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PubMedDate not supplied

A 10-year longitudinal study of fixed prosthodontics: clinical characteristics and outcome of single-unit metal-ceramic crowns.

PURPOSE: The purpose of this study was to report on the clinical characteristics and outcome of 688 single-unit metal-ceramic crowns placed in a specialist prosthodontic practice between January 1984 and December 1992. MATERIALS AND METHODS: Clinical and laboratory techniques were standardized and patients were recalled by the author between June and December of 1993. The outcome of all crowns was allocated to one of 6 fields in this assessment period. RESULTS: Clinical review examination by the author covered 87% of the crowns. Of these, 52% had been in service for 5 to 10 years and 48% for less than 5 years but more than 1 year; 67% of the crowns were placed on vital teeth and 94% were given a "good prognosis" rating at examination. The repair and failure rates of crowns in the 5 to 10 years in clinical service group were both 3%. Crowns on nonvital teeth in the same grouping had a significantly greater failure rate (5%) than crowns on vital teeth (1%), and anterior teeth had a significantly greater retreatment rate than posterior teeth. Retreatment for all 25 crowns occurred within 66 months after cementation. Tooth fracture accounted for 56% of retreatments, while caries and loss of retention accounted for only 24% of retreatments; 2% of initially vital teeth were endodontically treated during the survey period. CONCLUSION: Single-unit metal-ceramic crowns have a high expectancy of exceeding 10 years of clinical service when the described clinical and laboratory protocol is applied.

Adult↗
PubMedDate not supplied

The effects of cavity preparation and lamination on bond strength and fracture of tooth-colored restorations in primary molars.

PURPOSE: This in vitro study compared bond strength and fracture modes of tooth-colored restorations in 2 types of cavity preparations in human primary molars. METHODS: Standardized Class II cavities (40 dovetail and 40 box-only preparations) in extracted human primary molars were restored with packable composite resin (PC), resin-modified glass ionomer cement (RMGIC), resin-modified glass ionomer/packable composite resin laminate (RMGIC/PC), or resin-modified glass ionomer/packable composite resin laminate with an experimental bonding agent, K-14 (RMGIC/K-14/PC). The ultimate load at fracture was measured on marginal ridges, and fractured surfaces were examined microscopically. RESULTS: The mean (+/-SD) ultimate load at fracture (ULF, in Newtons) of PC and RMGIC/K-14/PC in box-only preparations (400+/-98; 386+/-82) did not differ significantly from that found in dovetail preparations (377+/-80; 317+/-92), and the mean ULF of RMGIC and RMGIC/PC in box-only preparations (307+/-44; 325+/-72) did not differ significantly from that in dovetail preparations (352+/-71; 353+/-70). No interactions were seen between materials and preparations (P=.09). Fracture modes for restorations in dovetail (predominantly mixed) and box-only preparations (predominantly mixed and adhesive) differed significantly (P=.003), but not between restorative procedures (P=.052). CONCLUSIONS: Tooth-colored restorations placed in vitro in box-only preparations did not differ in fracture resistance from those placed in dovetail preparations. On fracture loading, resin-modified glass ionomer restorations placed in box-only preparations were more likely to show adhesive failure than those placed in dovetail preparations.

Analysis of Variance↗
PubMed2003

Surgical crown lengthening: evaluation of the biological width.

BACKGROUND: Previous surgical crown lengthening studies have investigated positional changes of the free gingival margin but not the biological width. Histological studies utilizing animal models have shown that postoperative crestal resorption allowed reestablishment of the biological width. However, very little work has been done in humans. Therefore, the purpose of this study was to evaluate the positional changes of the periodontal tissues, particularly the biological width, following surgical crown lengthening in human subjects. METHODS: Twenty-three (23) patients who needed surgical crown lengthening to gain retention necessary for prosthetic treatment and/or to access caries, tooth fracture, or previous prosthetic margins entered the study. The following parameters were obtained from line angles of treated teeth (teeth requiring surgical crown lengthening) and adjacent teeth with adjacent and non-adjacent sites: plaque and gingival indexes, free gingival margin, probing depth, attachment level, bone level, direct bone level, and biological width. During surgery, the bone level was reduced based on the future prosthetic margin and predetermined biological width; flaps were placed at the bony crest. Patients were examined at baseline and at 3 and 6 months postoperatively. RESULTS: Eighteen patients completed the study. Overall, the amount of bone resected was 1 to 5 mm. At 90% of treated sites, > or = 3 mm of bone was removed. At 3 months, the apical displacement of the free gingival margin at non-adjacent, adjacent, and treated sites was 2.46 +/- 0.25 mm, 2.68 +/- 0.20 mm, and 3.07 +/- 0.16 mm, respectively. There was no significant change in the position of the free gingival margin from 3 to 6 months. The biological width at all sites was smaller at 3 and 6 months compared to baseline (P<0.05) except for the treated sites, which were not significantly different from baseline at 6 months. CONCLUSIONS: During surgical crown lengthening, the bone level was lowered for placement of the prosthetic margin and reestablishment of the biological width. The biological width, at treated sites, was reestablished to its original vertical dimension by 6 months. In addition, a consistent 3 mm gain of coronal tooth structure was observed at the 3- and 6-month examinations.

Adult↗
PubMed2004

[Background data about the high dental fear scores of Hungarian 8-15-year-old primary school children].

Free associations (coupling) of 139 Hungarian primary school children about their teeth was collected. Dental fear (DAS, DFS) and general anxiety scores were measured. Typical dental events (i.e.: loss of deciduous teeth, simple and traumatising dental treatments, tooth fractures) were coupled by the participants in 41.0% of the cases. Functions and importance of the teeth and oral hygiene were described in 20.1% of the cases. Simple, grotesque, or magical stories and tales about teeth were found in 8.6% of the cases. No answer was given in 30.2% of the cases. Highest dental fear and general anxiety scores were found in the group coupled traumatising dental treatment. Traumatising loss of deciduous teeth was caused by the dentist or by the father of the child, and was associated with higher dental fear and general anxiety comparing to simple loss of deciduous teeth. Higher dental fear and general anxiety scores were found in the group coupled functions and importance of the teeth comparing to the group coupled simple, grotesque, or magical stories and tales, or the group giving no answer.

Adolescent↗
PubMed1995

Midfacial fractures in pediatric patients. Frequency, characteristics, and causes.

OBJECTIVE: To determine the frequency, characteristics, and causes of midfacial fractures in children. DESIGN: A retrospective review of the patients' medical charts and radiographs. SETTING: Tertiary referral center. PATIENTS: Fifty-four patients under 16 years of age, with midfacial fractures diagnosed and treated in the Helsinki (Finland) University Central Hospital from 1980 through 1992. MAIN OUTCOME MEASUREMENTS: The data examined included sex, age, time and cause of the accident, type and location of the fractures, the presence and location of associated injuries, complications, and treatment methods. RESULTS: The male-to-female ratio was 1.16:1. Motor-vehicle accident was the most common cause of injuries. The frequency of injuries was in decreasing order: (1) maxillary alveolar bone, (2) zygoma, and (3) Le Fort fractures of the maxilla. The majority of injuries occurred in subjects who were 13 to 15 years old. In children less than 6 years old, only alveolar fractures occurred. For the other age groups, no significant difference in the fracture pattern was found. No fatalities occurred in this patient series. CONCLUSIONS: Midfacial pediatric fractures are rare. A high velocity force, such as that from a motor-vehicle accident is a factor producing the injury. Owing to the high impact, associated injuries are common. The severity of the insult is more essential than the age of the patient and the development of the paranasal sinuses.

Adolescent↗
PubMed1982

Osteogenesis imperfecta lethal in infancy: case report and scanning electron microscopic studies of the deciduous teeth.

Radiologic evaluation of the skeleton and scanning electron microscopic studies of the teeth were performed on an infant boy with a lethal osteogenesis imperfecta (OI) syndrome who died at 10 mo of pneumonia. The skeletal findings included ribs that were focally expanded by fracture calluses, flat vertebral bodies, and wide limb bones. On fractured tooth surfaces, the enamel and dentin were normal as was the dentin calcification front. Although microscopic abnormalities have been noted in teeth from previously reported infants with lethal OI, a few studies also report infants with normal teeth. These differences in dental findings may indicate heterogeneity in OI lethal in infancy. Results of our study indicate that, until the primary biochemical defects in the OI syndromes are elucidated, examination of teeth from other infants with lethal OI and detailed evaluation of other clinical and skeletal features will aid in delineating heterogeneity and variation in expression in lethal OI.

Humans↗
PubMed1987

The use of extraction replicas in scanning electron microscopy for the elemental analysis of marginal seals.

Elemental analysis of marginal seal material on 20 bulk samples of occlusally restored teeth have shown that, generally, more elements were detected in the seal material analyzed on the bulk restoration or fractured tooth surfaces than when such material was extracted using a nitrocellulose replica prior to analysis. No mercury was detected in any of the extracted seal material and only three of the replica specimens contained silver. This implies that the technique of using extraction replicas to remove material from the amalgam-tooth interface for subsequent x-ray microanalysis can provide an accurate elemental composition. The details of fabrication and the advantages of using high resolution nitrocellulose replicas for extracting marginal seal material from teeth for subsequent x-ray microanalysis are described.

Dental Amalgam↗
PubMed2006

Kitagawa-Takahashi diagrams define the limiting conditions for cyclic fatigue failure in human dentin.

As cyclic fatigue is considered to be a major cause of clinical tooth fractures, achieving a comprehensive understanding of the fatigue behavior of dentin is of importance. In this note, the fatigue behavior of human dentin is examined in the context of the Kitagawa-Takahashi diagram to define the limiting conditions for fatigue failure. Specifically, this approach incorporates two limiting threshold criteria for fatigue: (i) a threshold stress for fatigue failure, specifically the smooth-bar (unnotched) fatigue endurance strength, at small crack sizes and (ii) a threshold stress-intensity range for fatigue-crack growth at larger crack sizes. The approach provides a "bridge" between the traditional fatigue life and fracture mechanics based damage-tolerant approaches to fatigue-life estimation, and as such defines a "failure envelope" of applied stresses and flaw sizes where fatigue failure is likely in dentin This approach may also be applied to fatigue failure in human cortical bone (i.e. clinical "stress fractures"), which exhibits similar fatigue behavior characteristics, and in principle may aid clinicians in making quantitative evaluations of the risk of fractures in mineralized tissues.

Dentin↗
PubMed1979

A correlated scanning and transmission electron microscopic study of maturation ameloblasts in developing molar teeth of rats.

Maturation ameloblasts of developing molar teeth of the rate were studied by both scanning and transmission electron microscopy. After fixation, teeth were frozen and split. One face of the fractured tooth was used for SEM, the other for TEM. It was found that in some regions proximal junctional complexes separate the interameloblast space from the intercellular space of the papillary layer. Thereby an intercellular ameloblastic compartment is delineated which in some specimens contains a substance interpreted to be colloidal. Elsewhere the proximal junctions of ameloblasts are not present and free communication between the extracellular spaces is evident. The apical pole of ameloblasts varies in structure. Over some areas there is a distinct distal border zone with membranous infoldings which in some regions resembles a striated or ruffled border, but in other regions the membranes show whorl configurations. The distal border zone also contains granules with flocculent material. Elsewhere the ameloblasts display no distal border zone and the cells show a smooth membrane (except for pinocytotic vesicles and hemidesmosomes) facing the enamel surface. The lateral surface of ameloblasts exhibits a variety of surface configurations similar to but not as pronounced as those reported previously in rat incisor maturation ameloblasts.

Aging↗
PubMed1989

[Anterior tooth injury/anterior tooth loss--the epidemiological and orthodontic aspects].

Trauma to incisors, especially loss of permanent anterior teeth, often effects aesthetics, function, psychology and phonetics. The following article describes the frequency, cause and effect of incisors lost as a result of the trauma. The treatment possibilities are discussed with respect to the specific orthodontic considerations. In addition, the indications for space closure by orthodontic or prosthetic procedures are discussed.

Adolescent↗
PubMed2003

Composite resin fillings and inlays. An 11-year evaluation.

The purpose of this randomized, clinical study was to evaluate the clinical performance of composite resin materials used for fillings and indirect inlays. Twenty-eight sets of five class II restorations (two fillings, three inlays) were placed in 88 premolars and 52 molars in 28 adults. Brilliant Dentin and Estilux Posterior were used for both fillings and inlays, and SR-Isosit for inlays only. After 11 years, 27 sets of restorations (96%) were evaluated clinically using modified United States Public Health Service criteria. Replaced or repaired restorations were observed in 16% of the fillings and 17% of the inlays, and a further 5% of the restorations were replaced for reasons not related to the restoration. The remaining 107 restorations exhibited optimal ratings in 30% of the fillings and 12% of the inlays (P<0.05) and acceptable ratings in 70% and 88%, respectively. The reasons for failure were fracture of restoration (four fillings, five inlays), secondary caries (two fillings, four inlays), fracture of tooth (two inlays), loss of proximal contact (two fillings), and loss of restoration (one inlay). Failures were seen more frequently in molar than premolar restorations (P<0.05), with no significant difference between fillings and inlays or between the five types of restoration (P>0.05).

Acrylic Resins↗
PubMed1982

Root resorption after orthodontic treatment of traumatized teeth.

This study concerns the frequency and degree of root resorption in traumatized incisors that have been treated orthodontically. The subjects were twenty-seven patients (fifteen boys and twelve girls) with fifty-five traumatized incisors; fifty-five consecutive patients without traumatized teeth served as controls. All the control patients were treated with extraction of four first premolars and a fixed appliance (thirty-three with an edgewise and twenty-two with a Begg appliance). Signs of root resorption were registered with index scores from 0 to 4 (Fig. 1). The degree of root resorption in traumatized teeth was compared to that in the uninjured control teeth in the same patient and in the patients without trauma. Neither the intraindividual nor the interindividual comparisons support the hypothesis that traumatized teeth have a greater tendency toward root resorption than uninjured teeth. Root resorption (scores 2 to 4) was found in 51 percent of the traumatized incisors, in 43 percent of the incisors treated with edgewise appliances, and in 48 percent of those treated with Begg appliances. Traumatized teeth with signs of root resorption prior to orthodontic treatment may be more prone to root resorption during treatment.

Adolescent↗
PubMed1977

Composite resin repair of porcelain denture teeth.

An effective temporary repair of fractured poreclain denture teeth involves abrasive treatment of the fractured tooth surface followed by a composite resin buildup. This study has demonstrated that the best potential retention of the composite buildup can be obtained through abrasive treatment by a course diamond stone.

Composite Resins↗
PubMed1980

A review of the submerged-root concept.

The purpose of this article was to review and summarize the literature on the retention of submerged roots. It appears that the submerged-root procedures may have an accepted place alongside conventional overdenture techniques in the profession's continuing effort to retard alveolar bone resorption in the field of prosthodontics.

Acrylic Resins↗
PubMed1980

Orthodontic extrusion: its use in restorative dentistry.

The technique described in this study demonstrates that the use of orthodontic extrusion can provide an alternative to extraction and extensive periodontal surgery. Selection of patients is an important aspect when considering this type of treatment. The crown-root ratio, as well as the root anatomy, if inadequate, may render this type of treatment inappropriate. The concept of a biologic width is discussed, and its application to forced eruption is described.

Adolescent↗