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PubMed1997

Guidelines for the design and conduct of clinical trials on dentine hypersensitivity.

Clinical trials on dentine hypersensitivity have been numerous and protocols varied. To date there is little consensus as to the conduct of studies on this poorly-understood yet common and painful dental condition. A committee of interested persons from academia and industry was convened to discuss the subject of clinical trials on dentine hypersensitivity and a consensus report is presented. A double-blind randomized parallel groups design is recommended, although cross-over designs may be used for the preliminary screening of agents. Subjects may have multiple sites scored. Sample size will be determined by estimating the variability in the study population, the effect to be detected and the power of the statistical test to be used. Subject selection is based on a clinical diagnosis of dentine hypersensitivity, excluding those with conflicting characteristics such as currently-active medical or dental therapy. The vestibular surfaces of incisors, cuspids and bicuspids are preferred as sites to be tested. A range of sensitivity levels should be included. Tactile, cold and evaporative air stimuli should be applied. Negative and benchmark controls should be incorporated. Most trials should last 8 weeks. Sensitivity may be assessed either in terms of the stimulus intensity required to evoke pain or the subjective evaluation of pain produced by a stimulus using a visual analog or other appropriate scale. The subject's overall assessment may be determined by questionnaire. Outcomes should be expressed in terms of clinically significant changes in symptoms. Follow-up evaluation is required to determine the persistence of changes. At least 2 independent trials should be conducted before a product receives approval.

Air↗
PubMed1994

Proliferative potential of the attached cells of human junctional epithelium.

Samples of the attached cells of junctional epithelium (DAT cells) were obtained during extractions of eight erupted bicuspids from young healthy subjects. Each extracted tooth, with its layer of living DAT cells, was incubated for three hours in minimum essential medium (MEM) containing 5 microCi/ml of 3H-thymidine, and prepared for autoradiography. An average of 3 labeled cells per 1 mm of the epithelial attachment was found along the vertical dimension of the tooth. The attachment of an individual cell to the tooth surface was found to be a prerequisite for the cell's DNA synthesis suggesting that the tooth has a nonspecific epigenetic role in defining the functional phenotype of the DAT cells. Even the most coronal DAT cells located about 200 microns apical from the plaque border, were found to synthesize DNA. The finding suggests that mechanisms which regulate the multiplication of DAT cells are involved in the preservation of the integrity of the dentogingival junction.

Adolescent↗
PubMed2005

Measurements of tooth movements in relation to single-implant restorations during 16 years: a case report.

BACKGROUND: Osseointegrated implants behave as ankylotic abutments, and their positions are not affected by dentofacial changes. PURPOSE: To measure changes in occlusion in relation to single implants in one patient after more than 15 years in function. MATERIALS AND METHODS: One 25-year-old female was treated with two single implants in the upper central incisor and bicuspid area after trauma. Study casts made prior to treatment (1987) and after 16 years in function (2004) were scanned by means of an optical scanner. Using the palate as the reference, the models were placed in the same coordinate system and analyzed and compared in a computer-aided design (CAD) program. The results of the measurements of the casts were also compared with clinical photographs taken at the time of treatment (1988), after 9 years (1997), and after 16 years (2004) in function. RESULTS: The clinical photographs showed obvious signs of implant infraposition after 9 years. New crowns were made in the incisor region after 15 years (2002), but signs of infraposition were again present at the final examination (2004). Measurements of the casts indicated small tooth movements with a pattern of slight eruption of upper teeth combined with a palatal inclination, mesial drift, and lingual inclination and crowding of the lower anterior teeth. The small measured vertical eruption of the teeth was less than the observed clinical infraposition of the implant crowns, indicating that the vertical position of the palatal may have changed in relation to the implants as well. CONCLUSION: Obvious dentofacial changes may take place in adult patients. Teeth may adjust for this, and no major problems may arise in the dentate patient. However, because the positions of implants are not affected by dentofacial changes, other patterns of clinical problems can be seen when implant patients present with these changes. The character and frequency of these dentofacial changes that may compromise implant treatment in the long term are not yet known.

Adult↗
PubMed1986

Factors affecting the cost of fissure sealants: a dental insurer's perspective.

The slow adoption of sealants into dental practice is attributed partly to the fact that few prepayment plans pay for sealants. An important concern of insurers is how a sealants benefit will affect premiums. In this analysis, caries rates for various surfaces and teeth, failure rates for both sealants and amalgam restorations, fees and copayments, interest rates, reimbursement policies for replacement and repair, and the passage of time were studied to assess the cost to an insurer of amalgam restorations versus sealants. The results indicate: Sealants as a covered benefit for molars may not cause premiums to increase if fees and copayment levels are properly balanced. If caries in children continues to decline, however, higher premiums may be required if a sealant benefit is provided. Sealants as a covered benefit for bicuspids are likely to require higher premiums. The level of dental caries in the population should be monitored closely, because a further substantial decline in caries prevalence could diminish the economic argument for sealants.

Bicuspid↗
PubMed2004

An ex vivo assessment of gingivally offset lower premolar brackets.

OBJECTIVES: To compare the force to failure of standard premolar brackets to that of gingivally offset brackets and evaluate the site of bond failure between the two bracket types through the use of the Adhesive Remnant Index (ARI). DESIGN: An ex vivo study. SETTING: Dental Materials Science Laboratory, Dundee Dental School, Dundee. MATERIALS AND METHODS: Forty extracted lower premolar teeth (caries free, extracted as part of orthodontic treatment, all donors living in a non-fluoridated area), divided into two equal size sample groups, as follows: Group 1: Victory Series (3M Unitek, Monrovia CA, USA) lower premolar brackets bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Group 2: Victory Series Gingivally Offset Bicuspid Brackets (3M Unitek, Monrovia CA) bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Force was applied in the occluso-gingival direction using an Instron Model 4469 Universal Testing Machine (Instron Ltd, High Wycombe, UK) operating at a cross-head speed of 0.5 mm/min and its value at failure determined. Following debond, the site of bond failure and ARI were recorded. OUTCOME: Force to failure, site of bond failure and adhesive remnant index. RESULTS: The Weibull analysis gave higher values for the force to failure at 5% level (200 v. 159 N) and at all other levels of probability of failure for the gingivally offset bracket. The non-parametric survival analysis using Gehan-Wilcoxon tests with Breslow's algorithm (p < 0.0001) showed significant difference in force to failure between bracket types. Chi-square tests showed no significant (p = 0.55) relationship between the site of bond failure and the bracket types. CONCLUSION: Ex vivo testing suggests that there is a significant difference in the force to failure between gingivally offset and standard lower premolar brackets when force application is from an occluso-gingival direction. The site of failure (as given by the ARI) is insensitive to bracket types and force to failure.

Bicuspid↗
PubMed2004

Single-tooth implant restorations in the esthetic zone with PureForm ceramic crowns: 3 case reports.

The anterior maxillary jaw is frequently called the "esthetic zone" because of its high visibility and influence on facial appearance. Implant placement and single-tooth restoration in this region can present some esthetic challenges for the clinician. The underlying titanium abutment, for example, can diminish porcelain translucency and result in a darkened prosthesis. Subsequent changes in soft-tissue margins can also result in the visibility of titanium at the gingival crevice. In recent years, all-ceramic restorations have gained popularity in response to increasing patient demands for improved esthetics. This article describes the clinical use of a new, tooth-shaped, ceramic coping system in the restoration of single teeth in the esthetic zones of 3 patients. Four tapered screw implants were placed in the locations of the central incisors (n = 3) and bicuspid (n = 1). Conventional ceramic protocols were used to fabricate all-ceramic crowns that were cemented onto small core abutments attached to the implants. All prostheses restored the biomechanical needs of the patients and achieved excellent esthetic results.

Adult↗
PubMed2001

External resorption associated with tooth eruption.

A case is presented with severe resorption on the mesial root of the mandibular first permanent molar in a patient with Juvenile Periodontitis. The follicle of the bicuspid is seen in contact with mesial root of the molar.

Aggressive Periodontitis↗
PubMed1978

The natural history of periodontal disease in man. The rate of periodontal destruction before 40 years of age.

This longitudinal study of randomly selected Norwegian students and academicians has shown that 50% of the 17-year olds have lost no periodontal support, and the other 50% exhibited slight localized loss of attachment primarily on buccal surfaces of first molars and first bicuspids of both jaws. At 21 all students show one or more of these lesions as well as loss of attachment on interproximal surfaces. At 30 years of age the mean cumulative loss is still less than 1 mm. As they approach 40 years of age the mean individual loss of attachment is slightly above 1.5 mm or 10% of the total periodontal support, and the mean annual rate of attachment loss is 0.08 for interproximal surfaces and 0.1 mm for buccal surfaces. No case of juvenile periodontitis (periodontosis) or adult aggressive periodontitis were seen in this population. Seventy percent of the 15-year-old Sri Lankans have no or very little loss of periodontal support. However, approximately 30% exhibit localized lesions measuring between 2 and 9 mm and more than 1% have one or more root surfaces with 10 mm loss of attachment or more. In this age group the lesions occur at the interproximal and buccal aspects of lower central incisors and in first molars of both jaws. At 30 years of age the mean loss of attachment is 3.11 mm and approximately 25% of the tea laborers have lesions extending 10 mm or more below the cemento-enamel junction. As the Sri Lankan approaches 40 years of age the mean loss of attachment is 4.50 mm and the mean rate of progress of the lesion is 0.20 mm per year for buccal surfaces and 0.30 mm for interproximal surfaces. This study suggests that without interference the periodontal lesion progresses at a relatively even pace and that the progress is continuous.

Adolescent↗
PubMed1978

The relationship between attachment height and attachment area of teeth using a digitizer and a digital computer.

Nine lower first bicuspid teeth were mounted in blocks of plastic and their roots were serially sectioned and photographed. Data from the photographs were compiled by a digitizer and a digital computer, which calculated the cumulative root surface area for each millimeter of root height. From these data, three variables, which relate root surface area to root height, were calculated. It was found that if one-half of the height of attachment to the root were lost due to periodontal disease, a mean of 61.5% of the actual attachment area to the root is lost. If a mean of 5.72 mm of root attachment height is lost, or if a mean of 60.6% of the same root height remains, only one-half of the total root attachment area remains to provide tooth support.

Bicuspid↗
PubMed1980

Results of periodontal therapy related to tooth type.

Certain teeth or groups of teeth are prone to develop more severe periodontal destruction than other teeth in the same individuals. A test was made to assess if these same teeth or groups of teeth also respond less favorably to periodontal therapy than other teeth. Data from a longitudinal study of periodontal therapy for 78 patients over 8 years were analyzed with regard to effect of tooth types on treatment results. The response to periodontal treatment was only marginally related to tooth type with the most favorable responses in the maxillary and mandibular anterior teeth and the least favorable responses in the maxillary molars and bicuspids. Although a number of these differences were significant statistically, the actual values were too small to be of appreciable clinical significance. The overall prognosis for treatment of periodontal pockets apparently is good for all tooth types and this observation applies to moderate as well as to deep pockets.

Bicuspid↗
PubMed1998

Preservation of alveolar bone in extraction sockets using bioabsorbable membranes.

The purpose of this study was to evaluate the clinical effectiveness of a bioabsorbable membrane made of glycolide and lactide polymers in preserving alveolar ridges following tooth extraction using a surgical technique based on the principles of guided bone regeneration. Sixteen patients requiring extractions of 2 anterior teeth or bicuspids participated in the study (split-mouth design). Following elevation of buccal and lingual full-thickness flaps and extraction of teeth, experimental sites were covered with bioabsorbable membranes; control sites did not receive any membrane. Titanium pins served as fixed reference points for measurements. Flaps were advanced in order to achieve primary closure of the surgical wound. No membrane became exposed in the course of healing. Reentry surgeries were performed at 6 months. Results showed that experimental sites presented with significantly less loss of alveolar bone height, more internal socket bone fill, and less horizontal resorption of the alveolar bone ridge. This study suggests that treatment of extraction sockets with membranes made of glycolide and lactide polymers is valuable in preserving alveolar bone in extraction sockets and preventing alveolar ridge defects.

Absorption↗
PubMed2000

Treatment of periodontal destruction associated with a cemental tear using minimally invasive surgery.

BACKGROUND: A patient presented with moderate probing depth, pain on occlusal contact, and a fistula on a mandibular bicuspid. The probing depth increased 2 mm over a 3-month period despite relief of the occlusal trauma and resolution of the fistula. A radiograph showed an apparent separation of the cementum in the area of the pocket. METHODS: The lesion was treated using a minimally invasive surgical approach to place a bone graft. RESULTS: The probing depth was reduced to 2 mm with less than 1 mm of increased recession. A histologic examination of the damaged calcified tissue confirmed that it was cementum. CONCLUSIONS: The increasing probing depth associated with a cemental tear seems to indicate that this phenomenon contributed to loss of attachment and bone. Removal of the detached cementum in combination with bone grafting using a minimally invasive surgical approach appears to have successfully corrected the periodontal destruction.

Bicuspid↗
PubMed1982

Lead levels determined in Swedish permanent teeth by particle-induced X-ray emission.

The determination of lead in permanent teeth is a useful measure of past exposure in early childhood since these teeth are mineralized in early childhood. Particle-induced X-ray emission (PIXE) analysis has been shown to be a method with good applicability for the contamination-free analysis of elements heavier than calcium in dental hard tissues. The method is rapid and nondestructive. The purpose of this study, which used the PIXE technique, was to survey the average level of lead in the coronal dentin of permanent bicuspid teeth collected in three places representing Swedish urban and rural areas. In addition teeth from the New York City area were analyzed. The material comprised 165 teeth from Sweden and, for comparison, 14 teeth from New York City. The median value of lead in the Swedish teeth was 2.9 micrograms/g, a value indicating an insignificant influence from the environment in comparison to the New York teeth, for which the median value was 9.2 micrograms/g. There was however a statistically significant difference in the lead concentration of teeth from large and small Swedish cities; this finding may reflect different automobile traffic intensity.

Adolescent↗
PubMed1976

Creep in amalgam class V restorations.

The purpose of the investigation was to examine the creep rate in an amalgam Class V restoration. The stresses in a central bucco-lingual plane of a loaded bicuspid with a Class V restoration were computed with aid of the finite element method. When the stresses were known, the creep rate was calculated. The results showed that the creep rate of a load of 150 N varied between 0.6% and 3.5% per 104 s for amalgams with large differences between their viscoelastic behaviors. A gap between the restoration and the cavity margin will thus occur if a tooth is often heavily loaded.

Bicuspid↗
PubMed2000

[Comparative study of mandibular growth and rotation in two sample groups treated according to the "Distal Active Concept" or the Edgewise technique].

The "Distal Active Concept" therapy, favours an immediate repositioning of the mandible and introduces new therapeutic sequences which allow an easy correction of the Class II molar relationship, enhancing the mandibular growth simultaneously. The "Distal Active Concept" therapy is a combined treatment which induces the correction of the Class II malocclusion without extractions and without headgear. The dento-alveolar unit is used as a functional matrix to free, then enhance the mandibular growth and induce its counter-clockwise rotation. 35 patients treated with the "Distal Active Concept" therapy are compared to 33 patients, treated with the extraction of four bicuspids and in Edgewise therapy, in order to visualize the mandibular growth and the counterbalancing rotation described by Dibbets.

Adolescent↗
PubMed2000

Non-extraction treatment of a thirteen-year-old boy with a Class III skeletal discrepancy and severe crowding in both the upper and lower dentitions.

A thirteen-year-old boy presented with a Class III skeletal tendency in association with severe crowding in both the upper and lower arches. Whilst there was not a frank posterior crossbite, it was felt that the upper arch was narrow and that the lower arch was similarly constricted. Taking this into account along with the fact that his upper lip was flat and the nasolabial angle obtuse, it was decided to pursue a non-extraction treatment, with the aim of providing by expansion an extra 16 mm of space in the upper arch and 8 mm in the lower arch to accommodate the full dentition, and with a view to extracting third molar teeth later. This proved to be successful, albeit over an extended period of time, with active treatment taking nearly three and a half years. A realistic alternative would have been to remove four bicuspid teeth and pursue an orthodontic/surgical approach to treatment. In retrospect, and with the benefit of reviewing his records without surgical intervention, the treatment plan decided upon has been well justified.

Adolescent↗
PubMed2000

Local anesthesia in the palate: a comparison of techniques and solutions.

It was the purpose of the present investigation to determine if there were differences in soft-tissue anesthesia in the palate following infiltration and greater palatine nerve block anesthesia and to compare lidocaine with lidocaine plus epinephrine as palatal soft tissue anesthetics. Two studies using 10 volunteers were performed. In one trial, volunteers received a palatal infiltration opposite the second maxillary bicuspid on one side and a greater palatine nerve block on the other. Response to sharp probing and pain-pressure thresholds were measured on each side over a 1-hour census period. In the second trial, volunteers received 2% plain lidocaine as a palatal infiltration on one side and a similar infiltration of 2% lidocaine with 1:80,000 epinephrine on the other in a double-blind randomized fashion. Response to sharp probing was assessed over a 55-minute period. Data were analyzed using Student's paired t tests. The response to sharp probing and pressure-pain thresholds did not differ between palatal infiltration and greater palatine nerve block over the 1-hour period. Lidocaine with epinephrine provided longer lasting anesthesia than plain lidocaine following palatal infiltration (P < .001). Greater palatine nerve block and palatal infiltration provide similar soft-tissue anesthesia. Lidocaine with epinephrine produces longer-lasting soft-tissue anesthesia than plain lidocaine following palatal infiltration.

Adult↗
PubMed2001

Effect of gamma radiation on dentin bond strength and morphology.

Sterilization by gamma radiation is a method often used for bone and extracted teeth banking. The bond strength of human dentin submitted to gamma rays has not been reported. Therefore, the aim of this study was to assess the effect of gamma radiation on dentin shear bond strength and morphology. The roots were removed from extracted human bicuspids and their crowns divided into two groups: an untreated control and crowns submitted to gamma radiation sterilization. The crowns were mounted in epoxy resin and the buccal enamel removed exposing the subjacent dentin. SBMPPlus adhesive system was applied to a 3-mm diameter area after 15 s of 35% phosphoric acid etching. The samples were mounted in composite resin cylinders and stored in distilled water at 37 degrees C for 24 h until the shear test. Dental fragments from both groups were prepared for SEM analysis. There was no statistically significant difference between the results of the shear test for the two groups according to the Tukey test (p > 0.05). Scanning electron micrographs also did not show alterations. These results indicate that gamma radiation neither affected the shear bond strength of SBMPPlus nor altered the dentin surface morphology.

Analysis of Variance↗