Surface evaluation of titanium and vitallium dental implants using SEM

Abstract

In recent years Titanium (Ti) has been the metal of choice for use as a dental implant material. Vitallium (Vi, and alloy composed of Co, Cr, Ni, and Fe) was considered in the past as an ideal implant material, but current studies show Ti is perhaps better tolerated by tissues in the oral cavity. The purpose of this study is to evaluate the surfaces of Ti and Vi endodontic endosseous implants (EEI) placed in a primate model for one year. In human clinical situations this type of dental implant is sometimes used to stabilize compromised teeth. Under intravenous general anestheisia four cynomolgus monkeys had root canal instrumentation in all central incisors. Placement of the EEI followed a pulpectomy and hand drilling to the proper depth and size for the solid rods to use the bore as a pathway to supporting bone. A total of eight Ti and eight Vi, tapered, size 50, EEI were cleanned, sterilized, and cut to length. Two EEI were inserted in the maxillary (Mx) incisors and two in the mandibular (Md) incisors of each animal. One year after placement animals were perfused via carotid cannulation with an aldehyde fixative. The jaws were retrieved, decalcified, EEI separated from tissue, and processed for scanning electron microscopy (SEM). These experimental EEI samples were critical point dried, mounted on stubs, coated with gold palladium, examined, and photographed with an Amray 1820D SEM. Non-operative control EEI samples were treated, processed the same as the experimentals and photographed with a JEOL JSM 35C SEM. Evaluation of the SEM photomicrographs suggest surfaces of EEI change during: 1) handling to implantation, 2) one year in vivo, and 3) processing. Nonoperative Ti control surfaces (Figs. 1 & 2) appear smooth with crater-like concavities of many sizes, subtle valleying, and crisscrossing machine mark (arrow) [Angle measurements of the crisscross marks compared to the long axis were significantly near 40° for both Ti experimental & control]; Vi control surfaces (Figs. 3 & 4) appear rougher with crevasse-like pits and a machine mark (arrow). Md Ti EEI (Fig. 5) has a prominent insertion gouge (⋆), smoother edged concavities than the control, and pre-operative machine marks like those in Fig. 1 (arrow). Mx Vi EEI surface (Fig. 6) has rounder edged pits and a right side smooth surface blemish (⋆). In conclusion these data suggest that Ti EEI surfaces change less than Vi counterparts. This gathering of information is being correlated with concurrent tissue studies indicating Ti may be better tolerated than Vi EEI which supports the premise that Ti is the material of choice for some dental implants in the tissues of the oral cavity.