A microscopical evaluation of 24 retrieved failed hollow implants.

Twenty-four hollow ITI implants (four screws, and 20 cylinders) were retrieved because of failure, and evaluated in our laboratory, in a eight-year period (1989-1996), to see if a common cause could be observed in this implant design. No selection of these implants was carried out, and they represented the total number of implants of this type received in the above-mentioned time frame. The implants had been inserted by several different clinicians and were received from four universities and a private practice. The implants had been removed for mobility, pain, and presence of a vertical bone loss. About two-thirds of the implants were unstable in the jaw at the time of retrieval. Twenty implants had been used as single implants restoration and four in bridge reconstructions. Most of our specimens showed that the inflammatory process had reached the hollow portion of the implants. The following microscopical features were present in almost all our specimens: calculus and plaque on the coronal portion of the implant surface, presence of proliferating epithelium and of bone sequestra, and presence of bone apically to the inflammatory process. Perhaps, when the inflammatory process reaches the implant hollow portion, the infection runs a more rapid course due to the scarce vascularity of the bone inside this part.

Hollow implants retrieved for fracture: a light and scanning electron microscope analysis of 4 cases.

One of the possible complications of implant treatment is the occurrence of an implant fracture. Metal fatigue and biomechanical overload seem to be the most common causes of fractured implants. This study evaluated 4 implants (3 hollow cylinders and 1 hollow screw) which fractured after a mean loading period of 2.8 years. All implants had a 4 mm diameter and had been inserted in a posterior location. In 3 cases parafunctional habits were present. In all cases a vertical resorption of the peri-implant bone was present. The endosseous portion of the implant presented always a very high bone-implant contact percentage. Scanning electron microscopic examination showed that at least one of the implant holes was involved in the fracture line; no porosities or material defects were observed on the fractured surface of the implant. In hollow implants the holes could represent a site of less resistance.

Guided tissue regeneration versus coronally repositioned flap in the treatment of recession with double papillae.

Twenty buccogingival recessions (3 mm deep) in twenty patients were selected and divided into two groups. Periodontal parameters were recorded (recession reduction, probing depth, clinical attachment level, and keratinized tissue width), and both groups were treated with regenerative therapy using a resorbable polylactic acid membrane. The test group was treated using the double papilla flap procedure, and the control group was treated using the coronally repositioned flap procedure. The results obtained at a 1-year follow-up were comparable between the test and control groups for recession reduction, probing depth, and clinical attachment level, although the test group obtained a very large amount of keratinized gingiva (+74.7%) compared to the control group.

Histological evaluation of the peri-implant bone around plasma-sprayed non-submerged titanium implants retrieved from man: a report of two cases.

Two cases of non-submerged implants are reported: one was removed, unloaded, after 1 year, for psychiatric reasons, and the other, after a loading period of 4 years, for a fracture of the implant. The implants and surrounding tissues were processed to obtain thin ground sections. In the first case compact lamellar bone was observed in close contact with the titanium all around the implant perimeter. No connective tissue or empty spaces were found at the bone-implant interface. Histochemical staining with von Kossa demonstrated that all the bone around the implant was highly mineralized. No areas of osteoid tissue were found at the bone-implant interface. In the implant retrieved due to fracture it was possible to observe a very high percentage of bone-implant contact.

Maintenance of implants: an in vitro study of titanium implant surface modifications subsequent to the application of different prophylaxis procedures.

The aim of the present study was to evaluate surface alterations on titanium implant necks subsequent to different prophylaxis procedures. Fifty ITI implants were utilized. Forty implants were treated with 10 different prophylaxis procedures (ultrasonic scaler, plastic tip ultrasonic scaler, stainless steel curette, titanium curette, teflon curette, air powered system, abrasive rubber cups, polishing rubber cup and brush), and 10 implants were left as untreated controls. Surface alterations were studied on an area of 1 mm x 0.9 mm and quantified using optical microscopic, SEM and laser prophylometer analysis. The use of laser prophylometer provided an objective criterion for evaluation, expressing implant neck surface alterations in numeric values in terms of two roughness indexes, Ra and Rz. The results showed that, in comparison with the controls (Ra = 0.50; Rz = 3.98) the procedures investigated could be divided into 3 main groups: 1) Methods which altered the implant neck surface producing increased roughness (Ra = 0.68-2.08; Rz = 4.68-11.92); 2) Methods which left the implant neck surface unaltered (Ra = 0.44-0.57; Rz = 0.42-3.46); 3) Methods resulting in a smoothening of the implant neck surface (Ra = 0.36; Rz = 2.15). Group 1 included procedures that should be avoided. However, it appeared safe to apply the procedures of groups 2 and 3. To confirm these results, it will be necessary to evaluate the plaque- and calculus-removing efficacy from titanium neck implant surfaces in vivo.

Blood in saliva of HIV seropositive drug abusers: possible implication in AIDS transmission.

We have studied hemoglobin concentration in saliva of anti-HIV positive and anti-HIV negative intravenous drug abusers (IVDA) and normal controls and the relationship between hemoglobin concentration in saliva and number of CD4+ cells and clinical status of AIDS in anti-HIV positive IVDA. 120 anti-HIV positive IVDA, 112 anti-HIV negative IVDA and 116 normal healthy subjects not belonging to any risk group for HIV infection completed the study. Saliva was collected at awakening before brushing teeth and the concentration of hemoglobin was determined. Hemoglobin concentration in saliva in basal conditions is higher in anti-HIV positive IVDA with respect to anti-HIV negative IVDA (p less than 0.05) and controls (p less than 0.01). In anti-HIV positive IVDA hemoglobin concentration in saliva is higher in subjects with CD4+ cells less than 200/10(6) l with respect to subjects with CD4+ greater than 200/10(6) l (p less than 0.05) and in subjects with ARC/AIDS with respect to subjects with PGL or who are asymptomatic (p less than 0.01). Subjects with ARC/AIDS have a mean concentration of hemoglobin of 19 micrograms/0.1 ml saliva (range 0-153) which corresponds to 1.3 microliters of blood/ml saliva. If 10 ml of saliva are exchanged during kissing an average of 13 microliters of blood are transferred (110 microliters of whole blood at extreme range). Blood of symptomatic patients has an HIV titer of 7 TCID/microliters which for 10 ml saliva containing an average of 1.3 microliters blood/ml saliva corresponds to an average of 90 TCID (770 TCID at the extreme range).(ABSTRACT TRUNCATED AT 250 WORDS)

[The role of Langerhans cells in periodontal disease]. / Il ruolo delle cellule del Langerhans nella malattia parodontale.

Following a morphological description of Langerhans cells, the paper analyses their functional activity both as phagocytic cells and as antigen-presenting cells. The role of this cell population in periodontal disease is the examined in the light of recently reported findings.

[The role of LGL cells (NK and K) in periodontal disease]. / Il ruolo delle cellule "LGL" (NK e K) nella malattia parodontale.

The paper reports the morphological and functional aspects of NK and K cells in the light of the most recent advances in the field, and pays particular attention to their cytotoxic and suppressor capacities. The role of NK and K cells in periodontal disease is then described and it is observed how this cell population is absent in healthy gums, whereas it is found with increasing frequency at disease reaches the chronic stage. The presence of LGL cells is therefore thought to be associated with the development of plaque-induced inflammation.

[Environmental pathology and dentistry. Dental caries and periodontal disease]. / Patologia ambientale ed odontoiatria. La carie dentaria e la malattia parodontale.

Dental decay and periodontal disease are pathologies which are closely related to environmental factors. The study analyses the various etiopathological elements which influence the onset of these diseases and the different methods of prophylaxis which reduce their incidence.

[Environmental pathology and dentistry. II. Occupational diseases and stomatomucositis due to allergic factors]. / Patologia ambientale ed odontoiatria. Nota II. Le malattie professionali e le stomatomucositi da fattori allergici.

Professional diseases and stomatomucositis due to allergic factors represent two important aspects of odontostomatology in which there is a clear relationship with environmental factors. The paper analyses the etiopathogenetic and clinical aspects of the most common forms of disease which lead to alterations of the oral mucous.

[The relationship between lichen ruber planus orale, hepatopathies and hypersensitivity to the components of dental restorations]. / Studio sulla relazione tra lichen ruber planus orale, epatopatie ed ipersensibilità a componenti di restauri dentari.

A group of patients with lichen planus, a pathology affecting the cutis and mucosa which may affect the oral cavity, were studied. All patients underwent laboratory tests to assess hepatic function. Prick tests, using a series of haptens found in materials used in dental reconstruction work, were also performed in 53 patients who possessed dental prostheses. The statistically significant correlation between lichen planus, especially in its erosive form, and hepatic damage is underlined. However, the correlation between sensitivity to the haptens contained in materials for dental reconstruction work and lichen planus was not significant.

[Conservative therapy of coronal fractures with reattachment of the original fragment: indications for periodontal treatment]. / La terapia conservativa delle fratture coronali con riattacco del frammento originale: indicazioni del trattamento parodontale.

The AA, analyse the relation between dental fracture and relative parodontal tissues. A clinical case, treated with an intervention of parodontal surgery and with sticking of the coronal fragment, is shown.

[Relations of gingival hypertrophy and blood levels of cyclosporin A in patients with renal transplants]. / Relazione tra ipertrofia gengivale e livelli ematici di ciclosporina A nei pazienti con trapianto renale.

Gingival overgrowth is defined as hyperplasia of gingival tissue due to local, systemic or drug-related causes. To see if the incidence and severity of this side-effect are related to cyclosporine A (CyA) dosage and/or blood levels BCyA), we analysed data from 24 renal transplanted outpatients, grouped as follows: controls (C, n = 3): patients on immunosuppressive therapy other than CyA; group 1 (G1, n = 10): patients with BCyA steadily 300 ng/mL (RIA); group 2 (G2, n = 11): patients with BCyA steadily between 301 and 650 ng/mL. BCyA averaged 290 +/- 21 in G1 and 481 +/- 100 in G2 (p less than 0.001): mean cyclosporine A dosage (mg/kg/die) was not significantly different: 4.1 +/- 1.4 in G1 and 4.97 +/- 2.4 in G2. However, six patients in G2 also received calcium antagonists known to increase CyA blood levels (diltiazem and nicardipine) for clinical purposes or deliberately to increase CyA bioavailability. Mean time from transplant was (in months) 19 +/- 11 in G1, 16 +/- 15 in G2 and 62 +/- 24 in C (G1 vs G2: NS; C vs G1 and 2: p less than 0.001). Mean GFR (mL/min) was 75 +/- 22 in C, 65 +/- 18 in G1 and 53 +/- 19 in G2 (NS). Dental hygiene, as assessed by scoring (0-3: absent, mild, moderate and severe) the bacterial plaque, was similar in all groups. Gingival overgrowth, was similarly scored (0-3) and was absent in C and in 20% of G1, mild in 40% of G1 and 33% of G2, moderate in 40% of G1 and 33% of G2 and severe in 0% of G1 and 33% of G2 (G1 vs G2: p less than 0.05). Our data suggest that the severity of gingival overgrowth in transplanted patients with similar oral hygiene is mainly related to CyA blood levels.

[The free subepithelial connective tissue graft]. / L'innesto connettivale libero subepiteliale.

After a description of advantages and disadvantages of traditional surgical techniques for the correction of gingival retractions, a new surgical techniques is indicated: the subepithelial connective tissue graft. The latter technique is assessed and described in detail and its relative efficacy in comparison with the traditional techniques is emphasized.

[Oral lichen planus and dental materials. Etiopathogenetic and clinical relations]. / Lichen planus orale e materiali dentari. Rapporti eziopatogenetici e clinici.

The oral mucosa may be the site of lesions attributable to contact allergy with dental material. Studies carried out show that in oral LP dental materials may represent a factor of by no means negligible importance in determining the lesion as they might be the triggering cause and subsequently influence course and development. On the basis of these observations, an interpretative model of the aetiopathogenetic relationship between dental materials and oral LP is proposed and the problem is also addressed from the clinical viewpoint. The essential aspects are outlined and a diagnostic-therapeutic protocol proposed that differentiates patients suffering from oral LP with presence of dental materials and those without.

[Hyperthrophic-hyperplastic gingival diseases. Etiopathogenic, clinical assessment and diagnostic guide]. / Le gengivopatie ipertrofico-iperplastiche. Inquadramento etiopatogenetico, clinico ed indirizzi diagnostici.

The clinical and histological aspects of hypertrophic and hyperplastic gum diseases were examined in order to clarify the aetiopathogenesis of such conditions and facilitate their diagnosis. The latter is far from simple, given the variety of pathological pictures expressing a large number of conditions that present macroscopic similarities despite their different aetiopathogenesis.

[Desquamative gingivitis: etiopathogenetic and clinical assessment]. / La gengivite desquamativa: inquadramento etiopatogenetico e clinico.

The aetiopathogenetic, diagnostic, clinical and therapeutic aspects of a particular form of gingival condition given various names in the past but presently defined as "chronic desquamative gingivitis" have been examined. Desquamative gingivitis is an uncommon clinical condition whose aetiology remains uncertain. It has therefore not yet been definitely established wether it is a specific entity or whether, as is confirmed by much clinical evidence and laboratory data, it is merely an oral clinical sign of dermatological type pathologies (pemphigus vulgaris, benign mucosal pemphigoid, bullous pemphigoid, erosive lichen ruber planus, psoriasis).