The mechanism of gingiva metallic pigmentations formation

Influence of remaining coronal tooth morphology with resin abutment and fiber post on static and dynamic fracture resistances

This study aimed to clarify the fracture resistance of resin abutments built on endodontically treated roots with the remaining coronal teeth via static and cyclic loading tests. Endodontically treated bovine roots, which had a remaining coronal tooth covered with an occupied area for a quarter and half of the circumference at the tensile side or covered the circumference at both the tensile and compressive sides, were fabricated to build up to the resin abutment. Fracture resistance was evaluated via static and cyclic loading tests by applying a load of 30° to the tooth axis. Half of the circumference of the remaining coronal tooth showed a significantly higher static fracture load and survival rate. The remaining coronal tooth on the compressive side improved the dynamic fracture resistance associated with severe fractures. The occupied area and location of the remaining coronal tooth affected the static and dynamic fracture resistances.

Influence of one-wall remaining coronal tooth with resin abutment and fiber post on static and dynamic fracture resistance

The objective of this study was to determine the influence of height and thickness of the one wall remaining coronal tooth structure on the fracture resistance of an endodontically treated root with resin abutment build-up using resin composite and fiber-reinforced resin composite post. Static and dynamic fracture tests were performed by placing the remaining tooth wall on the tensile side and applying loads at an angle of 30° from the tooth axis. Superior static fracture resistance was observed when the wall remaining on the tooth had a height and thickness greater than 1.0 mm. The dynamic fatigue test showed high loading capacity or fracture resistance in specimens with large height and thickness. The dynamic fatigue test showed the influence of the remaining tooth structure on fracture resistance clearly. In conclusion, the static and dynamic fracture resistances increased with the height and thickness of the one wall remaining tooth structure.

A novel minimally-invasive approach for metal tattoo removal with Er:YAG laser

OBJECTIVE

Few effective and established treatment methods can remove gingival metal or amalgam tattoos. With this case series, we aimed to demonstrate the use of a novel minimally invasive technique to remove metal tattoos using an erbium-doped yttrium aluminum garnet (Er:YAG) laser.

MATERIALS AND METHODS

We retrospectively collected clinical data from 18 patients who had undergone Er:YAG laser treatment to remove metal tattoos. Minimal gingival ablation using an Er:YAG laser directed towards the pigmented area was performed, which exposed metal debris within the connective tissue that was carefully removed. A dental microscope was employed to identify the metal debris, for accurate irradiation, and to minimize wounding by reducing invasion. Postoperative gingival color and morphology, and visual analog scale as a patient-reported outcome assessing postoperative pain were evaluated.

RESULTS

All patients' metal tattoos were removed completely and safely during short procedures. Considerable esthetic improvements and favorable wound healing were achieved with almost no postoperative pain or complications.

CONCLUSION

The findings from this case series suggest that this novel minimally invasive therapy for metal tattoo removal that involved the Er:YAG laser is effective and safe, is associated with successful outcomes, and contributes greatly to patients' esthetic satisfaction.

CLINICAL SIGNIFICANCE

Metal tattoo removal using an Er:YAG laser safely and successfully improved gingival esthetics. This novel technique is much simpler and less invasive than conventional periodontal plastic surgery, and it may be more reliable regarding esthetic gingival improvements as it is associated with favorable wound healing, and it could offer significant benefits to patients by alleviating physical and mental stresses via reduced chair time and postoperative pain.

Surface analysis and corrosion behavior of pure titanium under fluoride exposure

STATEMENT OF PROBLEM

The corrosive effects of oral fluoride products on titanium have been reported, and chronic fluorosis, which causes hyperfluoemia, is one of the world's health problems. Nevertheless, the relationship between high serum fluoride and corrosion on the titanium surface, which might have adverse effects on titanium implant osseointegration, has not been elucidated.

PURPOSE

The purpose of this in vitro study was to investigate the corrosion behavior of pure titanium exposed to high serum fluoride with different pH values based on surface analysis.

MATERIAL AND METHODS

Pure titanium specimens, exposed to different electrolytes with 0.04 and 0.4 ppm NaF at pH 7.3 and 5.0 values, were examined for surface microstructure by using scanning electron microscopy (SEM) and for surface element composition with X-ray photoelectron spectroscopy (XPS). The corrosion behavior and metal ion release of specimens immersed in the Hanks' balanced salt solution (HBSS) containing 0.04 and 0.4 ppm serum fluoride concentrations (NaF) at 7.3 and 5.0 pH values were measured by electrochemical impedance spectroscopy (EIS) and inductively coupled plasma atomic emission spectrometry (ICP-AES).

RESULTS

Pitting holes were observed on pure titanium surfaces exposed to high serum fluoride. The surfaces became rougher with the increase of serum fluoride concentration, especially under acidic conditions. XPS analysis revealed a reduction of dominant titanium dioxide (TiO₂) on the pure titanium surface under serum fluoride exposure, corresponding to an increase in the relative level of F. EIS data showed an active corrosion behavior of pure titanium exposed to high serum fluoride and gradually decreased corrosion resistance with increasing concentration of serum fluoride, which was more severe under acidic conditions. The release of titanium ions was also induced by high serum fluoride and acidic conditions.

CONCLUSIONS

High serum fluoride had a negative influence on the corrosion behavior of pure titanium. The titanium oxide film barrier could be broken down in the fluoride ions condition, and the corrosion resistance of pure titanium decreased with the increasing concentration of serum fluoride. The increased corrosion susceptibility of pure titanium accelerated the release of titanium ions after exposure to high serum fluoride; this was more pronounced in an acidic environment.

The color of skin: blue diseases of the skin, nails, and mucosa

Diseases of the skin, hair, nails and mucosa can appear as flesh-colored lesions or may present as any of the colors of the visual spectrum. Diseases associated with blue (or shades of blue) discoloration represent a unique group of conditions that occur de novo or as a reaction to either a topical or a systemic agent to which the individual has been exposed. Blue diseases can affect the skin, the nails or the mucosal membranes of the mouth (buccal mucosa, gingiva, lips, palate or tongue) or eyes (sclera). In addition to appearing blue, they can also appear as blue-black, blue-brown, blue-gray, blue-green, blue-purple, blue-red, and blue-silver. The conditions range from those secondary to exogenous agents (systemic or tattoo or topical) to syndromes to systemic diseases to tumors (adnexal, melanocytic, vascular, or miscellaneous). A comprehensive attempt to include all conditions that have been described as blue (or a shade of blue) has been performed by evaluating the following terms using the medical search engine PubMed: blue and either gingiva, lips, lunula, mucosa, nails, oral, palate, sclera, skin, or tongue. Subsequently, the conditions were organized by color (blue and shades of blue) and within each color by location (skin, nails, oral mucosa and sclera). The results are presented in organized tables; in addition, there is discussion of some of the conditions that are unique to one or more specific locations. In conclusion, 'preserve and cherish the pale blue dot' and remember that a big red rock eater with chrysiasis is the answer to the riddle, "What is big and blue and eats rocks?"

Amalgam tattoo versus melanocytic neoplasm - Differential diagnosis of dark pigmented oral mucosa lesions using infrared spectroscopy

Background

Dark pigmented lesions of the oral mucosa can represent a major diagnostic challenge. A biopsy is usually required to determine the nature of such intraoral discolorations. This study investigates the potential use of infrared spectroscopy for differential diagnosis of amalgam tattoos versus benign or malignant melanocytic neoplasms.

Materials and methods

For this retrospective study, formalin-fixed paraffin-embedded tissue (FFPE) specimens of dark pigmented lesions concerning the oral mucosa or the lip were investigated using mid infrared spectroscopy. The samples were chosen from patients who had undergone a mucosal biopsy at the University Hospital Innsbruck (Austria) between the years 2000 and 2017. Principal component analysis was used for data exploration. Evaluation was based on the superimposition of the recorded spectra and the corresponding histologic slides.

Results

In total, 22 FFPE specimens were analyzed. Clear differences were found between amalgam and non-amalgam samples. A general weakening of the penetrating infrared radiation allowed for unspecific discrimination between these two classes. An overall accuracy in predicting the correct class of 95.24% was achieved.

Conclusion

Infrared spectroscopy appears to be a suitable technique to differentiate between amalgam tattoos and melanocytic lesions in FFPE samples. It could potentially be applied in vivo, too, serving as a non-invasive diagnostic tool for intraoral dark pigmented lesions.

Effect of Fixed Metallic Oral Appliances on Oral Health

There is a substantial proportion of the population using fixed metallic oral appliances, such as crowns and bridges, which are composed of various dental alloys. These restorations may be associated with a number of effects on oral health with variable degrees of severity, to review potential effects of using fixed metallic oral appliances, fabricated from various alloys. The MEDLINE/PubMed database was searched using certain combinations of keywords related to the topic. The search revealed that burning mouth syndrome, oral pigmentation, hypersensitivity and lichenoid reactions, and genotoxic and cytotoxic effects are the major potential oral health changes associated with fixed prosthodontic appliances. Certain oral disorders are associated with the use of fixed metallic oral appliances. Patch test is the most reliable method that can be applied for identifying metal allergy, and the simultaneous use of different alloys in the mouth is discouraged.

Clinical Characteristics of Abutment Teeth with Gingival Discoloration

PURPOSE

The grey-bluish discoloration of gingiva (known as "amalgam tattoo") does not appear only in the presence of amalgam restorations. It may also be seen in cases of teeth restored with cast dowels and porcelain-fused-to-metal (PFM) restorations. The aim of this article was to determine the clinical characteristics of abutment teeth with gingival discoloration.

MATERIALS AND METHODS

This research was conducted on 25 patients referred for cast dowel and PFM restorations. These restorations were manufactured from Ni-Cr alloys. Ninety days after cementing the fixed prosthodontic restorations, the abutment teeth (n = 61) were divided into a group with gingival discoloration (GD) (n = 25) and without gingival discoloration (NGD) (n = 36). The control group (CG) comprised the contralateral teeth (n = 61). Plaque index, gingival index, clinical attachment level, and probing depth were assessed before fabrication and also 90 days after cementation of the PFM restorations.

RESULTS

The gingival index, clinical attachment level, and probing depths of the abutment teeth that had GD were statistically higher before restoration, in comparison with the abutment teeth in the NGD and control groups. Ninety days after cementation, the abutment teeth with GD had significantly lower gingival indexes and probing depths, compared to the abutment teeth in the NGD group. Both abutment teeth groups (GD and NGD) had significantly higher values of clinical attachment levels when compared to the control group. There were no statistically significant differences in plaque index values between the study groups.

CONCLUSIONS

The results of this study indicated that impairment of periodontal status of abutment teeth seemed to be related to the presence of gingival discolorations. Therefore, fabrication of fixed prosthodontic restorations requires careful planning and abutment teeth preparation to minimize the occurrence of gingival discolorations.

CLINICAL RELEVANCE

With careful preparation of abutment teeth for cast dowels and crown restorations it may be possible to decrease the frequency of gingival discolorations adjacent to abutment teeth.

Tatuagem extensa por amálgama em mucosa gêngivo-alveolar

Tatuagens por amálgama são lesões pigmentadas, exógenas, de frequente ocorrência na mucosa bucal, que resultam da introdução acidental de partículas de amálgama nos tecidos moles. O diagnóstico da tatuagem por amálgama é simples, geralmente, baseado em achados clínicos, complementado pela história recente ou pregressa de remoção de restauração por amálgama. Radiografias intraorais podem ser úteis na detecção de radiopacidade, associadas à partícula de amálgama. Nos casos em que as tatuagens por amálgama não permitem diferenciação de outras lesões melanocíticas, o exame histopatológico deve ser realizado. Os autores relatam à ocorrência de lesão extensa por tatuagem de amálgama com confirmação histopatológica.

Microstructure analysis of dental castings used in fixed dental prostheses--a simple method for quality control

The aim of this study was to evaluate the microstructural quality of noble alloy castings from commercial dental laboratories using the wiping-etching method as a simple method for quality control. In total, 240 castings from two noble alloys (AuAgCuPt and AuPtZn) were taken from a day's production of five different dental laboratories. The casting quality was evaluated by determining the grain size and by assessing the number and size of shrinkage cavities after acidic etching of the alloy surfaces. The AuAgCuPt alloy castings showed an acceptable quality in the microstructural analysis. The results of AuPtZn castings, however, were not satisfactory because 50.8% of the samples showed a remarkably poorer quality compared to the specifications made by the manufacturer. The proportion of the employed reclaimed alloy had no influence on the casting quality when AuAgCuPt alloy was used, but was influential when casting restorations with AuPtZn alloy. When determining the quantity and size of shrinkage cavities, none of the evaluated castings was of such a poor quality that a replacement of the castings had to be considered. The differences in grain size and quantity of shrinkage cavities were reflecting the individual laboratory process rather than the admixture of new/reclaimed alloy. The presented analysis can be used as a simple method for quality control of dental castings.

Corrosion behaviour of titanium after short-term exposure to an acidic environment containing fluoride ions

The negative effect of fluoride ions on titanium has been known in dentistry for a long time. The presented work was aimed at the interaction between titanium and model saliva following a short-term exposure of a specimen to a model medical preparation rich in fluoride ions. The experimental work was carried out using titanium grade 2 in a physiological solution (pH non-adjusted, 5.8, 4.2; 5000 ppm F-) and in model saliva. Electrochemical measurement techniques were supplemented with XPS analysis. The presence of fluoride ions resulted in partial degradation of the passive layer even in a slightly acidic environment. The decrease of pH to the value of 4.2 and the presence of 5000 ppm F- caused titanium activation followed by a slow repassivation in model saliva. Formation of low soluble compound rich in fluorine explains experimental data. Short medical treatment can result in relatively long period of increased titanium corrosion.