Associations between measured masticatory function and cognitive status: A systematic review.

OBJECTIVE: This systematic review aimed to provide an overview of the most recent evidence on the association between measured masticatory function and cognitive status. MATERIALS AND METHODS: Literature and manual searches were conducted using three electronic databases (PubMed, Web of Science and CINAHL). Observational studies published between 2011 and 2021 investigating the association between masticatory function, dementia and cognitive status in adult humans were abstracted and reviewed by three reviewers. Studies that assessed participants' masticatory function using objective and subjective measurements and that individually examined its association with cognitive function were included. The included studies were divided into cross-sectional and cohort studies, and the quality of each study was analysed using critical appraisal skills checklists. Additionally, the main conclusions and strength of the evidence were assessed for each article. RESULTS: A total of 21 studies (11 cross-sectional studies that objectively evaluated masticatory function, 9 cross-sectional studies that subjectively evaluated masticatory function and 1 prospective cohort study) were evaluated. The poorer masticatory function was associated with lower cognitive status even after adjusting for potential risk factors of dementia in four of 11 and six of nine cross-sectional studies where the masticatory function was respectively evaluated objectively and subjectively. One prospective cohort study also demonstrated that masticatory function, as evaluated based on measurements of occlusal force, predicted cognitive decline during the follow-up period. CONCLUSION: Several studies demonstrated a positive association between masticatory function and cognitive status. However, further studies, particularly longitudinal studies, are required to determine whether the association is causal.

DO ORAL CARE AND REHABILITATION IMPROVE COGNITIVE FUNCTION? A SYSTEMATIC REVIEW OF CLINICAL STUDIES.

OBJECTIVES: An increasing number of studies have identified an association between oral health status and cognitive function. However, the effect of oral interventions, including oral health care, dental treatment and oral motor exercises, on cognitive function remains unclear. This systematic review examined whether oral interventions contribute to the long-term improvement of cognitive status. METHODS: Four databases were searched (MEDLINE, Web of Science, Cochrane Library, and ICHUSHI Web) to identify randomized and nonrandomized controlled trial studies and prospective cohort studies from inception until 1 September 2023, published in English or Japanese. The Cochrane risk of bias tool for randomized controlled trials and the risk of bias assessment tool for nonrandomized studies were used to assess bias risk. RESULTS: A total of 20 articles were included in the qualitative analysis; 13 articles were published in English, and 7 were published in Japanese. The implemented interventions were oral care in 8 studies, dental treatment in 8 studies, and oral motor exercise in 4 studies. One study found a significant effect on attention following oral care intervention. Some dental treatments influenced cognitive function, although a clear positive effect was not determined. In 1 study, attention and working memory improved in the chewing exercise group. CONCLUSIONS: Several studies verified the improvement effects of oral interventions, such as oral care, dental treatment, and oral motor exercise, on cognitive function or impairment. However, there was still a lack of conclusive evidence that such an intervention clearly improved cognitive function. To clarify the effects of oral interventions on cognitive function, it is necessary to examine participants, interventions, and outcome measures in detail.

Effects of Argon Gas Plasma Treatment on Biocompatibility of Nanostructured Titanium.

In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site.

Effect of Er:YAG Pulsed Laser-Deposited Hydroxyapatite Film on Titanium Implants on M2 Macrophage Polarization In Vitro and Osteogenesis In Vivo.

In a previous study, we successfully coated hydroxyapatite (HAp) onto titanium (Ti) plates using the erbium-doped yttrium aluminum garnet pulsed-laser deposition (Er:YAG-PLD) method. In this study, we performed further experiments to validate the in vitro osteogenic properties, macrophage polarization, and in vivo osseointegration activity of HAp-coated Ti (HAp-Ti) plates and screws. Briefly, we coated a HAp film onto the surfaces of Ti plates and screws via Er:YAG-PLD. The surface morphological, elemental, and crystallographic analyses confirmed the successful surface coating. The macrophage polarization and osteogenic induction were evaluated in macrophages and rat bone marrow mesenchymal stem cells, and the in vivo osteogenic properties were studied. The results showed that needle-shaped nano-HAp promoted the early expression of osteogenic and immunogenic genes in the macrophages and induced excellent M2 polarization properties. The calcium deposition and osteocalcin production were significantly higher in the HAp-Ti than in the uncoated Ti. The implantation into rat femurs revealed that the HAp-coated materials had superior osteoinductive and osseointegration activities compared with the Ti, as assessed by microcomputed tomography and histology. Thus, HAp film on sandblasted Ti plates and screws via Er:YAG-PLD enhances hard-tissue differentiation, macrophage polarization, and new bone formation in tissues surrounding implants both in vitro and in vivo.

Fixed Partial Denture Designed by Combining the Whole 3D Digital Surface Morphology of the Provisional Restoration and Abutment Teeth Surfaces.

We introduce a new digital workflow to fabricate a fixed partial denture (FPD) utilizing the three-dimensional surface morphology of provisional restoration (PR) and abutment teeth. Scanned images of the full maxilla with abutment teeth, full maxilla with PR, and PR alone were superimposed. The surfaces of the final FPD were designed based on the entire morphology of the PR and abutment teeth surfaces. The inner and outer surfaces converged at the margin lines of the abutment teeth. Fine modifications to the final FPD design were performed manually, and the final FPD was fabricated and successfully installed in the patient.

Osseointegration Properties of Titanium Implants Treated by Nonthermal Atmospheric-Pressure Nitrogen Plasma.

Pure titanium is used in dental implants owing to its excellent biocompatibility and physical properties. However, the aging of the material during storage is detrimental to the long-term stability of the implant after implantation. Therefore, in this study, we attempted to improve the surface properties and circumvent the negative effects of material aging on titanium implants by using a portable handheld nonthermal plasma device capable of piezoelectric direct discharge to treat pure titanium discs with nitrogen gas. We evaluated the osteogenic properties of the treated samples by surface morphology and elemental analyses, as well as in vitro and in vivo experiments. The results showed that nonthermal atmospheric-pressure nitrogen plasma can improve the hydrophilicity of pure titanium without damaging its surface morphology while introducing nitrogen-containing functional groups, thereby promoting cell attachment, proliferation, and osseointegration to some extent. Therefore, nitrogen plasma treatment may be a promising method for the rapid surface treatment of titanium implants.

Association of masticatory muscle activity with sleep arousal and other concomitant movements during sleep.

OBJECTIVE: This study aims to verify the associations among sleep bruxism (SB), sleep arousal (SA) and concurrent body movements. MATERIAL AND METHODS: Subjects underwent a standard overnight polysomnography test and audio-video recordings. Sleep quality was evaluated according to the Rechtschaffen and Kales criteria, while SA was determined as per the American Sleep Disorders Association criteria. Analyses were performed by an external institution after masking of the subjects' information. SB was assessed based on the presence/absence of rhythmic masticatory muscle activity (RMMA) episodes, which were identified by using electromyography of the masseter muscle. The observed simultaneous movements included lower leg movement (LLM), swallowing, face scratching, head movement, body movement, eye blinking, coughing, licking, sighing, body scratching, lip sucking, somniloquy and yawning. The LLM was determined visually, as well as through an increase in the tibialis electromyogram signal. Other movements were visually assessed using audio-video recordings. The incidences of all the simultaneous movements were compared between RMMA with intercurrent SA (SAwRMMA; RMMA episode derived from a masseter electromyogram showing more than 10% of maximum voluntary contraction) and SA without RMMA (SAw/oRMMA). RESULTS: Fourteen subjects were included in this study (females/males: 4/10, mean age: 31.5 ± 5.7 years). Among these, LLM, swallowing, body movement, licking, body scratching and lip sucking were frequently observed in SAwRMMA episodes than in SAw/oRMMA episodes, significantly. However, the non-specific simultaneous movements were higher observed in SAw/oRMMA episodes than that in SAwRMMA. CONCLUSION: Our results suggest that SB is concurrently activated with LLM in relation to arousal.

Distinct Osteogenic Potentials of BMP-2 and FGF-2 in Extramedullary and Medullary Microenvironments.

Bone morphogenetic protein-2 (BMP-2) and fibroblast growth factor-2 (FGF-2) have been regarded as the major cytokines promoting bone formation, however, several studies have reported unexpected results with failure of bone formation or bone resorption of these growth factors. In this study, BMP-2 and FGF-2 adsorbed into atellocollagen sponges were transplanted into bone defects in the bone marrow-scarce calvaria (extramedullary environment) and bone marrow-abundant femur (medullary environment) for analysis of their in vivo effects not only on osteoblasts, osteoclasts but also on bone marrow cells. The results showed that BMP-2 induced high bone formation in the bone marrow-scarce calvaria, but induced bone resorption in the bone marrow-abundant femurs. On the other hand, FGF-2 showed opposite effects compared to those of BMP-2. Analysis of cellular dynamics revealed numerous osteoblasts and osteoclasts present in the newly-formed bone induced by BMP-2 in calvaria, but none were seen in either control or FGF-2-transplanted groups. On the other hand, in the femur, numerous osteoclasts were observed in the vicinity of the BMP-2 pellet, while a great number of osteoblasts were seen near the FGF-2 pellets or in the control group. Of note, FCM analysis showed that both BMP-2 and FGF-2 administrated in the femur did not significantly affect the hematopoietic cell population, indicating a relatively safe application of the two growth factors. Together, these results indicate that BMP-2 could be suitable for application in extramedullary bone regeneration, whereas FGF-2 could be suitable for application in medullary bone regeneration.

Type XVIII Collagen Modulates Keratohyalin Granule Formation and Keratinization in Oral Mucosa.

Epithelial keratinization involves complex cellular modifications that provide protection against pathogens and chemical and mechanical injuries. In the oral cavity, keratinized mucosa is also crucial to maintain healthy periodontal or peri-implant tissues. In this study, we investigated the roles of type XVIII collagen, a collagen-glycosaminoglycan featuring an extracellular matrix component present in the basement membrane, in oral mucosal keratinization. Histological analysis of keratinized and non-keratinized oral mucosa showed that type XVIII collagen was highly expressed in keratinized mucosa. Additionally, a 3D culture system using human squamous carcinoma cells (TR146) was used to evaluate and correlate the changes in the expression of type XVIII collagen gene, COL18A1, and epithelial keratinization-related markers, e.g., keratin 1 (KRT1) and 10 (KRT10). The results showed that the increase in COL18A1 expression followed the increase in KRT1 and KRT10 mRNA levels. Additionally, loss-of-function analyses using silencing RNA targeting COL18A1 mRNA and a Col18-knockout (KO) mouse revealed that the absence of type XVIII collagen induces a dramatic decrease in KRT10 expression as well as in the number and size of keratohyalin granules. Together, the results of this study demonstrate the importance of type XVIII collagen in oral mucosal keratinization.

Loss of oral self-care ability results in a higher risk of pneumonia in older inpatients: A prospective cohort study in a Japanese rural hospital.

OBJECTIVES: To identify significant risk factors associated with incidence of mortality and pneumonia in whole-community-based older inpatients resident in Japanese rural region. METHODS: Patients older than 65 years admitted between 1 April and 15 April 2010 to a core hospital located in a rural region were exhaustively recruited, and incidence of mortality and pneumonia during the 32-month follow-up period were evaluated. Independent variables at baseline measurement included age, gender, body mass index, Charlson comorbidity index, functional dependency, oral self-care ability index, number of remaining teeth, hyposalivation and nutritional status. Dependent variables were incidence of mortality and pneumonia. Survival and non-pneumonia curves were drawn using Kaplan-Meier analysis. Cox proportional hazards analysis was performed to identify the risk factors related to incidence of mortality and pneumonia. RESULTS: The survival rate of 46 patients (male/female: 11/35; mean age: 83.8 ± 6.8 years) was 52.1%, and the incidence of pneumonia was 60.9%. Malnutrition and gender (male) were identified as significant risk factors for mortality (odds ratio [OR]: 8.18 and 4.90; 95% confidence interval [CI]: 1.77-37.3 and 1.50-16.0; P < 0.01 and <0.01, respectively). Loss of oral self-care ability and gender (male) were identified as significant risk factors for incidence of pneumonia (OR: 8.97 and 4.58; 95% CI: 1.70-47.4 and 1.50-14.0; P = 0.01 and <0.01, respectively). CONCLUSIONS: Malnutrition and loss of oral self-care ability were significant risk factors for incidence of mortality and pneumonia, respectively. In response, supplying nutrition with appropriate diet and personalised oral care might contribute to reduction in mortality and prevention of pneumonia.

Sleep bruxism frequency and platelet serotonin transporter activities in young adult subjects.

PURPOSE: To evaluate correlations between serotonin transporter (SERT) uptake ability in human peripheral platelets and sleep bruxism (SB) frequency. METHODS: Subjects were consecutively recruited from sixth-year students at Okayama University Dental School. Subjects were excluded if they (1) were receiving orthodontic treatment, (2) had a dermatological disease, (3) had taken an antidepressant within 6 months, or (4) had used an oral appliance within 6 months. SB frequency was determined as the summary score of three consecutive night assessments using a self-contained electromyography detector/analyzer in their home. Fasting peripheral venous blood samples were collected in the morning following the final SB assessment. SERT amount and platelet number were quantified via an ELISA assay and flow cytometry, respectively. Functional SERT characterization, 5-hydroxytryptamine (5-HT) uptake, maximum velocity (V max), and an affinity constant (K m ) were assessed with a [(3)H] 5-HT uptake assay. The correlations between these variables and SB level were evaluated. RESULTS: Among 50 eligible subjects (26 males, mean age 25.4 ± 2.41 years), 7 were excluded because of venipuncture failure, smoking, and alcohol intake during the experimental period. A small but significant negative correlation between SB level and [(3)H] 5-HT uptake was observed (Spearman's correlation R (2) = 0.063, p = 0.04). However, there were no significant correlations between SB level and total platelet amount, SERT, V max, and K m values (p = 0.08, 0.12, 0.71, and 0.68, respectively). CONCLUSIONS: Platelet serotonin uptake is significantly associated with SB frequency, yet only explains a small amount of SB variability.

Tooth morphology fusion technique is more accurate than conventional technique in transferring morphology of provisional to definitive screw-retained, implant-supported crown: A preliminary intervention study.

PURPOSE: To compare the accuracy of the tooth morphology fusion (TMF) digital technique and customized impression transfer coping (conventional) technique when transferring the morphology of a provisional crown to a definitive screw-retained implant-supported crown. METHODS: Six cases of partial edentulism (one anterior and five posterior) treated with oral implant placement in our clinic for the loss of three or fewer teeth in the maxilla or mandible between April 2017 and September 2018 were included. After implant placement and re-entry surgery, provisional restorations were made and adjusted to obtain the ideal morphology. Two definitive restorations were constructed by transferring the complete morphology of the provisional restorations, including the subgingival contour, using the TMF digital and conventional techniques. Three sets of surface morphological data were obtained using a desktop scanner. The three-dimensional total discrepancy volume (TDV) between the provisional restoration (reference) and the two definitive restorations was digitally measured by overlapping the surface data of the stone cast using the Boolean operation. Each TDV ratio (%) was calculated by dividing the TDV by the volume of provisional restoration. The median TDV ratios for TMF and conventional techniques were compared using the Wilcoxon signed-rank test. RESULTS: The median TDV ratio between provisional and definitive restorations constructed using the TMF digital technique (8.05%) was significantly lower than that obtained using the conventional technique (13.56%, P < 0.05). CONCLUSIONS: In this preliminary intervention study, the TMF digital technique was more accurate than the conventional technique for the transfer of morphology from provisional to definitive prosthesis.

Does maintaining the number of present and functional teeth benefit the longevity of life in older people requiring nursing care?: A prospective cohort study.

PURPOSE: This prospective cohort study examined the effects of the number of present and functional teeth on mortality among older Japanese adults requiring nursing care in an environment of comprehensive oral hygiene and nutritional management. METHODS: The study included 174 older adults (mean age: 84.4 ± 8.3 years; male/female: 49/125) in need of support or long-term care, who resided in either a local specialized healthcare facility or their own homes, and received daily oral hygiene and nutritional support at facilities in Okayama, Japan. The initial clinical oral examination along with assessment of general physical condition and nursing environment of the participants were performed in July 2013 and followed up for one year. RESULTS: All-cause mortality occurred in 28 (mean age: 88.7 ±13.4 years; male/female: 6 /22) individuals during the follow-up period. Cox proportional hazard analysis indicated that older age, low performance in activities of daily living (Barthel Index <40), and underweight status (body mass index <18.5) were significant risk factors for mortality. The number of present and functional teeth were not found to be significant risk factors for mortality. CONCLUSIONS: During the one-year follow-up period, the number of present and functional teeth did not have a significant impact on mortality among older Japanese adults requiring nursing care in a well-managed environment of oral hygiene and nutritional status.

Accuracy of a novel modified single computed tomography scanning method for assisting dental implant placement: a retrospective observational study.

PURPOSE: The aim of this study is to compare dental implant placement accuracy of three surgical guide fabrication methods: single (SCT) and double computed tomography (DCT), and a newly developed modified SCT (MSCT) scan method. METHODS: A total of 183 cases (183 surgical guides, and 485 implants) of static-guide-assisted implant placement surgery using the SCT, DCT, or MSCT methods in a dental clinic were included in the study. Three-dimensional (3D) deviations (mm) at the entry and tip of the implant body between preoperative simulation and actual placement were measured as surrogate endpoints of implant placement accuracy. The following survey details were collected from medical records and CT data: sex, age at implant placement surgery, surgical guide fabrication method, number of remaining teeth, implant length, implant location, alveolar bone quality, and bone surface inclination at implant placement site in preoperative simulation, etc. Risk factors for reducing implant placement accuracy were investigated using generalized estimating equations. RESULTS: The SCT and DCT methods (odds ratios [ORs] vs. MSCT method: 1.438, 1.178, respectively), posterior location (OR: 1.114), bone surface buccolingual inclination (OR: 0.997), and age at implant placement surgery (OR: 0.995) were significant risk factors for larger 3D deviation at the entry; the SCT (OR: 1.361) and DCT methods (OR: 1.418), posterior location (OR: 1.190), implant length (OR: 1.051), and age at implant placement surgery (OR: 0.995) were significant risk factors for larger 3D deviation at the tip of the implant body. CONCLUSIONS: Implant placement accuracy was better using the MSCT method compared to the SCT and DCT methods.

Prosthodontic treatment can improve the ingestible food profile in Japanese adult outpatients.

PURPOSE: To investigate the effect of prosthodontic treatment on the ingestible food profile in adult Japanese outpatients, and to identify the related risk factors that can deteriorate the profile. METHODS: The participants were 277 outpatients who visited university-based specialty clinics in Japan for prosthodontic treatment. The demographic data, number of present teeth assessed via intraoral examination, and oral health-related quality of life assessed by the total Oral Health Impact Profile (OHIP-J54) scores of all participants were recorded before treatment. Ingestible food profile score (IFS) was recorded using a validated food intake questionnaire. Eligible participants who answered the questionnaire before and after treatment were categorized into five groups based on the prosthodontic treatments they received (i.e., crowns, bridges, removable partial dentures, removable complete dentures, and removable complete and partial dentures). RESULTS: Multivariate analysis of covariance revealed a statistically significant main effect of prosthodontic intervention (time course: before and after treatment) on mean IFS (P=0.035, F=4.526), even after adjusting for covariates (age, number of present teeth, and treatment modality). Multiple linear regression analysis revealed that the low number of present teeth (r=0.427, P<0.001) and a high OHIP-J54 total score (r=-0.519, P<0.001) of the patients at the baseline were significantly associated with their baseline IFSs, even after adjusting for confounding variables. CONCLUSIONS: The findings of this multicenter follow-up study indicate the importance of prosthodontic rehabilitation in improving patients' ingestible food profiles.

Multiple sleep bruxism data collected using a self-contained EMG detector/analyzer system in asymptomatic healthy subjects.

PURPOSE: Small, self-contained electromyographic (EMG) detector/analyzer (D/A) devices have become available for the detection of jaw muscle activity events above threshold. These devices claim to be less intrusive to the subjects sleep so it is less prone to induce disturbed sleep. The objective of this study was to evaluate for night-to-night variability and examine for a systematic alteration on the first night in EMG levels. METHODS: Ten asymptomatic healthy volunteers (mean age, 26.8 ± 3.78) were recorded for six sequential nights in their home environment using EMG D/A system. The device yields a nightly EMG level above threshold score on a 0-4 level. Because the data are categorical and nonparametric, the data of the ten subjects across six nights were submitted to a Friedman repeated measures ANOVA. The significant level was set as alpha equal to 0.05. RESULTS: The median and mode values of the subjects were tabulated and analyzed and we did not find a significant difference in EMG D/A level across the six nights (p = 0.287, Kendall's coefficient of concordance = 0.124, Friedman two-way repeated measures ANOVA). The data did show clear and substantial night-to-night variability. CONCLUSION: Substantial night-to-night variability in masseter EMG activity levels was clearly observed in our subjects. There was no evidence of a suppressed or elevated first-night effect-like variability on masseter muscle EMG level seen in these subjects using a small portable self-contained EMG detector/analyzer. These data suggest that recordings should be at least 5-6-nights duration to establish a reasonable measure of an individual's average nightly masseter EMG level.

Test-retest reliability of MRI-based disk position diagnosis of the temporomandibular joint.

This study evaluated the test-retest reliability for determining the temporomandibular joint (TMJ) disk position, diagnosed using magnetic resonance imaging (MRI). These assessments were done as a base-line measurement for a prospective cohort study, which examines the risk factors for precipitation and progression of temporomandibular disorders. Fifteen subjects (mean age, 24.2 ± 0.94 years; male/female = 8/7) were recruited from the students of Okayama University Dental School. Sagittal MR TMJ images were taken with a 1.5-T MR scanner (Magneton Vision, Siemens) in close and maximal open positions twice at about 1-week (6-11 days) interval. The images were displayed using 200% magnification on a computer screen with a commercially available image software package (OSIRIS, UIN/HCUG). Three calibrated examiners diagnosed the disk positions using the standardized criteria. The disk position of each joint was classified as normal, anterior disk displacement with or without reduction, and others. The first and second disk position diagnoses were compared, and the test-retest reliability level was calculated using the kappa index. The second disk position diagnosis was consistent with the first in 27 out of 30 joints. The calculated kappa value representing the test-retest reliability level between the first and second disk position diagnosis was 0.812. These results indicated that the test-retest reliability of MRI-based diagnosis of TMJ disk positions at about 1-week interval was substantially high, even though they were not completely consistent.

A retrospective comparison of the survival of vital teeth adjacent to single, bounded edentulous spaces rehabilitated using implant-supported, resin-bonded, and conventional fixed dental prostheses.

OBJECTIVES: In this study, we aimed to compare the long-term survival of vital teeth adjacent to bounded edentulous spaces rehabilitated using an implant-supported prosthesis (ISP), a resin-bonded fixed partial denture (RBFPD), or a conventional fixed partial denture (CFPD). The risk factors for complications in teeth adjacent to the edentulous space (TAES) were also investigated. METHODS: We followed-up a consecutive series of 514 patients who underwent rehabilitation of a single bounded edentulous space with vital TAES (ISP: 103; RBFPD: 216; and CFPD: 195) from 2008 to 2017. Cumulative survival rates of prosthesis and TAES, and complication-free rates of TAES, were evaluated using the Kaplan-Meier analysis and log-rank test. Risk factors were evaluated using a Cox proportional hazards model. RESULTS: Cumulative complication-free rates of TAES showed no significant differences among the three groups. The cumulative survival rate of TAES in CFPD was significantly lower than that of ISP (p = 0.037); no significant differences were observed between ISP and RBFPD (p = 0.513), and RBFPD and CFPD (p = 0.076). Older age (p = 0.027) was the only independent significant risk factor for complications in TAES. Installation of CFPD (p = 0.019), ceramic prosthesis in edentulous space (p = 0.026), and deeper periodontal probing depth (p = 0.018) of TAES were significant risk factors for non-surviving TAES. CONCLUSIONS: Rehabilitating a single bounded edentulous space with CFPD could increase the risk for TAES loss compared with ISP. Risk of TAES loss remained similar between ISP and RBFPD, which can minimize the loss of coronal tooth structure during tooth preparation. CLINICAL SIGNIFICANCE: Teeth adjacent to edentulous space show equivalent longevity when rehabilitating a single bounded edentulous space with resin-bonded fixed partial dentures or single standing implant-supported prosthesis, at least 10 years post-installation.

Effectiveness of the socket shield technique in dental implant: A systematic review.

PURPOSE: Dental implant therapy is a common clinical treatment for missing teeth. However, the esthetic result is not as satisfactory as expected in some cases, especially in the anterior maxillary area. Poor esthetic results are caused by inadequate preparation of the hard and soft tissues in this area before treatment. The socket shield technique may be an alternative for a desirable esthetic outcome in dental implant treatments. STUDY SELECTION: In the present systematic review, PubMed-Medline, Google Scholar, and ScienceDirect were searched for clinical studies published from January 2000 to December 2018. RESULTS: Twenty studies were included, comprising one randomized controlled trial, two cohort studies, 14 clinical human case reports, and three retrospective case series. In total, 288 patients treated with the socket shield technique with immediate implant placement and follow-up between 3-60 months after placement were included. A quality assessment showed that 12 of the 20 included studies were of good quality. Twenty-six of the 274 (9.5%) cases developed complications or adverse effects related to the socket shield technique. Most studies reported implant survival without the complications (90.5%); most of the cases that were followed up for more than 12 months after implant placement achieved a good esthetic appearance. The failure rate was low without the complications, although there were some failures due to failed implant osseointegration, socket shield mobility and infection, socket shield exposure, socket shield migration, and apical root resorption. CONCLUSIONS: The socket shield technique can be used in dental implant treatment, but it remains difficult to predict the long-term success of this technique until high-quality evidence becomes available.