Intensity of bacteraemia associated with conservative dental procedures in children

OBJECTIVES

To explore the individual dento-gingival manipulative procedures that together lead to the placement of a restoration and to estimate the associated intensity of bacteraemia.

PATIENTS AND METHODS

Healthy children receiving dental treatment under general anaesthesia provided blood samples 30 seconds after one of four dento-gingival manipulative procedures: 1. Placement of rubber dam, 2. Use of the high speed drill, 3. Use of the slow speed drill, and 4. Placement of matrix band and wedge. Blood cultures were processed to give the percentage prevalence of bacteraemia, the intensity of organisms per millilitre of blood and the identity of the organisms cultured.

RESULTS

A total of 257 children were recruited to the study. The percentage positive prevalence of blood cultures was baseline--9.3%, rubber dam placement--31.4%, slow drill--12.2%, fast drill--4.3%, and matrix band and wedge--32.1%. The intensity of bacteraemia was baseline--1.2 cfu, rubber dam placement--1,962 cfu, slow drill--0.3 cfu, fast drill--1.9 cfu, matrix band and wedge--4.8 cfu.

CONCLUSIONS

These data indicate that dento-gingival manipulative procedures comprising a simple dental restoration can lead to a bacteraemia comparable to that from dental extractions. It is suggested that these data may indicate the need for antibiotic prophylaxis for some aspects of conservative dentistry.

Ultraconservative resin restorations. "Watch and wait" is not acceptable treatment

UltraConservative dentistry represents a great step forward for the dentist, the profession, and particularly for the patient. It involves the early detection and complete elimination of all accessible and non-accessible carious material from the tooth. Untreated caries, though they may be tiny, can be extremely and very rapidly destructive. The earliest interception of decay maintains total dental health, and increases the likelihood of the restored teeth lasting a lifetime.

The complexities of restoring devitalized teeth: applying new principles to old ideas

Because the physical and mechanical properties of vital and devitalized teeth differ, a variety of complexities can occur during the reconstruction of endodontically treated teeth. The three products described are recommended to help overcome some of the shortcomings encountered in present-day rehabilitation.

Internal adaptation and overhang formation of direct Class II resin composite restorations

The aim of the present in vitro study was to evaluate different restorative concepts for posterior resin composite fillings in terms of internal adaptation and overhang formation. Eighty standard occluso-distal cavities with and without a 1.5-mm bevel were restored in a phantom head using Syntac Classic and Tetric Ceram with and without Tetric Flow as thin lining or Solid Bond and Solitaire with and without FlowLine. The restorations were finished intraorally and afterwards subjected to thermal loading (1150 x +5 degrees C/+55 degrees C) for 24 h. The proximal margins of the original specimens were analyzed for overhangs under a stereo light microscope (100-fold magnification) before and after intraoral control with loupes, including additional polish. Afterwards the teeth were cut longitudinally, replicated, and their internal integrity analyzed under a SEM (200-fold magnification). The combination of flowable and viscous composites resulted in enhanced internal adaptation for both adhesive systems. However, Syntac Classic exhibited superior adaptation characteristics compared with Solid Bond. In terms of overhang formation, the use of flowable materials always led to higher percentages of marginal overhangs in beveled cavities. Higher viscous materials alone resulted in higher percentages of underfilled margins of beveled than box-shaped cavities. It was clear that the use of magnifying glasses during finishing was beneficial for reducing marginal overhangs up to 40%.

Foundation restorations in fixed prosthodontics: current knowledge and future needs

PURPOSE

The Ad Hoc Committee on Research in Fixed Prosthodontics established by the Academy of Fixed Prosthodontics publishes a yearly comprehensive literature review on a selected topic. The subject for this year is foundation restorations.

METHODS

Literature of various in vitro and in vivo investigations that included technical and clinical articles was reviewed to provide clinical guidelines for the dentist when selecting methods and materials for restoration of structurally compromised teeth. Topics discussed and critically reviewed include: (1) desirable features of foundation restorations, (2) foundations for pulpless teeth, (3) historic perspectives, (4) cast posts and cores, (5) role of the ferrule effect, (6) prefabricated posts, (7) direct cores, (8) foundation restorations for severely compromised teeth, (9) problems and limitations, (10) future needs, and (11) directions for future research.

CONCLUSION

This comprehensive review brings together literature from a variety of in vitro and in vivo studies, along with technique articles and clinical reports to provide meaningful guidelines for the dentist when selecting methods and materials for the restoration of structurally compromised teeth.

Cuspal reinforcement in endodontically treated molars

This in vitro study compared the ability of horizontal pins and a dental adhesive to reinforce the facial cusps of endodontically treated mandibular molars. Seventy-two mandibular molars were divided into six groups and mounted in acrylic blocks (n = 12). In Groups 1-5 standardized endodontic access and instrumentation in the coronal one-third of each root canal were completed. In Groups 1-4 the lingual cusps were reduced, leaving the buccal cusps intact. The facial cusps of the teeth in each group received one of the following modes of reinforcement: Group 1--no reinforcement; Group 2--dentin adhesive (Amalgambond Plus); Group 3--two horizontal TMS Minim pins; Group 4--two horizontal TMS Minim pins and Amalgambond Plus. Teeth in Group 5 were prepared for and restored with a complete cuspal coverage amalgam restoration using four vertical TMS Minim pins. Group 6 consisted of intact natural teeth. Using an Instron Universal Testing Machine, the lingual slope of the facial cusp of each specimen was loaded to failure using a compressive force applied at an angle 60 degrees to the long axis of the tooth. The mean fracture strengths for all groups were analyzed using a one-way ANOVA and Student-Newman-Keuls multiple range test (alpha = 0.05). Fracture patterns and modes of failure were also evaluated.

RESULTS

The intact teeth (Group 6) were significantly more fracture resistant than all other groups, with the exception of Group 4 (combination of pins and adhesive). Group 1 (non-reinforced teeth) was significantly weaker than all other groups. Groups 2-4 (specimens with reinforced cusps) were not significantly different from each other. The use of horizontal pins or a combination of horizontal pins plus dentin adhesive for cuspal reinforcement resulted in significantly more teeth demonstrating favorable fracture patterns than did the use of adhesives alone.

CONCLUSION

The buccal cusps of endodontically treated mandibular molars reinforced with a combination of horizontal pins and dentin adhesive were not significantly weaker than intact teeth. Of the restored teeth, those which had buccal cusps reinforced with horizontal pins and those treated with complete cuspal coverage amalgam restorations exhibited the most favorable restorative prognosis following cusp fracture.

In vitro effectiveness of hand excavation of caries with the ART technique. Atraumatic restorative treatment

The purpose of this study was to evaluate the effectiveness of the atraumatic restorative treatment (ART) hand-instruments and of round steel burs for removing caries at the enamel-dentine junction (EDJ) in occlusal cavities prepared in 50 extracted permanent molars. The teeth were divided randomly into two equal groups for the two treatments provided by 1 operator. Stained but hard dentine was not removed. The teeth were then sectioned vertically, buccolingually through the prepared cavities to give 200 sections, each 500 microm thick, which were photographed (x1 magnification) before and after staining with a caries detector dye. Assessments were made (x3 magnification) of (a) the amount of brown-stained residual dentine, and (b) the amount of red dye-stained dentine present at the EDJ, using two sets of standards devised and transparencies arranged as six-category incremental rating scales. There was no statistically significant difference found between the two caries-removal methods for the amount of residual brown-stained dentine present (chi(2 )= 3. 394, p = 0.64), but there was for the amount of red dye-stained dentine present (chi(2) = 32.137, p<0.0001), although 57% of the ART and 80% of the steel bur sections had very little to mild red-dye staining present. Excavation of caries at the DJE appeared to be less effective with the ART technique, although the clinical implications of this may not be significant.

The periodontal-restorative interface: enhancement through magnification

One critical factor associated with aesthetics, periodontal health, and the longevity of restorations is the precision of the margins at the periodontal-restorative interface. Improper margins can cause overhangs and overcontouring that may ultimately result in caries, periodontal inflammation and breakdown, and compromised aesthetics. In order to prevent pathology at the restorative-tooth interface, each phase of the aesthetic treatment must be performed with precision and care. This article presents the utilization of an operating microscope to improve the marginal adaptation of all-porcelain restorations.

Pulpo-dentin protection: the biocompatibility of materials most commonly used in restorative work. A literature review

The complexity and importance of the biological structures that form the so-called pulpal dentinal complex call for considerable accuracy during restorative procedures. In practice this means accurate techniques and appropriate dental materials, able to combine protective and restorative qualities, and above all, offering biocompatibility. In order to analyze this property, a number of international studies suggest the use of sequential tests divided into three different levels: initial tests, secondary tests and usage tests in the form of in vivo and in vitro tests to observe and simulate the biological reactions to dental materials used in particular tissues. The authors publish a review of the literature regarding the biocompatibility of intermediate materials regarded as useful aids in restorative dental practice; these include paints, liners and cavity bases made from Ca(OH)2, ZOE cements, zinc phosphate, polycarboxylic compounds, glass ionomers, bonding agents and mordents. The chemical, biological, clinical and utilization parameters are outlined for each compound, paying special attention to the problem of biocompatibility and indicating the pulpal reactions reported over the past decade in connection with their use. In conclusion, while waiting for a standard international document to codify evaluation methods and classify the results obtained, these experimental data can be used to programme a more correct and safer use of materials.

[Statistical analysis of fabrication of indirect single restorations]

A statistical survey based on laboratory records was performed on the number of indirect restorations fabricated at the dental hospital of Tokyo Medical and Dental University from April 1 to September 30, 1997. A comparison was also carried out with a previous survey, which had been carried out in 1986, in order to detect any change and possible alterations in the near future. Based on the results of this statistical survey, the conclusions were as follows: 1. A total of 9,126 indirect restorations were fabricated during the six month period in 1997; among them, 8,007 (87.7%) restorations were covered by health insurance and 1,119 (12.3%) restorations were not. 2. The most common restoration was the cast post and core (28.6%), followed by full crowns (18.5%) and removable partial dentures (15.6%). On the other hand, the least number were post crowns (0.03%) and resin jacket crowns (0.2%). 3. When making a comparison with the data in 1986, an increase in the number of removable partial dentures and a decrease in the number of inlays were the most distinctive features. 4. For anterior teeth, resin-veneered crowns were most common, especially for lower teeth. The percentage of restorations, which were not covered by health insurance, decreased from 45.0% (in 1986) to 12.3% (in 1997).

In situ microsampling technique for identification of elements of a restoration with exposed metal to identify potential allergens

STATEMENT OF PROBLEM

For clinical investigations of allergic reactions to dental materials, it is necessary to know the type of metal used in restorations in the mouth of the patient. However, an intraoral method of sampling the dental alloy without removing the metal restoration has not yet been established.

PURPOSE

This study attempted to establish a clinically serviceable method for microsampling dental alloy.

MATERIAL AND METHODS

A piece of silicone sampling tube is held on the surface of the metal restoration. This surface was ground with a carbide bur through the sampling tube, and the ground metal particles were then recovered from the inner surface of the tube. The recovered sample was subjected to energy-dispersive x-ray microanalysis. The percentage recovery of ground alloy by this microsampling method, which was the ratio of the recovered weight of metal to the total weight of the metal ground, was evaluated using 3 mm diameter x 1 mm thick disk-shaped specimens of Ag-Au-Pd and Ni-Cr alloys.

RESULTS

Elemental analysis of the retrieved alloys identified the component elements in the alloy compositions. The percentage recovery by this microsampling method was 75.0% for Ag-Au-Pd alloy and 69.9% for Ni-Cr alloy, respectively.

CONCLUSIONS

The microsampling method demonstrated a relatively high percentage recovery of the ground alloy particles. This microsampling method would be of great benefit clinically to patients who have allergic reactions to dental materials.

Stable matrix for amalgam build-up

A method is proposed of making amalgam build-ups for coronally debilitated teeth through the use of a stable matrix consisting of a disposable tray and polyvinylsiloxane occlusal registration material. For teeth with minimal remaining coronal tooth structure and/or the absence of adjacent teeth, this technique provides proper stabilization of the matrix band to permit adequate condensation of amalgam.

Resin composite polishing--filling the gaps

OBJECTIVE

The search for the ideal polishing agent for resin composite materials is still ongoing. A new polishing brush with abrasive bristles for polishing resin-based restorations was tested to determine if it polishes restorations, including those with concave surfaces, macrostructured occlusal surfaces, and textured surfaces, without destroying their delicate texture or microstructure.

METHOD AND MATERIALS

The polishing effectiveness and the ultimate destructive potential of these brushes were assessed quantitatively and subjectively in vitro. In addition, the durability of the brushes after repeated use and autoclaving was also evaluated.

RESULTS

The brushes were nondestructive to resin-based restorative, enamel, dentin, and the restoration interface. They produced a shiny surface on resin-based restorative materials without destroying the surface texture. The abrasive brushes were autoclavable and demonstrated satisfactory durability, despite multiple heat sterilization cycles.

CONCLUSION

These brushes can be considered to be key products to polish concave surfaces, anatomically shaped occlusal surfaces, and textured surfaces without damaging the surface characteristics.

[Survival of single surface ART-restorations in Zimbabwe after 3 years]

A 3 year longitudinal study to assess the survival of single-surface ART restorations, was carried out among first year secondary school students in and around Harare, Zimbabwe, during the period 1993-1996 and 1994-1997. The treatments were provided by dentists and dental therapists. The evaluation was carried out by independent evaluators, one of which was an expert from the USA. Actuarial life-table analysis was applied for survival estimations. The survival of ART restorations after 3 years was 85.3% in 1993-1996 and 88.3% in 1994-1997. The 3-years survival percentage per operator ranged from 96.1% (1993-1996) and 94.3% (1994-1997) for one of the dentists to 69.3% (1993-1996) and 65.4% (1994-1997) for one of the junior dental therapists. In 1994-1997, reasons for failure were predominantly operator and material related. Secondary caries was observed in 0.5% of the ART restorations evaluated. The 3-years survival outcomes of single-surface ART restorations are promising. The study has demonstrated that ART with glass-ionomer restorative material provided quality restorative dental care to these student populations. ART has become one of the treatment modalities available to oral health workers in managing dental caries. There is a need for further research into the efficacy of the ART approach and into its application in various types of communities.

Adhesive techniques

This paper describes the use of adhesive techniques to restore teeth previously affected by tooth surface loss so avoiding the need to remove sound tooth tissue.

[In vitro comparison of marginal adaptation of different filling materials. II. Effect of the site and method of preparation on the marginal adaptation]

In a two-month in vitro experiment we examined the marginal adaptation of ten dental materials. Fifty Class II restorations were prepared extending to the cemento-enamel junction. The cavities of the composite restorations were bevelled at the vestibulo-occlusal and -approximal enamel margins, on the other side enamel and gingival margins were prepared conventionally. The specimens were thermocycled and examined with SEM. The microleakage was measured at the vestibulo-occlusal and -approximal tooth-filling junction, where adhesive technique was used, and at the gingival, oroocclusal and -approximal margins, which were not bevelled before. The obviously most important conclusion of the study is, that in the case of deep Class II cavities the amalgam has a better adaptation at the gingival margin than the examined composite resins.

The search for a standard light-curing protocol

The selection of a curing light protocol is a multifactorial decision that will undoubtedly provide thought-provoking debate in the near future. While each method of polymerization presents unique clinical benefits, the optimal light-curing technique remains to be determined.