The effect of thermal change on various dowel-and-core restorative materials.

STATEMENT OF PROBLEM: Severe thermal stresses caused by food-induced temperature changes may result in dowel-and-core failure. PURPOSE: This study investigated the influence of thermal stresses on various combinations of dowel-and-core materials of a restored endodontically treated incisor. MATERIAL AND METHODS: A 2-dimensional finite element model was constructed in a labiolingual cross-sectional view of a maxillary central incisor, a dowel, a core, and the supporting tissues to investigate thermal stress distribution. Four combinations of dowel-and-core materials were used: (1) gold/gold, (2) stainless steel/resin composite, (3) stainless steel/amalgam, and (4) carbon fiber-reinforced composite/resin composite. For thermal analysis, a cold irritant (0 degrees C) was applied on the outer surface of a metal-ceramic crown for 7 seconds. RESULTS: The metal dowel and core generated lower thermal stresses in the restorations and dentin than the nonmetallic dowel and cores. CONCLUSION: Stress level is closely related to the degree of thermal gradient. The nonmetallic dowel and cores generated greater thermal stresses than metal dowel and cores.

Treatment of edentulism using Astra Tech implants and ball abutments to retain mandibular overdentures.

The goal of this study was to provide evidence to support simplified treatment of mandibular edentulism using denture fabrication and implant placement to circumvent the need for second-stage surgeries or prosthodontic superstructures. A 5-year prospective clinical trial is reported, which involved treatment of mandibular edentulism using the single-stage surgical placement of a TiOblast microthreaded titanium screw implant with immediate replacement of a relieved mandibular overdenture and eventual retention of the overdenture with reduced ball abutments. Fifty-eight patients were treated; 116 implants were placed using a single-stage surgical approach, with a duplicate mandibular denture as the tomographic/surgical template. Mandibular dentures were relieved and relined with a tissue conditioning material and placed immediately after implant surgery. After 3 months, Conical Seal Design ball abutments were placed and attachments were secured in the overdentures by heat-polymerizing laboratory reline methods. Five of the 116 consecutively placed implants failed at 2 to 4 months, providing an immediate implant survival rate of 95.69% at the time of attachment connection. Pain and inflammation were not common to all failures, and infection was not reported in any of the 5 failures. The immediate placement of implants by a single-stage surgical procedure in the parasymphyseal region of the mandible, followed by placement of a relined mandibular denture, results in predictable and asymptomatic healing of implants that display the clinical and radiographic features of osseointegration. Encouraging results at the immediate observation period (attachment connection) must be tempered by the need for prudent and detailed clinical and radiologic evaluation over the 5-year trial period.

Pattern of permanent teeth present in individuals with ectodermal dysplasia and severe hypodontia suggests treatment with dental implants.

PURPOSE: The objective of this study was to assess the pattern of permanent teeth present in a self-selected sample of 17 female and 35 male patients with ectodermal dysplasia presenting for treatment with dental implants. METHODS: Mean age of sample: 18.7 years, age range: 5.9 to 60.9 years. Panoramic radiographs were examined independently by two investigators to determine the permanent teeth present. None of the sample reported extractions of permanent teeth prior to presenting for implants. RESULTS: Permanent teeth most likely to be present, reported as a percentage of the patient sample with that tooth, were: maxillary central incisors (42%), maxillary first molars (41%), mandibular first molars (39%), maxillary canines (22%), mandibular second molars (17%), maxillary second premolars (15%), and mandibular premolars (12%). Comparing dentition by quadrants, mandibular anterior teeth (canines and incisors) were least likely to be present. CONCLUSIONS: Results support previous findings that the maxillary central incisors, maxillary first molars, mandibular first molars, and maxillary canines are the most conserved teeth in hypodontia. Successful use of osseointegrated implants in the anterior mandibles of most of these patients suggests that habilitation of the mandible with dental implant-supported prostheses is a reasonable option.

Prognostic variables associated with implant failure: a retrospective effectiveness study.

The purpose of this study was to determine implant survival rates by means of life table analyses for a cohort of patients not part of a prospective efficacy trial and treated by practitioners at varying experience levels. Prognostic variables associated with implant failure were identified by means of proportional hazards models and advanced statistical methods that account for patient effects. Ninety-nine consecutive patients treated from 1987 to 1991 with follow-up to 1994 were included in this retrospective study. A total of 384 dental implants (79.7% Brånemark, 19.3% IMZ plasma-sprayed, 1% IMZ hydroxyapatite-coated) were placed and subsequently supported 108 prostheses. Survival and proportional hazards modeling were used to generate Kaplan-Meier survival curves and to identify variables associated with implant failure. Survey data analysis was used to adjust for any patient effects for variables identified as significant through the proportional hazards models. Thirty-four implants failed over the follow-up period (median follow-up time 3.6 years), resulting in an overall failure rate of 8.9%. Seventeen of 99 patients experienced an implant failure. When prosthesis type was excluded from the modeling process, survey data analysis identified posterior location and an implant width of less than 4.0 mm as being associated with implant failure (all P < .05).

A conceptual framework for understanding outcomes of oral implant therapy.

The use of implants has expanded so rapidly that its effectiveness for many clinical situations has not been firmly established. Dentists are responsible for making appropriate therapeutic recommendations for the management of partial and complete edentulism. These decisions require an understanding of the consequences or outcome of treatment approaches. Outcome measures to evaluate the benefits of alternative therapies include longevity as well as physiologic, psychologic, and economic impacts. Future research should include outcome measures beyond implant prosthesis survival to more fully assess the practical impact of dental implants on the patient's oral health and to determine the most cost-effective approaches for managing completely and partially edentulous patients.

Nutritional adequacy of reported intake of edentulous subjects treated with new conventional or implant-supported mandibular dentures.

The nutrient content of the diet of edentulous patients who have various oral prostheses is of concern. This study compared baseline food records to those records kept semiannually for 3 years after treatment to ascertain whether nutrient intake of edentulous patients changed after they received new implant-supported mandibular dentures (n = 41) or new conventional dentures (n = 30). No significant differences in intake of calories or of 27 nutrients were noted between the two groups (p > 0.01). A decline in the percent of calories from fat with a corresponding increase in carbohydrate calories within both groups (p < 0.01) reflected a national trend; a slight decrease in calories was similarly observed (p < 0.02). More than 40% of patients in both groups were found to have inadequate intakes of dietary fiber, calcium, or both, and 25% to 50% had low intakes of vitamins A, E, D, B6 and/or magnesium. Intakes were similar to those reported for two age-matched populations.

Orofacial pain resulting from ill-fitting dentures.

The patient who presents to the physician with a history of facial pain can be a diagnostic challenge. The etiology can be elusive, and this problem is compounded by the subjective nature and the often multi-factorial causes of facial pain. The differential diagnoses to be considered include both local and systemic disorders such as neuropathy, myofascial pain, dentoalveolar pathoses, and psychological disturbances, among others. This paper presents the case of a patient with a history of left auricular pain that was managed for over 12 years with drug therapy with only limited success. A thorough head and neck evaluation revealed probable myofascial pain with a poorly occluding set of complete dentures as a potential etiology. Fabrication of a new set of dentures and modification of the patient's denture-wearing habits has produced an almost complete remission of the pain. This case demonstrates the importance of a dental consultation to rule out a possible oral-musculoskeletal and/or dental etiology in the management of the patient with facial pain.

Addition of an implant pillar to an existing implant prosthesis.

When an implant is lost, it is sometimes desirable to replace it to ensure adequate support of the prosthesis. Such an addition may necessitate a costly and time-consuming remake procedure. A technique is offered that, in some circumstances, may allow incorporation of the newly placed implant into the existing restoration.

Body and orofacial cathexis in edentulous complete-denture-wearing clients.

This description cross-sectional study examines cathexis, or satisfaction, with the body and the orofacial region in relationship to eight major demographic and health status variables in a nonprobability sample of 34 male and 47 female edentulous subjects aged 36 to 77 years. Kiyak's 27-item Body Cathexis Scale (BCS), including an innovative five-item Orofacial Cathexis Scale (OFCS), was shown to be reliable for use in elderly clients at least to age 77 (Cronbach's alpha = .95). More research is needed to validate the OFCS. Overall scores were in the neutral range, with teeth being the most negatively cathected body part. Longer periods of edentulism were associated with more dissatisfaction with the teeth. Body and orofacial cathexis were highly positively correlated. Chronic illness, education level, race, and religion were not significantly related to cathexis. Edentulism, especially recent edentulism in the elderly, female gender, and divorced marital status could be important indicators for body image disturbance.

A method for measuring secretions from the palatal minor salivary glands.

This study investigated the secretory pattern of unstimulated minor salivary glands in 10 contiguous specified areas of the hard palate in 12 healthy unmedicated adult men and women. Each participant was assessed twice at each of two visits in the same specific palatal areas from the distal portion of the second molar to 30 mm anterior. The 10 areas were isolated, dried, and sampled with a paper strip for 60 seconds. The strips were read with a Periotron device. The rates of flow were significantly influenced by position; higher values were noted posteriorly and medially during testing and retesting at both visits. The rates of flow from the palatal glands were greatest in the area between the maxillary second molars. This method proved to be simple, accurate, and reliable for measuring the secretions of the palatal glands. This method may prove useful for investigating how the relationship between the pattern and the secretory rate of minor salivary glands influences retention of the complete maxillary denture.

Binding of murine osteoblastic cells to titanium disks and collagen I gels: implications for alternative interpretations of osseointegration.

Using 3H-thymidine-labeled MC3T3-El osteoblastic cells, the number of osteoblasts bound to titanium surfaces after various surface treatments and incubation periods was directly measured. MC3T3-El cell binding to titanium surfaces was saturable at a low level (approximately 10,000 cells/cm2). Although treatment of these surfaces with fibronectin, keratin sulfate, and the fibronectin-derived peptide GRGDS (glycine-arginine-glycine-glutamate-serine) increases cellular binding by 29% to 31%, the relative binding to titanium was 5 to 10 times lower than binding to collagen I gels. A collagen I matrix competed with the commercially pure titanium surfaces for cell binding from solution, suggesting that direct binding of osteoblasts to titanium surfaces present within an organic matrix may not be favored. The significance of immediate and direct bone cell attachment to titanium surfaces for osseointegration should be reevaluated.

Implant rehabilitation in Erdheim-Chester disease: a clinical report.

Successful osseointegration of endosseous titanium implants is thought to be dependent upon close apposition of bone to the implant surface. The integration of implants in this patient was achieved despite the lipid-laden histiocytic infiltration of the bone marrow. Presumably, enough unaffected stromal cells were present to allow sufficient bone formation for osseointegration of the implant fixtures. This result invites speculation regarding both the mechanism of osseointegration and the minimum surface area of bone-implant interface necessary for achieving and maintaining osseointegration of titanium implants. This patient is periodically examined to determine if the loaded fixtures will remain clinically immobile for a prolonged period.

Conventional and implant oral prostheses.

Despite advances in preventive dentistry, many elderly persons present with several missing teeth replaced by oral prostheses of various kinds. An increasing number of prostheses are retained and supported by oral implants. Maintaining a complete dentition with fixed, removable, or implant-retained prostheses improves function and patient self-esteem. Irrespective of the prosthesis type, periodic functional and health reassessments are necessary. Strict oral hygiene protocols must be reinforced continually and appropriate modifications (relines) and repairs should be performed to prevent possible degeneration of supporting structures. Although implants promise enhanced function and greater patient satisfaction, they too require careful maintenance. Thus, all oral prostheses require close monitoring and maintenance care. A physician can make an important contribution to a patient's health and quality of life by ensuring that he or she receives routine oral health care.

Clinical evaluation of a composite resin system with a dentin bonding agent for restoration of permanent posterior teeth: a 3-year study.

This study evaluated the clinical performance of a visible light-cured small particle bimodally filled hybrid condensable composite resin system that included a dentin bonding agent compared with an amalgam alloy in class II restorations of permanent teeth. A total of 108 restorations were placed in 34 patients. Fifty-three composite resin and 55 amalgam restorations were inserted. Each restoration was evaluated immediately after placement and then on an annual basis for a 3-year period using the Public Health Service (PHS) criteria. In addition, the Moffa-Lugassy scale was used to measure the loss of material on the occlusal surface of these materials. One hundred percent of the resin and amalgam restorations were evaluated, measured, and reasons for replacement were recorded over the 3-year period. There was no significant difference (p greater than 0.05) in the clinical performance of the composite resin and the amalgam when evaluated by the PHS criteria. Analyses of wear at each of the three annual recall periods did not reveal any significant difference (p greater than 0.05) between the two restorative materials when measured by the Moffa-Lugassy scale.

Using endosseous dental implants for patients with ectodermal dysplasia.

Congenitally missing teeth and poorly developed or absent alveolar ridges are signs often associated with various types of ectodermal dysplasia. Endosseous dental implants may be used to support fixed mandibular prostheses in patients with ectodermal dysplasia. Anatomical factors and age considerations require careful attention to treatment planning.

Oral manifestations of the Rieger syndrome: report of case.

The Rieger syndrome is a rare, autosomal dominant disorder. It is characterized by defects of the anterior chamber of the eyes as well as developmental malformations of the dentition. A case is described that shows classic findings with emphasis on dental management. Oral abnormalities in the pedigree may also suggest subtle manifestations of the syndrome. Recognition of the dental anomalies may result in early diagnosis of the syndrome and prevent progressive visual loss.