Effect of denture fabrication and wear on closest speaking space and interocclusal distance during deglutition

Statement of problem. The accuracy of assessing maxillomandibular relationships for trial bases and dentures using phonetic and swallowing methods has not been compared to that observed with definitive prostheses. Thus, there is no evidence to prove whether measurements obtained through such methods remain the same after adaptation to dentures.Purpose. This study investigated changes in the closest speaking space, interocclusal rest space, and interocclusal distance during deglutition in edentulous patients during and after complete denture treatment.Material and methods. Eighteen edentulous subjects participated in this study and measurements were performed after 7 Intervals of time: (1) with occlusion rims and record bases following creation of the maxillomandibular relationship record, (2) with trial dentures, (3) at Insertion of definitive complete dentures, (4) 1 week, (5) 2 weeks, (6) 1 month, and (7) 3 months after insertion. Recordings of interocclusal distances were made with a mandibular kinesiograph. Closest speaking space was measured during the pronunciation of the word 'seis'. The distance between postural rest position and centric occlusion, or interocclusal rest space, was measured using a kinesiograph. Interocclusal distance during deglutition was tested by recording the closest mandibular position recorded during swallowing of 20 mL of water. Data were analyzed using repeated-measure ANOVA, followed by the Student-Newman-Keuls test (alpha=.05).Results. A significant (P <.01)reduction in the mean closest speaking space was found when it was evaluated using occlusion rims and record bases (4.6 mm) compared with other stages (3.0 to 3.4 mm). No significant differences were found in mean interocclusal rest space and interocclusal distance during deglutition among the time periods evaluated.Conclusions. The presence of occlusion rims can influence mandibular position during pronunciation of the /s/ sound. The arrangement of artificial teeth changes the closest speaking space. However, rest position and deglutition were not affected, either during denture fabrication or short-term use.

Penetration of 38% hydrogen peroxide into the pulp chamber in bovine and human teeth submitted to office bleach technique

This study evaluated the pulp chamber penetration of peroxide bleaching agent in human and bovine teeth after office bleach technique. All the teeth were sectioned 3 mm apical of the cement-enamel junction and were divided into 2 groups, A (70 third human molars) and B (70 bovine lateral incisors), that were subdivided into A1 and B1 restored by using composite resin, A2 and B2 by using glass ionomer cement, and A3 and B3 by using resin-modified glass ionomer cement; A4, A5, B4, and B5 were not restored. Acetate buffer was placed in the pulp chamber, and the bleaching agent was applied for 40 minutes as follows: A1-A4 and B1-B4, 38% hydrogen peroxide exposure and A5 and B5, immersion into distilled water. The buffer solution was transferred to a glass tube in which leuco crystal violet and horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to analysis of variance and Dunnett, Kruskal-Wallis, and Tukey tests (5%). A higher level of hydrogen peroxide penetrated into the pulp chamber in resin-modified glass ionomer cements in bovine (0.79 +/- 0.61 mu g) and human (2.27 +/- 0.41 mu g) groups. The bleaching agent penetration into the pulp chamber was higher in human teeth for any experimental situation. The penetration of the hydrogen peroxide depends on restorative materials, and under the conditions of this study human teeth are more susceptible to penetration of bleaching agent into the pulp chamber than bovine teeth.

Flexural strength of autopolymerizing denture reline resins with microwave postpolymerization treatment

Statement of problem. Microwave postpolymerization has been Suggested as a method to improve the mechanical strength of repaired denture base materials. However, the effect of microwave heating oil the flexural strength of the autopolymerizing denture reline resins has not been investigated.Purpose. This study analyzed the effect of microwave postpolymerization on the flexural strength of 4 autopolymerizing reline resins (Duraliner II, Kooliner, Ufi Gel Hard, and Tokuso Rebase Fast) and 1 heat-polymerized resin (Lucitone 550).Material and methods. For each material, 80 specimens (64 X 10 X 3.3 mm) were polymerized according to the manufacturer's instructions and divided into 10 groups (n = 8). Control group specimens remained as processed. Before testing, the specimens were Subjected to postpolymerization in a microwave oven using different power (500, 5,50, or 650 W) and time (3, 4, or 5 Minutes) settings. Load measurements (newtons) were made at a crosshead speed of 5 mm/min using a 3-point bending device with a span of 50 mill. The flexural strength values were calculated in MPa. Data analyses included 3-way and 2-way analysis of variance and the Tukey Honestly Significant Difference test (alpha=.05).Results. The flexural strengths of resins Duraliner 11 and Kooliner were significantly increased (P=.0015 and P=.0046, respectively) with the application of microwave irradiation using different time/power combinations. The materials Lucitone 550, Tokuso Rebase Fast, and Ufi Gel Hard demonstrated no significant strength improvement compared to the corresponding control. Only after microwave postpolymerization irradiation for 3 minutes at 550 W did Lucitione 550 show significantly higher flexural strength than Tokuso Rebase Fast and Ufi Gel Hard relining resins.Conclusion. Microwave postpolymerization irradiation can be an effective method for increasing the flexural strength of Duraliner II (at 650 W) and Kooliner (at 550 W and 650 W for 5 minutes).

Mineral trioxide aggregate as a root canal filling material in reimplanted teeth. Microscopic analysis in monkeys

This study analyzed mineral trioxide aggregate (MTA) as a root canal filling material for the immediate reimplantation of monkey teeth. Four adult capuchin monkeys Cebus apella were used, which had their maxillary and mandibular lateral incisors on both sides extracted and reimplanted after 15 min. During the extra-alveolar period, the teeth were kept in saline solution and after reimplantation retention was performed with a stainless steel wire and composite resin for 14 days. After 7 days, the reimplanted teeth were submitted to endodontic treatment with biomechanics up to file n. 30 and irrigation with a saturated solution of calcium hydroxide [Ca(OH)(2)], and then divided into two study groups: group I - root canal filled with a Ca(OH)(2) paste, and group II - root canal filled with MTA. Radiographic follow up was performed at 30, 60 and 90 days postoperatively, and after 180 days the animals were killed and specimens were processed for histomorphological analysis. The results revealed that most specimens of both groups presented organized periodontal ligament with no inflammation. The resorptions observed were surface resorptions and were repaired by cementum. Both MTA and Ca(OH)(2) were good root canal filling materials for immediately reimplanted teeth, providing good repair and also allowing biological sealing of some lateral canals. There was no significant difference between the study groups (alpha = 29.60%).

Influence of surgical repositioning of mature permanent dog teeth following experimental intrusion: a histologic assessment

The aim of this study was to evaluate, through histologic examination, the effect of surgical repositioning of intruded dog teeth upon the pulpal and surrounding tissues. Thirty teeth in 10 adult dogs, aged 2-3 years, were used. Fifteen teeth were intruded, surgically repositioned and fixed using orthodontics wire, composite resin, and enamel acid conditioning. All these teeth served as the experimental group. The remaining intruded teeth were not treated ( control group). The animals were sacrificed to allow observations at 7,15, and 30 post-operative days. The maxillary and mandibular archs were removed and processed for histologic exam. Based on the methodology and observed results, we concluded that: pulpal necrosis, external root resorption and ankylosis were common sequelae to severe traumatic intrusion; a careful immediate surgical repositioning of severed intruded permanent tooth with complete root formation has many advantages with few disadvantages.

A clinical follow-up study of the periodontal conditions of RPD abutment and non-abutment teeth

The purpose of this study was to evaluate the periodontal conditions of removable partial denture (RPD) wearers, comparing direct and indirect abutment teeth, and the teeth not involved in the denture design before denture placement and 1 year later. Fifty patients (32 women and 18 men), average age 45, were assessed by the same examiner at the moment of denture insertion and 3, 6, 9 and 12 months later. The following items were verified in each assessment: probing depth (PD), plaque index (PI) and gingival index (GI). PD and PI data were evaluated by ANOVA test for linear trend followed by Tukey-Kramer post-test, while GI data were analysed by Friedman's test. Results showed that the teeth not involved in the denture design were the least affected for all variables studied. It was also verified that PD and GI mean values increased from the initial assessment to 1 year of RPD wearing in every group, but that only PI showed a significant increase. This study indicated that direct and indirect retainer elements tend to undergo more damaging periodontal effects associated with RPD wearing when compared with non-abutment elements. Plaque index values were significantly higher after 1 year of denture use.

Resinas para facetas estéticas de próteses fixas. III. Análise conjunta das variáveis alteração dimensional e alteração de peso em função de materiais, condição de armazenamento e tempos.

The authors analysed the simultaneous effects of the dimensional and weight alteration of resins utilized for esthetic facets submitted to warehousing conditions and periods of time. The resins showed different behaviour and a neat correlation between dimensional alteration and weight. The condition of immersion promoted dimensional alteration 50% lower and an alteration of weight three times higher.

Estudo comaprativo da resistência da união esmalt/resina/metal. Efeito de resinas de fixação, artifícios retentivos e ligas metálicas.

The purpose of this study was to compare the enamel/resin/metal bond tensile strength by using human canines, in which castings were bonded. These castings were obtained by Co-Cr or Ni-Cr alloys and showed four types of mechanisms of retention: 50 micrograms aluminum oxide abrasive, electrochemical etch, acrylic beads metal mesh. The castings were bonded utilizing Comspan Opaque and Panavia Ex. The specimens were subjected to tensile forces after 24 hours in an Instron machine. The castings subjected to 50 micrograms aluminum oxide abrasive and bonded utilizing Panavia EX showed the biggest bond tensile strength.

Aesthetic posts and cores for metal-free restoration of endodontically treated teeth.

Utilization of contemporary post and core systems has facilitated the aesthetic restoration of endodontically treated teeth. Light transmission and biocompatibility have been enhanced by the introduction of metal-free post systems. The periodontal and endodontic status, root length, and histological structure of the devitalized teeth must be considered in order to achieve successful restoration following endodontic treatment. This article presents various restorative criteria for the aesthetic placement and buildup of post and core materials, as well as the preservation of maximum coronal and root structure.

Microleakage in primary teeth restored by conventional or bonded amalgam technique.

The aim of this in vitro study was to evaluate marginal leakage in class V restorations in primary teeth restored with amalgam, using three different techniques. Thirty maxillary anterior primary teeth, clinically sound and naturally exfoliated, were used. In group 1 (n = 10), two thin layers of a copal varnish (Cavitine) were applied. In group 2 (n = 10), Scotchbond Multi-Purpose Plus, a dual adhesive system, was used according to manufacturer instructions. In group 3 (n = 10), One-Step adhesive system in combination with a low-viscosity resin (Resinomer) were used according to manufacturer instructions. All samples were restored with a high-copper dental amalgam alloy (GS 80, SDI). After restoration, the samples were stored in normal saline at 37 degrees C for 72 h. The specimens were polished, thermocycled (500 cycles, 5 degrees and 55 degrees C, 30-s dwell time) and impermeabilized with fingernail polish to within 1.0 mm of the restoration margins. The teeth were then placed in 0.5% methylene blue for 4 h. Finally, the samples were sectioned and evaluated for marginal leakage. The Kruskal-Wallis test showed that the filled adhesive resin (group 3) had the least microleakage. There was no significant difference between groups 1 and 2.

Radiographic evaluation of periradicular repair after endodontic treatment of dog's teeth with induced periradicular periodontitis

Eighty-four root canals of premolars from six dogs were left open for 7 days, and then sealed and followed for 45 days until periradicular periodontitis developed. The root canals were then treated endodontically using 5.25% sodium hypochlorite as the irrigating solution. After instrumentation, all root canals were filled with a calcium hydroxide-based antibacterial dressing (Calen PMCC or Calasept) that was left in place for 30 days. After this period the root canals were filled with gutta-percha cones and a root canal sealer (Sealapex or AH Plus)-group I: Calen PMCC + Sealapex; group II: Calasept + Sealapex; group III: Calen PMCC + AH Plus; and group IV: Calasept + AH Plus. Periapical radiographs of the teeth were made after root canal filling and after 90, 180, 270, and 360 days. Radiographic images were digitalized by scanning, and the Mocha program was used to measure the periapical lesions. Analysis showed that the lesions of groups I to III were statistically similar reduction in size, whereas group IV had a smaller reduction in lesion size (p < 0.05). Copyright © 2001 by The American Association of Endodontists.

Resistance to maxillary premolar fractures after restoration of class II preparations with resin composite or ceromer.

OBJECTIVE: The aim of this study was to evaluate the resistance to fracture of intact and restored human maxillary premolars. METHOD AND MATERIALS: Thirty noncarious human maxillary premolars, divided into three groups of 10, were submitted to mechanical tests to evaluate their resistance to fracture. Group 1 consisted of intact teeth. Teeth in group 2 received mesio-occlusodistal cavity preparations and were restored with direct resin composite restorations. Teeth in group 3 received mesio-occlusodistal cavity preparations and were restored with ceromer inlays placed with the indirect technique. After restoration, teeth were stored at 37 degrees C for 24 hours and then thermocycled for 500 cycles at temperatures of 5 degrees C and 55 degrees C. RESULTS: Statistical analysis revealed that group 3 (178.765 kgf) had a significantly greater maximum rupture load than did group 1 (120.040 kgf). There was no statistically significant difference between groups 1 and 2 or between groups 2 and 3. CONCLUSION: Class II cavity preparations restored with indirect ceromer inlays offered greater resistance to fracture than did intact teeth. The fracture resistance of teeth restored with resin composite was not significantly different from that of either the ceromer or intact teeth.

Changes in occlusal vertical dimension in microwave processing of complete dentures.

This study investigated the effect of different microwave curing cycles on the changes in occlusal vertical dimension of complete dentures. Four test groups with 12 maxillary dentures each were evaluated. Groups 1, 2 and 3 were polymerized with different cycles by microwave radiation and Group 4 was the control and cured by water bath. The average pin opening for all groups was less than 0.5 mm. There was no significant difference between the groups polymerized by the microwave method and the control group. However, analyses of the vertical dimension changes showed statistically significant differences between groups 2 (0.276 +/- 0.141 mm) and 3 (0.496 +/- 0.220 mm).

Apical and periapical repair of dogs' teeth with periapical lesions after endodontic treatment with different root canal sealers.

The aim of this study was to evaluate the apical and periapical repair after root canal treatment of dogs' teeth with pulp necrosis and chronic periapical lesion using different root canal sealers. After periapical lesion induction, forty-four root canals of 3 dogs were submitted to biomechanical preparation using 5.25% sodium hypochlorite as an irrigating solution. A calcium hydroxide dressing (Calen PMCC) was applied for 15 days and the root canals were filled using the lateral condensation technique with gutta-percha points and Sealapex, AH Plus or Sealer Plus for sealing. After 180 days, the animals were sacrificed by anesthetic overdose and the obtained histological sections were stained with hematoxylin-eosin for optical microscopic analysis of the apical and periapical repair. The groups filled with Sealapex and AH Plus had better histological repair (p < 0.05) than the group filled with Sealer Plus, that had unsatisfactory results.

Restoration of severely decayed primary incisors using indirect composite resin restoration technique

Caries of primary incisors is a common problem in paediatric dentistry in some countries. The restoration of primary incisors which have been severely damaged by early childhood caries or trauma is also a difficult challenge for clinicians. This case report describes an indirect technique for the restoration of primary anterior teeth using composite resin reinforced with a fibreglass post. Over a one-year period, the crowns have demonstrated good retention and aesthetic results. The restorations were provided in two short chair-side sections, with satisfactory patient cooperation. © 2005 BSPD and IAPD.