Histiocytosis and adult-onset orbital xanthogranuloma in 2023: a review of the literature and mini case series.

PURPOSE: Within the large umbrella of histiocytosis are a few similar yet heterogenous entities involving the orbit and periocular tissues with or without systemic infiltration, termed adult onset xanthogranuloma or orbital xanthogranuloma. Due to rarity of these conditions, different classifications in use, diverse clinical presentations and still unknown etiology, the aim of this paper was to provide an up-to-date literature review of the actual understanding of histiocytosis and its subgroups involving the orbit and periocular area, diagnostic strategies and therapeutic modalities. METHODS: We present a review of literature and small case series comprising four patients diagnosed and treated in the period from 2001 until 2023 in our hospital. Clinical files of 4 patients with adult-onset xanthogranulomatous disease of the orbit and ocular adnexa (AOXGD) were reviewed retrospectively. Clinical, laboratory, radiological, histopathological, and immunohistochemical findings were reexamined. RESULTS: Reviewing medical records of our patients with AOXGD, we found significant overlap between histiocytosis and different immune disorders. A broad workup should be considered in these patients as they can harbour severe immune disfunctions and hematologic disorders. Preferred treatment modality depends on a histopathologic type of AOXGD, clinical presentation and systemic involvement and should be conducted multidisciplinary. CONCLUSION: The diagnosis is often delayed because of its rarity and diverse clinical findings. Development of molecular genetic tests, detection of BRAF V600E mutation and different types of kinase mutations, mutations in transcriptional regulatory genes as well as tyrosine kinase receptors have shed a new light on the etiopathogenesis and potential targeted treatment of histiocytosis.

Nonsurgical treatment for upper eyelid retraction in patients with inactive Graves' orbitopathy.

PURPOSE: To evaluate the effectiveness of incobotulinumtoxinA (Xeomin®) in treating upper eyelid retraction in patients with Graves orbitopathy (GO) initially scheduled for surgery via two different application sites. METHODS: This is a comparative, prospective study, conducted at the Department of Ophthalmology, Medical School, University Hospital Centre Zagreb, EUGOGO site (EUropean Group On Graves' Orbitopathy) in Croatia from January 2020 till January of 2021 in accordance with national health headquarter recommendations. All patients were classified as inactive with marked eyelid retraction and randomly divided into groups according to application sites. Group A underwent transconjunctival application (18 eyes) and group B transcutaneous application (20 eyes) of incobotulinumtoxinA. The primary end point of this study was lowering the eyelid, to alleviate anterior eye segment symptoms and achieve acceptable aesthetic appearance until surgery becomes available. RESULTS: There were no nonresponders and we found no statistically significant difference in the degree of lowering the eyelid between the two application sites. Following rules for avoiding spread of SARS-CoV-19, none of the patients included in this study were infected. Moreover, participants reported diminishing of anterior eye segment irritation and improved aesthetics. CONCLUSION: Treatment of inactive GO patients with incobotulinumtoxinA for upper eyelid retraction is efficient and safe and can be used as an adjuvant treatment while patients wait for surgery, by alleviating symptoms and improving the level of aesthetic satisfaction without causing a threat to anterior eye segment and visual function. The study showed that effect of treatment was the same, whether we applied the toxin transconjunctivaly or transcutaneously.

Rhenium Distribution and Behavior in the Salinity Gradient of a Highly Stratified Estuary and Pristine Riverine Waters (The Krka River, Croatia).

The abundance and distribution of dissolved Re (DRe) were determined in the freshwater part of the Krka River (Croatia), which drains a karst landscape, and in the salinity gradient of its highly stratified estuary. Due to the low DRe concentration, a batch procedure consisting of a pre-concentration step using an anion exchange resin (Dowex) and analysis of DRe in 8 M HNO3 eluate using high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS) was applied. Due to potentially inconsistent recoveries, which ranged from 60 to 87%, quantification was performed using the isotope dilution technique (ID). DRe concentrations in the Krka River increased downstream, from 6.2 pM at the spring site to 11.9 pM upstream of the estuary region. Weathering of the surrounding carbonate lithology is assumed to be the source of the natural Re. Two specific anomalies were registered: a strong increase in DRe concentration due to anthropogenic input near the town of Knin (27.5 pM) and a decrease at a downstream site caused by subsurface input of freshwater from the Zrmanja River, resulting in a relatively low DRe concentration (8.5 pM). In the estuarine region, a near-conservative behavior of DRe was found in the salinity gradient of the upper surface layer, with DRe concentrations ranging from 18 to 38 pM. Anthropogenic input was suspected within the estuarine segment near the urban area, causing a small positive deviation from the conservative line. In the bottom seawater layer, a minor decrease in DRe concentration in the most upstream estuarine regions was apparent, implying weak scavenging of Re.

Redox Speciation of Vanadium in Estuarine Waters Using Improved Methodology Based on Anion Exchange Chromatography Coupled to HR ICP-MS System.

An improved methodology was developed for V redox speciation in estuarine waters using a hyphenated technique consisting of ion chromatograph (IC) with an anion exchange column and a high-resolution inductively coupled plasma mass spectrometer (HR ICP-MS). This approach enables the direct determination of V(V), whereas reduced species (mainly V(IV)) are calculated by subtracting V(V) concentrations from the measured total V concentration. Based on the "on-column" V(V) chelation mechanism by EDTA, with the eluent composed of 40 mmol L-1 ammonium bicarbonate, 40 mmol L-1 ammonium sulphate, 8 mmol L-1 ethylenediaminetetraacetic acid and 3% acetonitrile, the method was successfully used for analyses of V redox speciation in samples taken in the vertical salinity gradient of the highly stratified Krka River estuary. Due to the matrix effects causing different sensitivities, a standard addition method was used for V(V) quantification purposes. The limit of detection (LOD) was also found to be matrix related: 101.68 ng L-1 in the seawater and 30.56 µg L-1 in the freshwater. Performed stability tests showed that V redox speciation is preserved at least 7 days in un-treated samples, possibly due to the stabilization of V-reduced species with natural organic matter (NOM). The dominant V form in the analysed samples was V(V) with the reduced V(IV) accounting for up to 26% of the total dissolved pool. The concentration of V(IV) was found to correlate negatively with the oxygen concentration. Significant removal of dissolved V was detected in oxygen depleted zones possibly related to the particle scavenging.

The levels of 12 cytokines and growth factors in tears: hyperthyreosis vs euthyreosis.

PURPOSE: Simultaneous analyses of the contents and ratios of 12 cytokines and growth factors in single samples of human tears were performed, and the results were compared between a group of healthy subjects and a group of patients with Graves' hyperthyreosis (GH) without thyroid-associated orbitopathy (TAO). METHODS: Determinations and concentration measurements of interleukins (IL-2, IL4, IL-6, IL-8, IL-10, IL-1α, and IL-1ß) interferon (IFN-γ), tumor necrosis factor (TNF-α), monocyte chemoattractant protein (MCP-1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) were performed with single tear samples from 21 patients with hyperthyreosis and 22 healthy subjects. The analyses were performed using a Randox microchip with an Evidence Biochip Array Analyzer. RESULTS: We found significant differences between the healthy donor group and the hyperthyreosis group in the levels of IL-6, IL-10, VEGF, IL-1α, and MCP-1. The concentration of IL-6 was considerably higher in the hyperthyreosis group, IL-10 was higher in the healthy donor group, and VEGF and MPC-1 were higher in the hyperthyreosis group. The IL-8 and IFN-γ levels were higher in the hyperthyreosis group. The ratios of all of the cytokines to anti-inflammatory IL-10 were significantly elevated in the hyperthyreosis group. CONCLUSION: There are clear differences in the levels of cytokines and growth factors in the tears of healthy subjects and patients with GH without TAO. Tear cytokine changes and related dysfunctional tear syndrome (DTS) could be an early sign of occult TAO in Graves' hyperthyreosis patients.

Quality of Life and Depression Level in Patients with Watery Eye.

BACKGROUND: The aim of this study was to assess subjective, human aspect of the medical condition, evaluate the quality of life (QOL) and level of depressive symptoms in patients with watery eye and compare it with patients with two most common causes of visual deterioration: cataract and macular region pathology. The results of this study may serve to raise awareness of watery eye impact on a large number of patients and subsequently promote their treatment in order to restore full visual and life quality necessary for normal human functioning. SUBJECTS AND METHODS: In this prospective, randomised, questionnaire-based study, we have surveyed three groups of patients with a total of 210 patients: group with the watery eye of different etiology (n=69), group with one pseudophakic eye and one cataract eye (n=73) and group with the unilateral pathology of the macular region (n=68). All three groups underwent a complete ophthalmologic examination. To examine the overall quality of life we have used a modified vision-related quality of life questionnaire (VR-QOL) and to evaluate depression level "Beck Depression Inventory - 2". The results were analyzed with statistical program STATISTICA 13. RESULTS: Compared to group with unilateral cataract eye and to group with unilateral pathology of the macular region, the results of this study show that patients with watery eye have significantly decreased quality of life in all daily activities, particularly in outdoor activities (F=125.80, df=2/143, p<0.01), during sports (F=36.67, df=2/143, p<0.01) and interpersonal relations (F=18.73, df=2/143, p<0.01). Results between three groups showed that group with watering eye expressed highest depression level and group with one pseudophakic eye and the other cataract eye the lowest (F=25.86, df=2/207, p<0.01). CONCLUSION: Watery eye has a significant impact on vision-related quality of life. Our research showed that patients with watery eye had expressed more depressive symptoms than other groups, but still without statistically significant value. Since it affects a large and heterogenic group of patients it is important to be recognized on time and treated etiologically in attempt to restore full function and life quality. The results of this study may serve to raise awareness of watery eye impact on a large number of patients and subsequently promote their treatment in order to restore full visual and life quality necessary for normal functioning.

Changes of Drusen Number and Central Retinal Thickness in Age-Related Macular Degeneration Patients Over Two Years

Age-related macular degeneration (ARMD) is the leading cause of blindness in developed world but there are still much unknown facts about the disease itself. Age, genetic factors and smoking are the three main risk factors for the development of ARMD, but the exact pathophysiological mechanism of the disease remains unknown. Current high resolution optical coherence tomography devices provide ample new information on retinal layers, drusen characteristics and their interaction. In this study, we analyzed 44 eyes with drusiform dry ARMD using high resolution optical coherence tomography over a 2-year period. Our results showed a statistically significant increase in drusen number in both females and males in the 2-year period. On average, increment by 4 and 5 drusen per eye during the 2-year period was recorded in female and male patients with drusiform dry ARMD, respectively. Also, statistical analysis of the central retinal thickness showed that women with drusiform dry ARMD had a statistically significantly thinner macula than their male counterparts.

Progression of conjunctival primary acquired melanosis (PAM) to widely spreaded malignant melanoma.

Primary acquired melanosis (PAM) is an acquired pigmentation of the conjunctival epithelium, a preinvasive pigmented lesion. When it is associated with cellular atypia it can lead to the developement of melanoma. We report a case report of malignant melanoma of the conjuntiva, which arrised from the conjuntival PAM. The disease was too extensive for ocular conservation, therefore exenteration was performed. This case highlights the need for regular follow-up of patients with melanocytic lesions of the ocular adnexa, and particular attention to the surgical technique, and careful follow-up to detect further disease activity.

Presentation of Graves' orbitopathy within European Group On Graves' Orbitopathy (EUGOGO) centres from 2012 to 2019 (PREGO III).

BACKGROUND: Graves' orbitopathy (GO) is subject to epidemiological and care-related changes. Aim of the survey was to identify trends in presentation of GO to the European Group On Graves' Orbitopathy (EUGOGO) tertiary referral centres and initial management over time. METHODS: Prospective observational multicentre study. All new referrals with diagnosis of GO within September-December 2019 were included. Clinical and demographic characteristics, referral timelines and initial therapeutic decisions were recorded. Data were compared with a similar EUGOGO survey performed in 2012. RESULTS: Besides age (mean age: 50.5±13 years vs 47.7±14 years; p 0.007), demographic characteristics of 432 patients studied in 2019 were similar to those in 2012. In 2019, there was a decrease of severe cases (9.8% vs 14.9; p<0.001), but no significant change in proportion of active cases (41.3% vs 36.6%; p 0.217). After first diagnosis of GO, median referral time to an EUGOGO tertiary centre was shorter (2 (0-350) vs 6 (0-552) months; p<0.001) in 2019. At the time of first visit, more patients were already on antithyroid medications (80.2% vs 45.0%; p<0.001) or selenium (22.3% vs 3.0%; p<0.001). In 2019, the initial management plans for GO were similar to 2012, except for lid surgery (2.4% vs 13.9%; p<0.001) and prescription of selenium (28.5% vs 21.0%; p 0.027). CONCLUSION: GO patients are referred to tertiary EUGOGO centres in a less severe stage of the disease than before. We speculate that this might be linked to a broader awareness of the disease and faster and adequate delivered treatment.

Chromatographic and spectrophometric studies of vanadate (+V) reduction by 3-mercaptopropionic acid.

The reduction of vanadate (+V) in the presence of 3-mercaptopropionic acid was studied using a chromatographic method for the determination of vanadate (+V) versus vanadyl (+IV) species. Ion chromatography was combined with spectrophotometric investigation of the absorption properties of the solution. The chromatographic method for the separation of vanadate (+V) and vanadyl (+IV) was carried out with an anion exchange column. In the initial reaction mixture containing vanadate (+V) and 3-mercaptopropionic acid, ethylenediaminetetraacetic acid - EDTA was added in an excessive amount relative to the concentration of reactants in the solution. After the ligand exchange reaction, the added EDTA terminates the reduction, allowing redox speciation in the solutions. A strong pH dependence of the reduction rates in the investigated solution was observed. The vanadate reduction seems to proceed in 2 steps: 1) formation of the intermediate vanadate (+V)-thioester; 2) reduction reaction and formation of the vanadyl (+IV)-thiol complex. The obtained results strongly suggest that the reaction of vanadate (+V)-thioester formation is proton catalyzed. It was observed that the overall reduction rates are pH dependent due to the complex vanadate (+V) solution speciation and changes in the ionic form of 3-mercaptopropionic acid.

Influence of Clinically Active Graves' Ophthalmopathy on Spherical Equivalent and Visual Acuity.

Purpose: Clinical experience regarding the fluctuations of the refractive error of the eye during the different stages of Graves' ophthalmopathy observed through outpatient clinic frequent check-ups points towards an underestimated and often overlooked problem. Published data about it are sparse. The clinical manifestations of Graves' ophthalmopathy can be understood from the perspective of "compartment syndrome" and literature implies how such changes can affect the refractive error and consequently, the visual acuity. The purpose of the study was to explore how the clinical activity score of Graves' ophthalmopathy affects refractive error and visual acuity. Patients and Methods: The study was prospective and observational, including 60 eyes of 30 patients with clinically active Graves' ophthalmopathy. All the patients were monitored and evaluated over a period of 36 months by the clinical activity score, spherical equivalent and visual acuity. All the observed parameters were statistically analyzed. Results: The mean values of spherical equivalent and visual acuity throughout the observed period showed continuous fluctuation. Repeated measure analysis of variance showed statistically significant differences in visual acuity and spherical equivalent over the observed period. There was a statistically significant positive correlation between visual acuity and clinical activity score. The correlation between spherical equivalent and clinical activity score was also positive but not statistically significant. Conclusion: A decrease in the clinical activity score is either the result of a spontaneously resolving course of Graves' ophthalmopathy or a consequence of treatment, so lowering in fluctuation of refractive error and improved visual acuity may be associated with a reduction in orbital inflammation.

Count Ivan VIII Draskovic: a case of Graves' orbitopathy?

There is a possibility that Count Ivan VIII Draskovic (1740-1787), a member of one of the oldest and most famous Croatian noble families, had Graves' disease and suffered from a thyroid disorder. Our suspicions were aroused by certain data, including his personal history, his lifestyle, including use of tobacco and iodine, as well as stress, and, finally, two portraits. If he was affected by Graves' disease and orbitopathy, his poor health might have been a consequence of thyroid disease, which was further worsened by injury and tobacco use. Later spontaneous remission could have been induced by higher iodine intake and bed rest.

Genotoxicity of fluoride subacute exposure in rats and selenium intervention.

The aims of this study were to: (i) examine the toxic effects of sodium fluoride (NaF) in blood, liver, spleen, and brain cells of Wistar rats after the subacute exposure; (ii) explore the potential protective properties of selenium (Se) against fluoride toxicity after the simultaneous administration. Twenty male Wistar rats, eight weeks old, weighing approximately 140-190 g, were divided into four experimental groups (n = 5) as follows: I control-tap water; II NaF 150 ppm; III NaF 150 ppm and Se 1.5 mg/L; IV Se 1.5 mg/L, and had available water with solutions ad libitum for 28 days. DNA damage detected by comet assay was confirmed in the liver, spleen, and brain cells, but not in blood. Selenium supplementation together with NaF decreased DNA damage in liver and spleen cells. According to the histological findings, no changes were observed in spleen and brain tissues after NaF administration. Unlike the observed Se protective effect on the DNA level, no significant reduction of liver tissue injury was observed after the NaF and Se treatment, resulting in mild inflammation. Data of this study suggest that DNA damage after NaF subacute exposure at moderately high concentration was reduced in liver and spleen cells due to Se supplementation, but a similar change was not seen in the brain.

Oral health status of psychiatric in-patients in Serbia and implications for their dental care.

AIM: To determine oral health status and identify predictors of oral health in a representative sample of psychiatric in-patients in Serbia. METHODS: The study included 186 psychiatric in-patients and 186 control participants without psychiatric illness matched to the study group by age, sex, marital status, education level, employment, and monthly income. Dental examinations were done in both groups to measure the following indices of oral health: decayed, missing, and filled teeth (DMFT) index; community periodontal index; and plaque index. Participants were also interviewed about their dental health behavior and their medical records were examined. RESULTS: Psychiatric in-patients had higher caries prevalence, poorer periodontal health, and poorer oral hygiene than controls. The average DMFT score in the patient group was 24.4 and 16.1 in the control group (P<0.001). Periodontal diseases were significantly more prevalent among psychiatric in-patients than among controls (P<0.001). The average plaque index for patients was 2.78 and 1.40 for controls (P<0.001). Multiple regression analysis demonstrated that 1) DMFT index was associated with age, male sex, duration of mental illness, use of antidepressants, time since the last visit to the dentist, and snacking frequency; 2) community periodontal index was associated with male sex; and 3) plaque index was associated with age, male sex, education level, employment, monthly income, tooth brushing technique, and snacking frequency. CONCLUSION: Psychiatric in-patients in Serbia have poorer oral health than healthy controls. It is necessary to intensify preventive dental care in this vulnerable population.

Can Fiber-post Placement Reinforce Structurally Compromised Roots?

PURPOSE: Immature teeth are characterized by short roots, thin root canal walls, and open apices, which makes them prone to fracture. The aim was to investigate whether fiber-post placement had an influence on the fracture resistance of endodontically treated immature teeth. MATERIALS AND METHODS: To simulate immature teeth, the apical third of 20 intact mandibular premolars was resected. After the access cavity was prepared, root canals and apices were enlarged. A 4-mm apical barrier was placed using calcium-silicate based material (Biodentine, Septodont). The teeth were then randomly assigned to two groups (n = 10). Root canals in group 1 were sealed using Acroseal (Septodont, France) and gutta-percha, followed by composite resin for the coronal restoration (Evetric, Ivoclar Vivadent). In group 2, fiber posts (FRC Postec Plus, Ivoclar Vivadent) were luted using self-adhesive composite cement (SpeedCEM Plus, Ivoclar Vivadent), followed by the same coronal restoration. The teeth were then subjected to fatigue and static load testing. RESULTS: The average loads (± SD) that led to tooth fracture were: 401.40 ± 296.83 N in group 1 and 636.20 ± 204.95 N in group 2. Unfavorable fractures were noted in 9 specimens from group 1 and in 7 specimens in group 2. No statistically significant difference in fracture resistance or fracture mode was found between the groups. CONCLUSION: Fiber-post placement had no significant influence on the fracture resistance of endodontically treated immature teeth.

Solidification of SMEDDS by fluid bed granulation and manufacturing of fast drug release tablets.

Solidification of self-microemulsifying drug delivery systems (SMEDDS) is a rising experimental field with important potential for pharmaceutical industry, however fluid-bed granulation with SMEDDS is yet an unexplored solidification technique. The aim of the study was to solidify carvedilol-loaded SMEDDS utilizing fluid bed granulation process and to investigate how the formulation variables (type of solid carrier, optimization of granulation dispersion) and fluid-bed granulation process variables can be optimized in order to achieve suitable agglomeration process, high drug loading and appropriate product characteristics. Obtained granulates exhibited complete drug release, comparable to liquid SMEDDS and superior to crystalline carvedilol, nevertheless compromise between large SMEDDS loading and appropriate flow properties of the granules has to be made. Representative granulates with highest drug loading were further compressed into tablets. It was shown that the optimal excipient selection of compression mixture and compression force can lead to fast carvedilol release even from the tablets. Selfmicroemulsifying properties were not impaired neither after the solidification process and nor after the compression of solid SMEDDS into tablets. This suggests that fluid-bed granulation with SMEDDS offers a perspective alternative for solidification of the SMEDDS, enabling preservation of self-microemulsifying properties, acceptable drug loading and complete drug release.

Polycyclic aromatic hydrocarbons in surface sediments of the mid-Adriatic and along the Croatian coast: Levels, distributions and sources.

This study provides contamination levels, distributions and source apportionment of PAHs in surface sediments in the mid-Adriatic and along the Croatian coast. Median summed concentrations of parent and alkyl-PAHs are circa 10 times lower in the off-shore transect stations of the mid-Adriatic (22.3 and 18.2 µg.kg-1 d.w.) than the ranges determined at the coastal stations, including those of Kastela bay (227-331 and 11.7-197 µg.kg-1 d.w., respectively). The highest levels, circa 20 times higher, were found in Sibenik bay (median 6603 and 3051 µg.kg-1). The overall range of PAH concentrations spans more than 2000 times between the lowest and the highest contamination level. The geographical distributions reflect the presence of strong gradients at local and regional scales. A major factor influencing sedimentary PAH distributions at local scale appears to be the distance from their known continental and coastal upstream emission sites (urban, industrial, harbour …), whereas at regional scale, this distribution depends more on the routes of entry of PAHs into the study area. Two combustion and one petroleum model source profiles of PAHs were determined by alternative least square analysis. Benzo[b+j]fluoranthenes and fluoranthene/pyrene are compounds characterizing two pyrogenic sources respectively, while signatures of alkyl-substituted homologues (phenanthrenes/anthracenes, fluranthenes/pyrenes, chrysenes and dibenzothiophenes) delineate a petrogenic source profile. The quantitative apportionment of source contributions shows significant geographical differences, with a dominant petrogenic source found along the mid-Adriatic transect (approximately 74%) and in Kastela bay (61%). In the coastal sediments about a fifty-fifty contamination mix is assigned to a petrogenic/pyrogenic source of PAHs (47% and 53% respectively), whereas in Sibenik bay a strong predominance is apportioned to the combustion compounds (81%).

Superior Ophthalmic Vein Thrombosis with Complete Loss of Vision as a Complication of Autoimmune and Infective Conditions.

PURPOSE: To present our experience in the management of superior ophthalmic vein thrombosis (SOVT), which is a rare, but extremely serious condition if not recognized and managed promptly and appropriately. METHODS: Two patients with septic and aseptic SOVT are presented. Clinical characteristics, radiographic features, management techniques, and outcomes are described. RESULTS: In the first case thrombosis occurred as a complication of functional endoscopic sinus surgery. In the second case thrombosis occurred as a complication of untreated inflammatory bowel disease: ulcerative colitis. Both cases resulted with permanent unilateral blindness. CONCLUSION: SOVT is a rare entity. There are no guidelines, just recommendations for disease management. Based on our experience, broad-spectrum intravenous antibiotic, anticoagulation, and steroid therapy should be promptly introduced and if needed surgical intervention. SOVT can lead to devastating complications which include permanent loss of vision and in some cases a fatal outcome.

[The application of air abrasion in dentistry].

One of the main objectives of contemporary dentistry is to preserve healthy tooth structure by applying techniques of noninvasive treatment. Air abrasion is a minimally invasive nonmechanical technique of tooth preparation that uses kinetic energy to remove carious tooth structure. A powerful narrow stream of moving aluminum-oxide particles hit the tooth surface and they abrade it without heat, vibration or noise. Variables that affect speed of cutting include air pressure, particle size, powder flow, tip's size, angle and distance from the tooth. It has been proposed that air abrasion can be used to diagnose early occlusal-surface lesions and treat them with minimal tooth preparation using magnifier. Reported advantages of air abrasion include reduced noise, vibration and sensitivity. Air abrasion cavity preparations have more rounded internal contours than those prepared with straight burs. This may increase the longevity of placed restorations because it reduces the incidence of fractures and a consequence of decreased internal stresses. However, air abrasion cannot be used for all patients, i.e. in cases involving severe dust allergy, asthma, chronic obstructive lung disease, recent extraction or other oral surgery, open wounds, advanced periodontal disease, recent placement of orthodontic appliances and oral abrasions, or subgingival caries removal. Many of these conditions increase the risk of air embolism in the oral soft tissues. Dust control is a challenge, and it necessitates the use of rubber dam, high-volume evacuation, protective masks and safety eyewear for both the patient and the therapist.