Influence of azathioprine on healing of exposed dogs' dental pulp capped with three different materials.

Background: Azathioprine is one of the earliest immunosuppressants prescribed for several autoimmune diseases. Yet there is a lack of research on the impact of azathioprine on pulp healing following the pulp capping procedure. Aim: This study aimed to investigate the effect of azathioprine on the healing ability of mechanically exposed dogs' dental pulps following direct pulp capping with mineral trioxide aggregate (MTA), bio-aggregates (BA), and Calcium hydroxide (Ca(OH)2). Methods: Four mongrel dogs were randomly assigned to two groups (two dogs/30 teeth in each group): immunosuppressed (group I) and control (group II). Group I received azathioprine for two months before surgical treatments and until the dogs were euthanized. Fifteen class V buccal cavities were performed in each dog. Each group was randomly divided into three subgroups (10 teeth each) based on the pulp capping substance. The pulps in subgroups A, B, and C were immediately capped with MTA, BA, and Ca(OH)2, respectively. Inflammation and dentine bridge development were histopathologically evaluated and scored at one and two months. The data were statistically analyzed. Results: The immunosuppressed group exhibited statistically greater inflammatory cell count and decreased dentine bridge thickness, compared to the control group in all subgroups (p < 0.05). Conclusion: Azathioprine has an adverse effect on the healing of exposed dogs' dental pulp following direct pulp capping with MTA, BA, and Ca(OH)2. Therefore, patients using azathioprine as an immunosuppressive medication may experience delayed healing of mechanically exposed pulps following capping with MTA, BA, or Ca(OH)2.

Inflammatory response and immunohistochemical characterization of experimental calcium silicate-based perforation repair material.

This study compares the immunohistochemical reaction of a new experimental tricalcium silicate perforation repair material to mineral trioxide aggregate (MTA) and Biodentine. A total of 162 mature premolar teeth from 12 dogs were divided into three experimental groups (n = 54 teeth each) according to the evaluation period: 1, 2 and 3 months. Each group was further divided into two equal subgroups (n = 27 teeth each) according to the time of repair: immediate repair and delayed repair. Each subgroup was subdivided according to the material used into three experimental subdivisions (n = 8 teeth each): MTA, Biodentine (Septodont) and experimental material, and two control subdivisions: positive control (n = 2 teeth) and negative control (one tooth). Under general anaesthesia, access cavity was done. Cleaning and shaping were performed using ProTaper universal rotary instruments. The canals were obturated using cold lateral compaction technique with Gutta percha and Adseal sealer. Furcation perforations were created then randomly sealed using the three materials either immediately or after one month (delayed repair). Inflammatory cell count and immunohistochemical analysis of osteopontin-positive area fraction were digitally analysed using the ImageJ software. Delayed furcal perforation repair showed significantly higher inflammatory cell count than immediate repair. No significant difference in inflammatory cell count and immunohistochemical analysis was detected between the three tested materials. The immunohistochemical analysis revealed the highest immunopositive area fraction in the 3-month evaluation period. The experimental tricalcium silicate cement performed similarly to Biodentine and MTA regarding the osteopontin expression during perforation repair, suggesting it is a suitable alternative with favourable handling characters.

A Promising Probiotic Irrigant: An In Vitro Study.

AIM: The present study aimed to investigate the inhibitory effect of Lactobacillus rhamnosus (B-445) as a probiotics irrigant on the growth of Enterococcus faecalis. METHODS: Forty-two extracted single human canal anterior teeth were prepared with rotary instrumentation and sterilised. Teeth were divided into 3 groups according to the type of irrigant, N = 14. Three experimental groups were inoculated with E. faecalis and cultured for 21 days before use; Group 1 was 2.5% NaOCl (positive control), Group 2 was saline (negative control), Group 3 was the experimental probiotic irrigant. Paper point sampling of the canals of each group was obtained before irrigation (S1), immediately after irrigation (S2) and after 24 hours (post irrigation samples) (S3) to determine remaining colony forming units for E. faecalis. Also, Colony counts for L. rhamnosus in Group 3 after immediate irrigation, as well as 24 hours post irrigation, was performed to determine the survival profile of these bacteria in infected root canal with E. faecalis. RESULTS: The NaOCl irrigant group had the lowest mean value of (log 10 CFU/mL) of E. faecalis after immediate irrigation and after 24 hrs post irrigation followed by the probiotic group, while the highest mean value was the saline group (P ≤ 0.001). The survival profile for L. rhamnosus in Group 3 after immediate irrigation and post-irrigation were slightly higher than for E. faecalis (P ≤ 0.001). CONCLUSION: Lactobacillus rhamnosus which revealed a potential inhibitory effect on the growth of Enterococcus faecalis, could be used as a new natural, safe probiotic irrigant agent.

Biological evaluation of a new pulp capping material developed from Portland cement.

This study evaluates the biological properties of a new pulp capping material developed from Portland cement. This study was conducted on 48 teeth in 4 dogs (12 teeth/dog). The dogs were classified into two equal groups (n=24 teeth) according to the evaluation period including: group A (3 weeks) and group B (3 months). Each group was further subdivided into three equal subgroups (n=8 teeth) according to the capping material including: subgroup 1: mineral trioxide aggregate (MTA), subgroup2: Portland cement+10% calcium hydroxide+20% bismuth oxide (Port Cal) and subgroup 3: Portland cement+bismuth oxide. After general anesthesia, a class V buccal cavity was prepared coronal to the gingival margin. After pulp exposure and hemostasis,the capping materials and glass ionomer filling were placed on the exposure sites. All histopathological findings, inflammatory cell count and dentin bridge formation were recorded. Data were analyzed statistically. After 3 months, the histopathological picture of the pulp in subgroup 1 showed normal pulp, continuous odontoblastic layer and complete dentin bridge formation while subgroup 2 showed partial and complete dentin bridge over a normal and necrotic pulps. Subgroup 3 showed loss of normal architecture, areas of necrosis, complete, or incomplete dentin bridge formation, attached and detached pulp stones and fatty degeneration in group B. For group A, MTA subgroup showed the least number of inflammatory cell infiltrate followed by Port Cal subgroup. While subgroup 3 showed the highest number of inflammatory cell infiltrate. For group B, the mean inflammatory cell count increased with the three tested materials with no statistical difference. Regarding dentin bridge formation at group A, no significant differences was found between subgroups, while at group B, MTA subgroup exhibited significantly higher scores than other subgroups. In conclusion, addition of calcium hydroxide to Portland cement improves the dentin bridge formation qualitatively and quantitatively.

Regenerative potential of immature permanent teeth with necrotic pulps after different regenerative protocols.

INTRODUCTION: Regenerative endodontics is a promising alternative treatment for immature teeth with necrotic pulps. The present study was performed to assess the regenerative potential of young permanent immature teeth with necrotic pulp after the following treatment protocols: (1) a mineral trioxide aggregate (MTA) apical plug, (2) the regenerative endodontic protocol (blood clot scaffold), and (3) the regenerative endodontic protocol with a blood clot and an injectable scaffold impregnated with basic fibroblast growth factor. METHODS: Immature necrotic permanent maxillary central incisors (n = 36) of patients 9-13 years old were divided into 3 groups according to the treatment protocol: the MTA group (MTA apical plug), the REG group (regenerative endodontic protocol [blood clot]), and the FGF group (regenerative endodontic protocol [blood clot + injectable scaffold]). Follow-up was done up to 18 months. Standardized radiographs were digitally evaluated for an increase in root length and thickness, a decrease in the apical diameter, and a change in periapical bone density. RESULTS: After a follow-up period of 18 months, most of the cases showed radiographic evidence of periapical healing. Groups 2 and 3 showed a progressive increase in root length and width and a decrease in apical diameter. CONCLUSIONS: The regenerative endodontic procedure allowed the continued development of roots in teeth with necrotic pulps. The use of artificial hydrogel scaffold and basic fibroblast growth factor was not essential for repair.