Effect of full crown preparation on pulpal blood flow in man

Analysis of the Pulpal Blood Flow Microdynamics during Prosthetic Tooth Preparation Using Diamond Burs with Different Degrees of Wear

Pulpal modifications taking place during prosthetic tooth preparation using worn-out burs may represent a risk for the vitality of the dental pulp. The aim of this in vivo study was to evaluate whether the wear of diamond burs has an influence on the vascular microdynamics at the level of the dental pulp, during vertical preparation for zirconia crowns. The study was performed with a split-mouth design and included 32 vital permanent monoradicular teeth (20 maxillary and 12 mandibular), from six subjects, aged between 20 and 50 years. The teeth were randomly assigned to two study groups of 16 teeth each. For prosthetic preparation, new burs were used in the first group, and burs at their 5th use were used in the second group. Four consecutive determinations of the pulpal blood flow by Laser Doppler flowmetry (LDF-laser Doppler MoorLab instrument VMS-LDF2, Moor Instruments Ltd., Axminster, UK) were taken for each tooth included in the study: before the preparation (control values), immediately, at 24 h, and at 7 days after the prosthetic preparation. A four-way ANOVA statistical analysis was applied to analyze the effect of four considered factors (bur wear degree, time of measurement, tooth number, and tooth location) on the pulpal blood flow (PBF). A significant increase in pulpal blood flow compared to the baseline was recorded immediately after preparation (p < 0.01), at 24 h (p < 0.01), and at 7 days (p < 0.05) in both groups, but more pronounced in the case of burs at the 5th use. The blood flow was significantly higher in upper jaw teeth, irrespective of the measurement time. In conclusion, the use of worn-out diamond burs produces lasting modifications in the pulpal blood flow of teeth that undergo prosthetic crown preparation. ISRCTN registry: ISRCTN49594720.

Evaluation of the effect of different desensitizers on pulpal blood flow after full crown preparation using laser Doppler flowmetry: a randomized clinical trial

This study aims to evaluate the effect of Teethmate, Bifluoride 12, and Copal Varnish on the treatment of dentin hypersensitivity and the pulpal blood flow using laser Doppler flowmetry (LDF) after full crown preparations. Eighteen patients with 42 teeth with dentine hypersensitivity after full crown preparations were randomly treated with Teethmate, Bifluoride 12, and Copal Varnish. Dentine hypersensitivity was measured using a visual analog scale (VAS) and Schiff air index (SAI). LDF was used to assess the pulpal blood flow and results were recorded in perfusion units (PU). All measurements were performed at baseline, 5 min, 7 days, and 1 month after the application of desensitizers. Data were statistically analyzed by Wilcoxon and two-way ANOVA tests (p < 0.05). There was no significant difference between the tested desensitizers regarding VAS and PU values. VAS values decreased significantly at 7 days and 1 month after the application of desensitizers compared to baseline in all groups. The decrease in PU values significantly differed only in the Copal Varnish group at 5 min and 7 days after the application of the desensitizer (p < 0.05). A statistically significant difference was found between different times regarding SAI scores in all groups (p < 0.05). Teethmate, Bifluoride 12, and Copal Varnish showed similar effectiveness on dentine hypersensitivity and pulpal blood flow. Long-term clinical trials with larger sample sizes and histological studies are needed to evaluate their impacts on pulpal status.

Gelatin methacryloyl-alginate core-shell microcapsules as efficient delivery platforms for prevascularized microtissues in endodontic regeneration

Combined injectable cell-laden microspheres and angiogenesis approaches are promising for functional vascularized endodontic regeneration. However, advanced microsphere designs and production techniques that benefit practical applications are rarely developed. Herein, gelatin methacryloyl (GelMA)-alginate core-shell microcapsules were fabricated to co-encapsulate human dental pulp stem cells (hDPSCs) and human umbilical vein endothelial cells (HUVECs) based on a coaxial electrostatic microdroplet technique. This technique enables high-throughput production, convenient collection, and minimal material waste. The average diameter of core-shell microcapsules was ∼359 µm, and that of GelMA cores was ∼278 µm. There were higher proliferation rates for hDPSCs and HUVECs co-encapsulated in the GelMA cores than for hDPSCs or HUVECs monoculture group. HUVECs assembled to form 3D capillary-like networks in co-culture microcapsules. Moreover, HUVECs promoted the osteo/odontogenic differentiation of hDPSCs in microcapsules. After 14 days of cultivation, prevascularized microtissues formed in microcapsules that contained abundant deposited extracellular matrix (ECM); no microcapsule aggregation occurred. In vivo studies confirmed that better microvessel formation and pulp-like tissue regeneration occurred in the co-culture group than in hDPSCs group. Thus, an effective platform for prevascularization microtissue preparation was proposed and showed great promise in endodontic regeneration and tissue engineering applications. STATEMENT OF SIGNIFICANCE: Cell-laden microspheres combined with the proangiogenesis approach are promising in endodontic regeneration. We proposed GelMA-alginate core-shell microcapsules generated via the coaxial electrostatic microdroplet (CEM) method, which utilizes a double-lumen needle to allow for core-shell structures to form. The microcapsules were used for co-culturing hDPSCs and HUVECs to harvest large amounts of prevascularized microtissues, which further showed improved vascularization and pulp-like tissue regeneration in vivo. This CEM method and the microcapsule system have advantages of high-throughput generation, convenient collection, and avoid aggregation during long-term culturing. We proposed a high-effective platform for mass production of prevascularized microtissues, which exhibit great promise in the clinical transformation of endodontic regeneration and other applications in regenerative medicine.

Coronal Restoration as a Predictor of Periapical Disease in Non-Endodontically Treated Teeth

Objectives

To compare the frequency of apical periodontitis (AP) in non-endodontically treated teeth restored with full coverage crowns, amalgam and resin composite fillings, and to disclose the association of type and quality of coronal restoration with periapical disease.

Material and Methods

The cross-sectional study involved 597 subjects who attended the Dental Clinic of the Clinical Hospital Centre, Rijeka, Croatia for the first time. Data were collected by means of a clinical and radiological survey. The following data were recorded for all permanently restored non-endodontically treated teeth: the type, the quality of coronal restoration according to clinical and radiographic criteria for marginal integrity as well as the recurrent caries presence, periapical status and marginal bone loss. Chi-square tests were used to analyze the difference in periapical status regarding the type and the quality of restoration. The multivariate logistic regression analysis was used to assess the effect of explanatory tooth-specific variables on periapical status.

Results

There was no significant difference in the proportion of AP with regards to the type and material of adequate quality coronal restorations (χ²=5.000, P=0.082). The regression analysis revealed significant positive associations with outcome variable (AP) for crowns (OR=3.39; P<0.001), recurrent caries (OR=4.67; P<0.001) and premolar teeth (OR=1.73; P=0.002).

Conclusion

If the quality of restorations is adequate, there is no difference in the periapical status of non-endodontically treated teeth regarding the type and material of coronal restoration.

The effect of inferior alveolar nerve block anesthesia of 4% articaine and epinephrine 1:100,000 on blood flow and anesthesia of human mandibular teeth

Background/purpose

Local anesthetics and anesthetic techniques affect the patterns of pulpal blood flow (PBF) and pulpal anesthesia in human teeth. This study aimed to determine PBF changes and pulpal anesthesia of intact mandibular first molars and canines after administration of 4% articaine with epinephrine 1:100,000 using inferior alveolar nerve block (IANB).

Materials and methods

Ten healthy subjects received IANB of 4% articaine with epinephrine 1:100,000. Laser Doppler flowmetry and electrical pulp testing were combined to assess PBF changes and pulpal anesthesia of intact mandibular first molars and canines. The data were analyzed using one-way repeated-measures analysis of variance and Student-Newman-Keuls test.

Results

IANB with 4% articaine and epinephrine 1:100,000 did not have any significant change in PBF for the first 20 min post injection in mandibular first molars, and for 45 min post injection in the canines (P > 0.05). However, a hyperemic response occurred during 25-60 min post injection in the molars, and between 60 and 75 min post injection in the canines (P < 0.05). Thereafter, the PBF in both teeth returned to the baseline. Onset of pulpal anesthesia was 8.60 ± 2.12 min in the molars, and 9 ± 1.94 min in the canines. Duration of pulpal anesthesia was 82.40 ± 41.56 min in the molars, and 84 ± 47.40 min in the canines.

Conclusion

In case of successful IANB, 4% articaine and epinephrine 1:100,000 caused insignificant changes in PBF up to 30 min but a hyperemic response at later time points. Thereafter, the PBF returned to the baseline.