Gianpaolo Guzzi

Oral lichen planus and malignant transformation: a longitudinal cohort study.

OBJECTIVE Oral lichen planus (OLP) is associated with risk for developing oral squamous cell carcinoma (OSCC). We performed a 7-year prospective study to assess the incidence of malignant transformation of OLP among adults. STUDY DESIGN Three hundred twenty-seven OLP patients, 229 women (70.0%) and 98 men (30.0%), were observed during the follow-up period. RESULTS During a mean follow-up of 81.7 months, 8 of 327 patients developed an OSCC in OLP areas (0.36%/y), yielding the high overall standardized incidence ratio of 17.7 (95% confidence interval [CI] 8.8-35.3). The standardized incidence ratio for OSCC was significantly higher in women [27.0 (95% CI 11.2-64.8)] than in men [11.2 (95% CI 3.6-34.9)]. Six OSCCs were well differentiated (75%) and 2 moderately differentiated (25%). Three subjects (37.5%) developed recurrences within 2 years (mean 16.1 ± 3.5 months). Disease-free survival rate after 69.8 months was 97.3%. CONCLUSIONS OLP was associated with a significant increase in the risk for OSCC. Close surveillance may help to reduce the morbidity of OSCC arising from OLP at 24 months.

Metal sensitivity in patients with orthopaedic implants: a prospective study

Background. Sensitization to orthopaedic implant materials is an unpredictable event that might affect implant performance.

Dental amalgam and mercury levels in autopsy tissues: Food for thought

Eighteen cadavers from routine autopsy casework were subject to a study of tissue levels of total mercury in brain, thyroid, and kidney samples by atomic absorption. On these same cadavers, all dental amalgam fillings (the most important source of inorganic mercury exposure in the general population, according to the World Health Organization (WHO) were charted. Total mercury levels were significantly higher in subjects with a greater number of occlusal amalgam surfaces (>12) compared with those with fewer occlusal amalgams (0-3) in all types of tissue (all P ≤ 0.04). Mercury levels were significantly higher in brain tissues compared with thyroid and kidney tissues in subjects with more than 12 occlusal amalgam fillings (all P ≤ 0.01) but not in subjects with 3 or less occlusal amalgams (all P ≥ 0.07).

Photopatch tests: an Italian multicentre study from 2004 to 2006

Background:  Evaluation of possible photoallergic contact dermatitis in at‐risk populations is often not undertaken, and an agreed methodology for investigation is uncommonly used.

Recovery from mercury-induced burning mouth syndrome due to mercury allergy

We report a case in which burning mouth syndrome (BMS) was associated with a strong allergy to mercury. The aim of this case history is to strengthen knowledge of the relationship among allergy to mercury, systemic allergic contact dermatitis, and hypersensitivity of the oral mucosa. We performed series of standard and dental patch tests for screening for contact allergy to dental materials, in accordance with International Contact Dermatitis Research Group guidelines. Positive extreme allergic reactions to mercury (+++) and amalgam (++) were seen at the patch site and caused a flare-up of the systemic erythematous reaction. Full recovery from BMS and complete remission of systemic dermatitis were achieved after the mercury tooth filling was removed. Mercury is thought to be an allergen implicated in BMS as well as in the systemic reactivation of allergic contact dermatitis. Patch testing with dental series seems to have greater sensitivity and relevance in BMS patients.

Inorganic mercury changes the fate of murine CNS stem cells.

Stem cells isolated from the central nervous system of both embryonic and adult mice can generate neurons and glia through the activation of different patterns of differentiation in dependence of exposure to appropriate epigenetic signals. On the other hand, environmental conditions might affect the proliferation, migration, and differentiation of these cells. We report here, for the first time, that inorganic mercury affects the proliferative and differentiative capacity of adult neuronal stem cells (ANSCs). Actually, inorganic mercury increases apoptosis in ASNC. Furthermore, in stem cell‐derived astrocytes, high levels of the 70 kDa heat shock protein (HSP‐70) occur, while the levels of GTP‐β‐tubulin activity dramatically decrease. Interestingly, when induced to differentiate, inorganic mercury modifies morphological proprieties of astrocytes, while the neuron population is reduced. These results demonstrate that inorganic mercury produces toxicity in the ANSC‐derived neuronal population and affects the biological properties of the glial‐derived population.

Titanium allergy associated with dental implant failure

Dear Editor, In their interesting article, Sicilia et al. (2008) assessed the prevalence of allergy to titanium in patients who received titanium dental implants. The authors report a prevalence of titanium allergy of 0.6% in a selected-based sample of 1500 implant patients. However, cutaneous and patch-testing procedures were performed to assess, respectively, immediate and/or delayed allergy to titanium in only a subgroup of 35 patients at a higher risk of implant failure (10 males and 25 females, aged between 21 and 68 years). The authors do not report the characteristics of titanium implants in their patients. Were the implants made in commercial pure titanium or were they titanium–alloy implants? (e.g., titanium, vanadium, and aluminum). We believe that it is important for readers to realize that there are two different typologies of titanium implants (Stenport & Johansson 2008): pure titanium and alloy dental implants, which are dissimilar in the rate of corrosion, and this dissimilarity influences the antigenicity of released metals in surrounding tissue. Interestingly, leukopenia has been observed in patients with adverse skin reactions to titanium-based implant in the head and neck region, especially low neutrophil counts (Holgers et al. 1992). It would be interesting to know whether Sicilia et al. detected any low white blood cell count in patients with documented titanium allergy in their study. We are pleased to note that Sicilia and coworkers state in the background that dentists are not aware of, or do not consider, allergy to titanium as a risk factor for dental implant failure. We also recommend the use of dental patch testing (Pigatto & Guzzi 2007) with dental series in all patients with titanium dental implant failure. Finally, from the clinical perspective, if a similar evaluation with patch testing of titanium had assessed the prevalence of allergy to titanium in the entire cohort of 1500 dental implant patients, the overall prevalence would have been higher than that found by the authors.

Allergological and Toxicological Aspects in a Multiple Chemical Sensitivity Cohort

Background. Multiple chemical sensitivity (MCS) is a chronic condition characterized by an exaggerated response to toxicants. We ascertained the prevalence of allergy to metals and toxicological aspects in MCS patients. Methods. We conducted a retrospective review of medical records of 41 patients with MCS. We performed patch testing (n = 21) for dental series and did lymphocyte transformation test (n = 18) for metals. We measured mercury in samples of blood (n = 19), urine (n = 19), saliva (n = 20), and scalp hair (n = 17) to investigate the association between mercury levels and cases of MCS. Results. The prevalence of metal immune hypersensitivity in a subset of 26 patients was 92.3 percent. Elevations of mercury occurred in 81.2 percent (26 of 32). The mean (±SD) in blood concentrations of mercury was 7.6 ± 13.6 μg/L; mean in urine was 1.9 ± 2.5 μg/L; mean in scalp hair was 2.2 ± 2.5 μg/g; mean in saliva was 38.1 ± 52.1 μg/L. Subgroup analyses showed that elevation of mercury levels in biological matrices were associated with mercury amalgams in patients with MCS (22 patients), compared with controls (8 patients) (odds ratio 11 : 95 percent confidence interval 1.5 to 81.6; P = 0.023). Conclusions. Our data show an increased prevalence of metal allergy and elevation of mercury levels in bioindicators among patients with MCS.

Photodynamic therapy to treat periimplantitis.

Aim: Periimplantitis is a bacterial complication after dental implants implantation. Photodynamic therapy (PDT) implies the use of low-power laser in combination with appropriate photosensitizer to increase the detoxification of the implant surfaces. Little information exists about PDT in the treatment of periimplantitis. A randomized comparative case-control study has been conducted with 20 patients and 20 controls to compare the efficacy of antimicrobial PDT versus surgical therapy in patients with periimplantitis, who have received dental implants with rough surfaces. Materials and Methods: In the surgery group, mucoperiosteal flap surgery was used with scaling on implant surfaces and debridement of granulation tissue. Microbiologic testing was evaluated before and after intervention treatment, at 12 and 24 weeks in the study subjects. Discussion: Total anaerobic counts of bacteria did not differ significantly between patients assigned to receive PDT and those assigned to receive surgical therapy (mean, 95.2% and 80.85%, respectively). PDT was associated with a significant decrease in bleeding scores (P = 0.02) as well as inflammatory exudation (P = 0.001). Conclusion: Treatment with PDT in patients with periimplantitis was not associated with major reduction of total anaerobic bacteria on the rough surfaces of dental implants as compared with surgical therapy. A significantly lower proinflammatory index of periimplantitis was observed in the PDT group at 24 weeks of follow-up.

Should amalgam fillings be removed

on the American DentalAssociation’s campaign to discouragepeople from having amalgam fillingsremoved deserves some comment. Inher report, she cites FrederickEichmiller’s concerns about the numberof patients with multiple sclerosis,Alzheimer’s disease, and autismrequesting removal of these fillings. Dental amalgam is a mercury-basedfilling that contains elemental mercuryat about 50% by weight. Amalgam isclassified as an intermetallic compound,because it is mixed with silver, tin,copper, and zinc. To the chemist, thisintermetallic compound is unstable bydefinition—and not a “stable alloy”, asreported by Eichmiller—and mercuryvapour leaks from dental amalgam overtime.Mercury adsorbed daily from dentalamalgam ranges from 2 to 17 g (not“minute” amounts as Eichmillerclaims), and people that use chewinggum or are affected by bruxism mayhave higher intake of mercury fromdental amalgams. Moreover, individ-uals with dental amalgams are exposedto continuous long-term amounts ofmercury (in vapour form and inorganic form from biotransformationby oral bacteria). Mercury vapour andorganic mercury are the two mostimportant forms of mercury in terms oftoxic effects, their major target organbeing the central nervous system.Furthermore, T Clarkson