Objectives Orifice barriers (OBs) are commonly placed as sub-seals following root canal treatment, to resist microbial leakage if the primary coronal seal fails. However, despite numerous in vitro studies, clinical evidence supporting their efficacy is limited. This is the first systematic review of the in vivo endodontic literature evaluating OB effectiveness in root filled teeth (RFT), addressing a critical research gap. Data sources MEDLINE, Embase, CENTRAL, Web of Science and Scopus were systematically searched from inception through 16th May 2025. Articles were screened using Covidence by two independent reviewers. Risk of bias and certainty of evidence assessments were undertaken to assess methodological rigour of included studies. Study selection and results Seven studies met the inclusion criteria. OBs improved outcomes for teeth with radicular cracks in two small single-arm cohort studies (90.6 % success & 96.6 % survival at 2-4years; 100 % at 1-3years). OBs were associated with lower apical periodontitis (AP) in one cross-sectional study (p < 0.005), while in a second, positioning the root filling/coronal restoration interface apical to marginal bone level was associated with lower AP (p < 0.005). Two remaining cohort studies showed no significant benefit for OBs in RFT. One randomised controlled trial showed no benefit of OBs, but follow-up was only one year. Heterogeneity among studies precluded meta-analysis. Conclusions Very low certainty in vivo evidence supports OBs in cracked RFT, but there is little evidence for OBs elsewhere. The limitations identified underscore the need for well-designed prospective in vivo studies to validate the evidence base for OBs. Clinical significance OB placement apical to radicular cracks may improve success and survival for cracked RFT, with specialist referral for treatment under microscopy recommended in such cases. OBs may play a role in creating a well-sealed coronal restoration following RCT, but further clinical research is required to determine their efficacy.

Rectangular Block Implant (RBIs) were manufactured, using computer-aided-design lathe turning, surface roughened with grit blasting and gamma irradiated. Implants were surgically placed into the resorbed edentulous mandibular ridges of both greyhound dogs (ex vivo and in vivo) and humans; the pooled total was 17 placements. The aim was to achieve mechanical stability and full implant submergence without damage to the mandibular canal and without bone fracture: fulfilment of all of these criteria was deemed to be a successful surgical outcome. Rectangular osteotomy sites were prepared with piezo surgical instrumentation. Sixteen implants were fully submerged and achieved good primary stability without bone fracture and without evidence of impingement of the mandibular canal. One implant placement was deemed a failure due to bone fracture: the event of a random successful outcome was rejected (p < 0.01 confidence, binomial analysis). Technique of placement yielded excellent mechanical retention: key biomechanical factors that emerged in this process included under preparation of the osteotomy site with the use of specifically designed trial-fit gauges, the viscoelastic property of the peri-implant bone, the flat faces and cornered edges of the block surfaces which enhance stress distribution and mechanical retention, respectively. It was concluded that the surgical protocol for the RBI placement in the resorbed alveolus is a predictable clinical procedure tailored to its specific, unique biomechanical profile.

OBJECTIVES:To compare the use of orifice barriers (OB) in root-filled teeth (RFT) between specialist endodontic practitioners (SEP) and general and other specialist practitioners (GDP+), and identify common materials, reasons for selection, and techniques. METHODS:An online survey was distributed to SEP and GDP+ practising in Australia. Demographic and multiple-choice questions relating to material selection and technique choices were asked to evaluate and relate usage patterns to practising and training backgrounds. Fisher's exact tests were undertaken to compare categorical variables across practitioner groups. Significance level was set at p<.05. RESULTS:There were 457 eligible responses: 393(86%) GDP+ and 64(14%) SEP. Of 429 reporting endodontically treating or restoring teeth, 317(73.9%) placed OB; preferred depth of root filling removal by most (91.8%) was ≤ 2 mm, with more SEP preferring 2 mm than GDP+(p=.02). Preferred materials for OB were conventional and resin-modified GIC (GIC), resin composite materials (RC), Cavit™ and zinc polycarboxylate cement (ZPC). 'Ease of use' was a common reason among all practitioners for GIC and RC. Significantly more SEP(p<.001) chose ZPC in all teeth and more commonly because of 'Ease of use' for both posterior (p<.001) and anterior (p=.002) teeth. All ZPC-using SEP preferred using a paste-filler/lentulo spiral, significantly more than GDP+ for posterior (p<.001) and anterior (p=.002) teeth. Cavit™ was often chosen for 'Sealing ability'. CONCLUSIONS:OB were widely placed by dental practitioners in Australia, with a small group of materials selected, most commonly for ease of use or sealing ability. The findings of this study suggest that further research should be undertaken to investigate the relative performance of these materials as OB and to inform the clinician's choices when restoring RFT.

Statement of problem. Research on the quantification of 3-dimensional tooth movements in patients undergoing treatment using the Dahl principle is lacking.Purpose. The purpose of this observational clinical study was to measure the magnitude, direction, duration, and rate of tooth movement occurring in patients to reestablish tooth contact and create restorative space.Material and methods. A total of 104 paired preoperative and postoperative physical and virtual casts from 26 patients were obtained. Commencement and completion dates were recorded to calculate movement duration to reestablish occlusion. Dental casts were digitized, and the 3 -dimensional digital casts obtained were superimposed via a surface matching and analysis software program by using the global registration function. Color maps were used to visualize direction, and the annotation feature quantified magnitude of tooth movement in millimeters when specific reference points were selected. Teeth within the arch were categorized as per their location to evaluate their impact on occlusal reestablishment. The average rate of movement was determined by time taken for extrusive and intrusive movements over the treatment duration. Post hoc Tukey tests were applied if a significant difference was present in the magnitude of movement between different tooth categories. Results. All participants showed evidence of tooth movement during treatment. Duration of occlusal reestablishment ranged from 3.9 to 28.2 months, with more posterior tooth extrusive movements (56.9%) than anterior tooth intrusive (43.1%) movements occurring. A comparison of magnitude of extrusive or intrusive movement between categories (molar-anterior, premolar -anterior, and premolar-molar) showed that premolar and molar extrusive movements and anterior intrusive movements were significantly different (P<.001). The amount of buccal and lingual movement for molars and premolars was similar. Anterior teeth demonstrated more buccal than lingual movements. All teeth showed more mesial than distal movements. The extrusive and intrusive movement rate was 0.13 and 0.11 mm/mo, respectively.Conclusions. Tooth movement occurred in patients regardless of age and sex. The results of this study indicated that tooth movements have a 3-dimensional nature. Occlusal reestablishment mainly occurred via a combination of extrusive and intrusive movements. The study further highlighted the advantages of digital technology such as surface scanners and 3-dimensional software programs that can be used to quantify change in patients undergoing treatment. (J Prosthet Dent 2023;129:554-60)

BACKGROUND:This study compared natural root caries lesions with artificial root caries lesions prepared with one of the two demineralising solutions. METHODS:Twelve natural root caries lesions on upper incisors and 24 artificial root lesions were prepared on sound root surfaces using 50 mM acetic acid, 1.5 mM CaCl2 , 0.9 mM KH2 PO4 at pH 5.0 or 80 mL/L Noverite K-702 polyacrylate solution, 500 mg/L hydroxyapatite, 0.1 mol/L lactic acid at pH 4.8 (n = 12/group) for 96 hours. Lesions were scanned using micro-CT. Inciso-gingival oriented images were analysed and mineral density calculated at 7.5 μm increments from the surface to 225-μm deep. Sectioned lesions were analysed by Knoop microhardness up to 250 μm from the lesion surface. Data were analysed by the Dunn's test with Bonferroni correction. RESULTS:Natural and artificial lesion mean mineral densities were not statistically different (P > 0.05). Mineral density from the surface to 75 μm was greater in natural lesions and from 150 to 225 μm was greater in artificial lesions (P < 0.05). Microhardness values were statistically higher in artificial lesions (P < 0.05); no difference was found among artificial lesions produced by the two solutions (P > 0.05). Mineral density and microhardness of natural and artificial root caries are different from each other. A greater mineralized surface layer existed on natural lesions.

There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers. © 2023 Australian Dental Association.

PURPOSE:To evaluate the effect of hydrothermal aging on the load to failure and number of cycles to failure of implant-supported monolithic zirconia molar crowns under cyclic loading.MATERIALS AND METHODS:Twenty identical implant-supported monolithic zirconia crowns with molar morphology were produced. Half of the crowns were aged according to ISO standard 13356 to simulate 5 years in vivo. The non-aged crowns served as a control group. All crowns were subjected to cyclic loading with increasing increments of load until failure. The load to failure, the number of cycles to failure, and the failure pattern were determined for each crown.RESULTS:The load to failure values were 3,630 N (SD: 547.8 N) and 3,640 N (SD: 389.3 N) for the non-aged and aged crowns, respectively. The non-aged crowns failed after 33,480.1 cycles (SD: 23,138.4 cycles), and the aged crowns failed after 28,456.1 cycles (SD: 10,158.7 cycles). There was no significant difference between the two groups for the load to failure or number of cycles to failure. The predominant form of failure was catastrophic crown fracture, which was observed for all the non-aged crowns and 9 of the aged crowns.CONCLUSION:Within the limitations of this study, aging of the implant-supported monolithic zirconia crowns with molar morphology did not affect the load to failure or the number of cycles to failure under cyclic loading. Since all the crowns failed at much higher loads than the expected physiologic loads, clinical application of implant-supported monolithic zirconia crowns to replace missing molars seems reasonable.

Aim: To load-test the osseo-integrated rectangular block implant (RBI), measure the generated cortical peri-implant strains, and relate these findings to known human physiological parameters. Materials and methods: Two RBIs were placed into the posterior mandibular saddle in a mature greyhound dog and allowed to osseo-integrate. The half mandible (implants in situ) was mounted in a servohydraulic system. Four triple-stacked rosette gauges were placed cortically (mesial, distal, buccal, and lingual). A modified ISO-14801 protocol was used (1000 N, 30(0), 2 Hz, 1 h) and the generated principal strains (ep, eq) and their angular orientations (F), were calculated. Results: (1) Bucco-lingual "horizontal" dimension: dominant "horizontal" compressive stresses were on the lingual aspect and "horizontal" tensile stresses on the buccal aspect. The buccal cortex was elastically tensile-stretched, while the lingual cortex was elastically compressed. (2) Bucco-lingual "vertical" dimension: dominant vertical torsional stresses were oriented buccally and apically, with an overall buccally inclined torsional effect. This was also evidenced on the lingual aspect, where there remained high torsional rotation elements (high F and e2). (3) Mesio-distal "horizontal" dimension: dominant torsional stresses oriented as a distal-lingual "counter-clockwise" rotation. Conclusions: The applied off-axial loads generated a heterogeneous pattern of bucco-lingual and mesio-distal cortical strains, both vertically and horizontally. The short dimensioned osseo-integrated RBI design appeared to biomechanically withstand the applied loads and to maintain the strains generated to levels that were within physiological limits. More studies and statistical analyses are needed to confirm these findings.

BACKGROUND:This study evaluated the ability of a CPP-ACP-modified Glass-ionomer cement (GIC) to inhibit demineralization around the margins of cervical cavities in natural teeth in comparison with a Giomer and conventional GIC with and without coating.METHODS:Thirty-two sound human molars were used. Box-shaped cavities were prepared along the CEJ. Teeth were randomly divided into four groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed.RESULTS:Microhardness tests on enamel showed a significant difference between the coated Equia group, Equia and Beautifil II groups (P &lt; 0.05). Dentine results showed significant differences between the coated Equia group and all other groups (P &lt; 0.05). Elemental analysis showed significant differences in calcium weight percentage among the first and second observation levels in all groups (P &lt; 0.05). A significant difference was found between the coated Equia group and the other three groups (P &lt; 0.05).CONCLUSIONS:All tested materials showed some ability to resist demineralization at the restoration margins. The coated GIC restoration showed better outcomes compared with the other tested materials.

Objective. The purpose of this laboratory study is to evaluate the application of a pre-sintered surface augmentation to zirconia (Zir) and lithium disilicate (LDS) ceramics on the delamination strength of adhesive resin cement. The applied surface augmentation was the ruling of lines to the pre-sintered surface of the ceramics. Methods. Ninety milled Zir and sixty pressed LDS specimens (3 mm & times; 0.5 mm & times; 25 mm) were created and divided into five groups (n = 30). Group 1: Zir no surface treatment (control Zir-NT); Group 2: Zir airborne particle abraded (Zir-APA) with 30 & micro;m CoJet; Group 3: Zir pre-sintered surface augmentation (Zir-SA); Group 4: LDS etched (control LDS-etched) and; Group 5: LDS with pre-sintered surface augmentation and etching (LDS-SA). A resin adhesive cement (3 mm & times; 1 mm & times; 8 mm) was then applied and cured to the ceramic specimens. The delamination strength values of the resin cement from the ceramic were recorded. The delamination strength data were analysed statistically using one-way ANOVA and Turkey post hoc analysis. Results. The mean delamination strength and standard deviation, when comparing only the Zir-SA to the resin cement were statistically different (p < 0.001); Zir-SA 63.42 +/- 11.85, Zir-NT 26.82 +/- 12.07, and Zir-APA 48.11 +/- 17.85 MPa. Comparison between LDS groups were not significantly different (p = 0.193); LDS-etched 33.49 +/- 16.07 and LDS-SA 28.83 +/- 10.15 MPa. The delaminated Weibull modulus was highest for surface augmentation Zir specimens (m = 13.56) but decreasing to less than half for Zir-APA (m = 6.27) and Zir-NT (m = 5.68). The Weibull values for the LDS-SA and LDS-etched specimens was 5.63 and 3.38 respectively. Significance. Incorporating the pre-sintered surface augmentation to zirconia improved the delamination strength and reliability of Zir to the resin cement but not for LDS. Crown Copyright (c) 2021 Published by Elsevier Inc. on behalf of The Academy of Dental Materials. All rights reserved.

BACKGROUND:Accurate implant impression is an essential requirement for the fabrication of implant prosthesis. This in vitro study evaluated the accuracy of digital impressions by intraoral scanner (IOS) systems in comparison to conventional impressions for recording the position of 2 parallel implants and 2 divergent implants.MATERIALS AND METHODS:In vitro 3-unit prosthesis master models with 2 tissue level implants were fabricated; one model had parallel implants, and the other model had one 15° tilted implant. The conventional open-tray impressions were obtained with non-splinted (NSP) and splinted (SP) impression copings. Trios 4 (TS), Medit i500 (MT), and True Definition (TD) were used to make digital impressions with scan bodies. A total of 10 impressions were obtained with every technique. The virtual test images of the conventional and digital impressions were converted to 2 virtual implant images. For each group, trueness, precision, inter-implant distance deviation, and angle deviation were measured.RESULTS:There was a general tendency for digital impressions to provide a more accurate outcome for trueness, precision, and angle deviation. The 2 conventional impressions showed similar accuracy, except for the angle deviation, where the NSP was significantly inferior than SP (p < 0.01) for the divergent implants model. The TD was generally the least accurate among all the IOS systems, especially for the inter-implant distance deviation (p < 0.05).CONCLUSIONS:Within the limitations of the laboratory set-up of the present study and the limited clinical resemblance, the digital impressions appeared to have sufficient accuracy for 2 implants and were least affected by the presence of angle between implants. The most inferior outcome was observed for the NSP technique.

Glass ionomer cements (GICs) are considered the material of choice for restoration of root carious lesions (RCLs). When bonding to demineralized dentin, the collapse of dentinal collagen during restorative treatment may pose challenges. Considering its acidic nature and collagen biomodification effects, proanthocyanidin (PAC) could be potentially used as a dentin conditioner to remove the smear layer while simultaneously acting to biomodify the dentinal collagen involved in the bonding interface. In this study, 6.5% w/v PAC was used as a conditioner for sound (SD) and laboratory demineralized (DD) root dentin before bonding to resin-modified GIC (FII), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-modified GIC (FVII), or a high-viscosity GIC (FIX). Root dentin conditioned with deionized distilled water (DDW) or polyacrylic acid (PAA) served as controls. Results indicated FII showed higher shear bond strength (SBS) on SD than the other 2 GICs, especially in PAA-conditioned samples; FIX showed significantly higher SBS than FII and FVII on PAA- or PAC-conditioned DD. In each category of GIC, PAA and PAC did not have a significant influence on SBS in most cases compared to DDW except for a significant decrease in PAC-conditioned SD bonded to FII and a significant increase in PAA-conditioned DD bonded to FIX. The bonding interface between GIC and SD was generally more resistant to the acid-base challenge than DD. Although the alterations in failure modes indicated a compromised interfacial interaction between GICs and PAC-treated root dentin, biomodification effects of PAC on dentin were observed from Raman microspectroscopy analysis in terms of the changes in mineral-to-matrix ratio and hydroxyproline-to-proline ratio of dentin adjacent to the bonding interface, especially of DD. Results from this study also indicated the possibility of using in situ characterization such as Raman microspectroscopy as a complementary approach to SBS test to investigate the integrity of the bonding interface.

A novel implant design, the rectangular block implant (RBI), was investigated as a possible solution to the restoration of the posterior resorbed ridge. To maximally load test the osseo-integrated RBI in shear and tensile loads and relate these findings to known human masticatory loads as biomechanical proof of the study concept. Twelve RBIs were design-manufactured and placed into posterior mandibular saddles in 3 mature greyhound dogs.—2 per left and right. After 12 weeks of healing, osseo-integration was confirmed using resonance frequency analysis (RFA) and wrench torque tests. Three bone blocks each with two RBIs were dissected and mounted in acrylic. Micro-computerized tomography (μ-CT) was performed to assess bone to implant contact (BIC), and load analysis was performed using a Universal Test System. Three force applications were conducted until failure: pull-out (tensile), buccal push from the lingual (shear) and distal push from the mesial (shear). The osteotomy sites were examined using light magnification and scanning electron microscopy (SEM). Pull-out, buccal and distal force failures occurred at differing levels. Post-detachment sites showed complex patterns of bone failure, including trabecular and cortical fracture, as well as shearing at varying distances from the BIC. Interfacial shear strength was calculated at 14.4 MPa. The osseo-integrated RBIs were able to withstand simulations of the demanding axially, bucco-lingually and mesio-distally oriented biomechanical challenges of the posterior saddle, under conditions of reduced bone volume. These values exceeded equivalent force components of maximal masticatory loads in humans.

The objectives of this study were to evaluate 4 aspects of ion-leaching restorative materials (ILMs): 4-point bending flexural strength (4 PB-FS) and relative mechanical properties; biaxial flexural strength (B-FS) in relation to 4 PB-FS; porosity; and surface morphology. Eleven ILMs were used for the 4-point bending test. Bar-shaped (n = 15) samples were fabricated, stored in distilled water for 7 days. Then 4 PB-FS and the other mechanical properties were determined. Five ILMs were selected for the B-FS test using disk specimens (n = 15). The correlation between 4 PB-FS and B-FS was addressed. After the 4 PB test, 5 randomised fragments from each material were used to make 0.5 mm-thick sections for light microscopy to investigate the degree of porosity using reflected and transmitted lights. Eight ILMs were selected for quantitative analysis of the fractional % pore volume (PV%) due to their relative pore prominence using ImageJ software. One-way ANOVA/Dunnett's T3 was used to test for significance. Resin-based ILMs (RB-ILMs) were ranked first (p < 0.05) for 4 PB-FS values (53.3-110.2 MPa) followed by resin-modified glass-ionomer cements (RMGICs; 30.9-44.3 MPa) and high-viscosity glass-ionomer cements (HVGICs; 12.9-19.6 MPa), respectively. 'Flexural modulus' (4 PB-E) and 'flexural toughness' (4 PB-T) of ILMs varied even though similar 4 PB-FS values were observed. There was a positive correlation (p < 0.001) between 4PB-FS and B-FS (R2 = 0.992) with B-FS>4 PB-FS. There was no correlation between PV% and 4 PB-FS. In summary, material type played a major role in 4 PB-FS outcomes, whereas PV% seemed to have a minor effect when evaluating each material group of ILMs. Brittleness/ductility of ILMs was observed when determining 4 PB-E and 4 PB-T relative to 4 PB-FS. When selecting materials for posterior load-bearing dental restorations in high-caries risk patients, RB-ILMs or RMGICs would be more appropriate due to their superior flexural properties compared with recently introduced HVGICs. The decision for each situation will also be dependent on further evidence of the ion-leaching capacity.

Objectives: The objectives of this study were to evaluate fluoride (F), calcium (Ca), and phosphate (P) release of ion-leaching restorative materials (ILMs), their recharge efficacy with a Ca/P-containing F varnish, and relative microhardness. Methods: Thirteen groups of materials were investigated. Cylindrical-shaped specimens were fabricated. Deionised water or lactic-acid solution were used as the storage media. Solutions were changed after 1d, 4d, 7d, and 14d of ion release and at the same periods after recharge with MI Varnish (7-h storage). F, Ca, and P measurements were accomplished using a fluoride-ion selective electrode, atomic absorption spectrometry, and colourimetric method by spectrophotometer, respectively. Relative Vickers hardness was proceeded with similar specimens used in the F assay (4 periods). SEM/EDS was additionally performed. Statistical analyses were calculated in each parameter (p < 0.05). Result: Hardness of several ILMs immediately increased after recharge. After 28d, Ketac Universal [a high-viscosity glass-ionomer cement (HVGIC)] showed the highest hardness similar to the resin composite control. Although 2 HVGICs (Zirconomer and Equia Forte Fil) ranked as first and second for F release/re-release, some HVGICs had inferior or comparable F capacity to RMGICs (Fuji VIII and Fuji II LC) and a resin-based (RB) ILM (Cention N). Cention N, Activa-Restorative (RB-ILM), and Zirconomer were the top-3 ranking for Ca release/rerelease. Activa-Restorative showed the highest P release, whereas Cention N displayed the greatest recharge ability for P. Conclusions: Zirconomer showed a versatile performance for ion-release/re-release, especially for F. Cention N had excellent capacity in relation to Ca release and recharge ability of Ca/P. Clinical significance: With the F varnish recharge protocol, Zirconomer, Equia Forte, and Fuji VIII seems to have an ability to inhibit initial caries initiation. Cention N is a promising resin-based material that could be an alternative for high caries risk patients due to the high Ca release/recharge with acceptable F release.

This study evaluated the effect of a modified tray design on the accuracy of implant impressions in comparison with the non-splinted and splinted impression techniques. Two titanium frameworks were produced to fit two parallel implants and two divergent implants with a 15o angle. According to the frameworks employed, two acrylic resin master models were fabricated. For each model, 10 impressions were taken with every technique. The maximum framework principal strain was calculated for every generated cast. For the parallel implant model, the strains of the non-splinted (118.4 με), splinted (89.0 με), and modified tray design impression (49.4 με) techniques were statistically similar (P = 0.16). For the divergent implant model, all the impression techniques showed a considerably higher strain than the parallel implant model. The splinted (287.0 με) and the modified (262.9 με) tray design impression techniques showed similar strains for the divergent implant model, which were significantly less than the strains for the non-splinted impression (518.0 με) technique (P < 0.05). Therefore, for two parallel implants, all the impression techniques exhibited similar accuracy. When angulation existed between the implants, the splinted and the modified tray design impression techniques were more accurate than the non-splinted impression technique.

Objectives. To evaluate the re mineralising effects of fluoride (F) varnishes containing bio avail- pro anthocyanidin able calcium-phosphate compound (Ca-P) based remineralisation systems and 5000 ppm F CPP-ACP toothpaste (FTP) on root caries lesions (RCLs) and the potential effects of proanthocyanidin TCP (PA) for the treatments of RCLs when used as an adjunct to F regimens. Methods. Demineralised root dentine and a pH-cycling model were used to mimic RCLs dentinal organic matrix and the oral environment. Remineralising effects of MI Varnish (TM) (MIV) containing casein root caries phosphopeptide-amorphous calcium phosphate (CPP-ACP) and Clinpro (TM) White Varnish (CPWV) containing tri-calcium phosphate (TCP) along with FTP and PA were evaluated regarding the birefringence, elemental composition, mechanical properties and mineral density of remineralised dentine with Duraphat (TM) as a comparison. Results. MIV, CPWV and Duraphat (TM) promoted the incorporation of F into RCLs and increased mineral density but did not change microhardness of root dentine significantly. Surface microhardness increased significantly when MIV or CPWV was used with 5000 ppm FTP. Application of PA with F regimens significantly increased subsurface mineral density. When PA was applied with MIV or CPWV along with FTP, the highest ion uptake and relative mineral gain (%Delta Z) was achieved, and significant increase of microhardness was up to 30 mu m depth. Generally, MIV was associated with a higher mineral content gain than CPWV. Significance. Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the highly organised structure of root dentine. Treatment strategies targeting both remineralisation and preservation of the dentinal organic matrix have the potential to improve the fluoride-mediated remineralisation approaches. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Purpose: To test a novel implant metal-acrylic prosthesis design in comparison to a conventional prosthesis design through simulation of cyclic masticatory loading. The novel design involved digital designing and fabrication of the framework and the matched veneering acrylic resin material. Materials and Methods: Ten prostheses were fabricated for each group. All the prostheses exhibited a similar external design on two implants with a distal cantilever. The conventional group comprised a milled metal framework with mechanically retained acrylic denture teeth via vertical pins. The digital prosthesis group incorporated an inverted T-shape bar and a monolithic milled acrylic resin veneer. The resin veneer was subsequently adhesively attached on the bar. All prostheses were thermally aged and subjected to laboratory cyclic loading at the cantilever region. The load-to-failure and the number of cycles until failure were collected. Furthermore, failed specimens were analyzed to determine the mode of failure. Results: The digital prostheses failed at significantly greater load-to-failure (1,570.0 N +/- 116.0 N) and number of cycles (124,857 +/- 21,608) than the conventional prostheses (load-to-failure = 1,015.0 N +/- 47.4 N; number of cycles = 28,452 +/- 6,559). The conventional prostheses failed by fracturing of the acrylic teeth and veneering material that led to exposure of the metal framework. Half of the digital prostheses failed by superficial chipping of the veneering material, while the other half failed by the deformation and fracture of screws. Conclusion: Within the limitations of this study, the digital prostheses with the novel design and monolithic veneering material showed significantly higher strength compared with the conventional prostheses. The mode of acrylic failure of the digital prostheses was more favorable.

Objective. To assess the effect of CPP-ACP/F recharging on ion release and hardness of GIC Fuji-Triage (VII) and Fuji-Triage-EP (VII-EP) containing CPP-ACP/F. Methods. CPP-ACP distribution in Fuji-Triage-EP was determined using immunofluorescence. Thirty blocks of Fuji-Triage and Fuji-Triage-EP with the same surface area were placed individually in 5 mL of 50 mM lactic acid (pH 5) for three days. Every 12 h ten Fuji-Triage and ten Fuji-Triage-EP blocks were treated with 2 mL of either MI Paste Plus (CPP-ACP/F) solution (1 g paste + 4 mL water), Placebo MI paste solution (no CPP-ACP/F), or distilled water for 2 min. After each 2 min treatment the blocks were rinsed with distilled water and placed back into the acid. Calcium, inorganic phosphate and fluoride levels in the acid solution were measured using atomic absorption spectrophotometry, colorimetry and ion specific electrode respectively. Vickers surface hardness of the GIC was also determined. Data were analysed using a two-sample t-test and one-way ANOVA with a Bonferroni-Holm correction for multiple comparisons. Results. CPP-ACP was distributed throughout Fuji-Triage-EP. Significantly (p < 0.001) higher calcium, inorganic phosphate and fluoride ion release and greater surface hardness (acid resistance) was observed in both GIC's treated with the CPP-ACP/F paste. Fuji-Triage-EP released higher ion levels and exhibited greater surface hardness (acid resistance) than Fuji-Triage. Significance. Topical application of CPP-ACP/F paste to GIC Fuji-Triage-EP recharged ion release and increased surface hardness (acid resistance) which may help improve properties and resistance to degradation as well as improve ion release for caries control. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Glass Ionomer Cements (GICs) are brittle materials with low fracture toughness and strength. Therefore, understanding the fracture toughness is an important parameter to know, due to GICs being promoted for load-bearing restorations. Also, little is known about the effects of artificial saliva (AS) on fracture toughness of GICs. This project aimed to study the effects of storage and compare two different fracture toughness test methods, namely: Compact-Tension test and 4-point bending test. Samples were made from a Zinc-reinforced-GIC (ChemFil), High viscosity bulk-fill-GIC (HV) with and without LC-coating (EQUIA), Resin-Modified GIC (RM-GIC) (Riva-LC), HV-RMGIC (Riva-HV-LC) and flowable bulk-fill Giomer (Beautifil-Bulk Flowable) using a custom-made mould. Specimens were stored in either AS or distilled-water (DW) for 7 or 30 days, After storage, specimens were tested for fracture toughness. Results were analysed with Analysis of variance (ANOVA), Mann-Whitney and Weibull statistics. ANOVA showed a significant difference (P < 0.05) between methods, however the same trend among materials was observed in both methods. Some materials showed significantly higher values for samples stored in DW and others revealed the same trend but were not significant. Significantly higher (P < 0.05) mean fracture toughness values were observed for materials stored for 30 days. Since both fracture toughness test methods revealed the same fracture toughness strength order among materials, either test appears appropriate. GICs maturation led to a difference between 7 and 30-day results. The AS used had a high ionic strength compared to DW, which may have led to increased solubility of GICs and consequently to the reduced fracture toughness values. The results revealed that coating the GIC has a protective effect against storage media.