PubMed Health⌕ Search

Biomedical subjects

J Van Reck

Publications and source records attributed to J Van Reck.

At least 19 recordsLinked to original sources
PubMed2005

Pulpal and periodontal temperature rise during KTP laser use as a root planing complement in vitro.

OBJECTIVE: The purpose of this study was to define the optimal irradiation conditions of a KTP laser during root planing treatment. METHODS: The surfaces of 60 single-root human teeth were scaled with conventional instruments before lasing. The pulpal temperature increase was measured by means of one thermocouple placed in the pulp chamber and a second one placed on the root surface at 1 mm from the irradiation site. The influence of variables of coloration by Acid Red 52 (photosensitizer), scanning speed, dentin thickness, and probe position was analyzed for a constant exposure time of 15 sec and 500 mw (spot size diameter, 0.5 mm). The pulpal temperature was below 3 degrees C for the adjustments. RESULTS: The irradiation on one point of root surface had the following results: The application of photosensitizer on the root surface before lasing produced a 50% higher temperature rise within the pulp than in the case without the application of the photosensitizer. The temperature rise in the pulp chamber was below 3 degrees C with the following settings of 500 mw: PW = 10 msec and PRR < 35; or PW= 20 msec and PRR < 20 Hz. On the other hand, for the same irradiation conditions, the temperature rise on the surface of the root was always below 7 degrees C. However, the temperature increase became higher than 7 degrees C (on the surface of the root) in the case of P > 500 mw, PW > 50 msec and PRR > 10 Hz of root surface or a scanning speed of irradiation of 1 mm/sec for a linear irradiation of 4 mm. CONCLUSION: The KTP laser may be used safely without thermal damage to pulp and periodontal tissue with respect to the biologically acceptable previously described parameters.

Body Temperature↗
PubMed2004

External temperature during KTP-Nd:YAG laser irradiation in root canals: an in vitro study.

To avoid the damage of periodontal tissues during laser irradiation of the root canal, the conditions of lasering must be carefully controlled. The aim of this study was to determine the safety parameters of the irradiation conditions during the use of a KTP-Nd:YAG laser in root canals. Root canals of 60 freshly extracted teeth were prepared (step-back technique) and filled with a photosensitiser (Acid Red 52). Different irradiation conditions [output power (P), pulse width (PW), pulse repetition rate (PRR, Hz)] were used. The laser beam was delivered by means of the KTP-Nd:YAG fibre tip with a beam spot-size diameter of 200 microm. The temperature increases were measured on the external apical third of the root surface using a thermocouple. The results showed that the temperature rise was always below 7 degrees C at the following laser settings: (1) single irradiation, P < or = 4 W, PW < or = 2.55 ms and PRR < or = 20 Hz; (2) repetitive irradiation series, five pulses of 1 s each, four resting times of 1 s each, P < or = 2.25 W, PW < or = 2.55 ms and PRR < or = 20 Hz. The use of resting times was necessary so as to avoid thermal cumulative effects. In these in vitro irradiation conditions, the use of the KTP-Nd:YAG laser in endodontics may be considered harmless for periodontal tissues.

Dental Pulp Cavity↗
PubMed2004

[Histoplasmosis of the oral cavity].

Histoplasmosis is an endemic mycosis. Histoplasma capsulatum, and duboisiï are the pathogenic agents in humans. The disease is reported as endemic in more than 30 countries. Three clinical forms are distinguished; acute, chronic and disseminated. Oral lesions may take on different clinical aspects which are often associated with disseminated histoplasmosis. Disseminated histoplasmosis is frequently diagnosed in immunocompromised hosts. High risk of mortality dictates rapid diagnosis and treatment.

AIDS-Related Opportunistic Infections↗
PubMed2004

[Mandibular ameloblastic fibro-odontoma].

Ameloblastic fibro-odontoma is a rare and benign tumor. It usually affects young patients. This report describes the case of a ten year old child presenting an asymptomatic and slow-growing tumor located in the posterior region of the mandible. The course was normal and no recurrence was found after simple enucleation of the tumor.

Child↗
PubMed2004

Safety parameters for pulp temperature during selective ablation of caries by KTP laser in vitro.

OBJECTIVE: To define the optimal parameters of KTP laser irradiation during a selective caries removal. MATERIALS AND METHODS: Twelve decayed human teeth, recently extracted were used. Their root canals were prepared for insertion of a thermocouple probe into the pulp chamber. The demineralized tissues were colored by Acid Red 52 before proceeding to different conditions of irradiation. RESULTS: Pulpal temperature increases (below 3 degrees C) were found under the following parameters with 15 sec of continuous lasing: 400 mWatts, 0.10-msec pulse width, PRR <50 Hz for efficient caries removal. A resting time average of 70 sec was necessary to allow pulp temperature to get back to its baseline. CONCLUSION: KTP laser can be used safely and without any pulp over-heating under certain irradiation conditions.

Body Temperature↗
PubMed2003

[Prevention of postoperative bleeding in patients taking oral anticoagulants. Effects of tranexamic acid].

INTRODUCTION: We present a prospective clinical study on use of tranexamic acid mouthwashes in patients taking oral anticoagulants and who have to undergo minor ambulatory oral surgery, without modifying their anticoagulant therapy. MATERIAL AND METHODS: Forty patients (18 men and 22 females) aged from 42 to 81 were studied from April 2000 to December 2002. All patients were under the same anticoagulant, vitamin K antagonist, (Sintrom) for different pathologies. The anticoagulant therapy was not modified neither before nor after surgery. More than 70 oral procedures were carried out under local anesthesia. The International Normalized Ratio of prothrombin time (INR) was<=4. Tranexamic acid 5% (Exacyl) mouthwashes were prescribed during and after surgery. RESULTS: All the patients were followed up during 2 weeks after surgery. There were no postoperative bleedings. DISCUSSION: Use of tranexamic acid mouthwashes under a specific protocol is an efficient, reliable and economic method in preventing postoperative bleeding in patients under oral anticoagulant therapy.

Acenocoumarol↗
PubMed2000

Adsorption of peroxidase on titanium surfaces: A pilot study.

The present study demonstrates the in vitro and in vivo adsorption of peroxidase onto titanium surfaces. Titanium foils (mean +/- SEM: 365 +/- 2 mm(2), n = 114) were incubated during 30 min with lactoperoxidase (4 mg in 5 mL 100 mM phosphate buffer pH 7). After 15 washings by H(2)O, titanium foils were incubated with o-phenylenediamine (6 mg/mL) and H(2)O(2) (7 mM) during 30 min. The reaction was then stopped by the addition of HCI 1M and the absorbance of the liquid phase was read on a spectrophotometer at 492 nm. In vitro adsorbed lactoperoxidase onto titanium surfaces was 0.70 +/- 0.05 ng/mm(2) (mean +/- SEM, n = 30). X-ray photoelectron spectroscopy confirmed the incorporation of protein nitrogen onto titanium surfaces: the nitrogen atomic percentage increased from 0.9 +/- 0.3 to 12.7 +/- 0.2% (n = 3) and from 3.7 +/- 0.1 to 14.4 +/- 0. 4% (n = 5) when titanium foils were incubated in the lactoperoxidase solution during 30 min and 24 h respectively. In vivo, oral peroxidases adsorbed on titanium healing abutments from 0.01 to 0.58 ng/mm(2) (n = 19) after 2 weeks in the oral environment.

Adsorption↗
PubMed2000

[Expression of heat shock proteins in salivary gland tumors. Immunohistochemical study of HSP27, HSP70, HSP90, and HSP110: apropos of 50 cases].

Heat shock proteins (HSPs) are known to be increased in response to biological stress. Recently some authors described their presence in tumors. Our immunohistochemical investigations revealed the expression of HSP27, HSP70, HSP90 and HSP110 in most of benign tumors of salivary glands (33 cases). In the malignant tumors, the reaction was immunopositive for HSP70 and HSP90 in 13/17 cases; but HSP27 and HSP110 were only expressed in 5/17 cases. In conclusion HSPs were expressed less in malignant than in benign cells. These results suggest that the loss of some HSPs may be a possible sign of malignancy.

HSP110 Heat-Shock Proteins↗
PubMed2000

The soft tissue response to contaminated and cleaned titanium surfaces using CO2 laser, citric acid and hydrogen peroxide. An experimental study in the rat abdominal wall.

The soft tissue response to clinically retrieved and decontaminated cover screws was evaluated in a rat model. The cover screws were cleaned by using citric acid, sterile water, hydrogen peroxide and CO2 laser alone or with a combination of these. In addition, decontaminated but not cleaned and unused cover screws were used as negative and positive controls, respectively. After cleaning the cover screws were implanted in the abdominal wall of the rat for 6 weeks. The thickness of the fibrous capsule and the number of macrophages within the capsule were measured by means of light microscopical morphometry. As compared to the negative control, CO2 laser on dry surface, CO2 laser + hydrogen peroxide and the positive control had statistically significant thinner fibrous capsules. As compared to the positive, only laser alone resulted in a similar tissue response. It is concluded that CO2 laser used alone or in combination with hydrogen peroxide may be used clinically for sufficient decontamination of titanium surfaces.

Abdomen↗
PubMed1999

Temperature increases during surface decontamination of titanium implants using CO2 laser.

The purpose of the present in vitro investigation was to measure temperature changes at the implant surface when using pulsed CO2 laser in a simulated implant surface decontamination protocol. Six threaded titanium implants were placed in a fresh resected pig mandible. A 4 x 4 mm defect was created buccally to each implant in order to expose the implant head and approximately 5 threads. Temperature changes were monitored by two thermocouples placed near the dehiscence and at the apical part of the implant. Several setting combinations of the CO2 laser with regard to output power, pulse width, pulse repetition rate and irradiation time were tested on dry and wet (distilled water) surfaces. Only minor temperature increases were measured when lasing wet titanium surfaces, while the temperature at dry surfaces exceeded the proposed thresholds for bone damage at clinically relevant settings. It is concluded that the CO2 laser when used on a wet implant surface in a pulsed mode at 8 W/10 ms/20 hz during 5 s induces a temperature increase of less than 3 degrees C. This would minimize the risk of temperature induced tissue damage as a result of lasing implant surfaces.

Animals↗
PubMed1998

An XPS and SEM evaluation of six chemical and physical techniques for cleaning of contaminated titanium implants.

The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.

Air Abrasion, Dental↗
PubMed1997

[Temporomandibular joint prosthesis. A retrospective study from 1947].

Degenerative troubles of the temporo-mandibular joint constitute a major pathology for the maxillo-facial surgeon. While articular replacements have long been developed and used by orthopedic surgeons, none of these seem to give satisfaction in the TMJ. After a short historical and physiological recall, a number of techniques are described, together with a short evaluation of their use. In all 597 cases are reported, whilst an attempt at classification is made in the different types of prostheses used, ie interpositional, endo-osseous, extra-cortical, and prostheses designed for extensive reconstruction.

Alloys↗
PubMed1996

[Oromandibular dystonia and botulinum toxins].

The authors describe the Meige's Syndrome also known as blepharospasm or mandibulo-oral dystonia. This Syndrome rather known by Neurologists and Ophthalmologists than by Stomatologists actually benefits by a specific treatment based on botulin toxins.

Aged↗
PubMed1996

[The frequency of various types of disk displacement and its relation to occlusion].

The aim of this study is to observe the frequency of the different types of disc displacements (d.d.) of the TMJ (ATM) and to evaluate if these types are related or not with malocclusions. One hundred patients and 13 asymtomatic volunteers underwent full clinic examination. sagittal MRI (mouth open and closed) and coronal MRI (mouth closed). The different types of disc displacements were noted and cumulated in frequency and in relation with several occlusal criteria. Unlike the general opinion stating that the antero-medial d.d. (d.d. a-m) are the most frequent amongst the internal derangements, the result of this study reveals that the antero-lateral d.d. (d.d. a-l) are more frequent amongst the patients (35.1%) and the asymptomatic volunteers in general and particularly in view of a malocclusion (exagerated anterior overlapping and posterior cross bite). The study gives rise to the question of the etiology of a antero-lateral d.d. and sets back the hypothesis of the lateral pterygoid muscle fundamental role in the disc displacements.

Adolescent↗
PubMed1996

[Titanium condylar abutment: the contribution of 3D computed tomography].

Various techniques have been described in the treatment of recurrent TMJ dislocations amongst which, joint arresters form a prominent part. We describe a new type of bio-integrable joint stop, custom made with 3D-CT help, which alleviates the two main drawbacks of the technique: lack of retention through insufficient extension, and secondary mobilization of the stop. Two cases are reported, amounting to four stops with satisfactory two years follow-up.

Aged↗
PubMed1991

[The use of a polyglycolic acid membrane in the reconstruction of the orbital floor and in loss of bone substance in the maxillofacial region].

The use of a new alloplastic biodegradable implant called BIOFIX made of polyglycolate is described. We used it to cover bone defects in maxillo-facial surgery, principally for orbital floor restoration and frontal sinus repair, with very good results. It is an excellent material of temporary support and guidance during the healing period and new bone formation. However, it will be necessary to wait for the results of a multicentric european study to confirm its superiority in maxillofacial surgery.

Adult↗