Mineral trioxide aggregate for apexification in non-vital teeth with open apices: A case report

Management of immature non-vital teeth poses challenge for the clinician owing to the thin root canal walls and open apices which may show apical divergence. Apexification is the technique of inducing the apical closure with a root end filling material for non-vital immature young permanent teeth. Traditionally, Calcium hydroxide was the material of choice for apexification of immature permanent teeth but introduction of MTA has shown remarkable promise as an alternative to calcium hydroxide. This report presents a case of apexification of anterior two young permanent teeth with open apices using MTA and Gutta percha followed by esthetic build up using cast metal posts and full coverage restorations.

Clinical Performance of Cast Metal and Fiber Post Retained Restorations in Endodontically Treated Teeth: A Systematic Review and Meta-Analysis

Purpose: The purpose of this systematic review was to assess the available literature to evaluate the clinical performance of different post systems for the rehabilitation of endodontically treated teeth (ETT). Clinical Significance: The loss of structural integrity of endodontically treated teeth usually requires the use of intra-radicular posts for the retention of the final restoration. The recent literature has reported controversial results regarding the clinical performance of different systems. Material and Methods: An electronic search restricted to the English language was performed up to May 31, 2020. Articles were selected if they met the following criteria: cohort studies and randomized clinical trials comparing the failure rate incidence between fiber and cast metal post, with a mean follow-up of 3 years. Results: 24 studies (14 cohort studies and 10 RCTs) published between 2000 and 2018 were included in this review. For cast metal posts, 210 cases were classified as failures (17.07%), and for fiber posts, 423 were classified as failures (10.6%). An unpaired t-test revealed that cast metal and fiber post values were not significantly different (p = 0.58) with the difference between means of 5.00 with 95% confidence of interval (-13.38 to 23.39). Four studies that presented cast metal and fiber posts groups were combined in the meta-analysis. There was no significant difference in the general failure analysis (risk ratio of 0.59 [95% CI: 0.30 to 1.18]; p = 0.13). Conclusions: Based on the present analysis results, the clinical performance of ETT restored with either cast metal- or fiber post-retained restorations presented similar results.

Alternative conservative approach for tooth build-up in patients with special healthcare needs

Purpose: The success of an artificial crown mainly depends on the biomechanical factors such as bonding capacity of cement between the crown and abutment tooth, and root strength of the abutment tooth. In this case series, we aim to provide insight on the potential use of the cast metal post and cost for patients with intellectual disabilities and severely compromised tooth structure. Material and methods: The first patient was a 41-year old male with the chief complaint of a dislodged porcelain fused metal (PFM) crown of tooth #20 (mandibular left second bicuspid). The patient was informed about the advantages, disadvantages, and risks of each option. After further consideration and discussion with the parents and the patient, we decided to rebuild the coronal tooth structure with the cast metal post and core and prosthetic restoration with the same crown. Patient satisfaction was measured on the visual analog scale as 10/10. The second case involves a 26-year old female, who presented with a chief complaint of chronic lingering pain on tooth #9. The tooth structure was extensively damaged and un-supportive of the ferrule, therefore, it was decided to build a metal post and core instead of a fiber post. The prosthetic restoration was made with a monolithic zirconia crown and the patient was followed up twice in 6 months and graded the satisfaction as 10/10 on a visual analog scale. Results: The most common type of posts used in dentistry has been cast post and cores in the last decade which generally includes an additional laboratory stage where a custom post is prepared according to the impression taken from the prepared post space. Conclusions: Both the presented cases explain an interesting advantage of restoring a root canal treated tooth with a metal post and core system which implies that in a prefabricated post and core restored tooth failure, a metal post, and core can potentially be the treatment of choice instead of extracting the tooth. Keywords: post and core; special needs; cast metal post.

Alternative Conservative Approach for Tooth Build-Up in Patients with Special Healthcare Needs

Purpose: The success of an artificial crown mainly depends on the biomechanical factors such as bonding capacity of cement between the crown and abutment tooth, and root strength of the abutment tooth. In this case series, we aim to provide insight on the potential use of the cast metal post and cost for patients with intellectual disabilities and severely compromised tooth structure. Material and Methods: The first patient was a 41-year old male with the chief complaint of a dislodged porcelain fused metal (PFM) crown of tooth #20 (mandibular left second bicuspid). The patient was informed about the advantages, disadvantages, and risks of each option. After further consideration and discussion with the parents and the patient, we decided to rebuild the coronal tooth structure with the cast metal post and core and prosthetic restoration with the same crown. Patient satisfaction was measured on the visual analog scale as 10/10. The second case involves a 26-year old female, who presented with a chief complaint of chronic lingering pain on tooth #9. The tooth structure was extensively damaged and un-supportive of the ferrule, therefore, it was decided to build a metal post and core instead of a fiber post. The prosthetic restoration was made with a monolithic zirconia crown and the patient was followed up twice in 6 months and graded the satisfaction as 10/10 on a visual analog scale. Results: The most common type of posts used in dentistry has been cast post and cores in the last decade which generally includes an additional laboratory stage where a custom post is prepared according to the impression taken from the prepared post space. Conclusions: Both the presented cases explain an interesting advantage of restoring a root canal treated tooth with a metal post and core system which implies that in a prefabricated post and core restored tooth failure, a metal post, and core can potentially be the treatment of choice instead of extracting the tooth.

The influence of aluminum on the formation of the hardening phase in magnesium alloys

Purpose. Study of the effect of alloying with aluminum on structure formation, mechanical properties and heat resistance of magnesium alloys Research methods. Methods of metallographic and micro X-ray spectral analysis. Determination of mechanical properties and heat resistance. Results. The regularities of the influence of alloying with aluminum on the formation of the hardening phase in magnesium alloys have been investigated. It is shown that an increase in the concentration of aluminum in magnesium alloy promotes refinement of the macro- and microstructure of the metal (reduces the grain size and the distance between the second-order dendritic axes) and also increases the amount of intermetallic phase. The positive effect of aluminum additives on the mechanical properties and heat resistance of cast metal has been established. The optimal level of alloying with aluminum (about 7,7 %) hes been determined, which ensures a sufficient level of mechanical properties and heat resistence. Scientific novelty. Based on the regression analysis of the experimental data, empirical equations were obtained that describe the dependences of the size of macro- and micrograins on the concentration of aluminum in magnesium alloys. It is shown that the optimal aluminum content in the magnesium alloy in the amount of ~ 7,7 % provides the best combination of mechanical properties (a sufficiently high strength and the highest plasticity) and heat resistance Practical value. It has been established that alloying magnesium alloys with aluminum is promising for improving the structure and increasing the mechanical properties and heat resistance of cast metal. This effect makes it possible to significantly expand the field of application of magnesium alloys in mechanical engineering and improve the performance of various equipment.