Biomedical subjects

M Avci

Publications and source records attributed to M Avci.

9 recordsLinked to original sources

PubMed2004

Long-term follow-up of otherwise healthy term infants with marked hyperbilirubinaemia: should the limits of exchange transfusion be changed in Turkey?

AIM: To evaluate prospectively non-haemolytic term infants with marked hyperbilirubinaemia treated by phototherapy only for evidence of bilirubin toxicity at 2-6 y of age, and to determine the suitability for Turkish children of the exchange transfusion limits recently reported by the American Academy of Pediatrics. METHODS: The study group included a total of 30 children, aged 2-6 y, who had developed marked hyperbilirubinaemia (20-24 mg dl(-1), 342-410 micromol l(-1)) during the newborn period (gestational age >37 wk, birthweight >2500 g) and were treated without exchange transfusion because intensive phototherapy, instituted during the preparations for exchange transfusion, was successful in decreasing their serum bilirubin levels. The control group consisted of 30 children of the same age group without clinical jaundice in the newborn period. Physical and neurological examinations, brainstem auditory-evoked potentials (BAEPs) and developmental tests for Turkish children were performed in both the study and control children. RESULTS: There was no difference between the groups with regard to mean BAEP latencies and developmental scores. None of the infants had hearing loss, developmental delay or abnormal neurological findings. CONCLUSION: The results suggest that successful intensive phototherapy without exchange transfusion in otherwise healthy term newborn infants with marked hyperbilirubinaemia (20-24 mg dl(-1), 342-410 micromol l(-1)) might not increase the risk of bilirubin brain injury and that the conventional limit of 20 mg dl(-1) (342 micromol l(-1)) could be changed to 22-24 mg dl(-1) (376-410 micromol l(-1)) for healthy term infants in Turkey. These limits, however, address only infants who do not have haemolytic disease, and the data are not sufficient to draw conclusions on the safety of even higher bilirubin levels (i.e. >24 mg dl(-1), 410 micromol l(-1)) in this population.

Bilirubin↗

PubMed1991

Measuring pressures under maxillary complete dentures during swallowing at various occlusal vertical dimensions. Part I: A new hydraulic pressure measuring system.

This study presents a "closed" hydraulic pressure measuring system capable of measuring pressures at the denture base-mucosal surface interface. Two pressure receptors are made in the denture base of a maxillary denture. The receptors are covered with a flexible membrane and are connected to pressure transducers by means of polyethylene tubes. The transducers convert the hydraulic pressures coming from the receptors to electrical signals. A polygraph is used to amplify and record the electrical signals. It is assumed that complete contact can be obtained between mucosa and the flexible membranes, which is the advantage of this system.

Calibration↗

PubMed1991

Measuring pressures under maxillary complete dentures during swallowing at various occlusal vertical dimensions. Part II: Swallowing pressures.

The swallowing pressures of seven edentulous patients were measured at seven different occlusal vertical dimensions. In addition, the projection surfaces of the maxillary dentures were measured and the forces on the maxillary denture-bearing surfaces were calculated. The swallowing pressures were measured from the maxillary denture base-mucosal surface interface by means of a "closed" hydraulic system described in Part I. The mean values of swallowing pressures increased from 7.95 +/- 2.25 to 10.18 +/- 3.42 kPa as the occlusal vertical dimension increased, and then decreased to 8.38 +/- 3.55 kPa at the highest occlusal vertical dimension. The results of a two-way analysis of variance showed significant differences of swallowing pressures between patients (p less than 0.001) and between different occlusal vertical dimensions (p less than 0.001). The projection surfaces of maxillary denture bases were measured and ranged from 21.65 to 27.78 cm2. The forces exerted on these surfaces during swallowing were also calculated and ranged from 12.5 to 47.7 N.

Adult↗

PubMed1990

Monopoly coating on acrylic resin surfaces: a bacteriologic study.

In an open bulb of a buccal flange obturator, it is almost impossible to polish the inner surface of the bulb. Because it cannot be cleaned easily, oral and nasal secretions lead to odors. To obtain a smoother surface, it is suggested that monopoly be painted on the unpolished surface of the open bulb. In this study, the effect of a monopoly coating on bacteria retention and washability of acrylic resin surfaces was investigated. Coated and uncoated acrylic resin samples were prepared and both were contaminated with Escherichia coli. After standard washing, the remaining viable E. coli colonies were counted. The statistical results showed that the difference in the number of E. coli colonies between coated and uncoated groups was highly significant (p less than 0.001). It was suggested that monopoly should be applied to the acrylic resin surfaces where mechanical polishing cannot be done.

Acrylic Resins↗

PubMed1990

[Speech and prostheses for congenital cleft palate patients in adulthood].

The surgical treatment should be preferred for cleft palate patients in childhood. However, a prosthesis is favorable for some adult patients. The construction of prostheses are rather complicated for patients who require pharyngeal speech aid in addition to anterior prosthesis. Sound prosthodontic rules are valid in designing a speech aid prostheses. Often stability and retention increase is required for these prostheses. Furthermore, the velar and the pharyngeal sections should not interfere with the muscular activity of pharynx and/or tongue movements during speech and deglutition. This article describes the prosthodontic habilitation of congenital cleft palate patients by means of pharyngeal speech aid prosthesis.

Adult↗

PubMed1990

[Non-precious alloys for ceramo-metal restorations].

Rapidly increasing gold prices hastened the widespread use of non-precious alloys for ceramo-metal restorations. Especially base-metal alloys has been considerably improved and has shown much progress after a long period of study and use. Among these alloys, nickel-chromium and cobalt-chromium alloys are quite popular in our country, like in Europe and in U.S.A. Their physical properties are superior than noble-metal alloys which are used for ceramo-metal restorations. However, some questions arise in the dental literature about their corrosion resistance, biocompatibility and porcelain bonding properties. This article reviews the constituents, physical properties, porcelain bonding, biocompatibility and corrosion resistance of nickel-chromium and cobalt-chromium alloys.

Biocompatible Materials↗

PubMedDate not supplied

An analysis of edentulous maxillary arch width and palatal height.

This study involving 500 edentulous patients (250 males, 250 females) was undertaken to introduce a dimensionless factor termed the "palatal height ratio," defined as the ratio of the width of the edentulous maxillary arch to the height of the palate. The authors categorized the height, width, and anteroposterior dimensions of the edentulous maxillae. Measurements were made on diagnostic casts at five defined points. The difference between males and females was statistically analyzed and the variables were categorized. The results of this study may be helpful for a better standardization of the same variables in future studies.

Analysis of Variance↗

PubMedDate not supplied

Efficacy of the intramobile connector in implant tooth-supported fixed prostheses: an experimental stress analysis.

An experimental model was designed to evaluate the effects of the intramobile connector in reducing stress concentration in an IMZ implant in fixed connection with a natural tooth abutment. The study analyzed the stresses produced at the cervical level of the implant when the superstructure arm was deflected within the limits of physiologic mobility under static axial loads. The designed experimental model was sensitive to changes in strain data with the applied loads and different internal elements. The intramobile connector resilient component reduced strain up to 60% compared to the rigid internal element.

Dental Abutments↗

PubMedDate not supplied

An experimental analysis of the stresses on the implant in an implant-tooth-supported prosthesis: a technical note.

When a natural tooth connected to an implant abutment by a framework is displaced within physiologic limits under functional loads, the superstructure acts as a cantilever moment arm and the implant is loaded additionally during that moment effect. The effects of a deflecting support connected to an IMZ implant, with either the IMC resilient or the titanium rigid element, were evaluated through an experimental model. The strain values measured when the moment arm was not allowed to deflect were only 30% lower than the strains measured when it was deflected within the limits of physiologic tooth mobility. The IMC was effective and achieved a reduction in the cervical strains up to 60% when compared with the rigid connector.

Bite Force↗