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Biomedical subjects

M Lorenzoni

Publications and source records attributed to M Lorenzoni.

16 recordsLinked to original sources
PubMed2003

The effect of three different periodontal pre-treatment procedures on the success of telescopic removable partial dentures.

In this prospective study, 120 teeth consisting of maxillary and mandibular canines and premolars were divided into three groups each containing 40 teeth. The teeth were assigned randomly in quadrants to three different periodontal treatment protocols. The first group was treated with professional prophylaxis only. The second group received additional deep scaling. With the third group, additional surgical periodontal flap surgery and scaling was performed. Both papillary bleeding index (PBI) and probing depth (PD) were evaluated before, during and after treatment. During the subsequent prosthetic treatment phase all teeth were then used as telescope abutments supporting a removable prosthesis. The documentation of the attachment level (AL) was then used as a clinical parameter. One year after the incorporation of telescopic removable partial dentures (RPDs), PD, PBI and AL were again evaluated. The resulting periodontal parameters were compared between the different groups using the general linear model (GLM) repeated measures and the Kruskal-Wallis test for non-parametric variables. Differences within the three treatment groups were determined using the t-test, e.g. the Wilcoxon test for dependent variables (P < 0.05). A significant decrease in inflammatory indices (PBI) was found for all types of periodontal treatment (P < 0.03 for all groups). Additionally, the reduction in PD was significant for all of the three groups (P < 0.001 for all groups). The greatest reduction in PD was observed in the group in which a surgical approach was used. Evaluation of the attachment level after the incorporation of the telescopic RPDs showed that tooth position did not influence the periodontal prognosis and that the use of telescopic RPDs exerted no ascertainable negative influence on the periodontium of the abutment teeth.

Adult↗
PubMed2001

A modified technique of harvesting tibial cancellous bone and its use for sinus grafting.

Autogenous bone is the gold standard graft for sinus augmentation. The harvest of autogenous bone grafts from intraoral sites does often not provide sufficient bone volume and quality. A modified technique of harvesting a tibial cancellous graft is presented. With a micro-bone saw, a bony lid is prepared at the medial condyle of the tibia. The lid stays attached to the tendinous pes anserinus. Following the harvest, the lid is repositioned accurately. This method offers some distinct advantages. A sufficient amount of biologically highly valuable cancellous bone may be harvested for sinus grafting and possibly other surgeries with bone augmentation. The procedure may be performed under local anaesthesia and does not require hospitalisation. Neither major complications nor serious postoperative morbidity were observed.

Alveolar Ridge Augmentation↗
PubMed2001

A comparison of the muscular relaxation effect of TENS and EMG-biofeedback in patients with bruxism.

This study investigated effects of electromyographic (EMG) biofeedback (BFB) and transcutaneous electrical neuromuscular stimulation (TENS) on the EMG activity of the masticatory muscles and skin conductance level (SCL) of patients, suffering from myofacial pain syndrome. In the course of the investigation, EMG activity as well as the SCL was measured after a 20 min BFB or, respectively, after a myomonitor session in 20 patients and pre- and post-treatment values were compared. Results showed tendencies of decreased mean-EMG levels for both groups after the treatment sessions, with higher EMG values for the myomonitor group. There was no indication of a significant decrease in mean EMG levels over the sessions. Furthermore, an increase of the SCL during the period of treatment was observed for both groups in session I and II, while session III produced nearly stable values. No existing correlations for changes in SCL and EMG-activity could be established.

Adult↗
PubMed2000

The function of tensor veli palatini muscles in patients with aural symptoms and temporomandibular disorder. An EMG study.

This preliminary study investigated Myrhaug's neuromuscular hypothesis by means of audiological and electromyographic assessment. After a clinical examination of the TMJ system, the activity of the tensor veli palatini muscles in the state of rest and during swallowing was investigated in 16 patients with the help of an EMG recording, and the tube-opening function was evaluated endoscopically. Results showed that 6.25% of the patients suffered from mild joint-dysfunction (group I), 81.25% from a moderate dysfunction (group II), and 12.5% from severe dysfunction (group III). Although five patients suffered from tinnitus and 11 from fullness in the ear, both the audio- and tympanogram performed on 15 patients displayed normal recordings. Only one patient suffered from moderate sensorineural hearing loss. In the EMG recording, 11 of the 16 subjects displayed normal EMG patterns in state of rest and during swallowing contraction. In two cases, abnormal EMG recordings were obtained due to incorrect insertion of the EMG needle. The study's results indicate that spasm in the masticatory muscles of TMJ patients neither seems to cause reflex spasm of the tensor palatini muscles nor to effect significant alterations in Eustachian tube function.

Adult↗
PubMed2000

Comparison of the transfer precision of three different impression materials in combination with transfer caps for the Frialit-2 system.

Transfer of the precise position of implants to a master cast is a prerequisite for accurate and passive fit of the superstructure. Implants lack the mobility of natural teeth and, therefore, inaccurate frameworks result in stress within the mechanical parts and the implant-bone interface. Various impression methods have been described to achieve accurate reproduction of the intra-oral relation of the implants. The aim of this experimental study was to compare three different impression materials (polyether, polyvinyl siloxane, hydrocolloid) with the Frialit(R)-2 system and with the indirect technique. In addition, the use of transfer caps (TCs) to improve transfer precision was tested with all three materials. All measurements were performed using a three-dimensional (3D) co-ordinate measuring machine that is capable of locating points in space and calculating the relative distortions as angles of tilt (rot-XY, rot-XZ, rot-YZ) and 3D displacement. The results suggest that addition-silicone (a-silicone) and polyether are the materials of choice for implant transfer procedures. The use of TCs resulted in a significantly reduced rotation in the XY-plane but did not improve the absolute 3D displacement. A-silicone with the use of TCs proved to be most precise. Comparison between polyether and polyvinyl siloxane showed significant differences in the XY-rotation and the 3D displacement in favour of the silicone. Because the mean distortions between the original model and the master casts were about 100 microm, absolutely precise fit may be unattainable owing to the physical properties of the materials. Further studies will have to evaluate the amount of tolerable stress at the implant-bone interface.

Alginates↗
PubMed2000

[The pregnant patient in dental care. Survey results and therapeutic guidelines].

In a telephone survey using a standardized questionnaire, 78 resident dentists in Germany, Switzerland and Austria were interviewed with respect to several aspects of the dental treatment of pregnant women. Only 58% of the interviewees decided clearly in favour of local anaesthetics, 59% supported the use of analgesics, 70% a possible antibiotic therapy and 33% a radiological examination during pregnancy. In addition, according to references in the specialist literature guidelines for the dental treatment, drug therapy and radiological diagnosis of pregnant women are presented. The local anaesthetics should have a high plasma protein bonding (articain, bupivacain, etidocain) and a minimum adrenaline concentration. Paracetamol is the analgesic of choice. If an antibiotic treatment is required, penicillin, cephalosporin and erythromycin are recommended. In particular during the first three-month period, radiological examinations should be restricted to the absolute minimum and performed only if no reasonable alternative is available, even though the radiological burden on the foetus falls 500,000 times short of the limit value of 50 mgray (5 rad) in the case of a microradiogram, and 50,000 times short of the limit value in the case of an orthopantomogram.

Anesthesia, Dental↗
PubMed2000

Retrospective analysis of Frialit-2 implants in the augmented sinus.

The aim of the present study was to investigate clinical and radiographic data of patients treated with implants in the posterior maxilla in combination with sinus augmentation. Study parameters included Periotest values, radiographic analysis, and survival/success rates up to 5 years. Clinical and radiographic criteria resulted in a success rate of 92.7% for sinus implants. Radiographically, the sinus implants showed a mean coronal bone loss of 0.5 mm at 6 months and 1.2 mm at 48 months. The results showed stable periimplant parameters for sinus implants during the observation period of 5 years. The success rates showed no significant differences regarding different implant-supported treatment options for the posterior maxillary region.

Adult↗
PubMed2000

Residual dentin thickness after 1.2-mm shoulder preparation for Cerec crowns.

Since the introduction of crown software for Cerec, it has been possible to produce full-ceramic crown restorations. Despite the excellent material quality of industrially made ceramic blocks and the good clinical long-term success of these ceramics in inlay- and onlay preparations, extended preparation with high loss of dental tissue is incident to crown restorations, which may endanger the vitality of the respective tooth. The aim of this experimental study was to determine the residual dentin thickness after preparation of an extended circular shoulder in the molar and premolar region. On extracted human molars and premolars, 1.2-mm-wide circular shoulders with rounded inner edges were prepared, and the thickness of the residual dentin wall was measured under a microscope. Using this preparation method, it was found that only the group of maxillary molars showed an average residual dentin thickness of more than 0.7 mm.

Bicuspid↗
PubMed1999

Fabricating auricular prostheses using three-dimensional soft tissue models.

This article describes a method for fabricating an auricular prosthesis. This procedure uses the contours of the soft tissue surface from computerized tomography scans to fabricate a computer-generated, side-inverted 3-dimensional soft tissue model from a solid block of polyurethane using an Endoplan milling machine. The resultant 3-dimensional soft tissue model can then be used as the basis for a wax sculpture. This procedure facilitates the planning of the prosthesis; symmetrical modeling, especially for large, hemifacial defects; and the impression, which can be made on the model itself.

Acrylic Resins↗
PubMed1999

Guided bone regeneration with barrier membranes--a clinical and radiographic follow-up study after 24 months.

The present follow-up study evaluated clinical and radiographic parameters of dental implants placed with simultaneous guided bone regeneration with expanded polytetrafluoroethylene (e-PTFE) membranes. All implants were functioning well 24 months after insertion. In all, 63 patients with a total of 91 e-PTFE-augmented implants were integrated in a regular maintenance protocol. Modified periodontal data of 85 implants in 59 patients were recorded at 24 months and indicated no difference to implants placed in sufficient pristine bone. The mean plaque score (mplI) was 0.29, 74% of the sites showed no plaque. The sulcular probing depth ranged from 1 to 7 mm with a mean of 2.6 mm (SD +/- 0.8). Of the sites 96.5% were < or = 4 mm deep, in 49% of them probing resulted in bleeding. Periotest values 6 and 24 months (mean: -3.4 and -3.4) after placement revealed stable peri-implant conditions and sustained osseointegration. The radiographic evaluation performed 6, 12 and 24 months post insertion yielded a mean bone loss of 0.93, 1.36 and 1.51 mm ranging from 0 to 4 mm. The short-term results of our clinical study demonstrated stable peri-implant conditions 2 years after membrane-protected osseous regeneration. The newly formed bone seemed to be able to withstand functional loading in a predictable manner after 18 months.

Adult↗
PubMed1999

Contemporary treatment of the resorbed avulsed tooth: a case report.

This report describes the treatment sequence after traumatic loss of a maxillary central incisor in a 15-year-old patient. Following extraoral root canal treatment and initially successful replantation, the case presented 9 years later with complete root resorption. After augmentation with an autologous mandibular corticocancellous graft, a dental implant was placed in a second stage surgery. The case highlights the challenge facing clinicians in providing the appropriate standard of care for today's treatment options.

Adolescent↗
PubMed1992

Growth stimulation of a human colorectal carcinoma cell line by interleukin-1 and -6 and antagonistic effects of transforming growth factor beta 1.

We analysed the effect of interleukin-1 (IL-1), IL-6 and transforming growth factor beta 1 (TGF beta 1) on the growth of a panel of eight colorectal carcinoma cell lines. IL-1 stimulated growth of two lines (LS411N and LS1034) up to 20-fold and IL-6 enhanced proliferation of LS1034 more than 5-fold. Both cytokines also augmented colony-formation of LS1034 in methylcellulose. Under both growth conditions IL-1 was the most potent stimulator. However, the addition of IL-6 to IL-1 synergistically enhanced proliferation of LS1034 in monolayer culture and additively augmented the number of colonies formed in methylcellulose. Furthermore, TGF beta 1 strongly reduced the growth rate of LS1034. Low amounts of TGF beta 1 markedly inhibited the response of LS1034 to IL-1 and totally abrogated proliferation induced by IL-6. We conclude that different cytokines can provide distinct signals for the regulation of growth of colorectal carcinoma cells.

Cell Division↗
PubMed1991

[Caries status and periodontal health in 6- to 10-year old elementary school children in Graz compared to Swiss, Swedish and WHO principles].

In a complete survey, 7500 primary pupils in Graz aged between six and ten years were examined for caries and periodontal health. Comparison with the DMF-T values of primary school pupils in Switzerland and Sweden indicated that considerable efforts are required in Austria if preventive dental health education is to achieve the standard status it has enjoyed for years in the other countries mentioned.

Austria↗
PubMedDate not supplied

Treatment of peri-implant defects with guided bone regeneration: a comparative clinical study with various membranes and bone grafts.

In this clinical study, a bioabsorbable membrane (Biofix) and two augmentation membranes made of expanded polytetrafluoroethylene (Gore-Tex) were tested for their osteopromotive potential. Forty-six implants were augmented with Gore-Tex membranes, 45 implants with titanium-reinforced Gore-Tex membranes, and 38 peri-implant defects with a resorbable polyglycolid membrane (Biofix). Autogenous bone (n = 85) and bovine bone matrix (Bio-Oss, n = 16) were used as filling materials beneath membranes. The results showed that bone repair is significantly improved by the use of membrane techniques. The average rate of bone regeneration with non-resorbable membranes was 84% (GTAM) and 81% (TR-GTAM). The use of Biofix membranes resulted in an average bone gain of 60%. The differences in efficacy established for the three types of membranes were found to be statistically significant (P < .001). Barrier membranes represent a valid technique for the treatment of peri-implant defects. Clinical and histologic results showed that Bio-Oss is an osteoconductive scaffold that promotes new bone formation.

Absorbable Implants↗