Prospective assessment of post-extraction gingival closure with bone substitute and calcium sulphate.

INTRODUCTION: The closure of post extraction gingival defects has not been studied in depth, although their achievement is of great importance in certain situations, such as prior to radiotherapy treatment in patients with oral cancer. The aim of this study is to assess the influence of bone substitutes on the time of closure of post extraction gingival defects. MATERIALS AND METHODS: 22 patients underwent two symmetrical dental extractions. Using a split mouth model, with random assignment to one or other group, one was considered a control group (no filling with any type of material post extraction), whereas the other was considered the experimental group (filling with bone substitute and calcium sulphate post extraction). Gingival closure and healing were assessed in the first group at 2, 3, 4 and 6 weeks after extraction. RESULTS: No differences were seen between both groups in gingival health. Gingival closure was greater and faster in the experimental group than in the control group, and was statistically significant in the first and second week after extraction (1st week, control: 19.63 mm(2) +/- 2.52--experimental: 11.76 mm(2) +/- 2.40 - p < 0.05) (2nd week, control: 15.09 mm(2) +/- 2.77--experimental: 7.98 mm(2) +/- 1.99 - p < 0.05), although these differences evened out during subsequent periods. No medical accidents were seen and tolerance to treatment was good in both groups. DISCUSSION: According to our data, the use of filling material allows a faster initial gingival closure of the socket post extraction. However, we must assess the cost of intervention, with the aim of applying it in situations in which it may be of significant advantage (for example, patients that will undergo radiotherapy treatment), or in cases in which the use of these materials is justified due to other reasons in addition to the one mentioned (such as maintenance of bone crest architecture for implant restoration).

Transmigration of impacted lower canine. Case report and review of literature.

Retention, that is, a permanent tooth which is unerupted more than a year after the normal age of eruption, is a relatively rare event, except in the case of the third molars and the upper canines. Transmigration is defined as the phenomenon of more than half an unerupted impacted tooth crossing the midline. We report the clinical case of a twenty-year-old patient presenting transmigration of the lower left canine, with a type 4 transmigration pattern (Mupparapu). Likewise, we carried out a review of the literature of the cases that have been published on transmigration, updating the main aspects of this pathology.

Intra-alveolar chlorhexidine gel for the prevention of dry socket in mandibular third molar surgery. A pilot study.

PURPOSE: Chlorhexidine is a good prophylactic agent for post-extraction dry socket alveolitis. The bio-adhesive 0.2% chlorhexidine gel could improve this action since its intra-alveolar positioning would allow a more direct action on the alveolus and more prolonged action of the medication. MATERIALS AND METHOD: We present a single blind, randomised study on 30 patients to evaluate the efficacy of the bio-adhesive 0.2% chlorhexidine gel, placed only once within the alveolus, on the reduction of the incidence of impacted third molar post-extraction dry socket alveolitis and its post-operative effects on patients. RESULTS: A reduction of 42.65% in the occurrence of alveolitis and a more favourable post-operative period in the experimental group was observed. In the control group, the appearance of alveolitis was 30.76% opposite to 17.64 % in the experimental group. CONCLUSIONS: The bio-adhesive 0.2% chlorhexidine gel, applied only once after the extraction of impacted third molars, seems to be an appropriate option for the reduction of alveolitis. It improves the buccal aperture and oedema in the post-operative period, although further double blind studies with larger samples are necessary.

Rescue surgery (surgical repositioning) of impacted lower second molars.

The impaction of lower second molars, given that its incidence is 0.03 to 0.21%, is a rare complication in tooth eruption. It has been detected more often in unilateral form than bilateral and is more common in the mandible than in the maxillary. It has a slight predilection for males, and mesial inclination is more usual. A wide variety of therapeutic approaches have been published, basically referring to surgical techniques, independent or complemented by means of orthodontic technical aids, with the aim of placing the tooth in the correct position, and which are encompassed under the concept of surgical rescue. In cases resolved with repositioning of an impacted tooth, prophylactic root extraction has been proposed as obligatory. We present a case of a 12 and a half year old patient referred to the University of Seville due to non-eruption of the left lower second molar. The patient was referred by her orthodontist, who detected the impaction before starting orthodontic treatment. The orthodontist requested that, if it was possible, we did not extract the root of the third molar, because its eruption would be feasible in the future (there would be sufficient space in the arch). The spaces available were measured and we decided to attempt the repositioning of the impacted tooth without extracting the root of the wisdom tooth, which was carried out successfully.

Mechanical behavior of single-layer ceramized zirconia abutments for dental implant prosthetic rehabilitation.

OBJECTIVES: This study was undertaken to characterize the mechanical response of bare (as-received) and single-layer ceramized zirconia abutments with both internal and external connections that have been developed to enhanced aesthetic restorations. MATERIAL AND METHODS: Sixteen zirconia implant abutments (ZiReal Post®, Biomet 3i, USA) with internal and external connections have been analyzed. Half of the specimens were coated with a 0.5mm-thick layer of a low-fusing fluroapatite ceramic. Mechanical tests were carried out under static (constant cross-head speed of 1mm/min until fracture) and dynamic (between 100 and 400N at a frequency of 1Hz) loading conditions. The failure location was identified by electron microscopy. The removal torque of the retaining screws after testing was also evaluated. RESULTS: The average fracture strength was above 300N for all the abutments, regardless of connection geometry and coating. In most of the cases (94%), failure occurred by abutment fracture. No significant differences were observed either in fatigue behavior and removal torque between the different abutment groups. CONCLUSIONS: Mechanical behavior of Zireal zirconia abutments is independent of the type of internal/external connection and the presence/absence of ceramic coating. This may be clinically valuable in dental rehabilitation to improve the aesthetic outcome of zirconia-based dental implant systems. Key words:Dental implant, zirconia, ceramic structure, mechanical properties.

Zirconia implant abutments: microstructural analysis.

PURPOSE: Yttria-stabilized zirconia (ZrO2-Y2O3) ceramics have received increasing attention in recent years because of their stress-induced tetragonal-to-monoclinic (martensitic) transformation. This unique process acts as a toughening mechanism, imparting strength and toughness to the ceramic alloy. This property, along with well-documented biocompatibility, is now being exploited in an increasing number of medical applications, including implant dentistry. To prevent clinical problems and predict their behavior and physical limitations, a characterization of the ceramic elements used in dental restorations is essential. The aim of the present study is to characterize the crystal structure, elemental composition, and micr ostructure of asreceived ZiReal Post (Biomet 3i) zirconium oxide abutments, as well as specimens coated with a first layer of a low-fusing fluoroapatite ceramic. MATERIALS AND METHODS: Zirconium oxide abutments, both as-received and porcelain-coated, were studied using the following techniques: x-ray diffraction, x-ray fluorescence, energy dispersive x-ray spectroscopy, optical microscopy, and scanning and transmission electron microscopy. RESULTS: X-ray analyses detected only the presence of Zr, O, Y, and hafnium (Hf), in an amount of 3% to 4% molecular weight Y2O3-ZrO2. X-ray diffraction measurements showed that the ceramic abutment crystallizes mainly in the tetragonal phase, with some residual monoclinic phase. The microstructure is characterized by a rather homogenous grain distribution, formed by equiaxed and fine grains with a mean size of 0.30 Μm. CONCLUSIONS: Compositional and diffraction results are consistent with polycrystalline yttria-stabilized tetragonal zirconia. The material is susceptible to undergoing the stress-induced transformation toughening mechanism because of the very fine grain size. Except for machining ring marks, the surfaces exhibit an excellent finishing quality. No structural modifications were observed in the fluoroapatite ceramic-coated abutments because of the relatively low temperatures used for ceramization compared with the phase transformation temperatures used for zirconia.

Update on dry socket: a review of the literature.

Dry socket is a postoperative complication that occurs after a dental extraction and has been defined as an inflammation of the alveolus. If this inflammation should surpass the alveolar walls, it would result in a located osteitis. The frequency of appearance of dry socket has been reported in a very wide margin, from 1% until 70%. It is generally accepted that most dry sockets appear after extraction of third retained molars, in which the occurrence of this complication is about 20-30% of dental extractions, ten times more than in the rest of dental extractions. In this work we review the forms of clinical appearance, the risk factors related to this affection and the etiopathogenic theories that try to explain its appearance. The treatment management is also examined. Fibrinolitic agents, laundries, antiseptic, and antibiotics have been studied for its prevention, according to the pathogenic theories of dry socket. We analyze and criticize the different drugs and their results. In conclusion from the revised data, we think it is possible to defend a pathogenic model in which the bacterial fibrinolytic mechanisms and the microorganism of the own patient may contribute to produce the dry socket.

Differential diagnosis and therapeutic approach to periapical cysts in daily dental practice.

The diagnosis and therapeutic approach to periapical cysts is an extremely controversial concern for dentists. Furthermore, as this complaint represents the most frequent cystic lesion of the maxilla, together with the fact that its differential diagnosis with chronic apical periodontitis presents special difficulty, the question takes on even greater importance. The purpose of this article is to assess the validity of the various diagnostic techniques used to differentiate between both pathologies and make a critical analysis of the controversy surrounding the therapeutic approach to suspected periapical cysts through non-surgical and follow-up treatment, or surgical enucleation and histopathological analysis.