Coronal Pulp Research Articles

Comparison of diffusion, cytotoxicity and tissue inflammatory reactions of four commercial bleaching products against human dental pulp stem cells

Multiple side effects related to bleaching were found to occur in the dental pulp tissue, including decreased cell metabolism and viability. In this work we evaluated the in vitro diffusion capacity, cytotoxicity and biocompatibility of four commercial bleaching products on stem cells from human dental pulp (hDPSCs). Two commercial bleaching gels hydrogen peroxide-based (HP), Norblanc Office 37.5% (Nor-HP) and Opalescence Boost 40% (Opal-HP) were applied for 30 min to enamel/dentine discs. Another two gels from the same manufacturers, 16% carbamide peroxide-based (CP), Norblanc Home (Nor-CP) and Opalescence CP 16% (Opal-CP), were applied for 90 min. The diffusion of HP was analysed by fluorometry. Cytotoxicity was determined using the MTT assays, the determination of apoptosis, immunofluorescence assays and intracellular reactive oxygen species (ROS) level. Tissue inflammatory reactions were evaluated histopathologically in rats. Statistical differences were performed by one-way ANOVA and Bonferroni post-test (α < 0.05). Normon products showed lower cytotoxicity and diffusion capacity than the Ultradent products. A high intracellular ROS level was measured in hDPSCs after exposure to Opal-HP. Finally, a severe necrosis of both coronal and radicular pulp was observed with Opal-HP. Similar concentrations of hydrogen peroxide and carbamide peroxide in a variety of bleaching products exhibited different responses in cells and dental pulp tissue, suggesting that bleaching products contain unknown agents that could influence their toxicity.

In vivo fate of bone marrow mesenchymal stem cells implanted into rat pulpotomized molars

In our previous work, we established an in vivo coronal pulp regeneration model in which biodegradable hydrogel-made scaffolds carrying rat bone marrow mesenchymal stem cells (BM-MSCs) were implanted in the coronal pulp chamber of pulpotomized rat maxillary first molars. In this study, we investigated the in vivo fate of LacZ-labeled BM-MSCs in our coronal pulp regeneration model. BM-MSCs were nucleofected with pVectOZ-LacZ plasmid encoding β-galactosidase 1 day before implantation, and the LacZ-transfected BM-MSCs were implanted into the pulpotomized pulp chamber with biodegradable preformed scaffold-hydrogel constructs. Empty vector was used as a control. After 3 and 14 days, the molars were retrieved and subjected to β-galactosidase staining. At 3 days, β-galactosidase-expressing cells with a round profile were located mainly around the scaffold. At 14 days, when the pulp-like tissue had been generated, the majority of β-galactosidase-expressing cells were detected under the newly formed dentin bridge-like structure, where nestin-expressing odontoblast-like cells were arranged. Immunoreactivity for dentin sialoprotein, a marker of mature odontoblasts, was strongly detected under the original dentin. No β-galactosidase staining was observed in the control group. Thus, we demonstrated that BM-MSCs survived for 2 weeks after implantation and colonized within the site of potential cytodifferentiation. Our findings indicated that BM-MSCs could differentiate into cells involved in mineralized tissue formation in the functionally relevant region.

The first Neanderthal specimen from Serbia: Maxillary first molar from the Late Pleistocene of Pešturina Cave

Neanderthals were the only human group in Europe throughout the Late Pleistocene until the arrival of modern humans, and while their presence has been confirmed in the surrounding regions, no Neanderthal fossils are known to date from the Central Balkans. Systematic excavations of Pešturina Cave (Serbia) resulted in the discovery of a permanent right M1 (Pes-3). The specimen was recovered from stratigraphic Layer 4b with an estimated age of 102.4 ± 3.2 ka, associated with Mousterian artifacts. The exceptional state of preservation and minimal wear of the molar enabled a detailed description and comparative analysis of the inner and outer dental structure, including non-metric dental traits and morphometric features of the crown, roots, and dental tissues. The results of this study strongly support the identification of Pes-3 as Neanderthal. Non-metric traits of the occlusal surface of the crown, enamel-dentine junction, and roots are consistent with Neanderthal morphology. The crown shows morphometric features typical for Neanderthal M1, such as a buccolingually skewed crown shape, internally compressed cusps, and a relatively large hypocone. The specimen also shows Neanderthal-like dental tissue proportions, characterized by relatively thin enamel and large coronal dentine and coronal pulp volumes. The discovery of the Pes-3 molar therefore confirms the presence of Neanderthals in the territory of Serbia and the Central Balkans at the end of Marine Isotope Stage (MIS) 5c.

Healing Capacity of Autologous Bone Marrow–derived Mesenchymal Stem Cells on Partially Pulpotomized Dogs' Teeth

IntroductionPartial pulpotomy is a vital treatment for carious and traumatic exposure, especially in young permanent teeth. Cell-based therapy for partially pulpotomized teeth can be considered a promising approach for dentin-pulp complex regeneration. This study evaluated the healing capacity of autologous bone marrow–derived stem cells (BMSCs) on partially pulpotomized teeth in a dog model. MethodsTwelve mongrel dogs were selected, and a total number of 192 posterior mandibular and maxillary teeth were involved in the study (16 teeth per dog). Partial pulpotomies were performed, and the dogs were assigned into 2 equal groups (groups 1 and 2), 6 dogs in each group. The coronal pulp cavities (n = 96) of group 1 were filled with calcium silicate–based capping material. Group 2 coronal pulp cavities (n = 96) were seeded with 1 × 105 cell/mL BMSCs, and then the cavities were filled with calcium silicate–based capping material. After placing the capping materials, the cavities of both groups (1 and 2) were filled with resin-modified glass ionomer restorative material. From each group, 48 teeth from 3 dogs were evaluated histologically after 1 week, and the other 48 teeth from the remaining 3 dogs were evaluated after 9 weeks. Scoring was done for the amount of inflammatory cell infiltrates, tissue necrosis, and thickness of hard tissue bridge formation. ResultsThe Mann-Whitney U statistical test performed for hard tissue bridge formation revealed significant differences between the 2 groups at the 1- (P < .05) and 9-week (P < .05) examination periods. ConclusionsAutologous BMSCs have significant therapeutic potential because they enhance the healing capacity of partially pulpotomized dogs' teeth.

Anti-inflammatory potential of a carvedilol gel in the pulpal tissue of rats after dental bleaching: A histopathological evaluation.

Carvedilol is an antioxidant that decreases inflammation in periodontitis. The hydrogen peroxide (H2 O2 ) of bleaching gel causes inflammation and necrosis of the dental pulp. In the present study, we evaluated the anti-inflammatory potential of carvedilol in the pulp of rats after bleaching. The right upper molars of rats received 35% H2 O2 (1× 30minutes), and the left upper molars were used as the control. Half of the rats received carvedilol gel (1× 10minutes), forming the following groups: bleached, bleached followed by carvedilol (bleached+carvedilol), and control. After 2 and 30days (N=7 hemi-maxillae/group), the rats were killed for histological evaluation, and statistical tests were performed (P<0.05). After 2days, the bleached group showed necrosis in the occlusal third of the coronal pulp, and in the bleached+carvedilol group, severe inflammation (P>0.05), both different from the control (P<0.05). In the middle third, the bleached group showed severe inflammation, and the bleached+carvedilol group showed moderate inflammation (P>0.05), with the only difference between the bleached and control groups (P<0.05). In the cervical third, the bleached group showed moderate inflammation, and the bleached+carvedilol group showed mild inflammation (P>0.05). The difference again was only between the bleached and control groups (P<0.05). At 30days, there was no inflammation and a marked amount of tertiary dentin in bleached teeth (P>0.05). Carvedilol gel has the potential of minimizing H2 O2 damage, especially in deep regions of the dental pulp of rats after bleaching.

Teeth as an anatomical modality for age estimation using radiographic approach

Introduction: Age estimation of adult individuals represents an important part of forensic anthropology, forensic medicine, forensic osteology, and forensic dentistry. Teeth proved to be a perfect anatomical tool for age estimation. The study was performed with aim to evaluate the coronal pulp cavity index (CPCI) using radiographic approach and to correlate the CPCI with the real age, i.e. chronological age of the individuals. Material and Methods: CPCI was radiographically evaluated using radiovisiographs (RVGs) of 320 individuals (160 males and 160 females) having age range of 15–54 years. The sample comprised of 1280 RVGs of 4 teeth per individual (maxillary canine, maxillary second premolar, mandibular canine, and mandibular first premolar). Two radiographic measurements were performed on all radiographs. One is coronal pulp height and another one is height of crown (coronal height). CPCI for each radiograph was calculated and correlated with the chronological age of the study individuals using statistical software SPSS (Version 21). Results: Intra-observer agreement of CPCI measurements was almost perfect. The accuracy of regression models, when applied to different set of radiograph samples, was within acceptable range of differences in the forensic anthropology. Discussion and Conclusions: All the selected teeth showed a strong negative correlation with the chronological age. However, all selected teeth do not have equal applicability for age estimation suggesting that further evaluation on different samples for teeth specific regression models for age estimation.

Comparative Evaluation of Mineral Trioxide Aggregate and Biodentine as Pulpotomy Agents in Primary Molars – An In Vivo Study

Aim: The aim of this study was to evaluate and compare Biodentine and Mineral trioxide aggregate (MTA) as pulpotomy agents by clinical and radiological assessments in primary teeth. Materials and methods: In this study, 30 decayed primary molars indicated for pulpotomy were randomly assigned to the Biodentine and MTA groups. After coronal pulp removal and hemostasis, the remaining pulp tissue was covered with Biodentine or MTA. All teeth were restored with GIC. Clinical and radiographic successes and failures were recorded at 1 week, 3 month and 6 months follow-ups. Data was statistically analyzed. Results: The 6-months follow-up evaluations revealed that the clinical success rate was 100 percent for both Biodentine and MTA. The radiographic success rates at 6 months were 93.3 percent for Biodentine and 86.7 percent for MTA. No significant differences were found among the groups at all follow-up appointments (P>0.05). Conclusion: Biodentine and MTA did not differ significantly in combined clinical and radiographic success after 6 months. Therefore, both can be considered reliable medicaments for pulpotomy treatment in primary teeth.

Consideration about long-term process of dental pulp conservative treatment for the coronal pulp widely replaced with hard tissue

Consideration about long-term process of dental pulp conservative treatment for the coronal pulp widely replaced with hard tissue

The coronal pulp cavity index: A forensic tool for age determination in adults

Various biochemical and histological methods are available for human age determination which are invasive and may require extraction of teeth. The present study aims to assess the accuracy of age estimation from tooth-coronal index (TCI) of known age and sex individuals and to present a noninvasive method for age estimation. This retrospective study comprised 88 patients, which included 54 males and 34 females. An orthopantomogram of these individuals were taken, and premolars and molars in the same were evaluated. The height of the crown (coronal height [CH]) and the height of the coronal pulp cavity (coronal pulp cavity height [CPCH]) was digitally measured on the computer screen. The TCI given by Ikeda et al. in 1985 (TCI = [CPCH × 100]/CH.) was computed on each tooth and regressed on real age of the sample. The mean, median, range, and standard deviation of the computed index were calculated. The correlation between the actual age and the estimated age was calculated using t-test. P < 0.05 was considered significant. Results revealed that there is a significant correlation between the TCI with age. Increase in TCI observed with age; however, it showed no significant sex difference. TCI is a precise, noninvasive and easily used reliable biomarker for age estimation and is applicable to both living and dead individuals.

The presence of osteocalcin, osteopontin and reactive oxygen species-positive cells in pulp tissue after dental bleaching.

To analyse the influence of H2 O2 on pulp repair through osteocalcin and osteopontin immunolabelling and in cellular defence by using the antireactive oxygen species (ROS) antibody. The maxillary molars of 50 rats were treated with 35% H2 O2 (Ble groups) or placebo gel (control groups). At 0h and 2, 7, 15 and 30days (n=10hemimaxillae), the rats were killed and pulp tissue was evaluated using inflammation and immunolabelling scores (osteocalcin/osteopontin); ROS-positive cells were counted. Paired t-test and Wilcoxon signed-rank test were used (P<0.05). The Ble group had necrosis in the coronal pulp at 0h and in the occlusal third of the coronal pulp at 2days; at 7, 15 and 30days, no inflammation was noted similar to the controls (P>0.05). Osteocalcin was absent in the Ble at 0h, moderate at 2days and increased thereafter, differing from the controls at all two periods (P<0.05). Osteopontin was higher principally at 7 and 15days in Ble groups, but differing with control groups from 2days after bleaching (P<0.05). The Ble group had more ROS-positive cells in the pulp at 7 and 15days (P<0.05). Tertiary dentine was observed at 7days, increasing thereafter (P<0.05). Post-bleaching pulp repair was associated with increased osteocalcin over time. Osteopontin also participated in this process, and anti-ROS was involved in cellular defence against H2 O2 .

Macrophage populations show an M1-to-M2 transition in an experimental model of coronal pulp tissue engineering with mesenchymal stem cells.

To assess M1/M2 macrophage phenotypes in a coronal pulp regeneration model in rats, under the hypothesis that there are dynamic M1/M2 phenotype changes during the different stages of the pulp regeneration. The maxillary first molars of Wistar rats were pulpotomized, and biodegradable hydrogel-made scaffolds carrying rat bone marrow mesenchymal stem cells were implanted in the pulp chamber. After 3, 7 and 14days, samples were processed for (i) histological analysis and double immunoperoxidase staining for CD68 (a general macrophage marker) and one of either CCR7 (an M1 marker), CD163 (an M2 marker) or CD206 (an M2 marker); (ii) real-time PCR for AIF1 (an M1 marker), CD163, CD206, IL-10 and TNF-α mRNA expression; and (iii) Western blotting for the detection of CD68, CCR7 and CD206 proteins. Histological analysis of the implanted region revealed sparse cellular distribution at 3days, pulp-like tissue with a thin dentine bridge-like structure at 7days, and dentine bridge-like mineralized tissue formation and resorption of most scaffolds at 14days. CCR7+ macrophages had the highest density at 3days, and then significantly decreased until 14days (P<0.05). In contrast, M2 marker (CD163 or CD206) expressing macrophages had the lowest density at 3days and significantly increased until 14days (P<0.05). AIF1 and TNF-α mRNA levels, and CD68 and CCR7 protein levels were highest at 3days. CD163 and CD206 mRNA levels, and CD206 protein levels increased with time and showed the highest at 14days. IL-10 mRNA was highest at 3days, decreased at 7days and increased at 14days. Macrophages in the regenerating pulp tissue underwent a distinct transition from M1-dominant to M2-dominant, suggesting that the M1-to-M2 transition of macrophages plays an important role in creating a favourable microenvironment necessary for pulp tissue regeneration.

Controlling In Vivo, Human Pulp Temperature Rise Caused by LED Curing Light Exposure.

The objective of this study was to evaluate the in vivo effectiveness of air spray to reduce pulp temperature rise during exposure of intact premolars to light emitted by a high-power LED light-curing unit (LCU). After local Ethics Committee approval (#255945), intact, upper first premolars requiring extraction for orthodontic reasons from five volunteers received infiltrative and intraligamental anesthesia. The teeth (n=9) were isolated using rubber dam, and a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted directly into the coronal pulp chamber. Real-time pulp temperature (PT) (°C) was continuously monitored, while the buccal surface was exposed to a polywave LED LCU (Bluephase 20i, Ivoclar Vivadent) for 30 seconds with simultaneous application of a lingually directed air spray (30s-H/AIR) or without (30s-H), with a seven-minute span between each exposure. Peak PT values were subjected to one-way, repeated-measures analysis of variance, and PT change from baseline (ΔT) during exposure was subjected to paired Student's t-test (α=0.05). Peak PT values of the 30s-H group were significantly higher than those of 30s-H/AIR group and those from baseline temperature (p<0.001), whereas peak PT values in the 30s-H/AIR group were significantly lower than the baseline temperature (p=0.003). The 30s-H/AIR group showed significantly lower ΔT values than did the 30s-H group (p<0.001). Applying air flow simultaneously with LED exposure prevents in vivo pulp temperature rise.

Ultrastructure of Substance P Immunopositive Axons in the Human Dental Pulp

There exists very little information on the ultrastructure of substance P immunopositive (+) fibers in the human dental pulp, which may help in understanding the mechanism for substance P associated pulpal inflammatory pain. To address this issue, we investigated the presence of substance P+ fibers in the human dental pulp by light- and electron-microscopic immunohistochemistry. Light microscopy revealed that substance P+ fibers ran within neurovascular bundles in the radicular pulp and in the core of coronal pulp. They were also frequently present in the peripheral pulp. Substance P+ fibers showed beads like swellings interconnected by thin axonal strand, in a manner similar to bouton en passants and interconnecting axonal strand in the spinal cord. Electron microscopy revealed that almost all the substance P+ axons were unmyelinated. The axonal swellings of the substance P+ contained numerous clear round vesicles (40-50 nm in diameter) and many large dense-cored vesicles (80-110 nm in diameter) as well as many mitochondria. The vesicles and mitochondria were rarely observed in the thin axonal strand interconnecting the swellings. Intimate interrelationship or synaptic structure between the swellings of substance P+ axon and nearby pulpal cells or axons was not found. These findings suggest co-release of substance P and glutamate from the substance P+ pulpal axons and its action on nearby structures in a paracrine manner.

A rare case of an immature incisor with horizontal root fracture traumatized at the time of eruption

Dental trauma resulting in root fracture is a rare condition that affects up to 7% of permanent teeth, and injury to immature teeth is even rarer. This case report aimed to show the prognosis of a horizontal root-fractured immature maxillary incisor traumatized at the time of eruption.&#x0D; Because of an accident, a 6-year-old boy was referred to our clinic with horizontal root fracture of the permanent maxillary left central incisor associated with an extrusive luxation. The coronal segment was repositioned, and a dental splint was applied for 7 weeks. After 48 months, clinical examination revealed a positive response to electrical pulp testing and an absence color change of the tooth. Continuation of root development and calcification of the coronal pulp space was observed radiographically. It was concluded that fixation of teeth is a conservative treatment for immature teeth with horizontal root fractures, resulting in the pulp vitality and spontaneous healing with no other treatment.&#x0D; &#x0D; How to cite this article: Erkmen Almaz M, Şaroğlu Sönmez I, Akbay Oba A. A rare case of an immature incisor with horizontal root fracture traumatized at the time of eruption. Int Dent Res 2018;8(2):94-6.&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

ПУЛЬПОТОМИЯ ПРИ ПРОТЕЗИРОВАНИИ ЗУБОВ. ПИЛОТНОЕ ИССЛЕДОВАНИЕ

The subject. Significant preparation of the teeth for metal-ceramic or ceramic crowns in most cases is accompanied by a preliminary devitalization of the teeth, which shortens the period of their survival. The problem of ensuring the vitality of supporting teeth can be solved by amputating only the coronal pulp, which inevitably overheats during preparation, while retaining the root pulp. The skeptical attitude of dentists to vital pulpotomy may be explained by the often unsuccessful (ineffective) use of this method for teeth with already affected pulp. The hope for success in this study is based on the choice of intact teeth for vital pulpotomy of subsequent prosthetics. Urgency. The amputation method of endodontic dentistry is not used for prosthetic purposes. This can be explained by its low efficiency when using teeth with inflamed pulp. The aim of the work is to confirm the effectiveness of vital pulpotomy in a typical dental situation and subsequent prosthetics. Methodology. Clinical observation of the patient before and during 1 year after treatment, with the use of clinical and modern paraclinical methods of examination. Diagnosed. Treatment is planned: removable denture on the upper jaw with a preliminary shortening of the tooth 46 and subsequent use of a metal-ceramic crown. Significant sosotoyanie hard tissues of the tooth 46 and the subsequent preparation for artificial crowns required endodontic-specific training. It was supposed to preserve the root pulp (vital pulpotomy). As a result, there were no complaints at the control examination 1 year after pulpotomy. The pain threshold from the electrode was 11 µa. Summary. The vital pulpotomy of the tooth with intact pulp showed the possibility of its effective prosthetics with an artificial crown while maintaining the viability of the root pulp. The technique of introduction of the electrode into the cavity of the tooth allowed to conduct direct measurements of the pain threshold of the root pulp in the dynamics of (application for invention No. 2017115518/17(026915) from 02.05.2017).

Dental Pulp Tissue Engineering Using Mesenchymal Stem Cells: a Review with a Protocol.

Mesenchymal stem cells (MSCs) are adult stem cells that can be isolated from human and animal sources such as rats. Recently, an in vivo protocol for pulp tissue engineering using implantation of bone marrow MSCs into rat pulpotomized molars was established by our research group. This coronal pulp regeneration model showed almost complete regeneration/healing with dentin bridge formation when the cavity was sealed with mineral trioxide aggregate (MTA) to create a biocompatible seal of the pulp. This method is a powerful tool for elucidating the processes of dental pulp tissue regeneration following implantation of MSCs. In the present review, we discuss the literature in the field of dental pulp tissue engineering using MSCs including dental pulp stem cells and stem cells from exfoliated deciduous teeth. In addition, we present a brief step-by-step protocol of the coronal pulp regeneration model focusing on the implantation of rat bone marrow MSCs, biodegradable scaffolds, and hydrogels in pulpotomized rat molars. The protocol may lay the foundation for studies aiming at defining further histological and molecular mechanism of the rat pulp tissue engineering.

Changes in the radicular pulp-dentine complex in healthy intact teeth and in response to deep caries or restorations: A histological and histobacteriological study

IntroductionThe present study reported the histological events that occurred in the radicular pulp of human mature teeth in the presence of medium/deep untreated caries lesions, and those teeth with restorations or direct pulp capping, with particular emphasis on the morphology of the canal wall dentine and the odontoblast layer. MethodsSixty-two teeth with medium/deep caries lesions, extensive restorations or after application of a direct pulp capping procedure were obtained from 57 subjects. Fourteen intact mature teeth served as controls. Stained serial sections were examined for the pulp conditions of the coronal pulp. The teeth were classified as those with pulpal inflammation, or those with healed pulps. Histological changes that occurred in the roots at the pulp-dentine junction were investigated in detail. ResultsAll teeth (100%) in the experimental group showed pathologic changes in the radicular pulp, with varying amounts of tertiary dentine on the canal walls and absence of odontoblasts. These changes were identified from different portions of the canal wall surface. Non-adherent calcifications in the pulp tissue were observed in more than half of the specimens. Changes that deviate from classically-perceived histological relationships of the pulp-dentine complex were also observed in the radicular pulps of 33.7% of the control teeth. ConclusionWhen challenged by bacteria and bacterial by-products invading dentinal tubules, odontoblasts in the radicular pulp may undergo cell death, possibly by apoptosis. This phenomenon may be caused by progressive root-ward diffusion of bacterial by-products, cytokines or reactive oxygen species through the pulp connective tissue. Clinical significanceAlthough the vitality of the dental pulp in teeth with deep dentinal caries may be maintained with direct pulp capping or pulpotomy, the repair tissue that is formed resembles mineralised fibrous connective tissues more than true tubular dentine.

Clinical and radiographic evaluation of biodentine versus calcium hydroxide in primary teeth pulpotomies: a retrospective study

BackgroundPulpotomy is the surgical removal of the entire coronal pulp with preservation of the radicular pulp vitality. The purpose of this retrospective study was to evaluate the clinical and radiographic success of pulpotomy of primary molars using two materials, biodentine and calcium hydroxide.MethodsRecords of 400 primary molars in 360 paediatric participants (mean age: 7.5 ± 1.6 years, ranging from 5 to 9 years) with dental caries who required pulp therapy were included in this study. Biodentine was used on 200 teeth, and calcium hydroxide (CH) was used on another 200 teeth, as a pulpotomy material. Clinical and radiographic evaluation was performed after 9 and 18 months. Statistical analysis was evaluated with the chi-squared test, and the level of significance was set at p < 0.05.ResultsThe treatment success with CH was 85.5% after 9 months and 79.5% after 18 months, while the success rate of biodentine was 94% after 9 months and 89.5% after 18 months. The statistical analysis with the Chi-squared test showed that the clinical and radiographic success rate with biodentine was significantly higher than CH (p < 0.05).ConclusionsBiodentine exhibited a higher clinical and radiographic success rate compared to CH. However, besides the clinical results, biodentine has some disadvantages, such as higher costs, compared to CH.

Study on Effect of Remaining Dentin Thickness and Coronal Pulp Size on Dentin Hypersensitivity Following Tooth Preparation

Background &amp; Objectives:Dentin hypersensitivity and pain following tooth preparation of vital teeth occurs with a highly variable prevalence often leading to constant pain requiring endodontic therapy. The study was conducted with objective to evaluate the impact of remaining dentin thickness, coronal pulp size, tooth wear on dentin hypersensitivity following tooth preparation.Materials &amp; Methods:Total 138 permanent vital teeth for abutment of fixed partial prosthesis were included in the study. Tooth wear measured using ‘exact tooth wear index’ and level of sensitivity to stimuli was recorded using a numerical rating scale. Following tooth preparation radiograph using paralleling technique were used for measurement of remaining dentin thickness and pulp chamber.Results:The multiple linear regression predictor model summary and overall fit statistics indicated a high degree of correlation (R = 0.661, 0.889, 0.839 for anterior, premolar and molar teeth respectively). The total variation for pain could be explained in 43.7% (anterior), 79.1% (premolar), and 70.4% (molar) by the independent variables and there was a significant linear relationship between the variables in the model (p &lt; .001).Conclusion:This study investigated few possible variables that may be taken into consideration before referring the vital abutment tooth for intentional root canal therapy so that every attempt can be made to avoid pulp amputation.

Influence of Class V preparation on in vivo temperature rise in anesthetized human pulp during exposure to a Polywave® LED light curing unit

ObjectiveThis in vivo study evaluated pulp temperature (PT) rise in human premolars having deep Class V preparations during exposure to a light curing unit (LCU) using selected exposure modes (EMs). MethodsAfter local Ethics Committee approval, intact first premolars (n=8) requiring extraction for orthodontic reasons, from 8 volunteers, received infiltrative and intraligamental anesthesia and were isolated using rubber dam. A minute pulp exposure was attained and sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted into the coronal pulp chamber to continuously monitor PT (°C). A deep buccal Class V preparation was prepared using a high speed diamond bur under air-water spray cooling. The surface was exposed to a Polywave® LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs, allowing 7-min span between each exposure: 10-s in low (10-s/L), 10-s (10-s/H), 30-s (30-s/H), or 60-s (60-s/H) in high mode; and 5-s-Turbo (5-s/T). Peak PT values and PT increases over physiologic baseline levels (ΔT) were subjected to 1-way, repeated measures ANOVAs, and Bonferroni’s post-hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. ResultsAll EMs produced higher peak PT than the baseline temperature (p<0.001). Only 60-s/H mode generated an average ΔT of 5.5°C (p<0.001). A significant, positive relationship was noted between applied radiant exposure and ΔT (r2=0.8962; p<0.001). SignificanceIn vivo exposure of deep Class V preparation to Polywave® LED LCU increases PT to values considered safe for the pulp, for most EMs. Only the longest evaluated EM caused higher PT increase than the critical ΔT, thought to be associated with pulpal necrosis.