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ABSTRACT: This investigation measured and compared shear bond strength (SBS) and adhesive remnant indices (ARIs) of Damon3 and Damon3MX brackets bonded with their recommended primer/adhesive combination or Transbond XT primer/adhesive, with APC II brackets bonded using Transbond XT. Sixty non-carious human third molars were collected and randomly divided into six equal groups of 10. Amongst these, one group was used to standardize the testing methodology, with the remainder constituting the five experimental groups. Upper right central incisor brackets represented each bracket type. Specifically, Damon3 brackets were bonded using either OrthoSolo primer/Blugloo (recommended) or Transbond XT primer/adhesive; Damon3MX brackets were bonded using OrthoSolo primer/Grengloo (recommended) or Transbond XT primer/adhesive, and APC II brackets were bonded with Transbond XT primer. Brackets were debonded by shear force using an Instron machine and the SBS measured. Scores for ARI were determined for all groups after bracket failure by magnified inspection of the tooth surface. Logrank tests showed a significantly higher SBS with Damon3 brackets bonded with OrthoSolo/Blugloo compared with Transbond XT, but no significant differences between the SBS of Damon3MX brackets bonded with OrthoSolo/Grengloo compared with Transbond XT. There were no significant differences in SBS of all three bracket types when bonded with Transbond XT. Pearson's chi-square test showed no difference in the locus of debond. All three adhesive systems are reliable when bonding Damon3 and Damon3MX brackets. Some caution should be taken when using Damon3 brackets bonded with OrthoSolo/Blugloo due to the higher SBS, although no enamel fractures were noted in this study.
The European Journal of Orthodontics 10/2011; · 0.89 Impact Factor
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ABSTRACT: The erbium laser has been introduced for cutting enamel and dentin and may have an application in the surface modification of high-strength aluminum oxide and zirconia ceramics. The aim of this study was to evaluate the durability of the bond of conventional dual-cured resin cements to Procera Al(2)O(3) and zirconium oxide ceramics after surface treatment with air abrasion and erbium laser.
One hundred twenty Al(2)O(3) and 120 zirconia specimens measuring 3 × 3 × 0.7 mm(3) were divided equally into three groups, and their surfaces treated as follows: either untreated (controls), air abraded with Al(2)O(3) particles, or erbium-laser-treated at a power setting of 200 mJ. The surface of each specimen was then primed and bonded with one of two dual-cured resin cements (either SCP-100 Ceramic Primer and NAC-100 or Monobond S and Variolink II) using a 1-mm thick Tygon tube mold with a 0.75-mm internal bore diameter. After 24 hours and 6 months of water storage at 37°C, a microshear bond strength test was performed at a crosshead speed of 1 mm/min. Surface morphology was examined using a confocal microscope, and failure modes were observed using an optical microscope. The data were analyzed using the Kaplan-Meier nonparametric survival analysis.
In the case of zirconia, air abrasion and Erbium:yttrium-aluminum-garnet (Er:YAG) laser treatment of the ceramic surface resulted in a significant reduction in the bond strengths of both resin cements after 6 months water storage; however, when the zirconia surface was left untreated, the SCP-100/NAC-100 group did not significantly reduce in bond strength. In the case of alumina, no treatment, air abrasion and Er:YAG laser treatment of the surface led to no significant reduction in the bond strengths of the three SCP-100/NAC-100 groups after 6 months water storage, whereas all three Monobond S/Variolink II groups showed a significant reduction.
Er:YAG laser treatment of the zirconia surface did not result in a durable resin cement/ceramic bond; however, a durable bond between a conventional dual-cured resin cement and Procera All Ceram and Procera All Zirkon was formed using a ceramic primer containing the phosphate monomer, MDP, without any additional surface treatment.
Journal of Prosthodontics 02/2011; 20(2):84-92. · 1.01 Impact Factor
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ABSTRACT: To measure the slot dimensions of 0.022 inch self-ligating upper central incisor brackets from six manufacturers using electron microscopy, to compare the measured dimensions with the manufacturers' published dimensions, and to determine if the walls of the slots were parallel.
Six self-ligating upper central incisor brackets from four manufacturers (SmartClip and Clarity SL, 3M Unitek, Monrovia, CA, USA; Speed, Strite Industries Ontario, Canada; Damon MX, Ormco, Orange, CA, USA; In-Ovation R and In-Ovation C, Dentsply GAC, Bohemia NY, USA) were imaged with a scanning electron microscope and the slots heights measured. Intra-operator repeatability and accuracy were determined.
All brackets had slot sizes that were significantly larger (p < 0.05) than the stated 0.022 inch. Speed brackets were 5.1 per cent larger (0.02311 inch) and the closest to the published dimension. The SmartClip brackets were 14.8 per cent larger (0.02526 inch) than the quoted slot size of 0.022 inch. In most brackets the distances between the slot walls was generally greater further from the bracket bases.
The actual measurements of upper central incisor self-ligating brackets from six manufacturers were larger than the manufacturers' stated dimension, and the walls of the slots diverged from the bracket bases.
Australian orthodontic journal 05/2010; 26(1):38-41. · 0.25 Impact Factor
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ABSTRACT: The aims of this study were to evaluate the flexural strength of two different types of glass fibre-reinforced posts bonded to dual-cure composite resin cements. Forty glass methacrylate-based fibre posts (GC Fiber Post) and 20 glass fibre inter-polymerizing network posts (everStick POST) were divided into three groups. Group 1 contained 20 GC posts that were bonded to a dual-cure composite cement (UnifilCore). Group 2 contained 20 Stick Tech posts that had adhesive applied (Scotchbond Multipurpose resin) and were bonded to a dual-cure composite resin cement (RelyX Unicem). Group 3 contained 20 GC posts that were pretreated with a silane-coupling agent before being treated with resin and composite, as in group 1. A 4-point bend test was carried out to failure on all of the groups. Failure modes were determined using scanning electron microscopy. Pretreatment of the post surface with the silane-coupling agent did not increase the flexural strength. The flexural strength of the Stick Tech post was significantly lower than the flexural strength of the GC post. The mode of failure for the GC Posts was adhesive, whereas the Stick Tech posts failed cohesively. Different flexural strengths and failure modes were observed among the two fibre post-resin systems.
European Journal Of Oral Sciences 04/2010; 118(2):197-201. · 1.88 Impact Factor
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ABSTRACT: This study aimed to investigate the null hypothesis that there is no relationship between the microhardness of carious dentine and its native autofluorescence (AF). Six extracted, carious molars were sectioned through natural lesions in the mesio-distal longitudinal plane. The Knoop microhardness (Knoop hardness number, KHN) of the cut surfaces of each sample was recorded at regular intervals through sound and carious dentine. Confocal fibre-optic micro-endoscopic (CFOME) examination of the carious dentine and the sound dentine was carried out at the same intervals using the Cellvizio system (600 microm wide, flat-end probe) with an excitation wavelength of 488 nm. The blindly collected numerical data were analysed using the original microhardness KHN. The data analysis indicated that the autofluorescence signals increased significantly when the microhardness of dentine dropped below 25 KHN. Therefore, the null hypothesis was disproved, and it was concluded from this investigation that the autofluorescent signal intensity recorded using CFOME could produce an objective and reproducible correlation to the microhardness of carious dentine. Confocal fibre-optic micro-endoscopic examination could have clinical potential as a technology to help delineate the carious dentine that might be excavated in a clinical procedure in vivo.
European Journal Of Oral Sciences 02/2010; 118(1):75-9. · 1.88 Impact Factor
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ABSTRACT: STATEMENT OF PROBLEM: Little information exists regarding the outcome of crown build-ups on endodontically treated teeth restored with metal- ceramic crowns or with only a direct-placed composite. PURPOSE: The aim of this study was to evaluate the clinical success rate of endodontically treated premolars restored with fiber posts and direct composite restorations and compare that treatment with a similar treatment of full-coverage with metal-ceramic crowns. MATERIALS AND METHODS: Subjects included in this study had one maxillary or mandibular premolar for which endodontic treatment and crown build up was indicated and met specific inclusion/exclusion criteria. Only premolars with Class II carious lesions and preserved cusp structure were included. Subjects were randomly assigned to 1 of the following 2 experimental groups: (1) teeth endodontically treated and restored with adhesive techniques and composite or (2) teeth endodontically treated, restored with adhesive techniques and composite, and then restored with full-coverage metal-ceramic crowns. Sixty teeth were included in the first group and 57 in the second. All restorations were performed by one operator. Causes of failure were categorized as root fracture, post fracture, post decementation, clinical and/ or radiographic evidence of marginal gap between tooth and restoration, and clinical and/ or radiographic evidence of secondary caries contiguous with restoration margins. Subjects were examined for the listed clinical and radiographic causes of failure by 2 calibrated examiners at intervals of 1,2, and 3 years. Exact 95% confidence intervals for the difference between the 2 experimental groups were calculated. RESULTS: At the 1-year recall, no failures were reported. The only failure modes observed at 2 and 3 years were decementations of posts and clinical and/or radiographic evidence of marginal gap between tooth and restoration. There was no difference in the failure frequencies of the 2 groups (95% confidence interval, --17.5 to 12.6). There was no difference between the number of failures caused by post decementations and the presence of marginal gaps observed in the 2 groups (95% confidence intervals, --9.7 to 16.2 and --17.8 to 9.27). CONCLUSION: Within the limitations of this study, the results upheld the research hypothesis that the clinical success rates of endodontically treated premolars restored with fiber posts and direct composite restorations after 3 years of service were equivalent to a similar treatment of full coverage with metal-ceramic crowns.
International Endodontic Journal 06/2009; 42(5):401-5. · 2.18 Impact Factor
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ABSTRACT: The purpose of this study was to evaluate the microtensile strength of composite bonded to interpenetrating polymer network (IPN) or cross-linked glass fibre posts and to observe the failure modes by using light and scanning electron microscopy.
Twenty posts containing IPN resin matrix and 20 posts containing cross-linked epoxy polymer matrix were used for testing. One half of the posts from each type was treated with Stick Resin, the other half was treated with OptiBond. Composite resin was used to build up a block on the bonding surface. Tensile strength data was analysed statistically using the non-parametric Kaplan-Meier survival analysis. The distribution of failure modes as a function of post type/bonding agent was evaluated using the chi(2) test.
The mean tensile strength values were lower for the groups bonded with OptiBond and higher for the groups bonded with Stick Resin (p = 0.017), the type of post used had no statistical significance (p = 0.263). All the IPN posts showed cohesive failure within the post The cross-linked posts demonstrated a higher number of adhesive failures and lower number of cohesive failures within the post (chi(2) = 0.0001).
Stick Resin was more effective than OptiBond in bonding composite cores to fibre posts. Post fracture was the failure mode of IPN posts, debonding of the composite core was the failure mode of most of cross-linked posts. These different failure modes may appear clinically in endodontically treated teeth restored with the post types tested in this study.
Medicina oral, patologia oral y cirugia bucal 12/2008; 13(11):E745-52.
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ABSTRACT: INTRODUCTION: The aim of this study was to compare the efficiency of mandibular tooth alignment and the clinical effectiveness of a self-ligating and a conventional preadjusted edgewise orthodontic bracket system. METHODS: A multicenter randomized clinical trial was conducted in 2 orthodontic clinics. Sixty-two subjects (32 male, 30 female; mean age, 16.27 years) with mandibular incisor irregularities of 5 to 12 mm and a prescribed extraction pattern including the mandibular first premolars were randomly allocated to treatment with Damon3 self-ligating (Ormco, Glendora, Calif) or Synthesis (Ormco) conventionally ligated brackets. Fully ligated 0.014-in nickel-titanium archwires were used first in both groups, followed by a sequence of 0.014 x 0.025-in and 0.018 x 0.025-in nickel-titanium, and 0.019 x 0.025-in stainless steel. Study casts were taken at the start of treatment (T1), the first archwire change (T2), and the placement of the final 0.019 x 0.025-in archwire (T3). Cephalometric lateral skull and long-cone periapical radiographs of the mandibular incisors were taken at T1 and T3. RESULTS: No significant difference was noted (P >0.05) in initial rate of alignment for either bracket system. Initial irregularity influenced subsequent rate of movement, but sex, age, and appliance type were statistically insignificant. Alignment was associated with an increase in intercanine width, a reduction in arch length, and proclination of the mandibular incisors for both appliances, but the differences were not significant. Incisor root resorption was not clinically significant and did not differ between systems. CONCLUSIONS: Damon3 self-ligating brackets are no more efficient than conventional ligated preadjusted brackets during tooth alignment.
American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 10/2008; 134(4):470-1. · 1.33 Impact Factor
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ABSTRACT: The aim of this study was to compare the efficiency of mandibular tooth alignment and the clinical effectiveness of a self-ligating and a conventional preadjusted edgewise orthodontic bracket system.
A multicenter randomized clinical trial was conducted in 2 orthodontic clinics. Sixty-two subjects (32 male, 30 female; mean age, 16.27 years) with mandibular incisor irregularities of 5 to 12 mm and a prescribed extraction pattern including the mandibular first premolars were randomly allocated to treatment with Damon3 self-ligating (Ormco, Glendora, Calif) or Synthesis (Ormco) conventionally ligated brackets. Fully ligated 0.014-in nickel-titanium archwires were used first in both groups, followed by a sequence of 0.014 x 0.025-in and 0.018 x 0.025-in nickel-titanium, and 0.019 x 0.025-in stainless steel. Study casts were taken at the start of treatment (T1), the first archwire change (T2), and the placement of the final 0.019 x 0.025-in archwire (T3). Cephalometric lateral skull and long-cone periapical radiographs of the mandibular incisors were taken at T1 and T3.
No significant difference was noted (P >0.05) in initial rate of alignment for either bracket system. Initial irregularity influenced subsequent rate of movement, but sex, age, and appliance type were statistically insignificant. Alignment was associated with an increase in intercanine width, a reduction in arch length, and proclination of the mandibular incisors for both appliances, but the differences were not significant. Incisor root resorption was not clinically significant and did not differ between systems.
Damon3 self-ligating brackets are no more efficient than conventional ligated preadjusted brackets during tooth alignment.
American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 10/2008; 134(4):470.e1-8. · 1.33 Impact Factor
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ABSTRACT: The purpose of this study was to investigate the quality and number of letters of referral for new patients received in the Prosthodontics Department of a Dental Teaching Hospital. Letters received during the month of May 2006 were included. Each letter of referral was tested against five criteria which might be expected in an appropriate letter of referral. These were information on the following: relevant dental history, relevant medical history, teeth present, diagnosis, and treatment plan. The results showed that only 8% of letters met all five criteria and 11% met none of them. Letters requesting better information were sent to referring practitioner as a result of this audit. However a re-audit in May 2007 showed that 9% of letters met all five criteria and 15% met none of them. A need has been identifiedfor better referral letters and ways of achieving this were discussed.
The European journal of prosthodontics and restorative dentistry 10/2008; 16(3):128-31.
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ABSTRACT: The aim of this study was to compare the degree of discomfort experienced during the period of initial orthodontic tooth movement using Damon3 self-ligating and Synthesis conventional ligating pre-adjusted bracket systems. Sixty-two subjects were recruited from two centres (32 males and 30 females; mean age 16 years, 3 months) with lower incisor irregularity between 5 and 12 mm and a prescribed extraction pattern, including lower first premolar teeth. These subjects were randomly allocated for treatment with either bracket system. Fully ligated Damon3 0.014-inch Cu NiTi archwires were used for initial alignment in both groups. Following archwire insertion, the subjects were given a prepared discomfort diary to complete over the first week, recording discomfort by means of a 100 mm visual analogue scale at 4 hours, 24 hours, 3 days, and 1 week. The subjects also noted any self-prescribed analgesics that were taken during the period of observation. Data were analysed using repeated measures analysis of variance. There were no statistically significant differences in perceived discomfort levels between the two appliances; discomfort did not differ at the first time point and did not develop differently across subsequent measurement times. Overall, this investigation found no evidence to suggest that Damon3 self-ligating brackets are associated with less discomfort than conventional pre-adjusted brackets during initial tooth alignment, regardless of age or gender.
The European Journal of Orthodontics 07/2008; 30(3):227-32. · 0.89 Impact Factor
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ABSTRACT: To investigate possible relationships between patient and clinical factors and patient satisfaction with new complete dentures.
Patients attending King's College London Dental Institute, Guy's Hospital, London, for new complete dentures were recruited. Relevant history was recorded and the edentulous mouth and existing dentures, where present, were examined at the beginning of treatment. The edentulous mouth, the previous and new dentures were re-examined at the first post-insertion visit. Three months after this visit, patients were sent a postal questionnaire to assess patient satisfaction. Data were analysed using structural equation modelling techniques.
723 patients were recruited. Significant relationships were found between quality of complete dentures, quality of residual alveolar, adaptability factors and patients' satisfaction with complete dentures.
Quality of the mandibular residual alveolar ridges, retention and stability of the mandibular dentures, accuracy of reproduction of retruded jaw relationship and patient adaptability were powerful determinants of patients' satisfaction with new complete dentures.
Journal of Dentistry 07/2008; 36(6):427-34. · 2.95 Impact Factor
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ABSTRACT: Water sorption decreases the mechanical properties and the bond strengths of resin-bonded dentine. The aim of this study was to evaluate the micropermeability of several self-etching and etch-and-rinse adhesives. Optibond FL, Silorane, Scotchbond 1XT, G-Bond, and DC-Bond were bonded under simulated pulpal pressure. A 10 wt% solution of ammoniacal silver nitrate and a 1 wt% solution of rhodamine B were injected into the pulp chamber at 20 cm of water pressure. The dentine-adhesive interfaces were examined using a confocal scanning microscope. Micropermeability was detected in all the adhesives. DC-Bond, G-Bond, and Scotchbond 1XT showed voids along the resin-bonded interface. Silorane and Optibond FL showed an adhesive layer that was free from water trees and micropermeability. The double staining technique is a method that gives accurate results in the study of the resin-dentine micropermeability. Each class of adhesive has a different distribution of micropermeability. The higher the micropermeability, the higher the risk of defects at the resin-dentine interface, which may represent the pathway for hydrolytic and enzymatic degradation of resin-dentine bonds over time.
European Journal Of Oral Sciences 05/2008; 116(2):184-93. · 1.88 Impact Factor
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ABSTRACT: The aim of this study was to investigate the different smear layer morphologies produced by instrumentation with a hand curette and a periodontal sonic scaler for potential removal by soft acidic solution. The effect of a new oxalate-containing phytocomplex spray in preventing tubules exposure after citric acid solution application was also evaluated.
Thirty recently extracted human teeth were used to obtain root dentinal fragments and divided in two groups: Curette treatment (CRT) root planed applying 30 working strokes to each surface using a Gracey's curette 5-6 and Ultrasonic scaler (USC) treated using a periodontal scaler mounted on an ultrasonic hand-piece for 30 seconds. Each principal group was further divided in three sub-groups (Control, Acid challenge and Acid/Phyto-oxalate). The control group samples were immersed in distilled water buffered to pH 7.4 using NH4OH solution. The samples of the acid challenge group were immersed in a solution of citric acid 0,02 M; [pH 2.5] for 3 minutes. The samples of the Acid/Phyto-oxalate group were sprayed for 15 sec with a 1.5% phytocomplex spray prior to immersion. Samples were examined using SEM.
Ultrasonic instrumentation created a very thin smear layer whereas curettes produced a multilayered smear layer. The acidic solution was able to remove the smear layer from root surfaces treated with ultrasonic instrumentation exposing the dentinal tubules. The smear layer on the root surfaces treated with hand instruments was not completely removed. The phytocomplex solution was able to prevent dentinal tubule exposure.
Acidic soft drinks are able to remove the smear layer created on root surfaces during different non-surgical periodontally treatments. The smear plugs created by hand instrumentation appeared to be more resistant to acid attack. The tested phytocomplex solution protected the dentine from demineralization and it might prevent post-treatment dentinal hypersensitivity induced by acidic soft drinks.
Medicina oral, patologia oral y cirugia bucal 01/2008; 12(7):E542-8.
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ABSTRACT: Application of ultrasensitive diagnostics has shown that small numbers of p53 mutation-positive cells may signify the presence of residual tumor in histologically normal tissues after resection of squamous cell carcinomas arising in the head and neck area. To date, most studies in this area have focused on analysis of tissues at the mucosal aspect of the resection and highlighted the importance of molecular changes in the field with respect to the risk of recurrence.
In the present investigation, we analyzed normal tissues from mucosal and deep surgical margins, referred to as "molecular margins," for the presence of the signature p53 mutation identified for each tumor.
The p53 mutation status of these carcinomas did not correlate with clinical or histopathologic variables, but these mutations provided an excellent target for ultrasensitive analysis of margin status. We found that 11 of 16 (68%) of cases with histologically tumor-free (including 9 without dysplasia), but with p53 mutation-positive molecular margins, developed recurrence. The probability of developing local recurrence was significantly higher for the group with p53 mutation-positive margins when compared with the group with clear margins (P = 0.048) and more strongly associated with p53 mutation-positive deep molecular margins than mutation-positive mucosal molecular margins or positivity at both sites (P = 0.009).
This shows that although persistent mucosal fields may contribute to recurrence, clonal p53 mutations in deep tissues are an important cause of treatment failure, and molecular margins from both sites should be analyzed in future prospective series.
Clinical Cancer Research 11/2007; 13(20):6099-106. · 7.74 Impact Factor
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ABSTRACT: To investigate the influence of patient personality on satisfaction with and use of complete dentures.
Patients attending a dental school for replacement of existing complete dentures completed a Personality Questionnaire and quality of existing complete dentures was assessed. After the first post-insertion visit quality of new dentures was assessed. Patients' satisfaction with the new dentures was elicited using a structured interview. Three months and 2 years after insertion of new dentures self completed denture satisfaction questionnaires were mailed to all participants.
Three hundred and eight patients participated and 217 completed all stages of the study. Use of dentures was not associated with personality. In the old dentures patient rating of the three aspects of satisfaction with the mandibular denture, of appearance and general satisfaction were significantly associated with neuroticism. In the case of the new dentures at first review, no aspects of satisfaction rated by patients were significantly associated with personality. Significant negative associations between Neuroticism and all aspects of satisfaction with new dentures were found at 3 months. At 2 years after the dentures were placed significant negative associations between Neuroticism and all aspects of satisfaction with new dentures except rating of appearance and maxillary denture chewing ability were found.
Neurotic patients were significantly less satisfied with complete dentures. Personality traits did not influence patients' use of dentures.
Journal of Dentistry 10/2007; 35(9):744-8. · 2.95 Impact Factor
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ABSTRACT: Little is known about the performance of Transbond Plus Self-Etching Primer (TPSEP), especially when used with Adhesive Precoated Brackets (APC 1 and APC 2). The aim of this study was to compare the shear bond and rebond strengths and failure sites of APC 1 and APC 2 with a non-coated bracket system [Victory Series (V)] using Transbond XT light-cured adhesive and TPSEP or 37 percent phosphoric acid as the conditioner. The results demonstrated that on dry testing of 120 brackets when applying an occluso-gingival load to produce a shear force at the bracket-tooth interface, there was no statistically significant difference in the shear bond strength (SBS) of APC 1 (68.4 N), APC 2 (74.9 N), and V brackets (75.4 N, control group). There was also no significant difference in bond failure sites of the APC 1 and APC 2 when compared with the non-coated bracket system using Transbond XT light-cured adhesive and TPSEP, with bond failure for all groups occurring mainly at the adhesive-enamel interface. There was a significant difference in the SBS of the V brackets when using TPSEP and 37 percent phosphoric acid as the conditioners. The latter was lower (60.6 N) and the bond failure site changed from the enamel-adhesive interface to the bracket-adhesive interface. The shear rebond strengths of all bracket types were statistically significantly lower (P < 0.05) than their initial SBS (APC 1, APC 2, and V: 35.9, 36.7, and 34.1 N, respectively) and the locus of bond failure altered from the adhesive-enamel interface to the bracket-adhesive interface. A clinical trial using TPSEP as a conditioner would be useful as the time taken to remove the adhesive from the enamel surface may be reduced following debond.
The European Journal of Orthodontics 09/2006; 28(4):400-4. · 0.89 Impact Factor
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ABSTRACT: A sample of 85 dental transpositions in 75 subjects (27 male, 48 female; mean age at diagnosis 12.25 years) involving both maxillary and mandibular arches was analysed using dental panoramic radiographs and clinical records. Transposition affected the maxillary dentition (76 per cent) more frequently than the mandibular dentition (24 per cent). Unilateral transposition accounted for 88 per cent of cases, with the maxilla being involved more commonly than the mandible. Overall, the most common transposition involved the maxillary canine and first premolar (58 per cent). Considering the jaws in isolation, the canine and first premolar were the most commonly affected teeth in the maxilla (83 per cent) whilst in the mandible, the canine and lateral incisor teeth were most commonly transposed (73 per cent). No significant difference in symmetrical distribution of the unilateral transposition sample occurred. There was evidence of associated hypodontia in 41 per cent of the sample; however, if third molars were excluded, this figure decreased to 25 per cent. Peg-shaped maxillary lateral incisors were judged to be present in 27 per cent of subjects, whilst 41 per cent had retained primary teeth; all of these, except one, were primary canines. Overall, the majority of the sample (76 per cent) demonstrated at least one of the dental anomalies under investigation. Multivariate analysis showed associations between unilateral transposition, gender, and the presence of peg-shaped maxillary lateral incisors; whilst bilateral transposition was more closely associated with gender and the presence of retained primary teeth. There was a poor association between both unilateral and bilateral transposition and hypodontia. Together, these results suggest a mutifactorial aetiology to this disorder, with both genetic and environmental factors playing an important role.
The European Journal of Orthodontics 05/2006; 28(2):145-51. · 0.89 Impact Factor
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ABSTRACT: The two objectives of this experiment were to determine the surface temperature of enamel following acid etching, rinsing and drying, and to see whether two commercially available orthodontic brackets could be bonded to enamel using an anaerobic adhesive.
Enamel surface temperature was determined in vivo using a surface temperature probe on a total of 60 patients. Stainless steel orthodontic brackets were bonded to human enamel using an anaerobic adhesive and a control orthodontic adhesive. The enamel was etched prior to bonding either with a solution of 37% o-phosphoric acid or, in the case of the anaerobic adhesive specimens, with a solution of 37% o-phosphoric acid containing copper (II) chloride. After bench curing the specimens were shear bond tested to failure and the load at debond recorded in each case.
The bond test results were analyzed using median force to debond (N) and 95% confidence intervals, Kaplan-Meier survival probabilities and log-rank tests.
After etching rinsing and drying the enamel surface temperature ranged from 21.54 to 24.19 degrees C, which is within the range suitable for anaerobic adhesive use. Bond testing to failure demonstrated that bracket base design affected the measured force to debond with both the anaerobic adhesive under test and the control adhesive. In addition, the anaerobic adhesive was affected by the material composition of the bracket base and curing time. After 1h of curing and using the Miniature Twin bracket, the measured force to debond exceeded the 10 min force to debond results of the control adhesive.
It is possible to bond commercially available orthodontic brackets to teeth using an anaerobic adhesive.
Dental Materials 03/2006; 22(2):112-8. · 3.13 Impact Factor
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ABSTRACT: Self-etching primers have recently been introduced to simplify the orthodontic bonding process. The aim of this investigation was to compare the enamel loss at each stage of the bonding and debonding process with the use of such a product compared with the conventional two-stage etching and priming process with 37% o -phosphoric acid. In the laboratory, a planer surfometer was used to measure enamel surface height before any enamel treatment, after pumicing, after etching, and once the brackets had been debonded, after enamel clean-up with one of 4 clean-up methods. The latter included a high-speed tungsten carbide bur, a slow-speed tungsten carbide bur, debanding pliers, and an ultrasonic scaler. A change in enamel surface height was seen at each stage of the bonding and debonding process. After pumicing and conventional etching, the cumulative median enamel loss was -2.76 microm; however, the range was from -1.11 to -4.57 microm. This observed loss was much less than in previous reports on enamel loss after acid etching. With the self-etching primer, the median enamel loss was significantly lower, at -0.27 microm (range, -0.03 to -0.74 microm). At debond, there was also a significant difference in the adhesive remnant index scores between the 2 groups, with more adhesive remaining on the enamel surface in the conventional-etch group. It was during enamel clean-up that most surface loss occurred. In both the conventional and self-etch groups, most enamel loss occurred after the use of the high-speed tungsten carbide bur or the ultrasonic scaler and least with the slow-speed tungsten carbide bur or the debanding pliers.
American Journal of Orthodontics and Dentofacial Orthopedics 01/2005; 126(6):717-24. · 1.38 Impact Factor
