Socket-shield Technique vs Conventional Immediate Implant Placement for Esthetic Rehabilitation: A Systematic Review and Meta-analysis.

AIM: The present systematic review and meta-analysis (SR/MA) aimed to test the null hypothesis that there is no difference between socket-shield technique (SST) and conventional immediate implant placement (CIIP) as an esthetic rehabilitation option for permanent human anterior teeth, against the alternative one of a difference. BACKGROUND: Socket-shield technique is considered as a highly promising procedure that has the potential to prevent resorption of anterior alveolar ridges, maintains white and pink esthetics, and provides a solution for esthetically critical cases. Controlled randomized clinical trials (RCT) and nonrandomized ones had been identified by searching the following databases: Google Scholar, Scopus, and PubMed. Literature search was determined from January 2010 up to June 2020. Hand searches were also accomplished for relevant abstracts, books, and reference lists. The eligibility criteria included prospective observational controlled RCTs and non-RCTs. POPULATIONS: patients with endodontically treated/nonrestorable permanent mature anterior teeth indicated for extraction. INTERVENTIONS: the sockets were subjected to immediate implant placement using SST. CONTROLS: implants placed with SST compared with those of CIIP. OUTCOME: the pink esthetic score measured for esthetic rehabilitation. To assess article quality, the Cochrane risk-of-bias tool was used by two independent authors. The data across quantitative studies were analyzed using comprehensive MA software. REVIEW RESULTS: The initial search found out 172 references through the search strategy and three additional ones were recognized through hand searching. After being filtered, 101 references were screened and recorded. After the inclusion and exclusion criteria were applied, only seven unduplicated prospective controlled RCTs and non-RCTs were involved in the quantitative MA. At the 6-month evaluation period, the total standard difference in mean was 1.07 and I 2 test value measuring heterogeneity was 77.182, whereas at the 12-month period, the total standard difference in mean was 1.43 and I 2 test value measuring heterogeneity was 64.914. CONCLUSION: SST had a positive effect on the esthetic rehabilitation for anterior teeth better than CIIP. However, this conclusion was dependent on a very few well-conducted prospective RCT and non-RCT. Further RCTs with longer observational time, proper methodology, and of larger sample size are still required to adequately answer the question of the present SR. CLINICAL SIGNIFICANCE: There is limited knowledge about the appropriateness of SST in the field of implant dentistry, specifically for esthetic consideration. This SR/MA confirmed the positive effect of the SST over CIIP for esthetic rehabilitation for anterior teeth. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, identifier CRD42020194086.

A new modification for improving shear bond strength and other mechanical properties of conventional glass-ionomer restorative materials.

PURPOSE: To study the effect of addition of poly(acrylamide-co-sodium acrylate) copolymer and/or TiO2 nanoparticles on the mechanochemical properties of conventional glass ionomer (GIC)-based restorative materials. MATERIALS AND METHODS: The copolymer was prepared, characterized and then added, either separately or in combination with different proportions of TiO2 nanoparticles to the conventional GIC powder. The developed composites were characterized using FTIR spectrometry, x-ray diffraction, and scanning electron microscopy. The mechanical properties of the obtained series of modified GIC formulations were investigated in comparison with other formulations containing only TiO2 nanoparticles through testing their compressive strength, flexural strength, and dentin shear bond strength. RESULTS: The preliminary data of the study showed a significant increase in the compressive strength of the conventional GIC after addition of 3% and 5% TiO2 nanoparticles by weight, but 7% decreased it. Upon addition of copolymer, the compressive strength was lower than that of the conventional GIC. The highest average compressive strength value was obtained upon incorporation of 7% 1:1 combination of copolymer-TiO2 nanoparticles. The results also demonstrated a significant increase in the flexural strength values after addition of both copolymer and TiO2 nanoparticles to the GIC powder. In addition, the results revealed a significant increase in values of dentin shear bond strength after copolymer addition with the highest value noted upon addition of 7% by weight of copolymer. CONCLUSION: The new series of modified glass ionomers developed here can be tailored to act as restorative materials with high quality performance in high stress-bearing areas.

Demineralized Dentin Matrix for Dental and Alveolar Bone Tissues Regeneration: An Innovative Scope Review.

BACKGROUND: Dentin is a permeable tubular composite and complex structure, and in weight, it is composed of 20% organic matrix, 10% water, and 70% hydroxyapatite crystalline matrix. Demineralization of dentin with gradient concentrations of ethylene diamine tetraacetic acid, 0.6 N hydrochloric acid, or 2% nitric acid removes a major part of the crystalline apatite and maintains a majority of collagen type I and non-collagenous proteins, which creates an osteoinductive scaffold containing numerous matrix elements and growth factors. Therefore, demineralized dentin should be considered as an excellent naturally-derived bioactive material to enhance dental and alveolar bone tissues regeneration. METHOD: The PubMed and Midline databases were searched in October 2021 for the relevant articles on treated dentin matrix (TDM)/demineralized dentin matrix (DDM) and their potential roles in tissue regeneration. RESULTS: Several studies with different study designs evaluating the effect of TDM/DDM on dental and bone tissues regeneration were found. TDM/DDM was obtained from human or animal sources and processed in different forms (particles, liquid extract, hydrogel, and paste) and different shapes (sheets, slices, disc-shaped, root-shaped, and barrier membranes), with variable sizes measured in micrometers or millimeters, demineralized with different protocols regarding the concentration of demineralizing agents and exposure time, and then sterilized and preserved with different techniques. In the act of biomimetic acellular material, TDM/DDM was used for the regeneration of the dentin-pulp complex through direct pulp capping technique, and it was found to possess the ability to activate the odontogenic differentiation of stem cells resident in the pulp tissues and induce reparative dentin formation. TDM/DDM was also considered for alveolar ridge and maxillary sinus floor augmentations, socket preservation, furcation perforation repair, guided bone, and bioroot regenerations as well as bone and cartilage healing. CONCLUSION: To our knowledge, there are no standard procedures to adopt a specific form for a specific purpose; therefore, future studies are required to come up with a well-characterized TDM/DDM for each specific application. Likely as decellularized dermal matrix and prospectively, if the TDM/DDM is supplied in proper consistency, forms, and in different sizes with good biological properties, it can be used efficiently instead of some widely-used regenerative biomaterials.

Challenges of Engineering Biomimetic Dental and Paradental Tissues.

BACKGROUND: Loss of the dental and paradental tissues resulting from trauma, caries or from systemic diseases considered as one of the most significant and frequent clinical problem to the healthcare professionals. Great attempts have been implemented to recreate functionally, healthy dental and paradental tissues in order to substitute dead and diseased tissues resulting from secondary trauma of car accidents, congenital malformations of cleft lip and palate or due to acquired diseases such as cancer and periodontal involvements. METHOD: An extensive literature search has been done on PubMed database from 2010 to 2019 about the challenges of engineering a biomimetic tooth (BioTooth) regarding basic biology of the tooth and its supporting structures, strategies, and different techniques of obtaining biological substitutes for dental tissue engineering. RESULTS: It has been found that great challenges need to be considered before engineering biomimetic individual parts of the tooth such as enamel, dentin-pulp complex and periodontium. In addition, two approaches have been adopted to engineer a BioTooth. The first one was to engineer a BioTooth as an individual unit and the other was to engineer a BioTooth with its supporting structures. CONCLUSION: Engineering of BioTooth with its supporting structures thought to be in the future will replace the traditional and conventional treatment modalities in the field of dentistry. To accomplish this goal, different cell lines and growth factors with a variety of scaffolds at the nano-scale level are now in use. Recent researches in this area of interest are dedicated for this objective, both in vivo and in vitro. Despite progress in this field, there are still many challenges ahead and need to be overcome, many of which related to the basic tooth biology and its supporting structures and some others related to the sophisticated techniques isolating cells, fabricating the needed scaffolds and obtaining the signaling molecules.

Biodentine versus mineral trioxide aggregate as a direct pulp capping material for human mature permanent teeth - A systematic review.

BACKGROUND: Biodentine is comparatively a new biomaterial claimed to have properties comparable to mineral trioxide aggregate (MTA). Biodentine and MTA are effectively used for direct pulp capping (DPC), and they are capable of regenerating relatively damaged pulp and formation of hard dentine bridge. OBJECTIVES: The aim of this systematic review was to test the null hypothesis of no difference between Biodentine and MTA as DPC materials for human permanent mature teeth, against the alternative hypothesis of a difference. DATA SOURCES: Clinical trials were identified by electronic databases searches of Midline, CENTRAL Cochrane Library, Latin American and Caribbean Health Sciences Literature, Scopus, Scientific Electronic Library Online, evidence-based endodontics literature, KoreaMed, and Google Scholar. The literature search was performed from January 2010 to February 2018. Hand searches were also performed for relevant abstracts, books, and reference lists. Titles and abstracts of studies identified using the above-described protocol were independently screened by two authors. Full texts of studies judged by title and abstracts to be relevant were independently evaluated by two authors for stated eligibility criteria. STUDY ELIGIBILITY CRITERIA: The eligibility criteria included randomized clinical trials (RCTs) and non-RCTs. PARTICIPANTS: Patients with permanent mature molars indicated for surgical extraction or molars that have symptomless exposure of vital pulp tissue by caries or trauma. In both cases, the molars were subjected to DPC. INTERVENTIONS: The pulp exposures were directly treated by Biodentine or MTA. STUDY APPRAISAL: To assess article quality, two authors independently used the risk of bias in nonrandomized studies - of interventions. METHODS: Qualitative metasynthesis was used to analyze data across qualitative studies. RESULTS: The initial search identified 8725 unique references through the search process. No additional studies were identified through handsearching. After filtering, 915 references were recorded and screened. After the eligibility criteria were applied, seven unduplicated prospective and retrospective cohort studies were included in the qualitative metasynthesis. LIMITATIONS: Further RCTs with much larger sample size and proper methodology with longer observational time are still in need to adequately address the questions of the present systematic review. CONCLUSION AND IMPLICATIONS OF KEY FINDINGS: Within the limitations of this review, it may be concluded that Biodentine had a similar effect on dentin bridge formation likely to MTA. However, this conclusion is based on only very few well-conducted prospective and retrospective cohort studies. SYSTEMATIC REVIEW REGISTRATION NUMBER: The review had been registered with PROSPERO (registration number CRD42018089302).

Translucency of monolithic and core zirconia after hydrothermal aging.

Objective: To evaluate the hydrothermal aging effect on the translucency of partially stabilized tetragonal zirconia with yttria (Y-TZP) used as monolithic or fully milled zirconia and of core type. Methods: Twenty disc-shaped specimens (1 and 10 mm) for each type of monolithic and core Y-TZP materials were milled and sintered according to the manufacturer's instruction. The final specimens were divided into two groups according to the type of Y-TZP used. Translucency parameter (TP) was measured over white and black backgrounds with the diffuse reflectance method; X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to analyze the microstructure of both Y-TZP types before and after aging. Data for TP values was statistically analyzed using Student's t-test. Results: Monolithic Y-TZP showed the highest TP mean value (16.4 ± 0.316) before aging while core Y-TZP showed the lowest TP mean value (7.05 ± 0.261) after aging. There was a significant difference between the two Y-TZP types before and after hydrothermal aging. XRD analysis showed increases in monoclinic content in both Y-TZP surfaces after aging. Conclusion: Monolithic Y-TZP has a higher chance to low-temperature degradation than core type, which may significantly affect the esthetic appearance and translucency hence durability of translucent Y-TZP.