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PubMed2005

Factors influencing the non-surgical eruption of palatally impacted canines.

BACKGROUND: Many palatally impacted canines in children do not require surgical exposure prior to the start of orthodontic treatment. They erupt in mid-alveolar positions providing excess space is made for them in the arch. The time required for an impacted tooth to emerge under these conditions is highly variable. AIM: To determine the factors influencing the time required for a palatally impacted canine to spontaneously disimpact following orthodontic treatment to create excess space in the arch. METHOD: Thirty palatally impacted canines, which emerged following orthodontic treatment to open excess space in the arch, were used. The impacted teeth were present in 28 children. No canines were surgically exposed. The positions of the impacted canines before treatment, the mesiodistal widths and rotations of the adjacent and contralateral lateral incisors, age and gender of the subjects, subjects' dental ages, presence of either incisor or premolar hypodontia, number of subjects with bilaterally impacted canines, and number of siblings with impacted canines were recorded. Canines that erupted in less than nine months of treatment were compared with canines that required more than nine months of treatment. The canines were grouped by severity of impaction (sectors II - IV) and compared. RESULTS: There were significantly more severe (sector IV) impactions in the long duration group compared with the short duration group. Significantly more cases of incisor-premolar hypodontia were found in the short duration group. Canines impacted in sector IV emerged after 21 months of treatment and canines in sectors II and III emerged after eight months of treatment. Lateral incisors adjacent to the impacted teeth were rotated mesiolabially to a greater extent in the sector IV group compared with lateral incisors in the sector II group. Differences in rotation of the adjacent and contralateral lateral incisors were significantly less in the sector II group compared with the lateral incisors in the sector III and IV groups. CONCLUSIONS: The sector of impaction was the best guide to the duration of treatment prior to emergence.

Adolescent↗
PubMed2005

Physical properties of human premolar cementum: hardness and elasticity.

AIMS: To determine if the cementum on the maxillary right and left first premolars has identical physical properties. METHODS: Ten normal maxillary first premolar teeth, extracted from five orthodontic patients with a mean age of 14.0 years, were used. The teeth had not been subjected to an orthodontic force. The hardness and elastic modulus of the cementum were measured on the buccal and lingual surfaces of the roots at three locations: cervical third, middle third and apical third. RESULTS: There were no significant side-to-side differences in cementum hardness (Mean side-to-side difference: 0.0063 GPa; SD: 0.0279; p = 0.525) or elastic modulus (Mean side-to-side difference: -0.027 GPa; SD: 0.111; p = 0.814). The hardness and elastic modulus of the cementum decreased from cervical to apical regions on both root surfaces. CONCLUSIONS: Similar physical properties of the cementum on the maxillary right and left first premolars suggest that intra-arch comparisons can be used to investigate root resorption caused by orthodontic forces.

Adolescent↗
PubMed2004

Prediction and causes of open gingival embrasure spaces between the mandibular central incisors following orthodontic treatment.

BACKGROUND: An open gingival embrasure space (OGES) between the mandibular incisors, also known as a "black triangle" (BT), can be an undesirable outcome of adult orthodontic treatment. OBJECTIVES: The purpose of this study was to determine the parameters that contributed most to the occurrence of an OGES between the mandibular central incisors, the area with the highest incidence of BT in the lower arch following orthodontic treatment. METHODS: A stepwise regression model was used to identify the variables (age, crowding, treatment duration, alveolar bone height, and six variables describing crown morphology) related independently to OGES score. Intra-oral photographs taken before and after orthodontic treatment, study models and intra-oral radiographs of 60 patients were used. Embrasures between the mandibular central incisors were measured and classified into three types: papilla filling, pinpoint, and BT. RESULTS: Age at the first consultation, length of active treatment and maximum crown width were larger in the BT group than in the normal group. In contrast, incisal edge - centre of the contact point, upper contact point - lower contact point, mesial CEJ - distal CEJ, and mesial CEJ - distal CEJ / maximum crown width were smaller in the BT group than in the normal group. Variation in OGES score was explained by the independent contributions of age at the first consultation, duration of active treatment, maximum crown width, and mesial CEJ - distal CEJ width. The multiple regression coefficient was 0.98, and the regression coefficient square was 96 per cent. CONCLUSION: We conclude that age at the first consultation, duration of active treatment, and crown morphology are involved in OGES manifestation. We suggest also that BT occurrence may be predictable prior to treatment.

Adolescent↗
PubMed2005

Celebrex offers a small protection from root resorption associated with orthodontic movement.

UNLABELLED: Tooth movement results from alveolar bone resorption/deposition following application of orthodontic forces, and root resorption can be an undesirable complication associated with this process. No treatment for external root resorption is available to date. OBJECTIVE: To determine if COX-2 inhibitors like Celebrex are effective in protecting root resorption associated with orthodontic forces. METHODS: A force of 80 grams was applied to the left maxillary first molars of 7-week-old female Wistar rats using nickel titanium closed coil springs attached to the cervical area of the incisors with 0.010 stainless-steel ligature wires. Twenty animals were divided into three experimental groups: one receiving no treatment, the second receiving 25mg/kg, and the third receiving 50 mg/kg of celecoxib (Celebrex) in their drinking water. Rats were maintained on a soft diet and euthanized two weeks after initial placement of the force. Paraffin-embedded sections of the right (control) and left (experimental) maxillae were stained with H&E and the areas of root resorption were examined by counting the number of lacunaes in the roots. RESULTS: No difference in the distance of tooth movement (0.5 mm/two weeks) was seen in all three groups. The rats that received the low dose of Celebrex showed no statistically significant difference in root resorption than that of the rats that received no dose. The rats that received the high dose of Celebrex showed a lower number of lacunaes (mean = 3.5) than that of the control group (mean 10.2; p=0.02). CONCLUSIONS: Administration of Celebrex during the application of orthodontic forces does not interfere with tooth movement and appears to offer some slight protection against root resorption.

Animals↗
PubMed2005

[Prevalence and etiologic factors of non-carious cervical lesions. A study in a Senegalese population].

The non carious cervical lesion (NCCL) is a loss of tooth tissue at the neck of affected teeth that is unrelated to tooth decay. They are commonly encountered in clinical practice and present in a variety of forms. The purpose of this paper is to determine the prevalence of the NCCL in a Senegalese population. From 655 patients, 112 with cervical lesions were identified i.e. a global prevalence of 17.10%. The prevalence rate for abrasion was reported to be 77.70%, 12.50% for abfraction and 9.80% for erosion. Etiological factors were studied for abrasion and erosion. 54% of the patients with abrasion used their toothbrush horizontally. For erosion, only external factors were identified: consumption of acidic drinks (9 patients) or alcohol (1 patient) and professional environment (1 patient). Dentists should consider these lesions in their daily practice.

Adolescent↗
PubMedDate not supplied

Non carious cervical lesions. A review.

Non-carious cervical lesions (NCCL) are characterized by a loss of hard dental tissue near the cement-enamel-junction. Commonly, their shape is like a wedge with the apex pointing inwards. Other times, they appear as regular depressions, like a dome or a cup. Their main characteristic is the presence of hard-mineralized tissue. According to the literature, the prevalence of cervical lesions is 85%, while their incidence is about 18% among permanent teeth. NCCL are currently classified as erosion, abrasion, or abfraction. Their etiology seems to be related to different factors: hexogen and endogen acids, mechanical abrasive action, tooth flexion under axial and non-axial loads. Moreover, it seems that a fundamental role is ascribable to tooth bending phenomena due to the strength components parallel or oblique to the occlusal level, which occur during the normal function as well as during parafunctions. The frequent therapeutic failures are probably due to the same factors causing the onset of the original lesion. Several materials have been proposed to restore NCCL: amalgam (abandoned), glass-ionomer cements, compomers, and composite resins. Early failures of these restorations have often been reported in the literature, probably due to the same factors which originally caused the lesions. Further investigations are required to determine more reliable restorative therapies.

Compomers↗
PubMed2006

Clinical evaluation of a resin-modified glass-ionomer liner for cervical dentin hypersensitivity treatment.

PURPOSE: To evaluate the effectiveness of two agents for treating cervical dentin sensitivity associated with gingival recession or noncarious cervical lesions. METHODS: 44 patients with at least mild sensitivity affecting cervical dentin were enrolled in a longitudinal randomized clinical trial. A resin-based desensitizer or an experimental glass-ionomer was assigned to treat at most two teeth from each side of the mouth. Sensitivity was assessed by tactile and cold tests, measured with a Visual Analogue Scale at baseline, after treatment, and at 1 week, 1, 3, 6, and 12 months after treatment. Other noteworthy clinical observations were recorded. RESULTS: Both treatments effectively reduced dentin sensitivity (mixed linear model analysis). Sensitivity score for the glass-ionomer was significantly lower than for the resin-based desensitizer after treatment and at all follow-up periods (P < 0.0001). Some overhanging margins were observed in the glass-ionomer group, which could accumulate plaque and cause gingivitis. Despite material loss from some teeth treated with the glass-ionomer, the follow-up sensitivity scores were still lower than baseline scores.

Adult↗
PubMed2006

[External root resorption].

Root resorption may be a physiological (resorption of deciduous teeth) or a pathological process (resorption of permanent teeth). In the latter case an external and an internal form of resorption can be distinguished. Root resorption may occur on one tooth or on several teeth within a dentition and it may be caused by trauma, periodontitis, orthodontic treatment, internal bleaching, cysts, tumors, or by stimuli from a necrotic dental pulp. Current knowledge concerning the pathogenesis of root resorption and therapeutic approaches are presented. For cervical resorption, it is assumed that the stimulus for the resorbing cells originates from the bacteria within the gingival sulcus and along the affected root surface. The case presented here was initially diagnosed as chronic periodontitis of medium severity. Scaling and root planing were performed resulting in a significant improvement of the periodontal status. Two years later, following a period of irregular recall visits, the patient presented with large areas of cervical resorption on teeth 36 and 37 which made it impossible to preserve these teeth. After another six months, teeth 34 and 35 showed deep destruction caused by external root resorption, mandating the extraction of these teeth as well. Fourteen months later, external root resorptions were evident on teeth 32 and 33, and at the same time, a recurrence of the chronic periodontitis was noted. Periodontal therapy was performed under a systemic antibiotic regime. It was possible to preserve teeth 32 and 33 through surgical crown lengthening procedures. No additional resorption has been observed ever since.

Adult↗
PubMedDate not supplied

Soft tissue management for difficult cervical restorations.

This article offers a rationale for choosing methods of isolation and soft tissue management that will result in the best possible operating conditions for treating cervical dental lesions. A surgical technique used in conjunction with rubber dam isolation is described for those Class V lesions that cannot be managed effectively in a routine manner.

Dental Restoration, Permanent↗
PubMed2006

Fracture resistance of fragmented incisal edges restored with fiber-reinforced composite.

PURPOSE: The aim of this study was to determine the static load-bearing capacity of fractured incisors restored with the conventional adhesive-composite technique or by using fiber-reinforced composites (FRC). MATERIALS AND METHODS: Twelve extracted sound maxillary incisors per group were prepared by cutting the incisal (one-third) part of the crown horizontally. Restorations were made using three techniques. Group A (control group) was restored by reattaching the original incisal edge to the tooth. Group B was restored using particulate filler composite (PFC). Group C was restored with PFC and FRC by adding a thin layer of FRC on the palatal surface of tooth. The bonding system used was the conventional etch system with primer and adhesive. All restored teeth were stored in water at room temperature for 24 h before they were statically loaded until fracture in a universal testing machine. Data were analyzed using ANOVA (p = 0.05). Failure modes were visually examined. RESULTS: Group A (reattaching fractured incisal edge) revealed the lowest load-bearing values, whereas preparation of the new incisal part with PFC revealed 148% higher load-bearing values compared to Group A. Group C (teeth restored with FRC) revealed a 254% higher load-bearing capacity than the control group. ANOVA revealed that the restoration technique significantly affected load-bearing capacity (p < 0.001). The failure mode in Groups A and B was debonding of the restoration from the adhesive interface, while in group C, 50% of the teeth fractured below the cementoenamel junction. CONCLUSION: These results suggest that an incisally fractured tooth restored with a combination of PFC and FRC provide the highest load-bearing capacity.

Acid Etching, Dental↗
PubMed2006

The clinical relevance and correlation between the initial straight length to the first curvature in human second maxillary premolars.

The aim of this study was to evaluate the straight lengths of the root canal of human second maxillary premolars using standardized radiological techniques in vitro. The distances were examined starting from the cemento-enamel junction (CEJ) to the appearance of a curvature. In particular recommendations which may facilitate decision making with regard to the length of post systems after successful endodontic treatment should be available. Extracted human second maxillary premolars (n = 210) were used; teeth with root caries, artificial crowns, extensive fillings or with previous endodontic treatment were excluded from this investigation. The teeth were fixed in a specially developed device with standardized and reproducible distances and digital radiographs using the parallel technique were made. A descriptive statistical analysis and the calculation of the cumulative frequencies were made. The values for the distance starting from the CEJ to a first curvature were as follows: a) For right second premolars: median value=10.3 mm (min.: 5 mm; max.: 15.8 mm) and mean value= 10.4 SD+/- 2.6 mm; b) left second premolars: median value =10.2 mm (min.: 5 mm; max.: 17 mm) and mean value =10.3 mm SD +/-2.2 mm. Based on our data, high number of second maxillary premolars showed a curvature (30.4%) 9 mm apically from the CEJ. These findings should be taken into consideration for endodontic treatments and post insertions.

Bicuspid↗
PubMed2006

Retention of restorations placed in noncarious cervical lesions after centric and eccentric occlusal loading in a chewing simulator--A pilot study.

PURPOSE: To evaluate in a pilot study whether (1) loading of restored teeth in a chewing simulator is an adequate method to reproduce clinical data about the retention rate of restorations placed in noncarious cervical lesions by means of the one-step self-etching adhesive system Prompt-L-Pop, and (2) whether eccentric loading contributes to the loss of Class V fillings. MATERIALS AND METHODS: In 12 extracted mandibular premolars with noncarious buccal cervical lesions of similar dimensions, restorations were placed without preparation using Prompt-L-Pop and Tetric Ceram. The adhesive was applied in one layer and cured at 650 mW/cm2 for 10 s, while the composite was placed in two increments and cured at 1200 mW/cm2 for 10 s. After storage in water at 37 degrees C for 7 days, the teeth were mounted in a chewing simulator that uses pneumatic cylinders as force actuators and subjected to a centric load of 50 N and 1,200,000 load cycles at a frequency of 1.6 Hz and simultaneously to 3125 thermocycles (5 degrees C/55 degrees C). The antagonists were standardized and made of Empress ceramic material. Every 100,000 load cycles, the fillings were evaluated with regard to retention. In the second phase, the same teeth were loaded on the lingual cusps with new antagonists for another 1,200,000 cycles. RESULTS: Neither during centric nor eccentric loading was any restoration loss observed. CONCLUSION: The short-term loading of extracted teeth with Class V fillings in a chewing simulator was inadequate to reproduce the data of clinical studies on the retention rate of a self-etching adhesive system. Obviously, long-term degradation mechanisms (eg, hydrolysis) acting on the composite/dentin interface play a more crucial role when it comes to the loss of retention of Class V restorations. Eccentric loading alone did not contribute to the loss of fillings, so that the theory--which maintains that this type of occlusal stress is a major cause for abfractions or the retention loss of restorations placed in abfraction lesions--may be questioned.

Aluminum Silicates↗
PubMed2006

Noncarious cervical lesions among a non-toothbrushing population with Hansen's disease (leprosy): initial findings.

OBJECTIVE: The purpose of this preliminary investigation was to examine the presence of noncarious cervical lesions (NCCLs) among a convenience sample of non-toothbrushing subjects with Hansen's disease (leprosy). METHOD AND MATERIALS: A cross-sectional sample of 102 non-toothbrushing subjects (20 to 77 years of age) was examined. The clinical parameter of interest for this study was the presence or absence of NCCLs and their probable etiology as it relates to the subjects' diet, occlusion, and use of medication. Subjects were examined clinically and interviewed according to study protocol. RESULTS: NCCLs were found in 48 subjects (47% of the studied sample). Widespread consumption of acidic foods and beverages acting as corrodents, signs of parafunction, and use of medication that causes xerostomia were also noted. Thus, all may be contributing factors in the etiology of NCCLs in this population. CONCLUSION: This preliminary report suggests that toothbrush/dentifrice abrasion was not a factor in the etiology of NCCLs in the population studied. The authors intend to expand their study among these non-toothbrushing

Adult↗
PubMed2006

Minimally invasive restorative dentistry: a biomimetic approach.

When providing dental treatment for a given patient, the practitioner should use a minimally invasive technique that conserves sound tooth structure as a clinical imperative. Biomimetics is a tenet that guides the author's practice and is generally described as the mimicking of natural life. This can be accomplished in many cases using contemporary composite resins and adhesive dental procedures. Both provide clinical benefits and support the biomimetic philosophy for treatment. This article illustrates a minimally invasive approach for the restoration of carious cervical defects created by poor hygiene exacerbated by the presence of orthodontic brackets.

Adolescent↗
PubMedDate not supplied

Find canals faster through basic research.

Achieving access and finding canals are the key first steps in the endodontic procedure. This has always been a time-consuming, qualitative procedure that relies on the dentist's experience and feel. Recent basic research has been published that shows that the anatomic morphological measurements concerning the pulp chamber are very consistent in every tooth. This research points the way to a quantitative, predictable and quick technique for making endodontic access preparations without risk. The research and clinical technique are described in this article.

Dental Pulp↗
PubMed2006

Clinical evaluation of self-etch adhesives in Class V non-carious lesions.

PURPOSE: To evaluate the clinical performance of two self-etching and one total-etch adhesives in Class V non-carious cervical lesions (NCCL). METHODS: Two self-etching primers, Clearfil SE Bond and Hybrid Bond, and one total etch adhesive, Admira Bond, were placed in 195 NCCL. Restorations were evaluated at baseline, 1 and 2 years using the USPHS criteria. RESULTS: No restoration was lost after 1 and 2 years for all materials. There was no significant difference between the baseline and 2-year results for Admira Bond and Clearfil SE Bond restorations. In contrast, Hybrid Bond restorations showed significant deterioration in marginal adaptation and cavosurface marginal discoloration after 2 years. Also, there was no significant difference between Admira Bond and Clearfil SE Bond at each recall period.

Acid Etching, Dental↗