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At least 883 records · Page 49Linked to original sources
PubMed2000

An ultrastructural study of the application of dentine adhesives to acid-conditioned sclerotic dentine.

OBJECTIVE: This in vitro study examined the ultrastructure of resin-infiltrated sclerotic dentine following the application of a self-etching primer, with or without the adjunctive use of phosphoric acid pre-conditioning. MATERIALS AND METHODS: Non-carious, natural cervical sclerotic lesions were hand-cleaned with a slurry of pumice and chlorhexidine and bonded without further cavity preparation. One group was bonded using Clearfil Liner Bond 2V (Kuraray Co. Ltd, Osaka, Japan) alone. Specimens from the other group were pre-conditioned with K-etchant (40% phosphoric acid gel, Kuraray) prior to the application of the same self-etching primer. Artificially prepared wedge-shaped lesions were also made in sound bicuspids, bonded using the two methods, and used as controls for the two groups. For SEM examination, each specimen was cryofractured into two halves through a pre-formed slit made on the lingual surface, after the respective conditioning treatment. Different locations within the lesions were examined after rinsing of the phosphoric acid/self-etching primer and specimen dehydration. For TEM investigation, specimens were bonded with the adhesive. Both demineralised and undemineralised ultrathin sections were prepared from the occlusal, gingival and deepest part of the wedge-shaped bonded lesions following specimen fixation, dehydration and resin embedding. RESULTS: A hypermineralised surface layer was present on the surface of etched sclerotic dentine. This layer was thicker in the deepest part of the natural lesions, where bacterial colonisation of the lesion surface was also apparent. Both treatment protocols were unable to effectively dissolve sclerotic casts that occluded the dentinal tubules. Depending upon the thickness of the surface layers at different locations in the natural lesion, self-etching primer treatment alone resulted in reduction of the thickness of the authentic hybrid layer (i.e. hybridised intertubular dentine). This was also true of phosphoric acid pre-conditioning along the deepest part of the natural lesions. Within this region, intertubular dentine completely devoid of an authentic hybrid layer could be seen in both treatment groups. Resin tags were also sparsely observed in such regions. CONCLUSIONS: Adhesive strategies that rely mostly on micromechanical retention alone may be compromised by the sporadic absence of the hybrid layer and resin tags in sclerotic dentine. Based on the ultrastructural features presented, it is further speculated that adaptive strategies such as removal of the surface layers and extended etching time may not be completely effective in improving bonding efficacy in highly sclerotic dentine. Interdisciplinary research should be continued to develop alternative procedures for bonding resins equally well to sound and sclerotic dentine.

Acid Etching, Dental↗
PubMed1997

A prospective study of Astra single tooth implants.

A new design of single tooth implant (AstraTech, Molndal Sweden) featuring a microthreaded conical neck and TiO blast surface was evaluated clinically and radiographically after 2 years in function. Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had 4, 13 mm and 11, 15 mm implants placed under local anaesthesia and left for a period of 6 months before exposure and abutment connection/crown fabrication. All patients were seen at 4 to 6 monthly intervals for hygienist maintenance. Radiographs using Rinn holders and a long cone technique were taken at the crown insertion and after 1 year (14 subjects) and 2 years (12 subjects). All implants were successfully integrated at stage 2, and no implants have been lost. The internal conical seal design of the abutment/implant interface facilitated connection and there were no cases of abutment screw loosening. No soft tissue problems were observed, and the gingival morphology/health was well maintained. One crown was recemented after 18 months in function, and 1 crown was replaced because of a fracture to the porcelain incisal edge. At crown insertion, the mean bone level was 0.46 to 0.48 mm apical to the top of the implant and there were no statistically significant changes in the bone level over the 2 years of the study. In conclusion, the single tooth Astra implants were highly successful and bone changes within the first 2 years of function were comparable with other systems reporting high long-term success rates.

Adolescent↗
PubMed2000

Determination of the in situ bactericidal activity of an essential oil mouthrinse using a vital stain method.

BACKGROUND: Recent research has indicated that bacteria within a biofilm may undergo changes in susceptibility to antimicrobial agents when compared to planktonic forms. This study was conducted to determine the bactericidal effect of an essential oil-containing mouthrinse (Listerine Antiseptic) on dental plaque bacteria in situ. METHODS: 1-day-old plaque in 17 subjects was sampled at baseline from the buccal surfaces of diagonally contralateral maxillary and mandibular bicuspids and 1st molars. Subjects were then randomly assigned either an essential oil mouthrinse or a sterile saline negative control and rinsed under supervision with 20 ml for 30 s. 30 min later, plaque was sampled from the remaining contralateral posterior teeth. Subjects repeated these procedures with their respective alternate rinse after 1 week. Pooled plaque samples from each subject at each sampling period were stained with a commercially-available fluorescent stain which fluoresces live and dead bacteria green and red, respectively. The stained plaque specimens were analyzed using computerized image analysis. A separate in vitro study was conducted to determine the relationship between the % red stain per sample and bacterial viability. RESULTS: Analysis of vital stained plaque specimens indicated that following rinsing with the essential oil mouthrinse, 78.7% of bacteria were dead compared to 27.9% following rinsing with the negative control (p<0.001). The in vitro findings demonstrated that the % red stain per sample is reflective of actual bacterial kill. CONCLUSIONS: This study confirms the findings of previous in vitro and in vivo studies which demonstrated the essential oil mouthrinse to have significant biocidal activity against oral micro-organisms. These studies all support the primacy of a bactericidal mechanism in producing the plaque and gingivitis reductions observed in numerous clinical trials conducted on the essential oil mouthrinse.

Anti-Infective Agents, Local↗
PubMed2005

Two- and three-dimensional orthodontic imaging using limited cone beam-computed tomography.

Considerable progress has been made in diagnostic, medical imaging devices such as computed tomography (CT). However, these devices are not used routinely in dentistry and orthodontics because of high cost, large space requirements and the high amount of radiation involved. A device using computed tomography technology has been developed for dental use called a limited cone beam dental compact-CT (3DX). The aim of this article is to demonstrate the usefulness of 3DX imaging for orthodontic diagnosis and treatment planning. We present three cases: (1) one case shows delayed eruption of the upper left second premolar, (2) the second case shows severe impaction of a maxillary second bicuspid; and (3) the third case shows temporomandibular joint disorder (TMD). In the tooth impaction cases, the CT images provided more precise information than conventional radiographic images such as improved observation of the long axis of the tooth, root condition, and overlap with bone. In the TMD case, clear and detailed temporomandibular joint images were observed and pre- and posttreatment condylar positions were easily compared. We conclude that 3DX images provide useful information for orthodontic diagnosis and treatment planning.

Adolescent↗
PubMed2005

Anchorage control in bioprogressive vs straight-wire treatment.

Orthodontic techniques with different concepts and philosophies have emerged to provide adequate anchorage control. The purpose of this study was to compare the effectiveness of the Bioprogressive and Straight-wire techniques in the control of lower anchorage. Data were obtained from the records of 40 patients presenting Class I and II malocclusions treated with first bicuspid extractions. One group of 20 patients was treated with a utility arch used to set up cortical anchorage in the lower arch and sectional retraction mechanics for space closure. The second group was treated with straight wire with a preadjusted appliance system. Treatment evaluation revealed no significant between-group differences in the amount of skeletal growth relative to cranial base and lower mesial movement of first molars. Mean lower anchorage loss was 3.1 mm in the Bioprogressive patients and four mm in the Straight-wire patients. The apical base change was the most important component to molar correction. Although cortical anchorage did not impede lower molar movement, it was no less effective in controlling molar movement with a partial appliance than was the fully banded Straight-wire appliance.

Adolescent↗
PubMed2001

The standardized-taper root canal preparation--part 5. GT file technique in small root canals.

AIM: To describe the shaping of Small Root canals with GT files. SUMMARY: Small Roots are lower incisors, two and three canal bicuspids, buccal roots of upper molars, and mesial roots of lower molars. The Shaping Objective instrument for such cases is usually a 0.08 or 0.06 taper GT file. After proper access, pulp tissue should be removed to prevent its compaction and canal blockage. Orifice shaping and smoothing is then achieved with a 35-0.12 accessory GT File, running at full slow-speed r.p.m. (5-20K).Crown-down preparation commences with the 0.10 GT file, followed by the 0.08 and 0.06 tapers as needed. Occasionally, a 20-0.04 Profile is required to reach length. Files are rotated at 300 r.p.m. with steady, light pressure, and withdrawn frequently for cleaning and inspection. Once one of these files has cut to length, the canal terminus is enlarged to Shaping Objective. If difficulty is encountered, be willing to accept a 0.06 instead of the original 0.08 taper Shaping Objective. If the terminal diameter is 0.2 mm you will have plenty of apical resistance form in a tortuous canal with the 0.06 taper preparation. It is definitely better to end up with a smaller shape than originally planned, than to experience the heartache of separation. KEY LEARNING POINTS: Small Root canals should be prepared to a Shaping Objective 0.08 or 0.06 taper. Pulp tissue should be removed before preparation to prevent compaction and blockage. Preparation follows in a crown-down sequence, and may occasionally require the use of small Profiles. Final apical shaping is easily achieved when root length is reached.

Bicuspid↗
PubMed2002

A comparison of ropivacaine and lidocaine with epinephrine for intraligamentary anesthesia.

OBJECTIVE: The purpose of this study was to compare the efficacy of 2 different concentrations of ropivacaine with lidocaine containing epinephrine for intraligamentary anesthesia. STUDY DESIGN: Ethical approval was obtained and a randomized, double-blind, cross-over volunteer investigation was conducted. Twenty-four volunteers had intraligamentary injections of 2% lidocaine with 1:80,000 epinephrine, 0.75% ropivacaine, or 1% ropivacaine at the upper lateral incisor and lower first bicuspid teeth. The response of the test teeth to electrical pulp testing and the reaction of the gingiva to sharp probing were assessed up to 29 minutes after injection. Injection discomfort and side effects were also recorded. Data were analyzed by using the chi-square test and analysis of variance. RESULTS: Lidocaine with epinephrine was more successful than the ropivacaine solutions in obtaining pulpal anesthesia (chi-square = 12; P <.002) and produced longer-lasting pulpal (F = 21; P <.001) and soft tissue (F = 16; P <.001) anesthesia. Injection discomfort and incidence of side effects were similar between solutions, and none produced serious adverse effects. CONCLUSION: Lidocaine with epinephrine is more effective than ropivacaine as an intraligamentary anesthetic.

Adult↗
PubMed2002

Prevalence of missing posterior teeth and intraarticular temporomandibular disorders.

STATEMENT OF PROBLEM: The association between missing mandibular posterior teeth and the development of intraarticular temporomandibular disorders (TMDs) remains unclear. PURPOSE: The purpose of this study was to evaluate the prevalence of missing mandibular posterior teeth and intraarticular TMDs in a mixed population of asymptomatic subjects and symptomatic TMD patients. MATERIAL AND METHODS: Eighty-two asymptomatic volunteers and 263 symptomatic TMD patients were included in this study. Asymptomatic volunteers completed a subjective questionnaire and underwent clinical examination to document the absence of TMD signs and symptoms. All symptomatic subjects had localized jaw joint pain and pain on movement or when eating. The number of missing mandibular bicuspid and molar teeth (excluding third molars) in each subject was recorded, and magnetic resonance images were made to document the presence or absence of disk displacement in the temporomandibular joints. Subjects were divided into 4 groups: group 1 = asymptomatic, normal magnetic resonance imaging result; group 2 = asymptomatic, disk displacement; group 3 = symptomatic, normal magnetic resonance imaging result; and group 4 = symptomatic, disk displacement. Collected data were analyzed with chi-square tests (P<.05) with no adjustment for multiple comparisons. RESULTS: A positive association between missing mandibular posterior teeth and the presence of disk displacement was found. CONCLUSION: The literature does not suggest that replacement of missing posterior teeth prevents the development of TMDs. However, missing mandibular posterior teeth may accelerate the development of degenerative joint disease.

Bicuspid↗
PubMed2003

pH changes in root dentin after intracanal placement of improved calcium hydroxide containing gutta-percha points.

The in vitro pH changes in root dentin over a period of 2 weeks was investigated in 48 extracted bicuspids after intracanal placement of either Roeko Calcium Hydroxide Plus Points, aqueous calcium hydroxide paste, or gutta-percha points (control group) after root canal preparation. Microelectrodes were placed in outer and inner root dentin at cervical, middle, and apical thirds of the root to measure the pH at 1 h, 2 h, 3 h, 1 day, 3 days, 7 days, and 14 days. Roeko Calcium Hydroxide Plus Points reached a peak inner dentine pH of 11.67 and a peak outer dentine pH of 10.82 at 3 h. In addition, Roeko Calcium Hydroxide Plus Points maintained an outer dentine pH above 9.5 for approximately 2 days, whereas the aqueous calcium hydroxide paste did not reach this pH. However, the alkalinity in dentin with Roeko Calcium Hydroxide Plus Points was maintained for 7 days only, whereas aqueous calcium hydroxide paste maintained an alkaline environment throughout the 2-week period.

Analysis of Variance↗
PubMed2003

An in vitro evaluation of the sealing ability of a new root-canal-obturation system.

In this study the sealing ability of a new urethane methacrylate resin-based sealer, EndoRez, was evaluated using a fluid-filtration model. Sixty-four single-rooted lower bicuspids were decoronated, instrumented, and divided into 3 groups of 20 each with 4 teeth used as controls. In group A, the roots were obturated with EndoRez and a single cone of gutta-percha, group B with AH Plus and a single cone of gutta-percha, and group C was obturated using gutta-percha with warm vertical compaction and AH Plus sealer. All specimens were allowed to set for 7 days in 100% humidity at 37 degrees C. The groups were compared for differences in the amount of leakage (mm/h) using a Chi-square test. The leakage of group A was significantly higher at p = 0.01 than the other two groups. There was no significant difference in leakage between groups B and C.

Bicuspid↗
PubMed2002

Immediate implant in extraction socket with acellular dermal matrix graft and bioactive glass: a case report.

A buccal plate destroyed as a result of a longitudinal root fracture was completely restored by the use of a Frialit-2 implant placed in the alveolus of the fractured maxillary left first bicuspid. An acellular dermal matrix material was used as a membrane barrier to cover the implant, and a bioactive glass was used as grafting material. After 6 months, the defect around the implant was completely filled by mineralized tissue.

Adult↗
PubMed2005

The effect of cavity preparation on substance P expression in human dental pulp.

Substance P (SP) plays an important role during neurogenic inflammation of dental pulp. The purpose of this study was to use a radioimmunoassay for determining the effect of cavity preparation on SP expression in healthy human dental pulp. Ten pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. Deep cavity preparation (<1 mm remaining dentine thickness) was performed before extraction in five of these bicuspids. All samples were processed and I-SP labeled; SP was quantified by competition assay. The results revealed SP expression in all human pulp samples. Mann-Whitney's U test revealed statistically significant higher expression in pulp from teeth where cavity preparation had been performed compared to control values (p < 0.05). These findings suggest that SP is released during common dental procedures (such as cavity preparation) and its expression may have an important clinical significance in terms of experiencing inflammation and pain.

Adolescent↗
PubMed1993

Taurodontism and length of teeth in patients with oligodontia.

Taurodontism and a reduced tooth length are reported to occur in patients with oligondontia. The aim of this study was to evaluate the occurrence of these factors in Dutch patients with oligodontia. Panoramic radiographs of 117 patients with oligodontia and 91 controls were collected. Taurodontism of the mandibular first molars was recorded and the length of cuspids, bicuspids and first molars of the mandible were measured. In patients with oligodontia 28.9% showed taurodontism of one or two mandibular first molars. The prevalence of taurodontism in normal Dutch subjects was 9.9%. No significant differences were found between the two sexes in both groups. Neither was there a significant difference in the unilateral and bilateral occurrence of taurodontism. The present findings supported the hypothesis that taurodontism may be the result of an ectodermal defect and a manifestation of developmental instability in patients with oligodontia. The length of mandibular cuspids and first molars in females were significantly reduced. In males only the lower right first molar was significantly reduced. The reduced length of the teeth may also be the result of a defect in ectodermal cells. Both taurodontism and a reduced length are of importance considering dental therapy.

Adolescent↗
PubMed1986

Longitudinal observation of "unattached," mobile gingival areas.

Facial gingival surfaces over cuspids and bicuspids in 20 patients were monitored for 5 years to evaluate the importance of attached gingiva in the maintenance of a stable periodontium. 43 surfaces "at risk" were compared to 36 "non-risk" surfaces within these patients. Surfaces "at risk" had to meet the following 3 criteria as established by both of 2 independent examiners: width of keratinized gingiva less than or equal to 1.0 mm; absence of attached gingiva; mobility of the gingival margin. During the 5 years of observation, "non-risk" surfaces showed a trend toward decrease in mean width of keratinized gingiva, while this measurement remained unchanged for the surfaces "at risk" Probing depths remained unaltered for both groups. A trend toward gingival recession and loss of probing attachment was observed for both "risk" and "non-risk" surfaces. Thus, this study failed to demonstrate that "unattached" and mobile facial gingival surfaces are more susceptible to periodontal breakdown than "attached" surfaces.

Adult↗
PubMed1995

Reliability of single and double probing attachment level measurements.

Clarification of the reliability associated with probing attachment level measurements and with diagnostic rules derived from them is necessary to examine the potential of these measurements as reliable markers of the disease process and as an outcome measure in clinical treatment studies. The purpose of the present study was to describe and compare the longitudinal reliability of single and double probing attachment level measurable by estimating false positive and false negative rates. In 20 systemically healthy adults with untreated advanced adult periodontitis, probing attachment levels and probing depth were measured at 6 sites in all teeth at the start of the study, and every 30 days thereafter for 11 months. Attachment levels were double measured, using acrylic onlays providing reference points and an electronic pressure sensitive probe. Attachment loss from baseline of 2.5 mm or more was used to accept dynamic attachment loss. The statistical methods for the cross-sectional analysis included mean absolute differences between double measurements and cross-correlations. Longitudinal analyses, expressing estimates of diagnostic error rates were made using maximum likelihood methods. 5 measurement protocols were compared. The results showed that the mean absolute difference between replicate measurements was 0.095 mm in bicuspids and 0.107 mm in molars. The mean absolute differences decreased over time from 0. 128 mm in visit 3 to 0.08 mm in visit 7. Correlation coefficients for replicate measurements were higher than 0.98. In general, false positive rates were markedly lower (< or = 0.02) than false negative rates (< or = 0.31). The relative sample size required to obtain comparable statistical power, was minimized in premolars when using the first of 2 measurements or the mean of 2 measurements, and in molars when using the first of 2 measurements. The methodology used in the present study provides guidelines for designing clinical studies which maintain statistical power by balancing off examiner reliability and sample size.

Acrylic Resins↗
PubMed1996

Effect of local application of delmopinol hydrochloride on developing and early established supragingival plaque in humans.

The aim of the study was to investigate the effect of delmopinol hydrochloride on the development of dental plaque and on newly established plaque. In addition, the influence of this compound on the composition of the microbiota colonizing the gingival mucous membrane was studied. 14 healthy male volunteers took part. After a 3 week pre-experimental period of intense oral hygiene, the participants refrained from all oral hygiene for 14 days. The buccal surfaces of cuspids and bicuspids on one side of the jaws were treated with a 1% aqueous solution of delmopinol hydrochloride (applied with a paint brush) 2 x a day for 7 days, while the contralateral side received placebo solution. On day 7, the application procedures were changed in that the test compound was applied on the teeth previously treated with placebo and vice versa. Plaque development was assessed clinically and by photo-based planimetric determination. The clinical recordings revealed that 89.3% of the placebo-treated surfaces displayed visible plaque on day 7, compared to 6.0% of the delmopinol hydrochloride treated surfaces. Delmopinol hydrochloride treatment of the previously placebo-treated surfaces resulted in a decrease in the number of surfaces with visible plaque from 89.3% on day 7 to 6% on day 14. These results were confirmed by the planimetric data. No significant change in the composition of the mucosal flora was observed during the experimental period. The present results indicate that delmopinol hydrochloride markedly reduces the formation of dental plaque on a clean tooth surface exposed to conditions which favour bacterial colonization. Furthermore, the substance appears to possess plaque-dissolving properties.

Administration, Topical↗