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Biomedical subjects

I Molyvdas

Publications and source records attributed to I Molyvdas.

13 recordsLinked to original sources
PubMed2004

Healing of a radiolucent periradicular lesion with periradicular radiopacity.

Periradicular radiopacities that reveal the existence of sclerotic bone are less common than periradicular radiolucencies. Replacement of a radiolucent periradicular area by sclerotic bone after endodontic treatment is not very often reported and may be confused with condensing osteitis. An unusual case is presented of sclerotic bone formation after endodontic treatment of a first mandibular molar with initial diagnosis of apical periodontitis.

Adolescent↗
PubMed1999

3D computer-aided reconstruction of six teeth with morphological abnormalities.

AIM: The purpose of this study was the 3D reconstruction of six teeth with morphological peculiarities using serial cross-sections. METHODOLOGY: All the teeth were put in 3% NaOCl solution after extraction, washed under running water and air-dried. They were then embedded in a two-phase polyester resin and serial cross-sections were produced from each specimen using a special microtome. The thickness of each section was 0.75 mm. Each section was photographed under a stereoscopic microscope. The photographs of the cross-sections were digitized and the external contours of the teeth and the root-canal outline were annotated for each section. Semiautomatic alignment of the sections was achieved with the use of image-processing techniques. Three dimensional surface representation was used in this project to reconstruct the inner and outer surface of the teeth. RESULTS: The results showed in detail the internal morphology of the teeth under investigation. The fact that it was possible to observe and study these teeth from different angles is one of the main advantages of this method as the three dimensional anatomy of these teeth was apparent. CONCLUSIONS: The 3D reconstructing method is a useful tool for the study of the morphology of the teeth.

Anatomy, Cross-Sectional↗
PubMed1997

3D reconstruction of two C-shape mandibular molars.

Two mandibular second molars, with an indication of C-shape morphology were processed for 3-D reconstruction. After serial cross sectioning, photographs of the sections were digitized and by using surface representation, 3D reconstruction was achieved. The first molar as the 3D reconstruction showed was single rooted with one C-shaped root canal with two foramens, while the second one was double rooted with two root canals, one C-shaped and one thin, having a common foramen.

Anatomy, Cross-Sectional↗
PubMed1997

Computerized 3-D reconstruction of two "double teeth".

"Double teeth" is a root malformation in the dentition and the purpose of this study was to reconstruct three-dimensionally the external and internal morphology of two "double teeth". The first set of "double teeth" was formed by the conjunction of a mandibular molar and a premolar, and the second by a conjunction of a maxillary molar and a supernumerary tooth. The process of 3-D reconstruction included serial cross-sectioning, photographs of the sections, digitization of the photographs, extraction of the boundaries of interest for each section, surface representation using triangulation and, finally, surface rendering using photorealistic effects. The resulting three-dimensional representations of the two teeth helped us visualize their external and internal anatomy. The results showed: a) in the first case, fusion of the radical and coronal dentin, as well as fusion of the pulp chambers; and b) in the second case, fusion only of the radical dentin and the pulp chambers.

Anatomy, Cross-Sectional↗
PubMed1992

Sealing ability of sectional injection thermoplasticized gutta-percha technique with varying distance between needle tip and apical foramen.

The purpose of this investigation was to evaluate the influence of the distance of the needle tip from the apical foramen on the apical seal and the length control of the root filling material when thermoplasticized gutta-percha is injected using a sectional injection technique. Ninety-nine human single-rooted mandibular incisors and permanent premolars with straight canals were divided into three equal Groups A, B and C. In Group A the teeth had relatively the wider root canal, in Group C the narrowest, while in Group B root canal size was intermediate. The root canals of all teeth were prepared with a step-back technique. Roots of Group A were instrumented to a Size 70 4 mm short of the working length, while roots of Groups B and C to a Size 70 6 mm and 8 mm short of the working length, respectively. The teeth of all groups were covered with aluminium foil and embedded in acrylic blocks. After the placement of sealer (Roth 811) the root canals of all teeth were obturated with injection-molded thermoplasticized gutta-percha using a three-stage sectional technique. The roots remained in India ink for three days and then cleared by successive immersion in nitric acid, ascending grades of alcohol and finally in xylene. The linear dye penetration and the linear apical underextentionion of the root canal filling were measured by two independent examiners under a stereo microscope. There was no significant difference in the linear dye leakage between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Bicuspid↗
PubMed1990

Apical placement of needle tip with an injection-thermoplasticized gutta-percha technique for root canal obturation.

It is recommended that when injection-thermoplasticized gutta-percha is used as the obturation technique, the root canal space should be prepared in such a way that the 23-gauge injection needle tip can be placed at a distance 3 to 5 mm short of the working length. In this study the apical seal and extent of gutta-percha were evaluated when the 23-gauge tip was placed at a distance 4 mm, 6 mm, and 8 mm short of the working length. Ninety-nine human single-rooted mandibular incisors and premolars divided into 3 equal groups were used. Their crowns were separated at the cementoenamel junction and their roots were stored in sodium hypochlorite for 1 week. The roots were then instrumented from size 20 at the working length to size 70:4 mm short of the working length in group A, 6 mm in group B, and 8 mm in group C. Following instrumentation, 3 randomly selected roots of each group were used as control. The remaining 30 roots of each group were covered with aluminium foil and embedded in acrylic blocks. The root canals were then dried, coated with sealer (Roth 811) and obturated by injection of thermoplasticized gutta-percha using the single-phase technique. Vertical condensation followed. The roots were immersed in dye for 3 days and then demineralized, dehydrated and cleared in xylene. Measurements of linear dye penetration for the apical seal and for underextension were done by 2 independent examiners under a stereomicroscope. The results of this study showed no statistically significant difference in leakage between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Coloring Agents↗
PubMed1990

[Clinical and roentgenographic follow-up study of tricalcium phosphate ceramic in bone cavities of apicoectomized teeth].

In 8 patients aged 16-30 years with periapical osteolytic areas (1,5-2 cm) of anterior maxillary and mandibular teeth root canal treatment and apicoectomy were performed. The bone cavity following apicoectomy was filled with tricalcium phosphate ceramic (small spheres diameter more than 1 mm and less than 2 mm). Patients were re-examined the following day as well as on the 4th, 7th, and 15th postoperative day. Follow up at the 1, 3, 6, 12 and 18 postoperative months did not show any problem of the healed wood nor any rejection of the implanted material. Radiographically, some resorption of the material as well as new bone formation were noticed 12 and 18 month after the operation.

Adolescent↗
PubMed1989

Periodontal tissue reactions following root canal obturation with an injection-thermoplasticized gutta-percha technique.

The thermoplasticized gutta-percha obturation technique is a relatively recent development in endodontics. In this study we evaluated the possible effects of heat transmitted to the periodontal tissues when the Obtura root canal filling device was used in dog teeth. Two 8-month-old beagle dogs were used; 56 root canals of 36 teeth (maxillary incisors and first, second and third premolars of both jaws) were divided into two groups. In Group A 26 root canals were obturated with the lateral condensation technique, while in Group B 30 root canals were obturated using the Obtura device, without sealer. Observation periods were 1, 3, 7, 28 and 56 days. After routine laboratory procedures, hematoxylin-eosin stained sections were examined under a light microscope. In this experimental model the thermoplasticized gutta-percha obturation technique caused a periapical inflammatory reaction at all observation periods. Inflammatory reaction and destruction of collagen fibers were localized in the area around the apical delta, while the alveolar founding bone, the roots of the teeth and the periodontal ligament at the side of the root surfaces remained normal.

Animals↗
PubMed1988

The tissue reactions after capping of dog teeth with calcium hydroxide experimentally crammed into the pulp space.

The pulps of 48 permanent dog teeth, incisors and canines, were evaluated histopathologically after capping treatment with pure calcium hydroxide placed by two methods: the experimental method, in which the calcium hydroxide was crammed into the pulpal space via the exposure site, and the usual method of direct pulp capping (controls). The results were recorded after periods of 2, 15, and 69 days. The healing process with hard-tissue formation was more evident in the experimentally capped teeth, despite the fact that pulpal necrosis occurred in a higher proportion of these teeth after use of this method of placement of the calcium hydroxide.

Animals↗
PubMed1987

The calcifying potential of the pulpless open apex in untreated teeth of dogs.

Pulpectomies were performed on 22 immature premolars (44 root canals) from 3 young dogs. The root canals remained unfilled and the access cavities were sealed with amalgam. After observation periods of 7, 15 and 45 days, the apical and periapical regions of the teeth were evaluated histopathologically. Hard tissue formation was found in 32 open apices. The apical calcification occurred only in specimens with intracanal vital tissue. The severity of periapical inflammatory response had no relationship to the presence or absence of apical hard tissue formation. No apical bridging was seen in specimens where epithelial proliferation had occurred.

Animals↗