Clonality of bacterial consortia in root canals and subjacent gingival crevices.

Aim: No oral niche can be considered to be segregated from the subjacent milieu because of the complex community behavior and nature of the oral biofilms. The aim of this study was to address the paucity of information on how these species are clonally related to the subjacent gingival crevice bacteria.

Methods: We utilized a metagenomic approach of amplifying 16S rDNA from genomic DNA, cloning, sequencing and analysis using LIBSHUFF software to assess the genetic homogeneity of the bacterial species from two infected root canals and subjacent gingival crevices.

Diagnostic performance of mandibular bone density measurements in assessing osteoporotic status.

Purpose: The study evaluated the diagnostic performance of computed tomography (CT) bone density measurements (in Hounsfield units [HU]) in assessing the osteoporotic status of edentulous subjects (21 men, 40 women) scheduled to receive mandibular implant-supported overdentures.

Materials And Methods: Density (in HU) of 61 left and 61 right mandibular canine sites was measured. Each subject was also subject to body bone mineral density measurements (dual-energy x-ray absorptiometry).

Correlation between dental implant insertion torque and mandibular alveolar bone density in osteopenic and osteoporotic subjects.

Purpose: Osteoporotic patients require particular attention during implant placement, and insertion torque (IT) has been established as a simple and noninvasive method to assess local bone quality and primary implant stability. This study aimed to test the hypothesis that IT was not significantly correlated with bone density, as assessed with computed tomography, in a group of osteopenic and osteoporotic patients. In addition, the hypothesis that IT was not significantly correlated with implant length was tested.

Effect of surface treatment on shear bond strength of zirconia to human dentin.

Purpose: The effect of surface treatment using tribochemical silica coating/silane coupling on the shear bond strengths of (1) a glass-infiltrated, zirconia-reinforced alumina (In-Ceram Zirconia) and (2) a yttria-stabilized zirconia ceramic (YZ Zirconia) to human dentin was studied.

Materials And Methods: Twelve specimens of each ceramic were randomly assigned to one of three surface treatments: (1) no surface treatment (control group); (2) a chairside tribochemical silica coating/silane coupling system (CoJet group); and (3) a laboratory tribochemical silica coating/silane coupling system (Rocatac group). The mode of failure of each specimen was determined under magnification.

Clinical considerations in managing severe tooth discoloration with porcelain veneers.

Background: Although porcelain veneer has been proposed as the treatment of choice in cases of severe tooth discoloration, clinicians should consider a multidisciplinary approach when treating complex cases. Clinicians also need to understand the masking ability of veneer restorations.

Case Description: A 20-year-old woman had severe tooth discoloration, enamel hypoplasia and malocclusion.

Oral health status of low-income, middle-aged to elderly Hong Kong Chinese with type 2 diabetes mellitus.

Purpose: To study oral health conditions, diabetic medical complications and their association in type 2 diabetes mellitus (DM).

Materials And Methods: Cross-sectional survey of 364 type 2 DM patients (63.6 +/- 10.

Shear bond strength between nickel-chromium and human dentine using a dual-cure, self-adhesive universal resin luting agent.

The adhesive property of a dual-cure, self-adhesive universal resin luting agent (Rely X Unicem, 3M ESPE) between nickel-chromium (Ni-Cr) and human dentine was compared with three conventional resin luting agents (Calibra, Dentsply; Panavia-F, Kuraray; All-bond 2 C & B cement, Bisco). Ten Ni-Cr rods were bonded to human dentine with each of the four luting agents, and were subjected to shear bond test. Results showed that there was no significant difference in shear bond strengths among the luting agents.

Chemical solubility and flexural strength of zirconia-based ceramics.

Purpose: This study was undertaken to investigate the chemical solubility and flexural strengths of 3 zirconia-based dental ceramics: In-Ceram Zirconia (IZ), In-Ceram 2000 YZ CUBES (YZ Zirconia) (Vita Zahnfabrik), and Cercon (Dentsply). A pressable lithium disilicate-reinforced glass ceramic (IPS Empress 2, Ivoclar Vivadent) was used as a control.

Materials And Methods: Ten block specimens (12 x 6 x 4 mm) of each ceramic material were prepared for chemical solubility testing.

The use of immediate implant placement for the replacement of a periodontally involved malaligned lateral incisor: a clinical report.

Localized severe chronic periodontitis is often seen in middle-aged patients, particularly when plaque control for malaligned teeth is not satisfactory. While orthodontic treatment can realign such teeth with reduced periodontal support, esthetics may be compromised by gingival recession due to preexisting bone loss and resolution of inflammation after periodontal treatment. This clinical report describes how a malaligned maxillary lateral incisor with severe periodontitis was replaced by an immediately placed implant and implant-supported crown with a good esthetic outcome.

Contrast ratios and masking ability of three types of ceramic veneers.

Statement Of Problem: Although ceramic veneers have been proven to be clinically successful in longevity studies, there is little information on the contrast ratios and masking ability of the available ceramic systems because dental laboratory technology and expensive experimental equipment are required for the investigation. Moreover, the complexity in understanding how to evaluate translucent ceramic materials may also explain why information in this area is limited.

Purpose: The purpose of this study was to determine the contrast ratios and masking abilities of 3 types of all-ceramic veneers by measuring their luminance and color difference over white and black backgrounds.

Comparison of the retentive characteristics of cobalt-chromium and commercially pure titanium clasps using a novel method.

This study aimed to compare the retentive forces of cast cobalt-chromium (Co-Cr) and commercially pure titanium (cpTi) clasps. A clasp assembly comprising a pair of symmetrical clasps was made to fit the opposite halves of a hardened stainless-steel sphere. This twin clasp was designed to counterbalance the tipping forces when the clasp assembly was drawn from the sphere.

Influence of dental status on nutritional status of geriatric patients in a convalescent and rehabilitation hospital.

Purpose: To investigate 6 dental statuses as risk factors for malnutrition in geriatric patients admitted to a convalescent and rehabilitation hospital.

Materials And Methods: One hundred twenty (59 men and 61 women) geriatric patients admitted to a convalescent and rehabilitation hospital were recruited. Three biochemical and hematologic parameters (albumin, hemoglobin, and lymphocyte count) were used for analysis.

Identification of cultivable microorganisms from root canals with apical periodontitis following two-visit endodontic treatment with antibiotics/steroid or calcium hydroxide dressings.

The study was aimed at comparing the efficacy of disinfection of root canals with periapical radiolucencies when treated with either antibiotics/steroid medicaments (Ledermix or Septomixine) or a calcium hydroxide paste (Calasept). Microbiological samples were taken before and after two-visit endodontic treatment from 88 canals with apical periodontitis. All of the canals but one (87 of 88) had cultivable growth before treatment.

Effect of original water content in acrylic resin on processing shrinkage.

Purpose: The aim of this study was to determine the original water content of a supplied acrylic resin powder and a monomer and of dry heat-processed acrylic bars. The effect of the original water content of acrylic resin on processing shrinkage was also investigated.

Materials And Methods: Ten bar specimens were fabricated using dried and as-supplied (control) acrylic resins.

Identification of cultivable microorganisms from primary endodontic infections with exposed and unexposed pulp space.

This study was aimed at comparing the cultivable microorganisms in canals with periapical radiolucencies with exposed and unexposed pulp space. Microbiological samples were taken and analyzed from 45 canals with exposed pulp space, and 43 canals with unexposed pulp space. The canal contents were analyzed by aerobic/anaerobic culture, and conventional identification techniques.

Color stability of provisional prosthodontic materials.

Statement Of Problem: Discoloration of provisional prosthodontic materials may result in patient dissatisfaction and additional expense for replacement.

Purpose: The purpose of this study was to determine the color stability of 5 provisional prosthodontic materials before and after immersion in distilled water or coffee for 20 days or exposure to ultraviolet (UV) light for 24 hours.

Material And Methods: A total of 105 disc-shaped specimens (20+/-0.

Rehabilitating a patient with bruxism-associated tooth tissue loss: a literature review and case report.

Tooth tissue loss from bruxism has been demonstrated to be associated with various dental problems such as tooth sensitivity, excessive reduction of clinical crown height, and possible changes of occlusal relationship. A literature search revealed a number of treatment modalities, with an emphasis on prevention and rehabilitation with adhesive techniques. Rehabilitating a patient with bruxism-associated tooth tissue loss to an acceptable standard of oral health is clinically demanding and requires careful diagnosis and proper treatment planning.

Implant-tissue supported, magnet-retained mandibular overdenture for an edentulous patient with Parkinson's disease: a clinical report.

Degenerative neurologic disorders such as Parkinson's disease are becoming more prevalent as life expectancy is improved. Although the use of an implant-supported overdenture is an acceptable treatment modality, the clinician should recognize the indications and maintenance requirements of different attachment systems for individual patients. The use of a magnetic attachment system in an implant-supported mandibular overdenture for an edentulous patient with Parkinson's disease is presented.

Threshold contrast ratio and masking ability of porcelain veneers with high-density alumina cores.

Purpose: The purposes of this study were to: (1) investigate the correlation between the color difference of bilayer porcelain veneers over white and black backgrounds (deltaE1) and their opacity (contrast ratios); (2) determine whether there is a recommendable threshold contrast ratio above which the color difference is clinically acceptable (when deltaE < or = 5); and (3) compare the ability of porcelain veneers to mask a color change from white to black backgrounds (deltaE1) and their ability to mask a color change from white to clinically discolored teeth (deltaE2).

Materials And Methods: Forty-four maxillary anterior teeth of eight patients with severe tetracycline discoloration were prepared for bilayer porcelain veneers in shade A2 porcelain. The cores were 0.

Implant treatment of macroglossia and edentulous mandible following radiotherapy for nasopharyngeal cancer: a case report.

Radiotherapy for the nasopharyngeal cancer patient with poor oral care may lead to severe deterioration of the dentition and may require multiple extractions. Although the use of an implant-retained overdenture can successfully restore the function and esthetics of edentulous patients, its use can be complicated by the tissue changes subsequent to head and neck irradiation. The difficulties in implant treatment planning for an edentulous patient with macroglossia and soft tissue changes following radiotherapy are discussed.

Clinical evaluation of packable and conventional hybrid resin-based composites for posterior restorations in permanent teeth: results at 12 months.

Background: Packable resin-based composites and simplified resin bonding systems are marketed to offer many advantages over conventional posterior hybrid composites and total-etch bonding systems. The authors conducted a study to evaluate the initial clinical performances of a packable and a conventional hybrid resin-based composite used with a simplified bonding system.

Methods: A total of 57 Class I and 45 Class II restorations were placed in the permanent teeth of 65 adult patients.

Direct detection of Actinomyces spp. from infected root canals in a Chinese population: a study using PCR-based, oligonucleotide-DNA hybridization technique.

Objectives: The poor sensitivity of phenotypic identification techniques has hampered the taxonomic differentiation of Actinomyces. Hence we developed a sensitive and specific, PCR-based oligonucleotide-DNA hybridization technique to detect Actinomyces spp. and, used this method to detect these organisms in samples directly obtained from infected root canals.

Magnet-retained auricular prosthesis with an implant-supported composite bar: a clinical report.

The use of craniofacial implants to assist in retaining auricular prostheses often requires complex laboratory procedures, involving production of an accurate casting, fitting of a precious alloy bar, and the use of clips. A simplified method for the retention of an auricular prosthesis with a composite bar and magnets is described in this article.

The use of lipiodol in spiral tomography for dental implant imaging.

Preoperative radiographic assessment is mandatory for the meticulous treatment planning and successful placement of implants. The precise topographical evaluation of selected implant sites, apart from the most straightforward cases, requires tomographic examination with the use of diagnostic radiographic templates. The incorporation of various radiopaque materials such as barium sulphate and lead foil as radiographic markers had not been entirely satisfactory.