Trakol Mekayarajjananonth

DENTAL IMPLANTS AND THE GERIATRIC PATIENT

Dental care of the aging patient presents a number of problems not encountered in younger patients. Most of these problems result from tissue changes that occur during aging. Dental implants and implant-retained and/or implant-supported prostheses are viable treatment options for older patients. The majority of elderly patients in their younger retirement years are relatively healthy and not limited in activity. The clinician must be aware of the physical, metabolic, and endocrine changes associated with aging and how these changes may affect implant treatment. The elderly deserve the best care the dental profession can offer.

Contact Angle Measurement on Dental Implant Biomaterials

Wettability may be one of the surface factors to be considered when selecting dental implant biomaterials. Contact angles of dental implant surface preparations influence wettability and tissue adhesion. The contact angles of eight implant surface preparations were determined in this study. Contact angles were measured by a tele-microscope equipped with a protractor eyepiece. Groups 1 to 6 had a Ti6Al4V substrate. Group 1 was metallurgically polished, group 2 was blasted with 180 microns Al2O3, group 3 was blasted with 710 microns Al2O3, group 4 was hydroxyapatite (HA) blasted (125 microns), group 5 had a Calcitite HA plasma-sprayed coating, and group 6 was coated with plasma-sprayed MP-1 HA. Group 7 was metallurgically polished commercially pure (CP) titanium (grade 1), and group 8 was etched CP titanium (grade 1). Contact angles were measured 30 times for each group with distilled water and glycerol, and the determinations were statistically analyzed. Mean contact angles for groups 1 to 8 were 65.5, 65.3, 62.5, 67.9, 46.6, 81.7, 58.5, and 69.0, respectively, when tested with distilled water, and 70.7, 68.3, 81.6, 75.4, 67.1, 70.7, 62.3, and 82.5, respectively, when tested with glycerol. Analysis of variance and Tukeys Honestly Significant Difference test (p = 0.05) demonstrated significant differences between group 5 and all other groups when groups were tested with distilled water and demonstrated no significant differences between groups 5 and 7 when groups were tested with glycerol. Surface preparation of implant biomaterials affects wettability. In this study, Ti6Al4V coated with Calcitite HA had the lowest contact angles and the best wettability.

The effect of compressive cyclic loading on retention of a temporary cement used with implants.

Masticatory forces cause fatigue to cement-retained crowns and abutments and may adversely effect retention. The relation between the number of load cycles and the retentive forces is important. This study evaluated the effect of compressive cyclic loading on the retentive forces of a temporary cement used to retain implant crowns and the relationship between load cycles and retentive forces. Ten castings and implant abutments were cemented with zinc oxide-eugenol temporary cement. The retentive force necessary to dislodge the casting from the abutment was determined before and after the application of 2 Hz of vertical off-axis 3-mm sinusoidal-type compressive cyclic loading between 20 and 130 N for 500000, 1000000, and 5000000 cycles. These forces were equivalent to approximately 6 months, 1 year, and 5 years of human mastication. Data before and after the applied loading were analyzed with a paired sample t test (alpha = 0.05). The retentive forces of the 3 groups were analyzed by 1-way analysis of variance and post hoc by Scheffé multiple comparison (alpha = 0.05). The relation of the loading and the altered retentive forces were analyzed with the Pearson correlation coefficient. Compressive cyclic loading reduced the retentive forces significantly in all groups (P = .000). The retentive forces were reduced 16.75%, 18.73%, and 19.68% during the applied loading cycles of 500000, 1000000, and 5000000. All reduced retentive forces were not significantly different (P = .792). Although cyclic loading reduced the retentive forces, the increased cycles had little relationship (R = 0.119) to the decreased retentive forces of the temporary cement. The relationship between occlusal loading and retentive force can influence the choice of a temporary cement for a particular clinical situation.

Improved mouth guard design for protection and comfort

Mouth guards worn during contact sports have been shown to provide considerable protection against traumatic injuries to the teeth and supporting structures. Of the 3 types available, the custom-made mouth guard is considered superior to stock and mouth-formed mouth guards. The procedure for making a special mouth guard designed for protection and comfort is described.

Alternative Retention for an Implant-retained Auricular Prosthesis

The introduction of intraoral endosseous implants was inevitably followed by their external use in maxillofacial prosthodontics. Bar and clip attachments provide satisfactory retention for auricular prostheses, although the bar may inhibit patient hygiene by limiting access to the defect area. A simple clinical and laboratory technique to enhance the retention of an implant-retained auricular prosthesis is described, with custom-made stud attachments used for retention. Improved access for hygiene is provided. A clinical case is presented.

Clear acrylic resin device for orientation and placement of a small facial prosthesis

A small-sized facial prosthesis can be difficult to orient accurately in correct relationship to a defect. This problem may be reduced by embedding a magnet in the prosthesis and constructing a magnetic holding device from clear acrylic resin. This device can be used as a stand during adhesive application to reduce adhesive contamination and acts as orientation guide during prosthesis placement.

Nutrition and the geriatric implant patient.

The clinician must be cognizant of nutritional factors and deficiencies that can adversely affect implant surgery and subsequent prosthodontic rehabilitation for the geriatric patient. There are many nutrients, vitamins, and minerals that may be useful and even necessary for the geriatric implant patient. Dental implants and implant-retained and/or supported prostheses are viable treatment options for older patients when certain age-related and nutritional factors are considered.

Simplified methods for fabricating tissue-supported implant-retained overdentures with retention from a resilient liner

Resilient denture liner materials can be useful for tissue-supported implant-retained overdentures. They allow physiologic movement of the denture toward the tissues. This article presents a technique that offers several advantages over other methods of fabricating the overdenture with a resilient liner, and of transferring the superstructure: the acrylic resin base and the heat-cured resilient liner material are cured simultaneously; superstructure blockout is performed in the laboratory instead of in the mouth, where blockout is difficult; and direct transfer of the superstructure bar is more accurate and eliminates possible fracture of the duplicated superstructure if formed in die stone.

The Effect of Fiber Dowel Heights in Resin Composite Cores on Restoration Failures of Endodontically Treated Teeth

In vitro and in vivo testing suggest that fiber posts may reduce the incidence of root fractures of endodontically treated teeth. The purpose of this in vitro study was to compare the effect of fiber post height in resin composite cores on the fracture resistance of endodontically treated teeth. Forty maxillary central incisors were randomly divided into 2 control groups (Groups 1 and 2) of 5 teeth each, and 3 experimental groups (Groups 3, 4, and 5) of 10 teeth each. The teeth in Group 1 had their opening restored with composite resin, the teeth in Group 2 were restored with quartz fiber posts without resin composite cores, and the teeth in Groups 3, 4, and 5 were restored with quartz fiber posts of 2, 4, and 6 mm high, respectively, in 6-mm resin composite cores. Ceramic crowns were fabricated for the specimens. Specimens were positioned in a mounting device and aligned at a 130-degree angle to the long axis of each tooth. A universal testing machine was used to apply constant load at a crosshead speed of 0.5 mm/min until failure occurred. The highest fracture load and mode of failure of each specimen was recorded. The highest fracture resistance force was observed in Group 2 (290.38 +/- 48.45 N) and decreased, respectively, in Group 1 (238.98 +/-26.26 N), Group 5 (228.35 +/-58.79 N), Group 4 (221.43 +/-38.74 N), and Group 3 (199.05 +/-58.00 N). According to one-way analysis of variance (ANOVA) and Duncans test (P < or = .05), there was no statistically significant increase in the force from Group 3 to Group 5, and the force in Group 2 was significantly higher than that of the experimental groups. There was no statistical significance difference in force among the experimental groups, and the amount of residual tooth structure was found to be the critical factor in fracture resistance. The results suggest that endodontically treated teeth should be restored with the longest possible post height while preserving maximum tooth structure.