Impact of Type 2 Diabetes Mellitus on the Occurrence of Vertical Root Fracture: A Case Control Study.

INTRODUCTION: The aim of this case-control study was to examine the relationship between type 2 diabetes mellitus (DM) and the occurrence of VRFs. The crack extension, dentin sclerosis, and chemical characteristics of root dentin in teeth with VRF from patients with/without DM were also compared. METHODS: One hundred and thirty-two patients diagnosed with VRF in crowned root filled posterior teeth were selected. The study was conducted in 2 parts. In Part-1: The cases were matched with control teeth (1:1) for age (±5 years), sex, tooth type, apical extent of root filling, time period after root filling to a diagnosis of VRF, presence or absence of intracanal post and abutment status. The presence or absence of type 2 DM (HbA1c > 6.5) was recorded. In Part-2: The extracted teeth with VRF from the case control study were used to evaluate the extension of VRF, presence of sclerotic dentin and isthmus using a microscopic analysis; while the levels of pentosidine, collagen cross-linking ratio and mineral-collagen ratio were determined by Fourier-transform infrared spectroscopy. The distribution of DM between cases and controls was analyzed using Pearson Chi-Square test and Odds Ratio estimated. Chemical composition data was analyzed using Mann-Whitney test. The extent of sclerotic dentin was analyzed using Pearson Chi-Square test. RESULTS: When compared to patients without DM, patients with DM had 2.67 (95% CI: 1.6-4.45) folds higher odds for occurrence of VRF. Pentosidine (P = .014), collagen cross-linking ratio(P = .047), mineral-collagen ratio (P = .009) and sclerotic dentin extent (P = .0009) were significantly higher in patients with DM and VRF. CONCLUSIONS: Type 2 DM was more often associated with VRFs in root canal treated teeth with crowns. Root dentin from patients with type 2 DM and VRF had higher levels of pentosidine, collagen cross-linking ratio, mineral to collagen ratio and sclerotic dentin.

Study of Root Transparency in Different Postmortem Intervals Using Scanning Electron Microscopy.

In the fields of forensics, the identification of human remains is a recurrent problem. The estimated age at death is one of the copious criteria to be evaluated. In adult teeth, the height of the root dentin transparency is used to estimate age. However, in archaeological material, this phenomenon appears inconstant. The aim of this work was to observe the structural modifications of the sclerotic dentin in the teeth for different postmortem intervals. The study included two parts (retrospective and prospective study) with 21 human monoradicular teeth, from bodies donated to medical science with postmortem intervals (PMIs) of 0, 1, 2 and 5 years and archeological excavation. After inclusion based on resin, section and polishing, the samples were analyzed with a scanning electron microscope (SEM) JSM-7800F®, and the procedure was completed via a semiquantitative analysis of calcium and phosphorus using EDX microanalysis. The analysis showed the existence of tubular and chemical modifications of sclerotic dentin at different PMIs. Our SEM study allowed us to observe a difference in tubule aspects linked to an increased PMI: the loss of peritubular collar and the lumen obstruction of tubules with a hyperdense material. Microanalysis highlighted variations in phosphocalcic ratios among the different groups, especially in the pulp area and the canine. Our hypotheses that explain these differences are based on the postmortem modifications of the crystals of the mineral phase of sclerotic dentin under the influence of chemical and/or bacterial action.

Comparison of Dentin Microstructure and Its Correlation to the Direction of Fracture Line in Mandibular Molars of Young and Older Individuals: In Vitro Study.

INTRODUCTION: The aim of the study was to assess the presence and extent of sclerotic dentin and to study its impact on the direction of fracture lines in extracted mandibular first molars of young (20-44 years) and older age groups (45 and older). METHODS: Extracted permanent mandibular first molars were collected along with the related demographic details. A total of 40 teeth were included in this study, 20 each from young age group (YA group) (20-44 years) and older age group (OA group) (45-70 years). All molars were decoronated, and the sectioned mesial roots were embedded in acrylic blocks. They were subjected to vertical force in a universal testing machine. Fractured roots were then examined under the stereomicroscope at ×8 magnification to determine the direction and pattern of the fracture line. The roots were then sectioned and evaluated at ×10 and ×20 magnification to assess the dentin microstructure and its correlation with the direction of the fracture line. Statistical analysis was done by using χ2 test (P < .05). RESULTS: A greater incidence and degree of sclerotic dentin were found in the OA group as compared with the YA group, which was statistically significant. The sclerotic dentin was distributed predominantly mesiodistally and the fracture line propagated buccolingually in both young and older groups, which was statistically significant (P < .05). CONCLUSIONS: The presence of sclerotic dentin mesiodistally may impede crack propagation in this direction for both young and older age groups, causing the fracture line to extend buccolingually in coronal third of the root.

Glass Hybrid Versus Nanocomposite for Restoration of Sclerotic Non-carious Cervical Lesions: 18-Month Results of a Randomized Controlled Trial.

PURPOSE: To compare the clinical performance and treatment times between glass hybrid (GH; EQUIA Forte Fil/EQUIA Forte Coat, GC) and adhesive/nanofilled resin composite restorations (RC; OptiBond FL, Kerr/Filtek Supreme XTE, 3M Oral Care) of sclerotic non-carious cervical lesions (sNCCL). MATERIALS AND METHODS: This is an 18-month interim analysis of a 36-month cluster-randomized trial (ClinicalTrials.gov Identifier: NCT02631161). Eighty-eight patients (50-70 years) with 175 sNCCLs were randomized to receive GH or RC restorations. Restorations were placed without mechanical cavity preparation, and treatment time was recorded. After 18 months, restorations were evaluated using FDI criteria. Factors associated with restoration survival were evaluated using multi-level Cox-regression analysis. Generalized linear mixed modelling was used to analyze factors associated with treatment time. RESULTS: After a mean of 18 months (min/max: 8/25), 78 patients (160 restorations) were assessed. Fifteen restorations (18%) failed in GH, and 11 (12%) in the RC, without a significant difference in survival (p = 0.904/Cox). Retention loss was the most common reason for failure in both groups. Restorations placed in older patients showed lower risk of failure [OR (95% CI): 0.90 (0.81-0.99) per year], while mandibular teeth showed higher risks [2.89 (1.00-8.31)]. Treatment time was significantly shorter for GH (mean ± SD: 8.6 ± 4.3 min) than RC (11.7 ± 5.7 min; p < 0.001). CONCLUSIONS: GH may be a suitable alternative to RC for restoring sNCCLs, without any significant difference in survival between the two materials at this interim analysis. In addition, placing GH restorations required less chairtime than did placing RC restorations.

INFLUENCE OF COMPOSITE RESIN ADHESIVE PROTOCOL ON NON-CARIOUS CERVICAL LESIONS ON SCLEROTIC DENTIN. SYSTEMATIC REVIEW. / INFLUENCIA DEL PROTOCOLO ADHESIVO DE RESINAS COMPUESTAS EN LESIONES CERVICALES NO CARIOSAS SOBRE DENTINA ESCLERÓTICA. REVISIÓN SISTEMÁTICA.

The amount of adult people around the world that present NCCL, is about 46,7% and with the growing trend of population aging, that condition has been growing last years, occurring frequently in the age group over 55 years. An important challenge for dentistry has been obtaining an adequate bond between the composite resin and the dentin, where it is still inaccurate around the junction in sclerotic dentin. It is necessary to contrast which protocol or adhesive technique provides an improvement in the adhesive-dentin interface, to achieve better adhesion of NCCL composite resin restorations on sclerotic dentin. This thesis project reviewed the literature on its way to find randomized clinical studies on adhesive protocols in composite resin restorations in NCCL on sclerotic dentin, by searching on MEDLINE/PUBMED, ELSEVIER/SCOPUS y WEB OF SCIENCE, hoping to identify the adhesive protocols that provide the best clinical behavior and longevity, presenting a surface treatment that improves the retention of composite resin restorations in NCCL with sclerotic dentin. 11 articles were studied meeting the standards established in this SLR. We conclude that there are techniques or protocols that have a very good influence adherence, where the vigorous application of adhesive systems and the pretreatment of the dentin with EDTA 15-17% for 1-2 minutes, increases the retention rates of the composite resin restorations in NCCL on sclerotic dentin.

La prevalencia de las LCNC a nivel mundial entre la población adulta es del 46,7%, y con una tendencia al envejecimiento poblacional, esta ha ido aumento, siendo más asiduo en el grupo de más de 55 años. Un reto importante para la odontología ha sido lograr una unión adecuada entre la resina compuesta y la dentina, donde aún es visible una nebulosa en torno a la unión en dentina esclerótica. Se hace necesario contrastar cual protocolo o técnica adhesiva otorga una mejora en la interfaz adhesiva-dentinaria, para lograr una mayor adhesión de restauraciones de resina compuesta en LCNC sobre dentina esclerótica. Esta revisión sistemática buscó en la literatura estudios clínicos aleatorizados sobre protocolos adhesivos en restauraciones de resina compuesta en LCNC sobre dentina esclerótica, mediante una búsqueda en MEDLINE/PUBMED, ELSEVIER/SCOPUS y WEB OF SCIENCE, en la cual, se espera identificar los protocolos adhesivos que otorguen el mejor comportamiento clínico y mayor longevidad, estableciendo un tratamiento de superficie que mejore la retención de restauraciones resina compuesta en LCNC con dentina esclerótica. Se consideraron 11 artículos, los cuales cumplían con los criterios de elegibilidad establecidos en esta RSL. Podemos concluir que existen técnicas o protocolos que influyen positivamente en la adhesión, donde la aplicación vigorosa de los sistemas adhesivos y el pretratamiento de la dentina con EDTA al 15-17% por 1-2min aumentan las tasas retención de las restauraciones de resina compuesta en LCNC sobre dentina esclerótica.

Glass hybrid versus composite for non-carious cervical lesions: Survival, restoration quality and costs in randomized controlled trial after 3 years.

OBJECTIVE: This study compared survival, restoration quality and costs of glass hybrid (GH; EQUIA Forte Fil/EQUIA Forte Coat) and resin composite restorations (RC; OptiBond FL/Filtek Supreme XTE) of sclerotic non-carious cervical lesions. METHODS: This is a cluster-randomized trial (ClinicalTrials.gov: NCT02631161). 88 patients (50-70 years) with 175 sNCCLs were randomized to receive GH or RC. Restorations were placed without mechanical cavity preparation and followed for a mean 36 (min/max: 31/55) months (variable follow-up due to COVID-19 lockdown). Restoration quality was re-evaluated at 1-, 18- and 36-months using FDI-criteria. Survival was assessed using multi-level Cox-regression analysis. Costs were estimated from a payer's perspective in Germany. Initial costs were determined based on micro-costing using time recordings and hourly costs, and follow-up costs based on statutory insurance fee-item-catalogues. RESULTS: 88 patients (175 restorations) were treated; 43 received GH (83 restorations), 45 RC (92 restorations). 17  GH and 19 RC showed total retention loss, 5  GH were partially lost (p = 0.396/Cox). FDI ratings were not sufficiently different for any domain except surface luster, where RC showed higher score (p < 0.001). Costs were initially lower for GH (32.57; SD 16.36 €) than RC (44.25; SD 21.40 €), while re-treatment costs were similar (GH: 9.15; SD 15.70 €; RC: 7.35; SD 14.51 €), resulting in significantly lower costs for GH (GH: 41.72; SD 25.08 €) than RC (51.60; 26.17 €) (p < 0.001/GLM). CONCLUSIONS: While survival was not significantly different, GH was significantly less costly both initially and long-term than RC for restoring non-carious cervical lesions. CLINICAL SIGNIFICANCE: Within this trial, survival was not significantly different between GH and RC to restore sclerotic NCCLs. As GH was significantly less costly both initially and long-term than RC, using RC was only cost-effective for payers willing to invest high additional expenses per minimal survival gains.

The "Butterfly Effect" and Its Correlation to the Direction of the Fracture Line in Root Dentin.

INTRODUCTION: The butterfly effect is an optical phenomenon and is related to the presence of sclerotic dentin in the roots. The unique pattern of sclerotic dentin formation produces a characteristic butterfly shape in transverse sections of the roots. The objective of this study was to evaluate the direction of the fracture line in roots that exhibit the butterfly effect. METHODS: Thirty single-rooted premolars with oval-shaped roots were decoronated and embedded in acrylic blocks and subjected to vertical force under a universal testing machine (HPBSD; Tec-Sol India, Chennai, India). Fractured roots were examined under a stereomicroscope (Model no. 080772; Lawrence and Mayo, Mumbai, India) at ×10 magnification to determine the location and direction of the fracture line. To evaluate the correlation between the direction of sclerotic dentin and the direction of the fracture line, teeth were sectioned and observed under a stereomicroscope at ×20 and ×40 magnification. The correlation was analyzed using the Fisher exact test (P < .05 for the coronal and apical thirds and P > .05 for the middle third). RESULTS: Sclerotic dentin was observed more in the apical area and less in the coronal third of the root. The correlation between the direction of sclerotic dentin and the direction of the fracture line was statistically significant in the coronal and apical thirds of the root. CONCLUSIONS: The vertical root fracture that runs buccolingually is correlated to the harder sclerotic dentin present in the mesiodistal direction.

Effect of different surface treatments of human occlusal sclerotic dentin on micro-tensile bond strength to resin composite core material.

The objectives of this study were to evaluate the micro-tensile bond strength (µTBS) of composite bonded to human occlusal sclerotic dentin following different surface treatments to determine the sclerotic dentin morphology. Human molars without (normal dentin; group 1) or with occlusal wear (sclerotic dentin; groups 2-5) were divided and subjected to different surface treatments, including the normal protocol for the Contax self-etch bonding system (group 1 and 2); doubled etch-prime time (group 3); pre-conditioning with 37% phosphoric acid before normal protocol (group 4); or pre-conditioning with 37% phosphoric acid before doubling the self-etching time (group 5). All teeth were restored with composite (Luxacore Z dual), sectioned into stick specimens and stored for 24 h in water before specimens were subjected to the µTBS test (n = 50 per group). The µTBS of normal dentin was not statistically significantly different from that of the sclerotic dentin groups, except for the doubled etch-prime time group which showed lower µTBS. Sclerotic dentin pre-treated with phosphoric acid resulted in less sclerotic casts and wider dentinal tubules, while doubled etch-prime time did not alter the morphology, as shown by scanning electron microscopy. In conclusion, the use of 37% phosphoric acid before applying self-etch bonding resulted in more tubule openings and a significantly higher µTBS when compared with the doubled etch-prime time group.

The microtensile bond strength test: Its historical background and application to bond testing.

Microtensile bond strength (µTBS) test was introduced in 1994. Since then, it has been utilized profoundly across many bond strength testing laboratories, making it currently one of the most standard and versatile bond strength test. Although it is a static and strength-based method, together with the morphological and spectroscopic investigations, it has been contributing immensely in the advancement of dentin adhesive systems. µTBS test has a greater discriminative capability than the traditional macro-shear bond test. During the early stage of its development, the authors predicted that this testing method would enable evaluation of the adhesive performances of resins to excavated carious or sclerotic dentin and the regional bond strengths of various portions of the cavity. In addition, they also stated the possibility of comparing the long-term stability of resin adhesion at various portions of the cavity walls on teeth extracted at various times after insertion of bonded restorations. In this review, we discussed the historical background, inception and the application of the µTBS test and proposed directions for further improvement of this testing method.

A comparative study of the microtensile bond strength and microstructural differences between sclerotic and Normal dentine after surface pretreatment.

BACKGROUND: The resin bond strength of sclerotic dentine is significantly lower than that of the normal dentine, which paused a challenge for bonding procedures clinically. The aim of this study was to compare the effects of different surface pretreatments on the micro-tensile bond strength and microstructure between sclerotic dentine and normal dentine. METHODS: Eighty teeth that were collected, forty premolars with typical wedge-shaped defects visually graded as class III were assigned as the sclerotic dentine group (SD), the other forty normal premolars with artificial wedge-shaped defects were assigned as the normal dentine group (ND). Each group was randomly subdivided into eight subgroups according to the solution used: 35% phosphoric acid, 15% EDTA, 5% or 10% NaClO. Then the dentine surface was examined using a scanning electron microscope (SEM). The lesions were restored using self-etching adhesive and the subsequent resin composite. The teeth were sectioned into sticks for the micro-tensile bond strength analysis, and the data were analysed using the SPSS17.0 software package (α = 0.05). RESULTS: First, for the ND groups, after pretreatment using 35% phosphoric acid, and 35% phosphoric acid + 5% or 10% sodium hypochlorite, the bonding strengths of the normal dentine were higher than that of the other groups (P < 0.05). Second, for the SD groups, after pretreatment using 35% phosphoric acid, 15% EDTA, and 35% phosphoric acid + 5% or 10% sodium hypochlorite, the bonding strengths of the sclerotic dentine were higher than that of the other groups (P < 0.05). Third, the bond strengths of the sclerotic dentine were lower than that of the normal dentine without any pretreatment (P < 0.05). After pretreatment using 35% phosphoric acid + 5% or 10% sodium hypochlorite, the bonding strengths of the sclerotic dentine were higher than that of the normal dentine (P < 0.05). SEM observation showed that the appearances of dentine surface were changed after pretreatment using the above solutions, with the reduced smear layer, opened small groove and increased dentinal tubules. CONCLUSION: Pretreatment of dentine using 35% phosphoric acid+ 5% or + 10% sodium hypochlorite changed the microstructure of the sclerotic dentine surface and subsequently increased the micro-tensile bond strength.

Sclerostin inhibits odontogenic differentiation of human pulp-derived odontoblast-like cells under mechanical stress.

Sclerotic dentin is a natural self-protective barrier beneath non-carious cervical lesions (NCCLs), which are mainly induced by mechanical stress. Sclerostin is a mechanosensory protein and serves as an inhibitor of dentinogenesis. However, its function on mechanotransduction in dentine-pulp complex has not been elucidated yet. In this study, decreased sclerostin expression was detected in odontoblasts beneath NCCL-affected sclerotic dentin. Then human pulp-derived odontoblast-like cells (hOBs) were subjected to mechanical strain (MS) in vitro: the results showed that MS-induced upregulation of odontogenic differentiation markers (dentin sialophosphoprotein, osteopontin, osteocalcin, and runt-related transcription factor 2) in hOBs with downregulated sclerostin expression, and this inductive differentiation was attenuated when sclerostin was overexpressed. Additionally, MS activated ERK1/2 pathway and ERK1/2 inhibition restored MS-induced downregulation of sclerostin. Proteasome inhibitor MG132 could also rescue MS-induced decrease of sclerostin. Furthermore, MS suppressed STAT3 pathway, which could be reversed by sclerostin overexpression. STAT3 inhibition was shown to ameliorate the reduction of odontogenic markers induced by sclerostin overexpression. Taken together, we conclude that MS downregulates sclerostin expression via the ERK1/2 and proteasome signaling pathways to promote odontogenic differentiation of hOBs through the STAT3 signaling pathway. It can therefore be inferred that under mechanical stress, sclerostin inhibition promotes reactive dentin formation by enhancing odontogenic differentiation of odontoblasts, which might be one of potential forming mechanisms of sclerotic dentin beneath NCCLs.

Alteraciones de la dentina con el envejecimiento / Dentin alterations with aging

Diferentes estudios han demostrado que después de la tercera década de vida hay una transición en la microestructura de la dentina. Dada la importancia de ésta como sustrato para la adhesión de materiales de restauración utilizados en operatoria y rehabilitación oral, ha sido objetivo de este trabajo realizar una búsqueda bibliográfica de las publicaciones existentes en inglés y español de los últimos 15 años, haciendo uso de buscadores científicos como Pubmed, Google Schoolar y LILACS que permitieran actualizar la información existente ayudando a entender los efectos biológicos del envejecimiento de la dentina, identificando los cambios de mayor relevancia a nivel histológico. De la búsqueda realizada se concluye que el envejecimiento de la dentina está asociado con aumento de dentina secundaria, formación de dentina esclerótica opaca, variaciones en la composición química de la matriz y disminución del número y actividad de los odontoblastos. Los conocimientos sobre el envejecimiento de la dentina deben tenerse en cuenta frente a estudios relacionados con materiales de restauración dental, ya que los cambios en la microestructura y capacidad funcional de la dentina con el envejecimiento requieren que éstos se adapten a dichas variaciones (AU)

Different studies have shown that aafter the third term of life there is a transition in the microstructure of dentin. Given the importance of dentin as a substrate for the adhesion of restorative materials used in operative and oral rehabilitation, the aim of the present work was to conduct a search of the scientific literature in English and Spanish, published in the last 15 years, using search engines such as Pubmed, Google Schoolar and LILACS, for an update on the biological effects of dentin aging, to identify the most relevant age-related histological changes in dentina. The data obtained from the literature review allow concluding that dentin aging is associated with an increase in secondary dentina, opaque sclerotic dentin formation, variations in the chemical composition of the matrix and a decrease in odontoblast number and activity. Updated information on dentin aging should be taken into account in studies on dental restoration materials, since the latter must adapt to aging-related changes in the microstructure and functional capacity of dentin (AU)

EDTA Conditioning Increases the Long-term Microtensile Bond Strength to Sclerotic Dentin Mediated by Self-etch Adhesives.

PURPOSE: To evaluate the immediate and 12-month microtensile bond strength (µTBS) of two self-etch adhesives on sclerotic dentin with or without previous EDTA conditioning. The conditioning pattern and the relative area of open dentinal tubules were also evaluated. MATERIALS AND METHODS: Twenty-eight bovine incisors with naturally exposed sclerotic dentin were used. For µTBS testing, 20 teeth were divided into 4 groups (n = 5) according to the combination of the main factors: 1. adhesive (Clearfil SE Bond [CSE, Kuraray] and Adper SE Plus [ADSE, 3M Oral Care]); 2. surface treatment (previous conditioning with EDTA and previous conditioning with distilled water [DW]). The sclerotic surfaces were conditioned with either 17% EDTA or DW for 2 min prior to adhesive application. Composite buildups were constructed. Specimens were sectioned to obtain composite-dentin sticks (0.8 mm2) to be tested immediately or after 12 months (distilled water at 37°C) in tensile mode (0.5 mm/min). The conditioning pattern and the relative area of open dentinal tubules (OT) were evaluated in the remaining eight teeth. After adhesive application, the surfaces were rinsed off with acetone and ethanol. Then the surface was evaluated by SEM with image software. Data from µTBS and OT were submitted to three-way repeated measures ANOVA and data from OT were submitted to one-way repeated measures ANOVA. After, for both tests, Tukey's post-hoc test was applied (α = 0.05). RESULTS: For both adhesives, EDTA resulted in the highest mean immediate µTBS (p = 0.002), which remained stable after 12 months of water storage (p < 0.38). CSE showed higher µTBS when compared to ADSE (p = 0.001). Degradation of the mean µTBS was observed for both adhesives only in the DW groups. Adhesive application plus with EDTA conditioning increased the OT area in comparison with only adhesive application (p < 0.001). CONCLUSION: EDTA conditioning increased the immediate microtensile bond strength in sclerotic dentin substrate and prevented degradation when associated with a self-etch adhesive.

Estudo comparativo in vitro das estruturas orgânicas e inorgânicas da dentina saudável e esclerosada humana e bovina: nanodureza, concentração de Ca e P e análise morfológica / In vitro comparative study of organic and inorganic components analysis of health and sclerotic human and bovine dentin: nanohardness, Ca and P concentration and morphological analysis

A dentina esclerosada é um substrato comumente encontrado em pacientes idosos. No entanto, existem poucos estudos comparativos entre dentina humana e bovina esclerosadas. O objetivo deste estudo foi comparar os componentes inorgânicos e orgânicos da dentina saudável e esclerosada humana e bovina, através de cinco parâmetros: nanodureza, módulo de elasticidade, análise quantitativa da concentração de Cálcio (Ca) e Fósforo (P), densidade tubular e morfologia do colágeno. Trinta dentes humanos e 30 bovinos foram distribuídos em 4 grupos experimentais (n=15 por grupo): dentina humana saudável (DHS), esclerosada humana (DEH), bovina saudável (DBS), e bovina esclerosada (DBE). Os dentes saudáveis foram preparados na mesma altura e inclinação dos dentes esclerosados expondo níveis similares da dentina e obtendo fragmentos com 2mm de espessura. Foram realizadas 3 medições por espécime em 3 áreas pré determinadas de dentina intertubular com a utilização do Nanoindentador (carga de 500N por 5 s). Cinco espécimes de cada grupo foram preparados para Microscopia Eletrônica de Varredura (MEV). Com o auxílio da Energia Dispersiva por Raios-X EDX foram obtidos os valores (em percentagem) das concentrações de Ca e P e calculada a relação Ca:P. A contagem dos túbulos por área foi realizada em todas as eletromicrografias. Após descalcificação e preparo, o restante dos espécimes foi analisado em Microscopia Eletrônica de Transmissão (MET)...

The sclerotic dentin has been commonly found in elderly patients. However, there are scarce reports in the literature comparing on the use of human and bovine sclerotic dentins. The objective of this study was to compare inorganic and organic components of healthy and sclerotic dentins from human and bovine. Five parameters were analyzed: nanohardness, elastic modulus, quantitative analysis of Calcium (Ca) and Phosphorous (P) concentrations, tubular density and ultrastructural morphology. Thirty human teeth plus 30 bovine teeth were distributed in 4 experimental groups (n=15 per group): human healthy dentin (HHD), human sclerotic dentin (HSD), bovine healthy dentin (BHD) and bovine sclerotic dentin (BSD). Healthy teeth were cut in the same level and inclination of the sclerotic superficial dentins. The nanohardness and elastic modulus (GPa) of three pre determined areas of each exposed dentin was measured using a nanoindenter (500N for 5s). Five samples of each group were prepared for scanning electron microscopy (SEM) examination. Energy Dispersive X-ray (EDX) was used for obtaining the Ca/P ratio. The tubular density was obtained by counting the tubules in scanning electron micrographs taken in the same magnification and work distance...

Ultrastructural study of non-carious cervical sclerotic dentin bonded by a all-in-one self-etch adhesive / 实用口腔医学杂志

Objective:To examine the ultrastructure of resin-infiltrated sclerotic dentine following the application of an all-in-one self-etch dentin adhesive. Methods:Naturally-occurring, non-carious cervical sclerotic lesions on 10 extracted premolars were bonded using an all-in-one self-etch dentin adhesive(Adper Prompt L-Pop,3M ESPE, St Paul, USA).Artificially prepared wedge-shaped lesions were also made in 10 extracted sound premolars and restored using the same adhesive as the controls. The morphological change of dentin surface conditioned by the adhesive and the dentin-resin interface were studied by SEM.Results:Most dentinal tubules were obliterated by rod-like sclerotic casts in the non-carious cervical lesion, the sclerotic casts could not be totally dissolved by the self-etch adhesive. After restoration the resin tags were fewer and shorter in sclerotic dentin than those in sound dentin.Conclusions:Bonding to sclerotic dentin is different from that to sound dentin, and may be compromised by the fewer resin tags.