A comparison of conventional and new rubber dam systems in dental practice.

OBJECTIVE: Rubber dam is an important tool in dentistry-in the past as well as today. As a result of a lack of acceptance of the conventional system, introduced by Barnum in 1869, new systems were developed (eg, OptraDam® by Ivoclar Vivadent AG, Schaan, Liechtenstein). This system was advertised as being very comfortable and easy to use, without distracting clamps. The aim of this study was to investigate if a new rubber dam system would be better accepted by patients and dentists than the conventional one. MATERIALS AND METHODS: Two hundred patients from the Department of Conservative Dentistry and Periodontology received at least one treatment with the conventional rubber dam (Dental Dam, Coltène Whaledent, Langenau, Germany) and one with the new rubber dam (OptraDam®, Ivoclar Vivadent). Staff/students and patients were asked to complete questionnaires with regard to the advantages and disadvantages of the particular system after every treatment. RESULTS: Among patients, students, and dentists in the dental school environment there is a high degree of acceptance of rubber dam in general. During the study there were only very few situations in which neither of the systems could be used. The conventional rubber dam was preferred by all patients, students, and dentists (p<0.0001). CONCLUSION: Our study confirms that there is a high degree of acceptance of the rubber dam when it is compulsory to use. The reasons for the refusal during the daily workload of a practice remain unclear, but appear to be independent of the material or design available. A new design does not necessarily imply better acceptance.

Clonal infection with Actinobacillus actinomycetemcomitans following periodontal therapy.

Mechanical debridement results in a shift of the bacterial composition in the periodontal pocket on the species level. It is unknown, however, whether a clonal change within a species could lead to the emergence of strains with different levels of virulence. Therefore, in the present study, the genetic variability of Actinobacillus actinomycetemcomitans was assessed and strains identified which were associated with periodontal disease progression following periodontal therapy, i.e., refractory periodontitis. Twenty adult patients with untreated periodontitis and subgingival colonization of A. actinomycetemcomitans were randomly assigned to receive full-mouth scaling alone or scaling with an adjunctive antimicrobial therapy. Both groups received supportive periodontal therapy at 3, 6, 9, 12, 18, and 24 months. Subgingival plaque samples were taken at every visit; venous blood was obtained at 24 months only. A. actinomycetemcomitans isolates were typed by the RAPD method, and antibody reactivity against outer membrane proteins was assessed by immunoblot analysis. Eleven distinct RAPD patterns were found in 18 patients completing the study. All patients harbored only one A. actinomycetemcomitans genotype, and within each patient this genotype persisted throughout the 24-month observation period. No differences in the expression of antibody reactivity against outer membrane proteins were found between strains isolated at baseline and at 24 months. Three genotypes were associated with reduced survival rates of teeth without probing attachment loss of 2 mm or more. The results indicated that (i) most patients harbored only one A. actinomycetemcomitans genotype; (ii) the genotype persisted following therapy; and (iii) only some genotypes were associated with refractory periodontitis.

Working parameters of a magnetostrictive ultrasonic scaler influencing root substance removal in vitro.

This study assessed defect depth and volume resulting from root instrumentation using a magnetostrictive ultrasonic scaler with a slim scaling tip (P 12) in vitro. Combinations of the following working parameters were analyzed: lateral forces of 0.5 N, 1 N, and 2 N; tip angulations of 0 degrees, 45 degrees, and 90 degrees; power settings of low, medium, and high; and instrumentation time of 10, 20, 40, and 80 seconds. Defects were quantified using a 3-dimensional optical laser scanner. Lateral force had the greatest influence on defect volume compared to tip angulation and power setting (beta-weights 0.53+/-0.04, 0.17+/-0.04, and 0.19+/-0.04, respectively). Lateral force and tip angulation had similar effects on defect depth, but both effects were greater compared to power setting (beta-weights 0.43+/-0.04, 0.49+/-0.04, and 0.19+/-0.04, respectively). The various combinations of the assessed working parameters showed synergistic effects resulting in a wide range of defect depths (14.1+/-1.7 microm to 410.5+/-51.1 microm) and volumes (0.0084+/-0.0057 mm3 to 1.3+/-0.079 mm3). Severe root damage (defect depth >50 microm) at 40 seconds instrumentation time occurred under most combinations of lateral force, angulation, and power settings. The only exceptions were combinations of: 1) 0 degrees angulation, 0.5 N and 1 N lateral force at any power setting and 2) 45 degrees angulation, 0.5 N lateral force at low and medium power setting. The efficacy of the assessed magnetostrictive ultrasonic scaler may be adapted to the various clinical needs by adjusting the lateral force, tip angulation, and power setting.

Long-term maintenance of alveolar bone gain after implantation of autolyzed, antigen-extracted, allogenic bone in periodontal intraosseous defects.

This randomized controlled trial assessed the long-term maintenance of alveolar bone gain after implantation of autolyzed, antigen-extracted, allogenic (AAA) bone. AAA bone is a demineralized freeze-dried bone allograft processed after previously described methods. In each of 14 patients, AAA bone was implanted into the intraosseous defect of 1 tooth (test); a second tooth with an intraosseous defect was treated by modified Widman flap surgery alone (control). All patients were offered supportive periodontal therapy at 3- to 6-month intervals following treatment. Clinical measurements were taken prior to surgery, 6 months, and 3 years following surgery. Of the 14 patients enrolled, 11 patients completed the 6-month and 8 patients the 3-year examination. In test teeth, bone gain was significantly greater compared to control teeth at 6 months (2.2+/-0.5 mm and 1.2+/-0.5 mm, respectively) and 3 years (2.3+/-0.7 mm and 1.1+/-0.8 mm, respectively) (P < 0.05). Also, more probing attachment was gained in test compared to control teeth at 3 years (2.0+/-0.7 mm and 0.8+/-0.5 mm, respectively; P < 0.05). At 3 years, Porphyromonas gingivalis was detected in 3 test and 2 control teeth by polymerase chain reaction, whereas no Actinobacillus actinomycetemcomitans was found. Due to the low detection frequency, there was no clear correlation between the maintenance of alveolar bone during supportive periodontal therapy and subgingival infection with P. gingivalis. The data indicated that alveolar bone gain after implantation of AAA bone may be maintained over a minimum of 3 years in patients receiving periodontal supportive therapy.

Effect of storage media on microleakage of five dentin bonding agents.

The objective of this study was to investigate the effect of different storage media on microleakage at the gingival margin of mixed Class V composite restorations. Human molars were either used immediately after extraction (control group) or after a 3-4 wk storage period in 1% chloramine, 70% ethanol, 10% formalin, or 0.1% thymol. Class V cavities with cervical margins in cementum or dentin were prepared and restored with a microfill composite using five different dentin bonding agents. After thermocycling (1440 x from 5 degrees C to 55 degrees C) and basic fuchsin staining, the depth of dye penetration at the gingival margins was determined and ranked on a scale of 0 to 4. Class V restorations in teeth stored in formalin showed significantly less microleakage (mean leakage score, MLS = 1.7) than restorations in freshly extracted teeth (control group; MLS = 3.1). Microleakage scores in teeth stored in chloramine (MLS = 2.7), ethanol (MLS = 3.0) or thymol (MLS = 3.2) were not significantly different from the microleakage scores in the control group. The improvement of in vitro efficacy of dentin bonding agents when using extracted teeth stored in formalin is probably a result of collagen cross-linking by formaldehyde. Since such an alteration of the dentin does not reflect the condition of the substrate in vivo, extracted teeth assigned for in vitro evaluation of dentin bonding agents should not be stored in formalin. In teeth stored in 1% chloramine, the sums of ranks and the rank orders of the dentin bonding agents were comparable to those in freshly extracted teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Shear bond strength to dentin by simulation of three-dimensional Class V cavity configuration.

The purpose of this study was to investigate the effect of composite polymerization contraction on early shear bond strength of conventional and new dentin adhesives to dentin. The dentin adhesives selected for this study, i.e., Bondlite, Gluma, Prisma Universalbond, Scotchbond LC, Scotchbond 2, and XR Bonding, were tested in combination with Silux and in combination with their respective composites. The composite was applied to the treated dentin surface in cylindrical brass moulds of 4 mm diameter and 3 mm length. The configuration of cylindrical butt-joint Class V cavities was simulated by the coating of the insides of the brass moulds with silane in order that a chemical bond to the composite could be established. The results showed that shear bond strength to dentin was higher for XR Bonding and Scotchbond 2 compared with conventional phosphate ester-based dentin adhesives and Gluma. When XR Bonding or Scotchbond 2 was used, the obstruction of polymerization contraction had no effect on the bond strength to dentin. In contrast, the dentin adhesion of Scotchbond LC/Silux, Prisma Universalbond/Prisma Microfine, Bondlite/Herculite, and Gluma/Lumifor was adversely affected by the reduction of the unbonded composite surfaces. However, this effect was not observed when Prisma Universalbond, Bondlite, and Gluma were tested in combination with Silux. It can therefore be concluded that the effect of polymerization contraction on the bond strength to dentin depends not only on the dentin adhesive but also on the type of composite used.

Erbium:YAG laser application in caries therapy. Evaluation of patient perception and acceptance.

OBJECTIVES: In previous studies it has been demonstrated that the Er:YAG laser can be used to prepare cavities efficiently and without thermal damage to the adjacent dental hard and soft tissues. To investigate the patients' response to Er:YAG laser preparation of teeth, a prospective clinical study was performed in five dental hospitals. METHODS: To evaluate patients' perception and response to cavity preparation a direct comparison was made between conventional mechanical preparation and Er:YAG laser preparation of caries in dental hard tissues. Half of the preparations were completed by the laser alone with standardized parameters, with the other half being mechanically prepared. The sequential order of treatment was randomized, and clinical parameters such as depth and location of the cavities were carefully balanced. A three-score evaluation scheme of patient responses was used: comfortable, uncomfortable, very uncomfortable. In addition the patients were asked to decide which was the more uncomfortable form of treatment and the preferred treatment for future caries therapy. RESULTS: The study included 103 patients with 206 preparations distributed amongst 194 teeth. All teeth gave vital responses (ice test) before and after both types of treatment. The laser treatment was found to be more comfortable than the mechanical treatment, with high statistical significance. During treatment, the need for local anaesthesia was 11% for mechanical preparation compared to 6% during laser application. It was found that 80% of the patients rated the conventional preparation as more uncomfortable than the laser treatment and 82% of the patients indicated that they would prefer the Er:YAG laser preparation for further caries treatment. CONCLUSIONS: The application of the Er:YAG laser system is a more comfortable alternative or adjunctive method to conventional mechanical cavity preparation.

Guidance of shrinkage vectors vs irradiation at reduced intensity for improving marginal seal of class V resin-based composite restorations in vitro.

This study evaluated the influence of radiation intensity on polymerization of a resin-based composite (RBC) and compared the influence of guidance of shrinkage vectors vs irradiation at reduced light intensity on the marginal seal of Class V RBC restorations in vitro. The degree of cure was studied indirectly by measuring the Vickers hardness (1.96 N, 30 seconds) at the bottom of disc-shaped specimens 2 mm in height at different periods of time after light irradiation. After one hour, irradiation using a high-intensity curing light (Heliolux GTE, Vivadent, 600 mW/cm2) [HICL] from close distance for 20 seconds, 40 seconds or 60 seconds or a low-intensity curing light (Vivalux, 250 mW/cm2) [LICL] from close distance for 60 seconds produced higher hardness values compared to 20 seconds or 40 seconds using the LICL or using the HICL from a distance of 10 mm. After three and 24 hours, higher hardness was observed for all irradiation protocols. After 24 hours, only specimens irradiated by the HICL for 20 seconds or 40 seconds from 10 mm distance featured significantly lower hardness compared to the remaining curing modes. The influence of different irradiation strategies on marginal seal of Class V RBC restorations was evaluated in vitro using dye penetration after water storage (60 days, 37 degrees C) and thermocycling (2500 cycles 5 degrees-55 degrees C). The HICL produced more dye penetration than the LICL. Placing the light tip directly over or 10 mm above the center of the cavity ("standard irradiation, ["distance irradiation"]") resulted in similar penetration values. In contrast, positioning the light tip apical to the cervical margin and moving it slowly to the center of the cavity ("cervical start irradiation") compromised the marginal seal.

[The surface conditioning of pressed ceramics and its effect on the bond strength to composites]. / Oberflächenkonditionierung gepresster Keramik und ihr Einfluss auf die Verbundfestigkeit zu Kompositen.

After removal of the investment material, unpolished surfaces of pressed glass ceramics (Empress) are covered by a layer containing magnesium and phosphorus. This layer most likely results from the contact with the investment material during pressing. Following short-time conditioning with 5% HF-gel the superficial layer stays amorphous. After etching for 120 s most of the surface layer is removed revealing the fine grained etching pattern characteristic for this type of ceramics. Shear strength of composite luted to unetched pressed ceramic samples was rather low. After etching for 60 s bond strength was considerably higher, but only following 120 s of etching shear strength reached a level comparable to that of ground pressed samples and ground ingots after 60 s of etching. Since mechanical removal of the surface layer by grinding is not recommended, pressed glass ceramics should be etched for 120 s or longer to achieve an optimal bond strength to the luting composite.

[The effect of cavity finishing on the initial sealing capacity of amalgam fillings in vitro]. / Einfluss der Kavitätenfinierung auf das initiale Abdichtungsvermögen von Amalgamfüllungen in vitro.

The effect of different cavity finishing methods on in-vitro microleakage of two amalgams (Amalcap non gamma 2 SAS, Tytin) was investigated by the dye penetration method. Amalcap non gamma 2 SAS demonstrated better sealing properties than Tytin. The highest degree of microleakage was observed when the cavities prepared with a diamond coated bur (mean particle size 80 microns) were left unfinished. The degree of marginal leakage in Class-I cavities was reduced by finishing their walls with tungsten carbide or diamond coated finishing burs. Cervical Class-II cavity walls finished with a tungsten carbide or a diamond coated finishing bur demonstrated lower marginal leakage than cervical walls finished with a gingival margin trimmer. Finishing of proximal Class-II cavity walls with tungsten carbide or diamond coated finishing burs followed by removal of the remaining enamel overhangs with a diamond coated file (Cavishape) resulted in a lower degree of dye penetration than finishing proximal walls with a proximal margin trimmer. The results indicate that Class-II cavities with minimal extension of the proximal walls can be effectively finished without using hand instruments.

[In vivo study of small class II composite fillings]. / In-vivo-Untersuchung von kleinen Klasse-II-Kompositfüllungen.

This clinical trial aimed at studying the medium term performance in routine clinical practice of drop-shaped Class II resin composite restorations. 111 preparations were completed with the Sonicsys micro-tips (KaVo) and filled with either of two light-cured composites (Tetric Flow, Tetric Ceram, Vivadent, Schaan, Liechtenstein) by 11 dentists in a university clinic. The restorations were evaluated after half a year and then annually, using the US Public Health Service criteria. After one to three years of service nearly all restorations were clinically successful and acceptable for continued use. In four cases, incomplete caries excavation was the cause of failure. We conclude that the drop-shaped Class-II-resin composite restoration should be considered a routine operative treatment for small proximal lesions in posterior teeth.

[In vitro study of marginal quality of small approximal composite fillings]. / In-vitro-Untersuchung zur Randqualität von kleinen approximalen Kompositfüllungen.

The aim of the study was to compare different preparation methods and filling techniques for class II microcavities in vitro. The following methods were evaluated: Sonicsys halftorpedo, Sonicsys halfsphere, Sonicsys approx, Siplus, Piezo cavity system and rotating finishing bur. Every cavity type was obturated with a flowable (Tetric flow) and with a hybrid composite (Tetric ceram). One group consisted of prefabricated ceramic inlays (Sonicsys approx) and one group was filled with a three-site light curing technique. This resulted in 128 composite fillings. The evaluation of the quality of the margins under the SEM demonstrated a statistically significant higher percentage of perfect margins for Siplus compared with the PCS-System (88% versus 58% perfect margins). Marginal adaptation before and after thermocycling demonstrated the following results: Bewelled margins showed in general better adaptation than box-shaped cavities. Similar results were found for normal and flowable composites. Microcavities with occlusal access prepared with the sonicsys halfsphere showed in general better marginal adaptation in comparison to the other methods tested. It was concluded that simple obturation techniques can lead to a stable adaptation of the margins.

[A retrospective in vivo study of Sonicsys approx restorations]. / Retrospektive In-vivo Untersuchung von Sonicsys-approx-Füllungen.

The purpose of this retrospective study was to determine the longevity and quality of Class II resin composite restorations with Sonicsys approx inserts placed in private practice. In 79 patients 213 composite restorations with margins in enamel and in dentin were evaluated clinically using a modified version of established USPHS-Criteria. The mean time in clinical service was 18+-8 months. The majority of the restorations investigated were rated as "good" (Alpha) or "clinically acceptable" (Bravo). In more than 90% sufficient proximal contact points were evaluated. Seven restorations had no contact to their adjacent tooth. Only one failed after an average period of 18 months in clinical service because of loss of the ceramic insert and was replaced. It is concluded that the composite restoration in combination with Sonicsys insert is an appropriate system for the restoration of Class II lesions in premolar and permanent molar teeth.

Nonsurgical endodontic management of a double tooth: a case report.

AIM: To present a case with various morphological irregularities requiring root canal treatment and to discuss the problems and options for orthograde root canal treatment. SUMMARY: Root canal treatment of a double tooth presenting with an acute alveolar abscess is described. The anatomical variations of this tooth included double tooth, dental invagination, incomplete apical closure, three root canal systems and an internal lacuna. The tooth was treated nonsurgically with orthograde root canal treatment resulting in nearly complete radiographic apical repair after 4 years. KEY LEARNING POINTS: *Double teeth occur infrequently and may be distinguished from fusion, gemination, concrescence and dental twinning. *Several malformations may be present in a single tooth. *Orthograde root canal treatment may be an adequate treatment option even in teeth with a complex internal anatomy.

[Technology and progress in conservative dentistry]. / Technologie und Fortschritt in der konservierenden Zahnheilkunde.

In a synopsis different possibilities for the use of tooth colored restorations as replacements for amalgam fillings are described and discussed: composite resin fillings, indirect or direct composite resin and ceramic inlays.

[Mercury vapor emission from amalgam capsules during trituration and storage]. / Quecksilberdampfabgabe aus Amalgamkapseln während Trituration und Lagerung.

Inhalation of mercury vapor is a potential hazard when handling dental amalgam. To prove the safety of modern capsule systems, we tested 21 brands of dental amalgam. Mercury vapor emission was measured at different stages during handling: a) immediately after opening of a capsule package, b) cumulative emission over 24 h of storage of an open package, c) during trituration and d) for different methods of waste capsule treatment. Highly significant differences between capsule types were found for the measured parameters. Disposable capsules that could be reassembled showed the most favorable results.

[The Stillman cleft--a consequence of undue stress?]. / Die Stillman-Spalte--Folge einer Fehlbelastung?

A clinical study employing instrumental functional analysis showed that no conclusive relationship exists between traumatizing occlusion and the appearance of Stillman clefts. Thirty-seven patients with a total of 142 clefts were studied.

[Brush abrasion with 27 commercial composites and their surface changes in the scanning electron microscope]. / Bürstenabrasion mit 27 handelsüblichen Composites und ihre Oberflächenveränderung im Rasterelektronenmikroskop.

Twenty-seven commercially available composites and three amalgams were examined under practical test conditions in terms of their abrasion behavior during brushing. Differences in wear of more than the factor 10 were established. In addition, quite different surface alterations are produced which can be explained by the special abrasion mechanism.

[Quantitative microbiologic studies of the sulcus fluid in patients with immunodeficiencies]. / Quantitative mikrobiologische Untersuchungen der gingivalen Sulcusflüssigkeit von Patienten mit Immundefekten.

Quantitative microbiologic examinations of fluid taken from gingival sulci were carried out with patients suffering from chronic lymphatic leukemia (CLL), i.e. with disturbed immune response, and with healthy subjects. The pathogen count in each case was correlated with the gingival index, the plaque index, the amount of fluid in the gingival sulcus, and the pocket depth. Patients with chronic lymphatic leukemia with gingiva clinically free of inflammation showed one to 20 times more bacterial flora in fluid from the gingival sulcus than fluid from healthy control subjects. The quantitative values tend to equalize only if imflammation is severe. If the pathogen count is considered a function of the amount of plaque or pocket depth, markedly more microorganisms/mm3 of sulcus fluid were found with CLL patients than in the control group. It therefore may be concluded that immunologic reactions contribute decisively to the causation and maintenance of gingivitis with all of its consequences and that these reactions play an important role in the destruction of pathogens found in the region of the gingival pocket.