Tooth color change due to different etching and debonding procedures

OBJECTIVES:

To compare the effects of different etching techniques, 12-, 24-bladed tungsten carbide burs, and polishing discs on tooth color changes during orthodontic treatment.

MATERIALS AND METHODS:

59 individuals (mean age: 15.20 ± 1.59 years) were divided into four groups: 37% phosphoric acid and adhesive primer was used in Groups I and II whereas self-etch primer was used in Groups III and IV for enamel preparation. After orthodontic treatment, residual adhesives were cleaned with 12-bladed tungsten carbide burs in Groups I and III, while 24-bladed tungsten carbide burs were used in Groups II and IV. All teeth were polished with medium and fine Sof-Lex XT discs (3M ESPE, St Paul, Minnesota). Color measurements were taken from upper incisors and canines at pretreatment (T0), after cleaning with tungsten carbide burs (T1) and polishing with discs (T2). Wilcoxon test was used for evaluation of L*, a*, b* changes and Kruskal-Wallis for intergroup comparison of color changes.

RESULTS:

L*, a*, b* values, except a* at Groups I, II, IV, and b* at Group III, changed significantly ( P < .05). Groups III and IV showed significantly different color alterations from T0 to T1 ( P < .05). After polishing, tooth color alterations were not significantly different among the groups.

CONCLUSIONS:

In self-etch bonding groups, a 12-bladed tungsten carbide bur caused less color change than the 24-bladed tungsten carbide bur. Orthodontic treatment resulted with visible and clinically unacceptable tooth color alterations regardless of the enamel preparation and clean-up techniques. Polishing reduced the effect of tungsten carbide burs, but did not affect the total influence of orthodontic treatment on the tooth color.

Comparison Of Frequency Of Post Operative Sensitivity In Amalgam Restorations Using Copal Varnish And Dentin Adhesive Liner

BACKGROUND

Micro leakage around the margins of a restoration is believed to be one of the main causes of postoperative sensitivity. Dental amalgam is a non-insulating material and has the potential to transfer heat and cold causing irritation of the pulp. Different dentin tubule sealers are used under amalgam restoration to compensate for this post-operative sensitivity. This study was conducted to compare the frequency of sensitivity in amalgam restorations using copal varnish and dentin adhesive liner (dentin bonding agent).

METHODS

A total of 60 patients of either gender, aged 18-40 years having class 1 carries in posterior teeth were included. Teeth with restorations, dentinal sensitivity and patients taking analgesic drugs for chronic pain conditions were excluded. The selected patients were placed randomly into Group A (copal varnish) & Group B (dentin adhesive liner), by using computer generated table of random numbers. Restored teeth were evaluated 1-month post operatively for sensitivity.

RESULTS

Mean age was 25.63±5.42 years. Out of 60 patients, 68.0% were females and 32.0% were males with a female to male ratio of 2:1. The mean post-operative pain score was 2.83±2.79 in Group A and in Group B, it was 1.43±2.14 with a p-value of 0.03. There was no pain on application of a cold stimulus in 14 (46.7%) patients in Group A (copal varnish) while in Group B (Dentin adhesive), no pain was seen in 23 (76.7%) patients with p-value of 0.02.

CONCLUSIONS

This study concluded that dentin adhesive liner (dentin bonding agent) is better than copal varnish in reducing postoperative sensitivity in amalgam restorations.

Nonsurgical Management of Peri-implant Bone Loss Induced by Residual Cement: Retrospective Analysis of Six Cases

This report presents six consecutive cases of peri-implantitis associated with residual methacrylate cement. The cases responded to cement removal and disinfection procedures. Six patients, each presenting one methacrylate cement-retained implant restoration and showing peri-implant inflammation and bone loss, were treated. All the cases were negative for bleeding on probing after 6 weeks, and this was maintained at 1 year of follow-up from nonsurgical therapy and crown refixation with alternative and resorbable cement. The treatment effectively solved the inflammation and led to complete restoration ad integrum, as evaluated clinically and radiographically, after 1 year.

Platform Switching and Screw- and Cement-Retained Restorations: Effects on Peri-Implant Tissue Health and Disease

As dental implant therapy has evolved since its early days more than five decades ago, its effects have been mostly extremely positive. However, over the course of time, several undesirable, unanticipated consequences have also materialized, most notably peri-implant disease. In this article, the authors propose that many of the challenges clinicians see today regarding increased peri-implant disease represent negative effects of interventions that, though well-intended, had unforeseen shortcomings. Sufficient time has now passed for these adverse effects to manifest, and clinicians today are better able to understand how their attempts to solve problems in some ways produced new challenges. The article also shows how new innovations in engineering and digital technology allow clinicians to address the problems of the past and avoid increasing the risk of peri-implant disease.

Effect of Oxygen Inhibition Layer of Universal Adhesives on Enamel Bond Fatigue Durability and Interfacial Characteristics With Different Etching Modes

OBJECTIVE

The purpose of this study was to evaluate the effect of the oxygen inhibition layer of universal adhesive on enamel bond fatigue durability and interfacial characteristics with different etching modes.

METHODS

The three universal adhesives used were Scotchbond Universal Adhesive (3M ESPE, St Paul, MN, USA), Adhese Universal (Ivoclar Vivadent, Schaan, Lichtenstein), and G-Premio Bond (GC, Tokyo, Japan). The initial shear bond strength and shear fatigue strength to enamel was determined in the presence and absence of the oxygen inhibition layer, with and without phosphoric acid pre-etching. The water contact angle was also measured in all groups using the sessile drop method.

RESULTS

The enamel bonding specimens with an oxygen inhibition layer showed significantly higher (p<0.05) initial shear bond strengths and shear fatigue strengths than those without, regardless of the adhesive type and etching mode. Moreover, the water contact angles on the specimens with an oxygen inhibition layer were significantly lower (p<0.05) than on those without, regardless of etching mode.

CONCLUSION

The results of this study suggest that the oxygen inhibition layer of universal adhesives significantly increases the enamel bond fatigue durability and greatly changes interfacial characteristics, suggesting that the bond fatigue durability and interfacial characteristics of these adhesives strongly rely on its presence.

Comparison of Hypersensitivity in Metal Ceramic Crowns cemented with Zinc Phosphate and Self-adhesive Resin: A Prospective Study

BACKGROUND

Luting agents used to fix artificial prostheses, such as fixed partial denture (FPD) to tooth are basically viscous in nature and show chemical reaction for fixation. Postcementation hypersensitivity is a frequent complaint of patients. The present study was conducted to compare postcementation hypersensitivity with zinc phosphate and self-adhesive resin in complete coverage crown.

MATERIALS AND METHODS

This study included 30 patients in which 60 porcelein fused to metal crowns was placed. Two metal crowns were placed in each patient in nonantagonis-tic contralateral quadrants. First crown was cemented with zinc phosphate cement, while the other was cemented with self-adhesive resin. Hypersensitivity was evaluated by visual analog scale (VAS) score and by clinical test. For clinical evaluation of sensitivity, hot and cold water was applied to the cervical margin of restoration for 5 seconds and response was recorded.

RESULTS

This study consisted of 30 patients in which 60 crowns were given. There was no statistical difference in VAS score of mastication in zinc phosphate cement recorded at baseline, 1 week, 4 weeks, 6 months, 1 year, and 2 years (p > 0.05). Cold response also did not show a significant difference at six time points. Warm response showed slight decrease in subsequent time points but was nonsignificant (p > 0.05). Similarly, with self-adhesive resin cement, VAS score during mastication, hot and cold response was statistically nonsignificant (p > 0.05).

CONCLUSION

Postcementation hypersensitivity is a frequent complaint that patient may experience. However, we found no statistically significant difference in both cements tested.

CLINICAL SIGNIFICANCE

Postcementation hypersensitivity is an unpleasant sensation experienced by patients. This may affect the success of any prosthesis. Thus, selection of luting agent for cementation plays an important role to eliminate this symptom.

Tooth discoloration induced by calcium-silicate based materials: a literature review

INTRODUCTION

Endodontic therapy may not focus only on biological and functional aspects, but should take esthetic considerations into account as well. It is common knowledge that calcium-silicate based materials may cause discoloration and thus impair the esthetic outcome of the treated tooth. The purpose of this review is to summarize the existing knowledge on the discoloration potential of these materials used for endodontic procedures.

EVIDENCE ACQUISITION

A comprehensive literature search covering the period from 2000 to 2015 was conducted on PubMed and Google Scholar, using different keyword combinations including "tooth", "color", "discoloration", "staining", "endodontic", "root canal", "calcium silicate", "MTA", "portland cement", "Endocem" and "biodentine". Any relevant literature in the English language was considered for inclusion. In addition, previous review articles were hand-searched, and reference lists from endodontic textbooks were also reviewed. Articles were excluded if only single clinical reports or conference reports were included or if the topic was not related to the subject.

EVIDENCE SYNTHESIS

For a wide range of these materials currently available in the market, only scarce or no evidence exist regarding their discoloration potential.

CONCLUSIONS

The need for further research in this field and development of non-staining calcium silicate based materials is evident.

Histologic findings within peri-implant soft tissue in failed implants secondary to excess cement: report of two cases and review of literature

A link has been established between peri-implant disease and excess cement extrusion in cement-retained implant restorations. The histologic findings of two patients with failed implants secondary to residual excess cement are reported here. If excess cement is detected early and adequately removed, resolution can occur in the majority of situations. Simple recommendations are proposed, with the intention of preventing further implant failures from residual excess cement.

Tooth discoloration after the use of new pozzolan cement (Endocem) and mineral trioxide aggregate and the effects of internal bleaching

INTRODUCTION

The aim of this study was to evaluate tooth discoloration after the use of mineral trioxide aggregate (MTA) and to examine the effect of internal bleaching on discoloration associated with MTA.

METHODS

Thirty-two teeth were endodontically treated. Three-millimeter plugs of MTA, ProRoot, Angelus, or Endocem were placed on the access cavities of 24 teeth. Eight teeth served as the control group. After 24 hours, the access cavities were restored, and the tooth color was recorded at baseline and at 1, 2, 4, 8, and 12 weeks. After 12 weeks, the MTA materials were removed under a microscope, and an internal bleaching treatment was performed. After removal of the MTA materials and after a 1-week bleaching treatment, the color changes were measured, and the MTA-dentin interfaces were observed under a microscope.

RESULTS

The ProRoot and Angelus groups displayed increasing discoloration during a period of 12 weeks. The discoloration associated with ProRoot and Angelus was observed at the MTA-dentin interface and on the interior surface of the dentin. However, the Endocem groups demonstrated no significant discoloration (P < .05). No marginal discoloration was observed around the material in the Endocem group. Removal of the discolored MTA was effective for resolving the discoloration in all of the experimental groups (P < .05). However, a subsequent internal bleaching treatment was not significantly effective compared with the removal of MTA.

CONCLUSIONS

ProRoot and Angelus caused tooth discoloration. However, Endocem did not affect the contacting dentin surface. Removing the discolored MTA materials contributed more to resolving the tooth discoloration than post-treatment internal bleaching.

Bracket base remnants after orthodontic debonding

OBJECTIVE

To evaluate whether the debonding procedure leads to restitutio ad integrum of the enamel surface by investigating the presence of enamel within the bracket base remnants after debonding.

MATERIALS AND METHODS

Sixty patients who completed orthodontic treatment with fixed appliances were included. A total of 1068 brackets were microphotographed; the brackets presenting some remnants on the base (n = 818) were selected and analyzed with ImageJ software to measure the remnant area. From this population a statistically significant sample (n = 100) was observed under a scanning electron microscope to check for the presence of enamel within the remnants. Energy dispersive x-ray spectrometry was also performed to obtain quantitative data.

RESULTS

Statistically significant differences in the remnant percentage between arches were observed for incisor and canine brackets (P < .0001 and P = .022, respectively). From a morphologic analysis of the scanning electron micrographs the bracket bases were categorized in 3 groups: group A, bases presenting a thin enamel coat (83%); group B, bases showing sizable enamel fragments (7%); group C, bases with no morphologic evidence of enamel presence (10%). Calcium presence was noted on all evaluated brackets under energy dispersive x-ray spectrometry. No significant difference was observed in the Ca/Si ratio between group A (16.21%) and group B (18.77%), whereas the Ca/Si ratio in group C (5.40%) was significantly lower than that of the other groups (P < .323 and P = .0001, respectively).

CONCLUSION

The objective of an atraumatic debonding is not achieved yet; in some cases the damage could be clinically relevant.

Zinc toxicity: denture adhesives, bone marrow failure and polyneuropathy

A 36-year-old female developed bone marrow failure diagnosed as myelodysplastic syndrome (MDS) (Sidebar), followed shortly by a peripheral neuropathy and a gait disturbance. While waiting for a bone marrow transplant, she reported to us that she had seen attorney-generated, televised advertisements concerning the role of denture adhesives relating to her malady. Labs were then obtained demonstrating she had dramatic and unsuspected hypocupremia and hyperzincemia. Administration of copper and cessation of denture adhesives resulted in recovery of her hematopoietic system and partial resolution of the neurological sequela.

Crestal bone loss and the consequences of retained excess cement around dental implants

Crestal bone loss around dental implants has been a subject of discussion in implant dentistry since its inception. Many of the research and design developments related to dental implants have sought to limit the amount of crestal bone loss. While there are a variety of possible causes for crestal bone loss around dental implants, one iatrogenic cause that has become the subject of several articles is retained dental cement. The focus of this article will be to discuss the predisposing factors that can lead to retained cement and clinical strategies to minimize or prevent cement peri-implantitis. Case reports are presented in which retained cement resulted in significant peri-implant inflammation and bone loss around restored dental implants. Strategies for early detection to limit the damage from retained dental cement and cementing techniques are also discussed.

Temperature changes caused by light curing units on dentine of primary teeth

AIM

This was to determine the temperature changes produced in dentine discs of primary teeth placed below a glass ionomer, microhybrid flow resin or microhybrid resin during the photocuring process with conventional halogen lamps and LEDs at different distances.

STUDY DESIGN

Experimental design.

MATERIALS AND METHODS

This in vitro study was carried out in the research laboratory of the Universitat International de Catalunya. We cut 1 mm thick dentine discs with the IsoMet 1000 cutting machine. Thereafter, we cut stainless steel rings of different heights. Subsequently, to facilitate the temperature measurement, we prepared silicone moulds, in which the dentine disc, stainless steel ring and the digital thermometer/ thermocouple were positioned. Once the silicone mould was finished, a 2 mm thick layer of the restorative material was placed on the dentine disc. Finally, the polymerisation process was conducted according to the times recommended by the manufacturers, and the temperature produced was recorded at the end of the procedure. STATISTICAL EVALUATION: Replies were analyzed using the STATGRAPHICS® Plus Version 5.0 statistics software system, in order to obtain comparative diagrams and graphs using the ANOVA multifactorial system.

RESULTS

The photocuring lamps used on the restorative materials produced statistically significant differences in temperature, with p = 0.00001.

CONCLUSION

Halogen lamps cause a greater temperature rise in materials than LEDs lamps, and the greatest rise is produced when microhybrid flow resin is photocured with the Optilux 501 halogen lamp.

[Efficiency of fixed partial dentures]

A proposal for restorative treatment is based on the expected efficiency of the treatment. Efficiency is determined by measuring the investment, such as the monetary and biological cost, against what is gained, such as functional restoration and durability. If one's goal is to save tooth tissue in the restorative process, it is interesting to compare the conventional fixed partial denture with the adhesive fixed partial denture. The mean survival rate of conventional fixed partial dentures clearly exceeds the mean survival rate of adhesive fixed partial dentures but there are biological risks. Loss of vitality of the abutment teeth and the occurrence of caries are more prominent with conventional fixed partial dentures than with adhesive fixed partial dentures. Consequently, the possibility of replacing a conventional fixed partial denture with a new conventional fixed partial denture is limited. Because this and other clinical aspects can not easily be expressed numerically, the patient should be informed qualitatively about the advantages, disadvantages and uncertainties of the various types of fixed partial dentures.

[Response of dental pulp to self-etching adhesive systems used in indirect capping. A literature review]

OBJECTIVE

To review the literature on dental pulp responses to self-etching adhesive systems used in indirect capping.

MATERIAL AND METHODS

Many studies in vitro and in vivo focused on biocompatibility of the self-etching adhesive system used in deep defects. Clinical and radiographic findings from animal and human studies are compared and discussed.

RESULTS

Self-etching adhesive systems may be useful when applied to dentin. The results in animal studies cannot be extrapolated directly to humans. Many studies in vitro have shown that components of self-etching adhesive systems exhibit cytotoxic effects in contact with cell cultures.

CONCLUSIONS

The reaction of dental pulp to self-etching bonding agents depends on the depth of defect, type of agent, and method of application.

One year clinical performance and post-operative sensitivity of a bioactive dental luting cement--a prospective clinical study

A one-year clinical study was performed on the efficacy of a bioactive dental cement (Ceramir C&B) with calcium aluminate and glass ionomer components. The study was performed on 38 crown and bridge abutments in 17 patients. Preparation parameters were recorded, as well as working-times, setting-times, and other handling characteristics. Baseline data were also recorded for gingival inflammation (GI) and pre-cementation sensitivity. Post-cementation parameters included sensitivity, gingival tissue reactions, marginal integrity and discolorations. All patients were seen for recall examinations at 30 days, and 6 months. For sixteen patients one-year recall data were collected on retention and subjective sensitivity. Fifteen subjects were available for one year clinical examinations. Three independent examiners found the working and setting time of the cement to be well within expected limits and that cement removal was easy. Four patients reported low-grades of immediate post-cementation sensitivity, however, this disappeared after an occlusal adjustment or without intervention within one month. At 12 months no retentive failures were recorded and no subjective sensitivity reported. All crowns were rated in the "Excellent" quality category for marginal integrity. Both GI-scores and scores for tooth sensitivity decreased during the course of the study. One year recall data yielded no incidence of secondary caries and no visible marginal discoloration. The new cement was thus found to perform favorably as a luting agent for permanent cementation.

Immediate dentin sealing using an antibacterial self-etching bonding system

The pathway to the dental pulp through the cut dentin can lead to pulpal pathology following a crown preparation. While eugenol temporary cements can occasionally reduce dentin sensitivity following tooth preparation, this material can be problematic due to its unfavorable reactivity with composite resin cements. To protect the prepared substrate prior to its definitive restoration and to minimize post-operative sensitivity attributed to thermal changes or bacterial invasion of the dentin tubules, a treatment option that is more effective biologically and chemically is required. This article demonstrates the clinical application of an antibacterial self-etching bonding system.

The use of mineral trioxide aggregate in endodontics

Mineral trioxide aggregate (MTA), composed mainly of tricalcic silicate, tricalcic alluminate, bismuth oxide, is a particular endodontic cement. It is made of hydrophilic fine particles that harden in the presence of dampness or blood. It is biocompatible, radiopaque and it is harder to infiltrate, compared to classic materials for root filling such as amalgam, cements, Super-EBA, and IRM. and SEM studies of sections and copies in resin of root neoapices filled with amalgam, IRM, Super-EBA and MTA, as well as tests of microinfiltration have shown that MTA has excellent sealing capacities. It requires a working time of about 5 min and a hardening time that varies from 2 h and 45 min to 4 h according to the density of the air entrapped during mixing and the dampness of the receiving site. The long hardening time reduces internal tensions and the incidence of marginal infiltration, but it forces to definitively fill the tooth in the following sitting, with an interval of at least 3 days from the MTA application. Clinical experience shows how MTA is a material of choice in cases not only of endodontic surgery, apicectomy and retrograde filling but also in the sealing filling of perforations of the pulp chamber and of the root, stripping, internal reabsorptions, readaptations, lacerations, and apical transports. It has been used with success also in direct cappings and in apexifications instead of calcium hydroxide, leading to quicker therapies and more predictable

RESULTS

The authors outline the operative phases of the different treatments proposed, make a survey of the most important studies published so far and hope that a new sealing cement with more reduced hardening times will soon be available.

Ultrastructure of gingival sulcus mucosa after application of hybrid heliocomposites

Hybrid heliocomposites were used for repair of the carious tooth crown. Ultrastructural study of mucosa biopsy specimens from sites adjacent to the filling 3 weeks after treatment showed that Charisma, Herculite, and Esterfil Ca filling materials led to degenerative changes in the mucosa, while Filtek Z-250 heliocomposite caused no pathological changes in the gingiva at the site of contact.

A temporary filling material may cause cusp deflection, infractions and fractures in endodontically treated teeth

AIM

To test the hypothesis that Coltosol F might cause infractions and cusp fracture in root-filled teeth because of material expansion.

METHODOLOGY

Thirty-two extracted human molar teeth were root filled and prepared with mesial-occlusal-distal (MOD) cavities with or without undercuts. The specimens were filled proximally with glass-ionomer cement and then occlusally with either Coltosol F or zinc oxide eugenol (ZOE). The tooth specimens were kept in water at 37 degrees C for a period of 20 days, and every second day the intercusp distance (ICD) of each specimen was measured in a travelling microscope, and the number of infraction lines as well as fractures were noted.

RESULTS

The number of infraction lines increased in teeth filled with Coltosol F. Between day 8 and 16, seven of 16 teeth filled with Coltosol F showed fracture and exhibited a mean increase in ICD of 316 +/- 156 microm. Teeth filled with ZOE did not show an increase in number of infraction lines or in ICD, and none showed fracture.

CONCLUSIONS

The hygroscopic expansion of Coltosol F in a cavity may lead to cusp deflection, infraction development and fracture. Masticatory forces will in vivo aggravate this unfavourable condition. The material is not recommended for temporary filling in root-filled teeth except for a few days.

Expression of contact allergy in undergoing prosthodontic therapy patients with oral diseases

AIM

Contact allergy is a postponed reaction of hypersensitivity where a localised cutaneous or mucosal lesion occurs due to a recurrent contact with an allergen. Placement of a fixed or removable prosthetic replacement into the oral cavity causes corrosive processes on the surface of the restoration and discharge of ions, which as haptens can induce allergic reactions. The purpose of this study was to examine occurrence of allergies to basic and auxiliary restorative dental materials in patients with lichen, stomatitis and stomatopyrosis by means of an epicutaneous allergy test.

METHODS

The study included 32 patients with a fixed and/or removable replacement and 7 patients with one of the mentioned diagnoses, but without any replacement. Testing was conducted using a standard method (patch test), and hypersensitivity to 13 most common allergens in prosthodontics was examined.

RESULTS

The research results revealed higher frequency of positive allergic reactions in persons with the mentioned diseases and with a restoration. Patients with lichen indicated positive patch test in the majority of cases. The allergens of nickel, cobalt and chromium demonstrated the highest score of positive results, and negative score was found for dibutylphthalate and HH mix. Stomatopyrosis was more common in persons with hypersensitivity to chromium. A lower incidence of positive allergic reactions to epoxide resins was found in female than in male subjects.

CONCLUSIONS

The epicutaneous (patch) test performed in the subjects examined in this study, showed that the majority of positive reactions was caused by mixes of nickel, cobalt and chromium; however, unwanted reactions also to other auxiliary materials used in dental practice should also be considered.

Microleakage of various cementing agents for full cast crowns

OBJECTIVES

To evaluate microleakage and marginal gaps in full cast crown restorations bonded with six different types of cementing agents.

METHODS

Sixty non-carious human premolars and molars were prepared in a standardized manner for full cast crown restorations. The mesial and distal margins were located in dentin, while the vestibular and palatal/lingual margins were located in enamel. Crowns were made from a high-gold alloy using a standardized technique. The specimens were randomized to six groups of cementing agents: one zinc-phosphate cement (Harvard cement), one conventional glass-ionomer cement (Fuji I), one resin-modified glass-ionomer cement (Fuji Plus), two standard resin cements (RelyX ARC, Panavia F), and one self-adhesive universal resin cement (RelyX Unicem). After 4 weeks of storage in distilled water at 37 degrees C, the specimens were subjected to 5000 thermocycles ranging from 5 to 55 degrees C. Then, they were placed in a silver nitrate solution, embedded in resin blocks, and vertically cut in buccolingual and mesiodistal direction. Subsequently, the objects were evaluated for microleakage and marginal gap using a high-resolution digital microscope camera.

RESULTS

A number of inter-group differences were statistically significant. RelyX Unicem showed the smallest degree of microleakage both in enamel and in dentin. Panavia F und RelyX Unicem were associated with significantly larger marginal gaps than all other cementing agents. No association was observed between microleakage and marginal gap other than a weak direct correlation when using Harvard cement on enamel.

SIGNIFICANCE

The cementing agents investigated revealed different sealing abilities. These differences were not associated with specific types of materials.

Stimulation of glutathione depletion, ROS production and cell cycle arrest of dental pulp cells and gingival epithelial cells by HEMA

2-Hydroxy-ethyl methacrylate (HEMA) is the major component released from resin-modified glass ionomer cements and dental adhesives. Human tissues mainly affected by HEMA are oral epithelium and dental pulp. We treated human gingival epithelial S-G cells and pulp fibroblasts (HPF) with various concentrations of HEMA, to evaluate its effects on cell growth, cell cycle progression, intracellular glutathione (GSH) level and reactive oxygen species (ROS) production. HEMA-induced growth inhibition in HPF and S-G cells in a dose-dependent manner, which may be partially explained by induction of cell cycle perturbation. G(2)/M phase arrest was noted after exposure of HPF to 5 and 10mm of HEMA, concomitant with glutathione depletion and ROS production. S-phase arrest occurred in S-G cells when treated with 2.5 and 5mm, while at 10mm a sub-G(0)/G(1) peak was noted, indicating the potential induction of apoptosis. GSH depletion was marked in S-G cells only at concentrations of 5 and 10mm, but excessive ROS production was noted at concentration of 1mm and rose with dose increase between 1 and 5mm, then lessened at 10mm. This suggested that the increase of ROS in S-G cells was not mainly caused by GSH depletion. These results helped to define the mechanism of the cytotoxicity caused by HEMA.

Management of peri-implant bone loss using guided bone regeneration: a clinical report

This clinical report presents a patient who developed peri-implant bone loss around 2 maxillary endosseous root-form implants after restoration with cement-retained single crowns. Significant localized bone loss occurred around 1 of the implants due to retained excess cement. Reparative treatment consisted of a guided bone regeneration technique. Following a 9-month period of submerged healing, the implants were re-exposed and restored to complete function.

Osmotic blistering in enamel bonded with one-step self-etch adhesives

One-step self-etch adhesives behave as permeable membranes after polymerization, permitting water to move through the cured adhesives. We hypothesize that osmotic blistering occurs in bonded enamel when these adhesives are used without composite coupling. Tooth surfaces from extracted human premolars were bonded with 5 one-step self-etch adhesives. They were immersed in distilled water or 4.8 M CaCl(2), and examined by stereomicroscopy, field-emission/environmental SEM, and TEM. Water blisters were observed in bonded enamel but not in bonded dentin when specimens were immersed in water. They collapsed when water was subsequently replaced with CaCl(2). Blisters were absent from enamel in specimens that were immersed in CaCl(2) only. Water trees were identified from adhesive-enamel interfaces. Osmotic blistering in enamel is probably caused by the low water permeability of enamel. This creates an osmotic gradient between the bonded enamel and the external environment, causing water sorption into the interface.

A two-year clinical evaluation of a new calcium aluminate cement in Class II cavities

A calcium aluminate cement (Doxa Certex, Uppsala, Sweden) has recently been developed intended for use as direct restorative filling material for posterior restorations. The material is inorganic and non-metallic and the main components are CaO, Al2O3, SiO2, and water. The aim of this study was to evaluate intra-individually the experimental calcium aluminate cement (CAC) and a resin composite (RC) in Class II restorations. Each of 57 participants received at least one pair of restorations of the same size, one CAC and one RC (Tetric Ceram). Sixty-one pairs were performed. The restorations were evaluated clinically, according to slightly modified USPHS criteria, at baseline, after 6 months, 1, and 2 years. One-hundred-and-twenty restorations were evaluated at 2 years. Postoperative sensitivity was reported for 5 restorations (2 RC, 3 CAC). Significantly better clinical durability was shown for RC. Five non-acceptable CAC restorations (8.2%) were observed at 6 months, 10 CAC (16.7%) and 2 RC (3.3%) at 12 months, and 11 CAC (18.3%) at 24 months. This resulted in a cumulative failure frequency of 43.3% for the CAC material and 3.3% for the RC material. Main reasons for failure for the CAC were partial material fracture (7), cusp fracture (5), and proximal chip fracture (6). The CAC showed a non-acceptable clinical failure rate for Class II restorations, probably caused by its difficult handling and low mechanical properties.

[The reaction of pulp vessels to various adhesive systems]

The reaction of pulp vessels to various adhesive systems was studied: qualitative and quantitative characteristics of pulse curves reflecting the pulp blood filling were studied. Study of the reaction of pulp vessels showed that acetone-containing adhesive systems immediately caused a constrictive reaction, while use of an acetone-free adhesive system led to the minimum changes in the functions of pulp vessels.

Postcementation hypersensitivity: scientific data versus dentists' perceptions

PURPOSE

The purpose of this article was to obtain dentists' opinions via an Internet survey as to the prevalence, causes, and prevention of postcementation sensitivity and compare their responses with published data on the problem.

MATERIALS AND METHODS

Information as to respondents opinions of postcementation sensitivity was obtained from an Internet survey asking about their experience and for a ranking of the importance of each of 15 factors.

RESULTS

A total of 466 valid responses were received. The incidence of postcementation sensitivity was estimated to be less than 2% by more than 2/3 of the dentists. The factors considered "very important" in reducing sensitivity by more than 50% of the respondents were desiccation, luting agent, occlusion, provisional, and water spray.

CONCLUSIONS

Comparing respondents' opinions with published clinical studies, the incidence of postcementation sensitivity appears to be underestimated. There is little published evidence to support the importance of antimicrobials, desensitizing, or bonding agents, although these are considered effective by some dentists. Many respondents consider luting agent to be an important variable.

Use of cyanoacrylate gel as a substitute for dental cement in intracerebroventricular cannulations in rats

This study was carried out to determine whether cyanoacrylate gel was suitable for use as a substitute for dental cement during brain implant surgery of rats. Intracerebroventricular (ICV) cannulations were performed in 24 rats by two surgeons, one with 3 years' experience in this type of surgery, and one novice, with only basic training performed on cadavers. Each surgeon prepared six randomly allocated animals using dental cement to secure the cannula and six with cyanoacrylate gel. Time to complete surgery was recorded. Wound healing was scored and body weight recorded for each animal every day for 7 days, then on day 14 after surgery. The use of gel led to an overall reduction in surgical time of 8 min (approximately 30%) per animal when compared with dental cement. No significant differences in the animals' recovery (wound healing and body weight) were found between surgeons or techniques. We find the use of cyanoacrylate gel to be a suitable and less time-consuming alternative to dental cement for ICV cannulations in rats.

Microleakage of temporary endodontic restorations in overdenture tooth abutments

PURPOSE

The sealing of provisional filling material in overdenture tooth abutments during provisional rehabilitation is of primary importance to the long-term success of roots bearing gold casting copies. The aim of this in vivo study was to evaluate the microleakage of four different provisional filling materials after a period of 1 week.

MATERIALS AND METHODS

Five patients needing treatment with overdenture prostheses and scheduled for the extraction of at least four teeth were chosen. After performing endodontic treatment on the roots to be extracted, a standardized cavity preparation 3 mm in depth was made using a diamond bur. Each cavity was filled with one of the four provisional materials selected for the evaluation (Cavit-W, IRM Caps, Guttapercha, Fermit-N), and the interim prostheses were delivered to the patients. After 1 week, the roots were extracted and stored for 24 hours in 0.5% basic fuchsin at 37 +/- 1 degrees C for 24 hours. Subsequently, the roots were severed and observed under a stereomicroscope for microleakage evaluation.

RESULTS

The materials showed different degrees of microleakage, but none allowed dye penetration to the bottom of the cavity. IRM Caps showed the lowest mean value of dye penetration (168 microns), while Fermit-N showed the highest (1,475 microns). All materials differed from each other (P < .05).

CONCLUSION

Within a period of 1 week, the materials provided acceptable to good sealing properties. All of the materials may be considered suitable for provisional fillings if they do not remain in the oral cavity for more than 1 week.

Prosthodontic biomaterials and adverse reactions: a critical review of the clinical and research literature

Prosthodontic biomaterials include impression materials, luting cements, and restorative materials. They consist of metals and alloys ceramics, and polymer materials and are retained in patients for <60 min or for decades. Oral release of compounds from biomaterials occurs, and adverse reactions may follow dental treatment. Especially in allergically vulnerable patients contact allergy may occur. There are reports from many different countries on contact allergy from gold/palladium alloys, components from polymer-based materials, chromium/cobalt alloys, and nickel. Notifications on adverse reactions in Norway, Sweden, and England are handled by a registry in which patient reactions and occupational exposure are recorded. Data from The Adverse Reaction Unit in Bergen and Umeå have been a most valuable basis in extending knowledge in a field of current interest in dentistry. A review of the clinical and research literature relating to prosthodontic biomaterials and adverse reactions shows that reliable methods seem necessary to expose the frequency of adverse reactions in general dentistry, including prosthodontic treatment.

Response of the pulp of dogs to capping with mineral trioxide aggregate or a calcium hydroxide cement

This study was conducted to observe the response of dogs' dental pulp to mineral trioxide aggregate (MTA) and a calcium hydroxide cement when used as pulp capping materials. After the pulps of 30 teeth were exposed, they were capped with either MTA or a calcium hydroxide cement. Histological analysis was performed 2 months after treatment. Results showed a healing process with complete tubular dentin bridge formation and no inflammation in any of the pulps capped with MTA. On the other hand, only five specimens from the calcium hydroxide cement group formed a complete dentin bridge. In this experimental group, pulp inflammation was observed in all but three cases. In conclusion, MTA exhibited better results than the calcium hydroxide cement for the capping of the pulp in dogs.

In vitro investigation of aluminum and fluoride release from compomers, conventional and resin-modified glass-ionomer cements: a standardized approach

The amount of fluoride release from dental cements necessary for an anticariogenic effect is not established: moreover, the possible toxic effects due to high fluoride and aluminum release are not well known and the results are still controversial. The aim of our study was to evaluate fluoride (F) and aluminum (Al) release from dental cements using a 'standardized approach' according to the end-use of the materials, i.e. biocompatibility testing. Two polyacid-modified resin composites of recent application, commonly called compomers (Dyract and Dyract Cem), were compared with two conventional acid-based (Fuji I, Ketac-Cem) and two resin-modified (Vitremer, Vitrebond) glass-ionomer cements (GICs). All types of cement are used in dentistry and are commercially available. Extracts of the cements into minimum essential medium, after setting over a 1-h (group A) and 1-week (group B) period, were performed. The extraction conditions were rigorously standardized. Mean values +/- standard deviation of F- and Al-levels in such extracts were measured and were expressed as microg g(-1) (micrograms of ions per gram of cement). A great difference in the amount of ion release, both F and Al, was shown among the tested materials. The GICs, as well as Ketac-Cem, released more F and Al than the compomers. All of the materials released the greatest proportion of ions when the extraction was performed in the first hour after mixing (group A). Al- and F-values showed a highly significant positive correlation, independently from the curing time. We conclude that the biological assessment of dental cements can be performed only if a pre-evaluation of the leachables is obtained by applying a standardized protocol which allows a useful comparison between the different materials.

Complications associated with excess cement around crowns on osseointegrated implants: a clinical report

The potential advantages and disadvantages of cement-retained implant crowns are reviewed, with a focus on complications related to residual excess cement. A series of 4 case reports illustrates the symptoms and treatment modalities associated with excess cement around implant crowns, and suggestions are offered for the prevention of such problems.

Retention of adhesive cement on the tooth surface after crown cementation

STATEMENT OF PROBLEM

Adhesive cements increase crown retention, but it is unknown if traces of cement remain undetected on the tooth surface after clinical removal of excess cement, which could exacerbate plaque retention.

PURPOSE

This study measured the surface area, volume, mean depth, and maximum depth of a resin composite and a compomer luting cement left adherent on the tooth surface after removal of excess cement, as judged clinically.

METHODS AND MATERIAL

Four groups of specimens (n = 48) were prepared for full coverage crowns: group AC bonding alloy with chamfer finish line, group G gold alloy with chamfer finish line, group PC porcelain with a chamfer finish line, and group PS porcelain with a shoulder finish line. Two profiles of the mesial and distal surfaces of the teeth were carried out: (1) tooth with crown seated but not cemented and (2) tooth with the crown cemented in place. Two cements and 2 methods of cement removal were studied.

RESULTS

A 4-way analysis of variance for cement, crown type, method of removal, and tooth surface morphology showed that significantly greater volumes and mean depth, but not surface areas, of resin composite cement remained adherent than compomer cement (P<.05). Among crown types, significant differences were found for cement volume (group G>AC, G>PC, G>PS), cement surface area (group AC>PC, G>PC, G>PS), and maximum cement depth (group G>AC). There was no significant difference between the 2 methods of cement removal. Significantly larger surface areas and maximum depths of cement were retained on the anatomically grooved mesial surface of the maxillary first premolars than on the ungrooved distal surface.

CONCLUSION

Subclinical cement retention occurred after crown cementation, which was influenced by cement, crown type, and tooth surface morphology but not method of cement removal.