ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00344.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

An orotracheal route is frequently the preferred method of intubation for premature infants. Nasal intubation may contribute to airway obstruction and possible hypoxia, further contributing to labored breathing. Additional complications include occlusion of the nasal aperture during a crucial period of development, nasal infections, and hypertrophy of the nasal lining. Oral mucosa is less susceptible to damage than nasal mucosa; however, orotracheal tubes must be stabilized against displacement from tongue and jaw movements to prevent discomfort and subsequent tissue trauma. Problems associated with rehabilitation of very‐low‐birth‐weight neonates and other infants requiring long‐term oral intubation include palatal grooving, acquired cleft palate, and damage to the primary dentition. Various intraoral aids have been used to reduce pressure application from intubation and feeding tubes on the palatal tissues. References to these procedures have yet to be reported in the prosthodontic literature. This article presents a rationale for design and construction of an intraoral device which protects the palatal tissues and stabilizes the orotrache

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00345.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

PurposeThis study focuses on the curvature and inclination of the lingual surfaces of the maxillary anterior teeth from the transition point on the cingulum to the incisal edge.Materials and MethodsOn 32 sets of mounted casts, 768 measurements were made of the curvature of the lingual surfaces utilizing radius gauges. The inclination of the lingual surface relative to the occlusal plane was recorded. The relationship of the incisal edge of the mandibular teeth to the transition point on the cingulum of the maxillary teeth was determined. Centric occlusion contact was noted on each tooth.ResultsSignificant differences were found between the measured areas of any one tooth and between the types of teeth. The average radius ranged from 20.5 mm on the mesial ridge of the canine to 5.3 mm in the fossa of the central. The average inclination of the lingual surfaces was 46%. In centric occlusion, 97% of the canines and 59% of the centrals and laterals were in contact with the opposing teeth. These contacts occurred 2.8 mm incisal to the transition point. The centrals contacted two opposing teeth (45%), and canines contacted one opposing tooth (53%).ConclusionsThe function and curvature of the incisor teeth vary considerably from those of the canines. Overcontouring the lingual surfaces of the maxillary incisors to gain contact is not normal and may be detrimental.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00346.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

PurposeThis study assesses the clinical performance of 92 resin‐bonded fixed partial dentures (FPDs) placed at four private practices in Karachi, Pakistan, between 1982 and 1991.Materials and MethodsThe distribution of the FPDs was 9 perforated, 45 electrolytically etched, and 38 silicoated. Twenty‐five FPDs replaced anterior teeth and 67 replaced posterior teeth. There were 66 FPDs with single pontics and 26 with multiple pontics. The perforated designs used a restorative composite for cementation, whereas the electrolytically etched and silicoated designs used a composite luting cement. The observation periods for the perforated, electrolytically etched, and silicoated FPDs were 114,99, and 30 months respectively.ResultsDuring the evaluation period, 27 FPDs (29%) failed; of these, 4 were perforated, 18 were electrolytically etched, and 5 were silicoated. The mean (±SD) duration of the successful clinical service for all FPDs was 41 ± 26 months. The mean time to failure for the FPDs that did not survive was 35 ± 23 months. The silicoated FPDs tended to have early failure, as did the FPDs with multiple pontics and those in the mandibular arch. Anterior and posterior FPDs performed equally well.ConclusionsThese findings, in conjunction with those from Europe and North American, show that resin‐bonded FPD technology is as successful in a developing country as in industrialized areas of t

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00347.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

PurposeCrown and fixed partial denture fabrication using In‐Ceram all‐ceramic restorative material (Vita Zahnfabrik, Bad Säckingen, Germany) involves the veneering of a glass‐infiltrated alumina core with porcelain. The manufacturer instructs that excess infiltration glass be removed from all core surfaces before porcelain application; however, meticulous removal may not be practical. This study evaluates the failure behavior of two different types of In‐Ceram structures with or without thin layers of excess infiltration glass left on core surfaces.Materials and MethodsTwo groups of porcelain‐veneered incisor crowns were fabricated having either (1) excess infiltration glass removed from the aluminous core (n = 10) or (2) a thin layer (0.1 to 0.3 mm) of excess glass remaining on the core (n = 10). Each crown was loaded on its incisal edge against a flat compression platen at 0.5 mm/min. Two groups of core disks (thickness, 1 mm; radius, 7.5 mm) underwent similar surface treatments; ie, group A as recommended (n = 15) and group B having excess glass (n = 15). Disks were veneered with porcelain, polished to 1.5 mm, and loaded in biaxial flexure at 0.5 mm/min. All fracture surfaces were analyzed using light microscopy and a select sample were examined using scanning electron microscopy. A simple two‐dimensional finite‐element model was used to evaluate the stress state at the core‐veneer interface of bend samples.ResultsFailure loads were significantly higher for crowns having excess glass (Student'sttest,P.8). Scanning electron microscopic analysis of disk samples revealed that failures originated either at core‐veneer interfaces or at lower disk surfaces, consistent with the finite‐element analysis.ConclusionExcess infiltration glass on the core surface will not degrade the strength of In‐Ceram structures. Central incisor crowns (as tested) were strengthened by excess infiltration glass, but disk samples (stressed differently) were not. Finite‐element results suggest that disk failure originates

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00348.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00349.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

PurposeTo measure and compare strains transferred to a bone simulant by screw‐fastening implant overdenture bars with various levels of fit or misfit.Materials and MethodsPhotoelastic resin was cast directly to two 3.75 × 13‐mm Branemark fixtures (Nobelpharma USA Inc, Chicago, IL) situated 20 mm apart in a silicone mold of an edentulous mandible. Two strain‐gauge rosettes were also incorporated in the resin to allow precise determination of principal stresses at two locations. Four groups of three overdenture bars with 0‐, 180‐, 360‐, and 500‐μm vertical gaps were fabricated. These bars were sequentially secured to the abutments with gold slot screws tightened to 10 N · cm. Strain indicator readings were recorded at a standardized time following the initial fastening of each bar. The test was repeated three times for each overdenture bar.ResultsMean principal stresses and strains at the location of the rosettes were determined. The magnitude of these stresses and strains increased significantly with each increase in gap size. Strains were several times larger mesial to the fixture than they were distal.ConclusionsStrains are transferred to the bone when misfitting prostheses were secured. Some of the strains mesial to the fixture appeared to be unfavorable for regions of lower bone density when the groups with designed gaps were secured. These data will be compared with those in ongoing animal studies regarding the cellular response to p

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00350.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

PurposeReduced cement film thicknesses can improve crown seating and decrease marginal discrepancies. Improved marginal adaptation has the potential to reduce plaque accumulation, periodontal disease, and cement dissolution. Studies have indicated that dynamic seating methods can reduce seating discrepancies associated with zinc phosphate and resin cements. However, other types of cements and other dynamic techniques have not yet been studied or compared, nor has the mechanism for improved seating been fully explained. Therefore, the purpose of this study was to investigate the effect of a variety of loading methods on the film thicknesses of current types of crown and fixed partial denture cements compressed between glass plates.Materials and MethodsThis study investigated the effect of three dynamic loading methods on film thickness of six representative fixed prosthodontic cements. These included zinc phosphate, resin‐modified glass ionomer, encapsulated glass ionomer, adhesive composite resin, composite resin, and polycarboxylate. The method was derived from American Dental Association specifications for cement film thickness. In control groups, the cements were placed between two glass plates and statically loaded with a 15‐kg weight. The test groups were initially similarly loaded, and then for 30 seconds further subjected to simulated repeated patient opening and closing, vibrations from an electromallet, or an ultrasonic device.ResultsMean film thicknesses ranged from 7.4 μm for polycarboxylate/ultrasound up to 40.3 μm for composite resin/static. Two‐way analysis of variance revealed that the effects of material type and cementation method and their interaction all significantly affected film thickness (P<.0001). Multiple range analysis showed that dynamic methods were generally superior to static loading and that the ultrasonic method was the best overall.ConclusionsThe different dynamic loading methods all significantly decreased cement film thicknesses between glass plates. The ultrasonic method was the most effective. The type of cement used also influenced film thickness. Composite resins were more affected than other ma

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00351.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

At the University of Iowa, senior dental students direct rather than perform laboratory construction of clinical prosthodontic work. This report highlights the fundamentals of a successful curriculum based on this concept. One critical component of the curriculum involves teaching the process of self‐evaluation of laboratory work as well as the evaluation of work received from a commercial laboratory. Instructors teach students how to evaluate a product in the sophomore preclinical curriculum. A computerized evaluation form, developed by the prosthodontic faculty, allows assessment of the students' laboratory work in addition to self‐evaluation. To incorporate patient care into the appraisal process, a modified preclinical evaluation framework is used during the junior clinical clerkship. This expanded framework takes into consideration patient treatment factors such as degree of difficulty, diagnosis and treatment planning, use of infection control, and students' understanding of patients' comprehensive treatment plan. In the senior clinic, the students' ability to direct the construction of a prosthesis is enhanced by the unique diversity of faculty within the Department of Family Dentistry at the University of Iowa. This department unites private practice dentists with academicians and general practitioners with speciali

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00352.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Board certification in any health care–related area is one mechanism that promotes high standards of practice and assures public confidence. Certification eligibility and requirements for dental technicians and laboratories are reviewed. Issues affecting the future of dental technology are discusse

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1995.tb00353.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY