Quantitative discoloration assessment of peri-implant soft tissue around zirconia and other abutments with different colours: A systematic review and meta-analysis.

OBJECTIVES: The implant abutments, which had their own colour, might cause the discoloration of peri-implant mucosa. We aimed to appraise trails comparing the discoloration of peri-implant soft tissue around zirconia and titanium or golden abutments, the tints of which were vastly different. DATA: We included randomized controlled trials (RCTs), controlled clinical trials (CCTs), cohort studies with patients rehabilitated with zirconia, titanium or golden implant abutments, quantitatively comparing the discoloration of peri-implant soft tissue according to CIE-Lab colour scale. SOURCES: A systematic search was conducted in PubMed, EMBASE, CDSR, and CENTRAL databases without any restriction on September 23, 2017. "Grey" literatures were also searched. A manual search was carried out as well. STUDY SELECTION: Of 584 articles initially retrieved, eight were eligible for inclusion. After data extraction, meta-analyses with mean differences (MDs) and their 95% confidence intervals (CIs) were employed. Moreover, the risk of bias within or across studies was assessed by Cochrane Collaboration's tool for assessing risk, the Newcastle-Ottawa scale, funnel plots, or Egger's test. RESULTS: Four RCTs and four cohort studies were included. Soft-tissue discoloration around zirconia abutments was significantly less likely compared to that around titanium abutments (MD = -1.84; 95% CI = -3.62 to -0.07; P = 0.04 < 0.05) or golden abutments (MD = -0.90; 95% CI = -1.60 to -0.20; P = 0.01 < 0.05). CONCLUSIONS: Zirconia abutments with white tint compared to grey titanium or golden abutments seem to restore a more appropriate colour match between peri-implant mucosa and natural teeth. CLINICAL SIGNIFICANCE: Based on the present evidence, the "nature-like" zirconia abutments should be applied more often in the clinic. PROSPERO REGISTRATION NUMBER: CRD42017075930.

Histological evaluations and inflammatory responses of different dental implant abutment materials: A human histology pilot study.

BACKGROUND: Improvements of soft tissue to the abutment surface results in more stable peri-implant conditions, however, few human histological studies have compared soft tissue responses around different abutment materials. PURPOSE: To describe the peri-implant tissue around 3 abutment materials; titanium, zirconia, and gold alloy, over an 8-week healing period. MATERIALS AND METHODS: Fifteen edentulous sites were treated with implants. Eight weeks later, peri-implant tissue was harvested and processed using a nonseparation resin embedded technique. The tissue attachment characteristics were assessed at clinical stages using the gingival index (GI) score, surgical stage (surgical score), and histological stage (histological attachment percentage). Additionally, the inflammatory responses were evaluated using inflammatory extent and inflammatory cellularity grades. Nonparametrical statistics were used to describe the GI and surgical scores, and analytical statistics were used to analyze the histological attachment percentages as well as the inflammatory extent and cellularity grades amongst the 3 groups. RESULTS: There were no statistically significant differences among the groups for GI score (P = .071) and surgical score (P = .262). Titanium and zirconia exhibited nearly similar mean histological attachment percentages while gold alloy had a significantly lower percentage (P = .004). For the inflammatory extent and cellularity grades, the odds of being one grade higher for gold alloy abutment was 5.18 and 17.8 times that of titanium abutment, respectively. However, for the zirconia abutment, the odds were 0.87 and 7.5 times higher than the titanium group. CONCLUSIONS: The tissue around the gold alloy abutments resulted in worse attachment conditions compared with the titanium and zirconia abutments. Inflammation tended to be higher in the tissue around the gold alloy abutments than the titanium and zirconia abutments.

Regression of oral lichenoid lesions after replacement of dental restorations.

The aim of the study was to determine the prognosis and to evaluate the regression of lichenoid contact reactions (LCR) and oral lichen planus (OLP) after replacement of dental restorative materials suspected as causing the lesions. Forty-four referred patients with oral lesions participated in a follow-up study that was initiated an average of 6 years after the first examination at the Department of Odontology, i.e. the baseline examination. The patients underwent odontological clinical examination and answered a questionnaire with questions regarding dental health, medical and psychological health, and treatments undertaken from baseline to follow-up. After exchange of dental materials, regression of oral lesions was significantly higher among patients with LCR than with OLP. As no cases with OLP regressed after an exchange of materials, a proper diagnosis has to be made to avoid unnecessary exchanges of intact restorations on patients with OLP.

Health-related quality of life and symptoms in patients with experiences of health problems related to dental restorative materials.

OBJECTIVES: The question of health risks associated with dental materials, especially dental amalgam, has long been controversial and remains unresolved. For the past 10 years, people in Sweden with perceived adverse reactions to dental restorative materials have been entitled to apply to their local county council for subsidized replacement of restorative materials. The aim of the study was to investigate symptoms, perceived health changes over time and health-related quality of life (HRQoL) in this population, comprising subjects with subjective health impairment, allegedly because of dental materials. A further aim was to compare their HRQoL with that of the general population. METHODS: A comprehensive questionnaire was sent to 515 people who had applied for subsidized replacement of dental restorations. The questionnaire covered general and oral symptoms, HRQoL, health ratings over time and dental restoration replacement. RESULTS: The response rate was 54.4% (n=280). Most (83.2%) answered that they had undergone replacement of restorative materials because of impaired health, perceived to be related to dental restorative materials. The most common symptoms were musculoskeletal pain (67.5%), sleep disturbance (60.0%) and fatigue (58.6%). The HRQoL of the study subjects was significantly lower than that of the Swedish population in general. CONCLUSIONS: Subjects who had undergone subsidized dental restoration replacement reported persistent subjective symptoms and low HRQoL. The results indicate that replacement of restorative materials alone is insufficient to achieve improved health in patients with symptoms allegedly attributable to dental restorations.

Contact allergic gastritis: an underdiagnosed entity?

Only a few cases of contact allergic gastritis in patients with nickel allergy have been reported. We report a case of probable contact-allergic gastritis in a 46-year-old woman. Clinical examination revealed lichenoid mucosal lesions of the gums adjacent to bridges and crowns that had been implanted several weeks back. Since implantation, the patient had suffered from gastrointestinal complaints (including stomach pain). Gastroscopy showed eosinophilic gastritis. Patch testing done under the diagnosis of contact allergic stomatitis showed positive reactions to: gold sodium thiosulphate; manganese (II) chloride; nickel (II) sulphate; palladium chloride; vanadium (III) chloride and zirconium (IV) chloride. The crowns and bridge contained gold, palladium and zirconium chloride, hence they were replaced by titan-based dentition. Shortly after replacing the artificial dentition, all gastrointestinal symptoms resolved spontaneously without further treatment. Delayed-type allergy against the components of artificial dentition seemed to be the cause of gastritis.

Initial in vitro bacterial adhesion on dental restorative materials.

OBJECTIVES: The purpose of this study was to evaluate initial bacterial adhesion on several restorative materials with similar roughness. MATERIALS AND METHODS: Sixty cylindrical slabs were prepared from four restorative materials: zirconia (Zr), alumina-toughened zirconia (Al-Zr), type III gold alloy (Au), and cp-titanium (Ti). All the materials were polished until a mirror-like shine was achieved. The average surface roughness and topography were determined by atomic force microscopy. Contact angles were measured to calculate surface free energy by the sessile drop technique. After the formation of a salivary pellicle, S. sanguinis, S. gordonii, and S. oralis were inoculated onto the specimens and incubated for 4 h. Quantification of the adherent bacteria was performed by crystal violet staining technique and resazurin reduction assay. One-way ANOVA and Tukey's post hoc test were adopted for statistical analysis. The level of significance was 0.05. RESULTS: The Ra values determined with atomic force microscopy for all specimens were lower than 5 nm. Surface free energy increased in the order of Al-Zr, Zr, Ti, and Au. Differences were significant between the investigated materials in both crystal violet absorbance and fluorescence intensities. Gold alloy showed the highest values for all bacterial strains (p<0.05). CONCLUSIONS: Zirconia, alumina-toughened zirconia, and titanium may be more suitable than gold alloy as an abutment material with respect to the initial bacterial adhesion and subsequent advance of peri-implantitis.

[Effect of four different types of base metal alloy crown on the expression of prostaglandin E2 and cyclo-oxygenase-2 by human gingival fibroblast].

OBJECTIVE: To investigate the effect of alloy leaching liquor of four different types of base metal alloy on the expression of prostaglandin E(2) (PGE(2)) and cyclo-oxygenase-2(COX-2) by human gingival fibroblast(HGF) in vitro. METHODS: Ni-Cr, Co-Cr, pure Ti and Au ceramic alloys were incubated in Dulbecco's modified Eagle's medium (DMEM) to prepare alloy leaching liquor, and then added in HGF medium. DMEM was prepared as negative control. Aliquots were taken from exposed media after 1, 6, 12, 24 h. Assays for PGE(2) were carried out by enzyme-linked immunosorbent assay (ELISA). RESULTS: In 6, 12, 24 h, the expression of PGE(2) in Ni-Cr and Co-Cr alloy groups (Ni-Cr: 45.568 ± 0.926, 60.538 ± 0.988, 73.754 ± 0.507; Co-Cr: 40.496 ± 0.693, 53.216 ± 0.327, 65.470 ± 1.086) were significantly higher than those in other experimental groups (Ti: 31.564 ± 0.719, 31.998 ± 0.856, 32.066 ± 0.513; Au alloy: 31.540 ± 0.821, 31.136 ± 0.518, 31.340 ± 0.443) and control group (31.122 ± 0.642, 31.230 ± 0.634, 30.980 ± 0.746) (P < 0.05). No significant difference were found in the expression of PGE(2) among pure Ti, Au alloy groups and the control group (P > 0.05). Immunofluorescence showed dark and uniform COX-2 stain in Ni-Cr and Co-Cr alloy groups, while in pure Ti group, Au alloy group, and negative control group shallow and uneven distribution of COX-2 stain were observed. CONCLUSIONS: Our findings suggested that pure Ti and Au alloy did not cause elevated PGE(2) and COX-2 release from HGF. However, Ni-Cr and Co-Cr alloy caused increase in PGE(2) and COX-2 levels.

The mechanism of gingiva metallic pigmentations formation.

The occurrence of blue-grey areas in the soft tissue represents one of the problems affecting patients whose teeth have been restored using metallic materials. It is generally accepted that it is caused by mechanical penetration of a metallic material into the soft tissue. Several facts indicate that this mechanism is not general. The aim of the study was to determine an alternative mechanism of the origin of pigmentations, based on the corrosion interaction of metallic materials used in prosthodontics with the oral environment. The study was comprised of an analysis of pigment particles, determination of exposure conditions of metallic materials in vivo and laboratory evaluation of corrosion properties of the studied materials. Particles containing silver, sulphur and/or selenium could be seen in ultra-thin sections in the lamina propria gingivae. Comparison of the corrosion laboratory results with the results of in vivo measurements indicated the intensification of corrosion under these conditions. Amalgams and silver-containing alloys used for teeth restorations may release silver under the conditions of the oral cavity. The formation of soluble silver compounds in the sulcular area or in a crevice between the crown and the cast post-and-core reconstruction facilitates their transport to the soft tissue and subsequent deposition.

A correlation found between gold concentration in blood and patch test reactions in patients with coronary stents.

BACKGROUND: Patients with dental gold restorations are known to have a higher level of gold concentration in blood (B-Au). OBJECTIVES: To further investigate, in a study on patients with intracoronary stents and contact allergy to metals, the gold and nickel release from stainless steel stent with (Au stent) and without (Ni stent) gold plating. METHOD: A total of 460 patients treated with stenting underwent patch testing with metals, and information on gold and nickel exposure and blood samples were collected. About 200 blood samples were randomly selected and the analysis of B-Au and nickel concentration in blood (B-Ni) was made using inductively coupled plasma mass spectrometry. RESULTS: There was a correlation between the intensity of Au patch test reaction and B-Au (P < 0.001). This correlation could not be seen between Ni patch test reaction and B-Ni. A Au stent gave a fivefold higher B-Au than a Ni stent. CONCLUSIONS: Gold is released from the Au stent and patients with a Au stent have a fivefold higher B-Au than patients with an Ni stent. The patch test reactions for gold were correlated with B-Au.

[Health complaints related to dental filling materials]. / Pasienter med helseplager relatert til tannfyllinger.

BACKGROUND: A wide range of materials is used in dental treatment. To what extent these materials lead to adverse reactions is under dispute. The aim of this study was to investigate whether patients with suspected adverse reactions to dental materials experienced an improvement in health after these materials were replaced. MATERIAL AND METHODS: Information on health complaints related to dental materials was obtained from the Dental Biomaterials Adverse Reaction Unit in Bergen, Norway for 142 patients. A follow-up questionnaire regarding subjective health was sent to these patients 1(1/2) to 2(1/2) years later. A similar questionnaire was sent to a reference group of 800 persons drawn from the general population. RESULTS: The patient group had more health complaints than the reference group (p < 0.001) at baseline. Of the 84 patients who completed the questionnaire (59%) 35 had changed dental materials. Amalgam fillings had been replaced in most of these patients. 23 patients (66%) reported improved health after replacement. Intraoral complaints decreased significantly (p = 0.022), and were most pronounced in patients with lesions in contact with dental materials. The intensity of various health complaints decreased slightly in most patients with replaced dental materials, but the patient group still had significantly higher health complaint indices than the reference group. INTERPRETATION: The intensity of subjective health complaints was reduced after replacement of dental materials, but it was still higher than for a comparable group in the general population. The results indicate that there may be a specific health effect of replacing dental materials, but normal symptom fluctuations over time and placebo effects such as positive effects from expectations and general care from the health personnel may have had an influence.

An evaluation of wear when enamel is opposed by various ceramic materials and gold.

STATEMENT OF PROBLEM: Ceramic restorations have been known to cause wear of opposing enamel. PURPOSE: The purpose of this study was to evaluate enamel wear caused by 3 ceramic substrates in the glazed and polished conditions. MATERIAL AND METHODS: Sixty ceramic discs (10 x 2 mm)-20 each of Finesse, All-Ceram, and IPS-Empress-were prepared and glazed. Each group of 20 was divided into 2 groups of 10. The surfaces of one group were ground and polished using a porcelain polishing kit (Dialite). The remaining 10 were left as glazed. Ten specimens of a type III gold alloy were cast into rectangular shapes of 10 x 12 x 2 mm and polished. Seventy human cusps were prepared from sound, caries-free, extracted teeth and abraded against the substrates in a wear machine for a total of 10,000 cycles. The cusp height loss was traced before and after the wear test using a profile projector. Mean surface roughness (R(a)) values for the substrates were also recorded with a profilometer before testing. Differences in R(a) were evaluated using 1- and 2-way ANOVA and the Scheffe post hoc test (alpha = .05). RESULTS: One-way ANOVA indicated that enamel height loss was significantly different by material (P < .001) and surface condition (glazed and polished or glazed; P < .05). Gold, polished Finesse, and polished All-Ceram were the least abrasive, whereas glazed IPS-Empress was the most abrasive. There was no significant interaction effect between substrate type and surface condition. Significant differences were found when R(a) of the substrate condition was compared with enamel wear (P < .01). CONCLUSIONS: Gold, polished Finesse, and polished All-Ceram caused the least enamel wear, whereas IPS-Empress caused the most wear. Cast gold was significantly different than glazed IPS-Empress (P < .05), whereas other groups overlapped. There was significant correlation between R(a) and enamel wear (P < .01).

In vivo galvanic currents of intermittently contacting dental amalgam and other metallic restorations.

OBJECTIVE: It was the objective of this study to determine the magnitude of in vivo galvanic currents produced by simulating electrical contact between occluding metallic restorations, and to examine the influence of restoration age, difference in pre-contact corrosion potentials, and surface area. METHODS: A convenience sample of 106 human subjects was studied. A Ag/AgCl micro-reference electrode and a high impedance voltmeter were used to measure the pre-contact corrosion potentials. Galvanic couples (n = 194) were next formed by simultaneously contacting occluding restorations with gold-plated probe tips for 15 s. The resulting current-time transients were measured with a zero-resistance ammeter and recorded with an electronic data acquisition program. The vast majority of couples measured contained at least one dental amalgam restoration. RESULTS: Galvanic current-time transients were typically characterized by an immediate and rapid rise to a peak current, followed by an exponential decay to a much lower value at 15 s. For couples with a restoration < or = 12 mo old, median peak current and median current at 15 s were 2.26 microA (range 0.24-13.06 microA) and 0.57 microA (range 0.03-6.47 microA), respectively. For couples with a restoration >12 mo old, median peak current and median current at 15 s were 1.40 microA (range 0.24-12.09 microA) and 0.37 microA (range 0.00-3.05 microA), respectively. Couples with fresh amalgams (< or = 6 mo) generally had elevated currents (range 2.56-102.54 microA). SIGNIFICANCE: A wide range of galvanic currents resulted from electrical contact of restorations in vivo. These currents were influenced by restoration age and total surface area of the galvanic couple. For amalgam-amalgam couples, the difference in the pre-contact corrosion potentials may be useful in predicting galvanic currents, when the difference is at least 24 mV.

Contact orofacial granulomatosis caused by delayed hypersensitivity to gold and mercury.

Orofacial granulomatosis, an entity with characteristic clinicopathologic features, is thought to be a reactive process. The authors describe orofacial granulomatosis associated with contact allergy to gold in dental crowns in one patient and a possible allergic contact reaction to mercury from dental fillings in another one. Thus allergic contact dermatitis to the metals gold and mercury should be considered as a possible etiologic agent of orofacial granulomatosis.

Dental gold alloys and contact allergy.

Contact allergy to gold as demonstrated by patch testing is very common among patients with eczematous disease and seems to be even more frequent among patients with complaints from the oral cavity. There is a positive correlation between gold allergy and the presence of dental gold. Gold allergy is often found in patients with non-specific stomatitides as well as in those with lichenoid reactions or with only subjective symptoms from the oral cavity. The therapeutic effect of substituting other dental materials for gold alloys is conspicuous in casuistic reports but less impressive in larger patient materials. The amount of dental gold is correlated qualitatively and quantitatively to the blood level of gold and the effects if any of circulating blood gold are unknown. There is clearly a need for prospective studies in the field and gold sodium thiosulfate is considered an important item in the dental series for patch testing.

Contact allergy to gold is correlated to dental gold.

Questionnaire studies have indicated that patients with dental gold will more frequently have contact allergy to gold. This study aimed at investigating the relationship between contact allergy to gold and the presence and amount of dental gold alloys. A total of 102 patients were referred for patch testing because of suspicion of contact allergy. Patch tests were performed with gold sodium thiosulphate 2% and 5%. The patients underwent an oral clinical and radiological examination. Contact allergy to gold was recorded in 30.4% of the patients, and of these 74.2% had dental gold (p=0.009). A significant correlation was found between the amount of gold surfaces and contact allergy to gold (p=0.008), but there was no statistical relationship to oral lesions. It is concluded that there is a positive relationship between contact allergy to gold and presence and amount of dental gold alloys.

The influence of restorative materials on marginal gingiva.

BACKGROUND: A great variety of dental materials are now available for use in restorative treatments. Much attention has been devoted to physical and chemical properties, but the biological effects of these materials have been less frequently studied. AIM: The aim of this study is to test the influence of resin based restorations, amalgams and gold alloys, as restorative materials in immediate contact with the gingival tissues. METHODS: In 103 patients (54 male and 49 female, 39 smokers and 64 non-smokers, mean age: 34 +/- 13 years) with 255 restored teeth (101 resin-based materials, 98 amalgams, and 56 gold inlays), the marginal gingiva was examined. The restorations selected had to be in place more than 6 months. The patients participating in the study had no systemic diseases and pregnant patients were excluded, as were those under long-term medication and those with severe periodontal disease. The filling materials were examined for surface roughness, secondary carious lesions and gaps. The marginal gingiva in contact with the restorative materials was tested by reference to Bleeding Index (BI), Gingiva Index (GI), probing depth and degree of tooth mobility. As controls 255 teeth without fillings, of the same type, in the opposite jaw were used. RESULTS: The 101 resin-based restorations had a mean age of 3.1 (+/- 2.0) years, the amalgam fillings were in place 6.6 (+/- 4.1) years and the gold inlays had an average age of 4.7 (+/- 4.6) years. Surface roughness was observed in 66.3% of the resin-based restorations, in 47.9% of the amalgams and in 10.7% of the gold inlays. Absence of bleeding after probing was observed for 25.7% of the resin-based restorations, for 55.1% of the amalgam fillings, and for 58.9% of the gold inlays. All classes of restored teeth showed significant differences from the controls without fillings. The mean probing depth for the resin-based fillings was 3.6 mm (control 2.4 mm), for teeth with amalgams 3mm (control: 2.4 mm) and for teeth with gold inlays 2.5 mm (control 2.1 mm). A significant difference between smokers and non-smokers was only found in the group of resin-based restorations. The Bleeding Index was significantly higher in the group of smokers (p = 0.0005) in comparison to the non-smokers, as was the Gingiva Index (p=0.0106). CONCLUSION: The marginal adaptation of the restored teeth examined showed materially specific differences. The handling of resin-based materials, in comparison to amalgam or gold remains very sensitive and consequently there is prevalent error of technique. The high prevalence of gingival irritation in association with resin based materials may be caused by non-indicated applications, failures of technique, or simply the chemical properties of the materials.