Prosthetic and orthodontic rehabilitation of a patient with severe maxillary central incisor root resorption associated with impacted maxillary canines.

OBJECTIVE: This case report describes the orthodontic and prosthetic rehabilitation of a patient with resorption of the roots of the maxillary central incisors due to the ectopic maxillary canines. CLINICAL CONSIDERATIONS: A 16-year-old woman presented with severe resorption of the roots of the maxillary central incisors due to the ectopic maxillary canines. The impacted canines were orthodontically tracted with a lingual arch-supporting temporary central incisors and vertical elastics, and, undesirable root proximity was later corrected by moving the canines distally 1.5 mm apart. Gingival replacement cords were placed into the gingival sulcus of the canines, and tooth preparation was performed along with rotary gingival curettage of the interdental papilla. Convex form was provided for the mesial and labio-distal subgingival contour of the restorations. CONCLUSIONS: The creeping attachment of the interdental papilla was successfully achieved by the orthodontic arrangement of interdental distance and the prosthetic stimulus via the retraction cord, rotary curettage, and convex mesial subgingival contours. In addition, selective retraction of the labio-distal gingiva by overcontoured restorations moved the gingival zenith position (GZP) distally. Finally, the canine crown morphology and gingival level mimicked the central incisors. CLINICAL SIGNIFICANCE: This clinical report introduces a treatment workflow of to recover the esthetic disturbance due to severe root resorption of the maxillary central incisors associated with impacted maxillary canines. The present orthodontic and prosthetic procedure can improve both hard and soft tissue esthetics and could be used in similar cases, such as malformed teeth and tooth autotransplantation or transposition with disturbances in the interdental papilla height or the GZP.

A method of transferring the subgingival contour of interim restorations to definitive restorations by using zirconia copings customized with casting wax.

Establishing continuous and symmetric gingival levels is essential to achieving optimal gingival esthetics. Adjustment of the subgingival contour of the interim prosthesis is useful for managing gingival levels. This article illustrates how to accurately and predictably transfer the adjusted subgingival contour of interim restorations to the definitive restorations by using zirconia copings customized with casting wax.

Improvement of cell adhesion on poly(L-lactide) by atmospheric plasma treatment.

The purpose of this study is to elucidate the interaction between the cell and the surface of poly(L-lactide) (PLLA) samples, which were modified using a low-temperature plasma treatment apparatus at atmospheric pressure. The plasma treatments were carried out in the atmospheres of air, carbon dioxide (CO2), and perfluoro propane (C3F8) gas. The PLLA samples before and after the plasma treatment were analyzed by XPS and their contact angles with water. Furthermore, the cell adhesion capability and cell mass culturing tests on the PLLA samples were carried out using MC3T3-E1 cells. The results showed that the contact angle of the samples, which was plasma treated in air or in CO2 gas, decreased compared with that of the untreated samples. On the other hand, the contact angle of the samples, which was plasma treated in the C3F8 gas, increased compared with the untreated plasma samples. The cell response on the PLLA samples plasma treated in air or in the CO2 gas were significantly superior to that of the PLLA samples, which was plasma treated in the C3F8 gas.

Surface modification of pure titanium by plasma exposure and its bonding to resin.

The purpose of this study was to investigate the effects on shear bond strength to resin after pure titanium (Ti) was exposed to plasma under different kinds of gas atmosphere. Polished Ti samples were treated using a plasma exposure apparatus in gas atmospheres of air, CO2, and C3F8. Surface analysis of Ti exposed to plasma was achieved through surface free energy and XPS measurements. The Ti sample was bonded with adhesive resin (4-META, MAC-10, HEMA, MDP, VBATDT) to a stainless steel piece. After which, shearing adhesion test was done. It was observed that plasma exposure in a specific gas atmosphere in regulated the bonding strength of titanium surface to resin. Based on the results of this study, we concluded that plasma exposure was a useful surface treatment method for dental practices.