[Radiographic identification of dental implants in Israel].

Not infrequently a patient will attend seeking treatment for replacement of a lost abutment and crown from an implant placed by another dentist and no dental records are available. Many different root form implants of various designs, dimensions, surfaces, and connectors are available today posing a problem for the restorative dentist who must choose prosthetic parts that fit the implant or for a forensic dentist attempting to identify a victim. Implants installed in bone may be identified only by radiographs and knowledge of implant morphology. Four articles (1-4) were published between 1992-2002 dealing with the radiographic identification of implants. Since then many new implants have appeared on the market. Implants made in Israel do not appear at all on any of the lists. The object of this article is to provide radiographic pictures of implants available in Israel today together with a description of their radiographic features to enable Israeli dentists to identify implants where no dental records are available.

Isolation of Enterobacteriaceae from the mouth and potential association with malodor.

Bad breath is a common phenomenon, usually the result of bacterial metabolism in the oral cavity. It is generally accepted that Gram-negative bacteria are responsible for this problem, largely through degradation of proteinaceous substances. In initial experiments, screening of malodorous isolates following outgrowth of samples obtained from saliva, periodontal pockets, and the tongue dorsum yielded enterobacterial isolates. Clinical studies were conducted to examine the prevalence of such bacteria in four different populations: orthodontic patients, malodor clinic patients, complete-denture wearers, and a healthy young population. The prevalence of Enterobacteriaceae in the oral cavities of the denture-wearing population was very high (48.0%) as compared with the other groups: 27.1% in the malodor clinic patients, 16.4% in the normal population, and 13% among orthodontic patients. Isolates of Klebsiella and Enterobacter emitted foul odors in vitro which resembled bad breath, with concomitant production of volatile sulfides and cadaverine, both compounds related to bad breath. When incubated on a sterile denture, enterobacterial isolates produced typical denture foul odor. Isolates exhibited cell-surface hydrophobic properties when tested for adhesion to acryl and aggregation with ammonium sulphate. The results, taken together, suggest that Klebsiella and related Enterobacteriaceae may play a role in denture malodor.

Post-irradiation polymerization of different anterior and posterior visible light-activated resin composites.

The Knoop hardness number was measured for bottom and top surfaces of 2 mm thick specimens of different anterior and posterior visible light-cured composites. The variables for this study included various exposure times and a series of time intervals from immediately after curing up to 72 h. Post-irradiation microhardness at the bottom and top surfaces increased rapidly over the first hour, was slower during 24 h and showed no further increase after 24 h. Increasing exposure time resulted in higher microhardness values at both surfaces. Magnitudes of change were larger for the bottom surface. Exposure times longer than those recommended by the manufacturers were needed, especially for the anterior microfilled composites, to achieve adequately photo-activated resin that had an optimum bottom/top surface microhardness of 80-90%. Maximum hardness values were found to be dependent on the volumetric fraction but not on the average inorganic filler size. The post-irradiation increase in hardness value was independent of composite parameters and is probably commensurate with polymerization kinetics.

A survey of output intensity and potential for depth of cure among light-curing units in clinical use.

OBJECTIVES: The light intensity of curing lights used in private dental offices was measured using commercial curing and heat radiometers and related to uniformity of cure depth of standardized composite specimens. METHODS: The intensity of 130 curing light from 107 dental offices was measured with curing and heat radiometers. Due to analogue readings, results were recorded in steps of 25 mW cm-2 and assigned a category number. A total of 50 lights were randomly selected to polymerize standardized 3 mm thick composite cylinders. The composite was irradiated for 50 s according to the manufacturer's instructions. The Knoop hardness value was measured at the top and bottom surfaces and the uniformity of cure depth was calculated from the ratio of these two values. RESULTS: Light intensity measured by the curing and heat radiometers was in the range of 25-825 and 0-325 mW cm-2, respectively. Functions of maximum likelihood estimation of the top and bottom surface hardness were 57 N/N + 1.3 and 80 N/N + 17.7, respectively (N = light intensity category number). The relationship between the logarithmic transformation of the hardness ratio and light intensity was linear (R2 = 0.84 p < 0.001). CONCLUSION: According to the manufacturer, a curing light is considered as unsuitable for use with a reading of < 200 mW cm-2 by the curing radiometer and > 50 mW cm-2 by the heat radiometer. Applying these criteria to the present study, 46% of the lights (without repetitions) required repair or replacement. The strong correlation found between the hardness ratio and light intensity verifies the usefulness of the curing radiometer in predicting the polymerization ability of the light activation units.

Effect of preliminary treatment of the dentin surface on the shear bond strength of resin composite to dentin.

This study evaluated the effect of two dentin disinfectants (Consepsis, Tubulicid), one aqueous HEMA solution (Aqua Prep), a combination of Aqua Prep and Tubulicid and an air abrasion treatment (50 microns aluminum oxide) on the shear bond strength (SBS) of two acetone-based single bottle adhesives (One Step and Prime & Bond 2.1). The occlusal surfaces of 167 freshly extracted human third molars were ground flat to expose the dentin, then polished with a 600 grit-polishing disc. The teeth were randomly assigned to 12 test groups (two bonding agents, six pretreatment protocols). The exposed dentin was etched with 35% phosphoric acid for 20 seconds, rinsed and briefly (1-2 seconds) air dried. Six pretreatment protocols were then applied. The air abrasion groups were exceptional, as etching was carried out only after pretreatment. One Step, or Prime & Bond 2.1 was applied according to the manufacturer's instructions. Cylinders of Z-100 composite were bonded to the flat dentin surfaces by transparent gelatin capsules. Specimens were thermocycled in water baths between 5 degrees and 55 degrees C, then sheared in an Instron Testing Machine. One-way and two-way ANOVA and Tukey HSD post-hoc tests were used for statistical analysis. In the One Step group, Consepsis yielded a significantly higher SBS (17.8 MPa) than air abrasion (9.5 MPa), Control (11.8 MPa) and Aqua Prep + Tubilicid (11.9 MPa), and a comparable SBS with Tubilicid (12.5 MPa) and Aqua Prep (14.8 MPa). In the Prime & Bond 2.1 group, Aqua Prep (24.9 MPa) showed a significantly higher SBS than all other groups: air abrasion (9.3 MPa), Control (9.97 MPa), Tubilicid (12.2 MPa), Consepsis (13.0 MPa) and Tubilicid + Aqua Prep (13.3 MPa).

The fluid-filled gap under amalgam and resin composite restorations.

This article discusses the factors involved in the formation of marginal gaps between amalgam or resin composite restorative materials and cavity walls. The fluid that penetrates the microspace from the oral cavity and from the dentinal tubules is followed by bacterial invasion. This process can lead to secondary caries and irritation of the dentin/pulp complex. The bacterial growth is controlled by effective sealing at the tooth/restoration interface, partial obliteration of the gap, accumulation of solids at the cavosurface margins of the restorations, and by antibacterial linings.

Varnish application technique and microleakage of amalgam restorations.

Various techniques for applying two types of varnish to control microleakage of Class V amalgam restorations were compared in vitro. The drying time for each layer of varnish with a gentle air spray was varied, including delays in applying the second coat and the placement of the amalgam restoration. Microleakage was recorded by dye penetration. Both varnishes were inefficient at reducing dye penetration at the gingival wall. There were no statistical differences in dye penetration at the gingival wall between the two varnishes, regardless of the method of application, or the presence of varnish. Both varnishes exhibited good sealing properties at the occlusal wall when used according to the manufacturer's instructions, but varnish application was technique-sensitive. Short-cuts in the procedure may increase leakage; too short a drying time of either varnish can cause microleakage similar to the control group without a varnish.

Long term sealing properties of Amalgambond under amalgam restorations.

The degree of microleakage at 14 days, 6 months and 1 year between Class V amalgam restorations lined with Copalite varnish or with Amalgambond was compared in this in vitro study. The restored teeth were subjected to cyclic occlusal loading, thermocycling procedures and then stored in a dye solution at the appropriate intervals. Dye penetration was assessed at the gingival and occlusal margins of the restorations. The results showed that with Amalgambond, there was significantly better sealing of the dentin tubules than with Copalite or unlined restorations (P < 0.001) at all times tested. Amalgambond showed significantly less microleakage as compared to unlined restorations (P < 0.01) at all time periods, and significantly less short-term (14 days) microleakage compared with the Copalite-lined group (P < 0.01).

RLS--the lingually retained clasp assembly for distal extension removable partial dentures.

The design of clasp for a distal extension removable partial denture that helps preserve both the abutment teeth and the tissues of the edentulous ridge is described. The clasp assembly takes advantage of surveyed lingual undercuts to provide support, retention, and stability. It consists of a mesio-occlusal rest, a distolingual L-bar direct retainer that is located on the abutment tooth adjacent to the residual ridge, and a distobuccal stabilizer (RLS).

Removable partial denture with a lateral rotational path of insertion.

A removable partial denture with a lateral path of insertion is useful when unsightly facial clasps are objectional to the patient. Rounded rest seat preparations allow extensions of the minor connector to rotate laterally into embrasure undercuts, providing retention. Guiding planes on the contralateral side ensure a different path of withdrawal from the retentive elements. A Kennedy Class IV arch with a long edentulous span is used to illustrate the denture design.

A technique for removing cemented posts.

An efficient and safe technique for removing a cemented post using the Saca Pino post extractor has been described.

Transferring anterior occlusal guidance to the articulator.

Anterior disclusion has become accepted as an optimal therapeutic model in the restoration of the anterior dentition. The ability to achieve anterior disclusion is influenced by the anterior determinants of esthetics, phonetics, skeletal relation, tooth position, abutment distribution, and alveolar bone support in addition to the posterior condylar determinants. Temporary restorations are made to incorporate these factors and it becomes necessary to transfer the information to working models of the articulator. A technique is described whereby a wax or silicone index fixed partial denture is made at chairside, duplicating the temporary restoration that is directly transferable to the working casts of the articulator. This technique allows the technician to make final restorations according to the index fixed partial denture, thus incorporating the anterior determinants of occlusion in conjunction with the posterior condylar determinants specific to each patient.

An innovative method of monitoring denture hygiene.

A simple and rapid test for measuring oral hygiene was recently developed. It is based on the rate of oxygen consumption of oral expectorates of milk. This investigation modified the test to study denture hygiene. The dentures of 20 patients were immersed in 10 mL of sterile milk. After a 2-minute agitation, 3 mL of milk was added to test tubes containing methylene blue. The time required for color change at the bottom of the test tube, which is indicative of the rate of oxygen consumption, was recorded. For comparison with visual plaque accumulation, the dentures were coated with disclosing solution and the extent of plaque was scored by three examiners. A correlation was found between the plaque index scores and results of the milk test (r = -0.64; p less than 0.005). The data suggests the use of this test to monitor denture hygiene.

In vivo retrospective study of cement thickness under crowns.

PURPOSE: This study evaluated the cement thickness under crowns cemented with zinc phosphate cement that had been in clinical use for at least 10 years. MATERIAL AND METHODS: A total of 97 teeth were extracted because of periodontal disease as part of a new treatment plan. Teeth were sectioned and the cement thickness measured at predetermined points on the occlusal and axial walls with a measuring microscope at x150 magnification. RESULTS: Mean cement thicknesses on buccal and lingual walls were similar (116 microns and 109 microns, respectively), but much smaller than on occlusal walls (310 microns). Cement thicknesses at occlusal locations were significantly thicker in molars than in premolars. Poor correlations existed between cement thicknesses on buccal and lingual walls (0.26) and between these and the occlusal walls (0.35) implying that incomplete seating is strongly related to tilting or oblique seating. CONCLUSION: Under clinical conditions where more inherent difficulties exist, special measures must be taken to alleviate the consequences of cement fluid dynamics.

The immediate overdenture. A case history.

A case is described of application of the immediate overdenture technique to restore function, speech and aesthetics in a patient with extreme resorption of the maxillary anterior residual ridge. In the opinion of the authors, retention of the roots of the remaining teeth most definitely contributed to the retention, stability and overall success of the denture (Figs. 9, 10).

Combining final impressions with maxillomandibular relation records in stabilized record bases.

The postinsertion problems of complete denture prostheses are closely related to accurate recording of maxillomandibular relationships. It is essential that these recordings be made with stable record bases; making the final impressions within the record bases prevents movement and tilting. Face-bow and centric relation records properly orient the casts in the articulator. A method to obtain all of these records in one dental appointments has been described.

Prevalence of Candida albicans in denture wearers in an Israeli geriatric hospital.

Thirty-seven patients wearing complete dentures were investigated for Candida albicans. Twenty-five of the patients suffered from denture stomatitis and twelve had clinically normal mucosa. Candida albicans was isolated and identified from Sabouraud dextrose agar culture medium models constructed from impressions of the maxilla and from the upper dentures. The presence of Candida albicans was demonstrated in all denture wearers suffering from denture stomatitis and in 82% of denture wearers in a control group. A higher concentration of Candida was found in the denture stomatitis group. Large quantities of Candida resided in the denture base and not in the palate. Candida was also found in the denture base in areas not related to the lesion. The concentration of Candida was related to denture cleanliness.

A clinical evaluation of materials used in registering interjaw relationships.

Three recording media used to relate stone casts for 15 dentate patients were compared for accuracy. Interjaw relationships at the maximum intercuspation position and the retruded contact position were recorded using impression plaster, wax, and Duralay acrylic resin. A Lucia programming jig was used in the retruded contact position. The vertical distance and horizontal deviation between the casts were measured from reference points on the casts using each recording material. The average percentage differences between the recording materials were calculated. Hand articulation was the most accurate method of relating the casts at maximum intercuspation. The most accurate recording medium was impression plaster, followed by dental wax and Duralay resin at the maximum intercuspation and retruded contact positions.