed higher fabrication accuracy than printed resin templates. The three-dimensional stability and implant accuracy of printed metal templates remained unaffected by one month of storage. CLINICAL SIGNIFICANCE: With superior three-dimensional stability and acceptable implant accuracy, printed metal templates can be considered a viable alternative technique for guided surgery.

Investigating the effects of buccal bone fenestration on maxillary anterior implants: A 1- to 6-year retrospective study.

PURPOSE: To examine the effects of buccal bone fenestration on maxillary anterior implants. MATERIALS AND METHODS: Patients who underwent implant placement in the maxillary anterior region between January 2017 and December 2021 and had received final restorations 1 to 6 years prior were screened for inclusion in the present study. Propensity score matching was used to match the two-group sample size and reduce the influence of potential confounding factors. Generalised linear mixed models were employed to evaluate the correlation between buccal bone fenestration and peri-implant marginal bone loss. RESULTS: A total of 42 patients with 50 implants were included in the study, 16 of whom had buccal bone fenestration (group 1) and 26 of whom did not (group 2). No implant failures occurred, resulting in a cumulative implant survival rate of 100.0%. There was no statistically significant difference between the pink aesthetic scores for the two groups. The mean marginal bone loss was 0.44 ± 0.46 mm for group 1 and 0.33 ± 0.32 mm for group 2 (P > 0.05). Buccal bone fenestration was not the influencing factor of marginal bone loss (P > 0.05). Marginal bone loss was greater around implants used to replace canines than those inserted to replace central incisors (P < 0.05). Far less marginal bone loss occurred around immediately loaded implants than delayed implants with cover screws (P < 0.05). When there is sufficient keratinised mucosa around the implant, marginal bone loss will decrease significantly (P < 0.05). CONCLUSIONS: Within the limitations of this study, buccal bone fenestration defects around dental implants cannot influence peri-implant bone loss. CONFLICT-OF-INTEREST STATEMENT: The authors report no conflicts of interest relating to this study.

Integrated-omics profiling unveils the disparities of host defense to ECM scaffolds during wound healing in aged individuals.

Extracellular matrix (ECM) scaffold membranes have exhibited promising potential to better the outcomes of wound healing by creating a regenerative microenvironment around. However, when compared to the application in younger individuals, the performance of the same scaffold membrane in promoting re-epithelialization and collagen deposition was observed dissatisfying in aged mice. To comprehensively explore the mechanisms underlying this age-related disparity, we conducted the integrated analysis, combing single-cell RNA sequencing (scRNA-Seq) with spatial transcriptomics, and elucidated six functionally and spatially distinctive macrophage groups and lymphocytes surrounding the ECM scaffolds. Through intergroup comparative analysis and cell-cell communication, we characterized the dysfunction of Spp1+ macrophages in aged mice impeded the activation of the type Ⅱ immune response, thus inhibiting the repair ability of epidermal cells and fibroblasts around the ECM scaffolds. These findings contribute to a deeper understanding of biomaterial applications in varied physiological contexts, thereby paving the way for the development of precision-based biomaterials tailored specifically for aged individuals in future therapeutic strategies.

An alternative technique for the accurate transfer of periimplant soft tissue contour.

This article presents a technique for an accurate transfer of periimplant soft tissue contour during implant impression by combining the use of a conventional implant level impression and a silicone impression. This is an accurate and time-effective chairside procedure which produces minimal discomfort for the patient.

Combination of a surgical template and a collagen strip for guiding sinus floor elevation in the oblique sinus floor: A technical note.

Sinus floor elevation (SFE) by transcrestal approach has been proven to be a predictable and minimally invasive treatment that augments posterior maxilla with insufficient bone height, allowing the prosthetic rehabilitation of this area with dental implants. However, precise and sufficient elevation of the Schneiderian membrane without perforation is challenging through this blind technique especially in the presence of anatomical restrictions. This note describes a novel technique combining a surgical template and an absorbable collagen sponge (ACS) strip for transcrestal SFE in the oblique sinus floor. A surgical template was used to locate the oblique sinus floor and a collagen strip was placed to orient membrane elevation, meanwhile, protect the sinus membrane. Within the limits of present observation, this technique may increase the manipuility while reducing the risk of complications.

Tracing immune cells around biomaterials with spatial anchors during large-scale wound regeneration.

Skin scarring devoid of dermal appendages after severe trauma has unfavorable effects on aesthetic and physiological functions. Here we present a method for large-area wound regeneration using biodegradable aligned extracellular matrix scaffolds. We show that the implantation of these scaffolds accelerates wound coverage and enhances hair follicle neogenesis. We perform multimodal analysis, in combination with single-cell RNA sequencing and spatial transcriptomics, to explore the immune responses around biomaterials, highlighting the potential role of regulatory T cells in mitigating tissue fibrous by suppressing excessive type 2 inflammation. We find that immunodeficient mice lacking mature T lymphocytes show the typical characteristic of tissue fibrous driven by type 2 macrophage inflammation, validating the potential therapeutic effect of the adaptive immune system activated by biomaterials. These findings contribute to our understanding of the coordination of immune systems in wound regeneration and facilitate the design of immunoregulatory biomaterials in the future.

Macrophage response mediated by extracellular matrix: recent progress.

Biomaterials are one of efficient treatment options for tissue defects in regenerative medicine. Compared to synthetic materials which tend to induce chronic inflammatory response and fibrous capsule, extracellular matrix (ECM) scaffold materials composed of biopolymers are thought to be capable of inducing a pro-regenerative immune microenvironment and facilitate wound healing. Immune cells are the first line of response to implanted biomaterials. In particular, macrophages greatly affect cell behavior and the ultimate treatment outcome based on multiple cell phenotypes with various functions. The macrophage polarization status is considered as a general reflection of the characteristics of the immune microenvironment. Since numerous reports has emphasized the limitation of classical M1/M2 nomenclature, high-resolution techniques such as single-cell sequencing has been applied to recognize distinct macrophage phenotypes involved in host responses to biomaterials. After reviewing latest literatures that explored the immune microenvironment mediated by ECM scaffolds, this paper describe the behaviors of highly heterogeneous and plastic macrophages subpopulations which affect the tissue regeneration. The mechanisms by which ECM scaffolds interact with macrophages are also discussed from the perspectives of the ECM ultrastructure along with the nucleic acid, protein, and proteoglycan compositions, in order to provide targets for potential therapeutic modulation in regenerative medicine.

Star-shaped incision technique for gingiva patients treated with implant-supported fixed prosthesis.

To evaluate the modified star-shaped incision on gingival sulcus for reducing horizontal food impaction around implant-supported restoration. Total 24 patients receiving bone-level implant placement were enrolled, a star-shaped incision was made on the gingiva sulcus before the placement of zirconia crown. Follow-up examination was carried out 3 and 6 months after final restoration, respectively. Assessment of soft tissue includes papilla height, modified plaque index, modified sulcus bleeding index, periodontal depth, gingival biotype and gingival margin level. Marginal bone level was measured on periapical radiographs. Only 1 patient complained about the horizontal food impaction. Both the mesial and distal papilla almost filled the entire proximal space, in good harmony with the adjacent papillae. No recession of the gingival margin was found around the crown even in the patients with thin gingival biotype. Other parameters of soft tissue including modified plaque index, modified sulcus bleeding index and periodontal depth remained low during the whole follow-up visit. The resorption of marginal crestal bone was less than 0.6 mm during the first 6 month, and there was no significant difference among baseline, 3-month and 6-month visit. The modified star-shaped incision on the gingiva sulcus maintained the gingival papilla height and reduced the occurrence of horizontal food impaction, and no recession of the gingiva margin was found around implant-supported restoration.

Using the intact periosteum for horizontal bone augmentation of peri-implant defects: a retrospective cohort study.

The objectives of this study were to observe hard tissue changes in guided bone regeneration (GBR) with intact periosteum and soft block deproteinised bovine bone mineral (DBBM), and evaluate whether the result of horizontal bone augmentation varied by initial peri-implant defect depth. Forty patients with a single missing tooth and contained peri-implant defect were categorised into three groups according to their presurgical defect depth (≤ 2, 2-4, and 4-6 mm). Cone-beam computed tomography (CBCT) images were collected and reconstructed preoperatively, postoperatively, and at six months' follow up. The buccal bone width (BBW -0, -3, -5), alveolar bone width (ABW -0, -3, -5) and volume of augmented area were measured. At the six-month follow up the increase in BBW, ABW at all levels, and in bone volume, was statistically significant (all p < 0.001). No statistical significance in bone dimensions or bone resorption was found among groups (all p > 0.05). Histological analysis detected new bone formation in intimate contact with bone grafts underlying the periosteum. Within the limitations of this study, the insights gained may be of assistance to suggest that comparable and acceptable results of horizontal bone augmentation can be achieved in cases of peri-implant defect depth of ≤6 mm by means of GBR with intact periosteum.

Application of biomaterials in periodontal tissue repair and reconstruction in the presence of inflammation under periodontitis through the foreign body response: Recent progress and perspectives.

Periodontitis would cause dental tissue damage locally. Biomaterials substantially affect the surrounding immune microenvironment through treatment-oriented local inflammatory remodeling in dental periodontitis. This remodeling process is conducive to wound healing and periodontal tissue regeneration. Recent progress in understanding the foreign body response (FBR) and immune regulation, including cell heterogeneity, and cell-cell and cell-material interactions, has provided new insights into the design criteria for biomaterials applied in treatment of periodontitis. This review discusses recent progress and perspectives in the immune regulation effects of biomaterials to augment or reconstruct soft and hard tissue in an inflammatory microenvironment of periodontitis.