A comparison of fluoride release by resin-modified GIC and polyacid-modified composite resin.

The objective of this study was to compare the fluoride release of 2 fluoride-containing orthodontic adhesives from bracketed teeth and adhesive disks, a resin-modified glass ionomer cement (Fuji Ortho LC, encapsulated; GC America Corp, Aslip, Ill) and a polyacid-modified composite resin (Assure; Reliance Orthodontic Products, Itasca, Ill). A composite resin without fluoride (Transbond XT; 3M Unitek, Monrovia, Calif) was used as a reference control. Metal brackets were bonded to the buccal surfaces of 120 human premolars (40 teeth per adhesive), and disks were made from each adhesive. The deionized storage water was changed, and fluoride release was measured at specified intervals up to 28 days for the bracketed teeth and up to 150 days for the disks. Fuji Ortho LC released 75% more accumulated fluoride than Assure (6.61 microg/bracket vs 3.77 microg/bracket) from bracketed teeth over the 28-day observation period. Assure released more fluoride per day than did Fuji Ortho LC from the disks during the first 3 months. For the rest of the 150-day period, Fuji Ortho LC released more fluoride per day than did Assure. The amount of fluoride released by these materials varied dramatically with different water-changing protocols. The large discrepancy between fluoride released from disks compared with that released from bracketed teeth suggests that caution must be used in extrapolating fluoride-release levels of adhesive disks to in vivo treatment conditions.

Dental experience of cleft affected children in the west of Ireland.

AIM: To investigate caries experience and initial access to dental services in a group of children with cleft lip/palate in the west of Ireland. DESIGN AND METHOD: Cross sectional study with prospective data capture and matched control. Details of children born with a cleft were obtained from all health professionals likely to be involved in delivering care to these children. Existing databases were cross-referenced to eliminate duplication or missed patients. A matched control sample was recruited from 14 schools in the region. RESULTS: A sample of 90 cleft affected children (48 male, 42 female) with any category of cleft born between 1980-1996 (i.e. 16 years) was compared with a control group of 100 non cleft children (60 male, 40 female). The DMF index was determined by a trained and calibrated clinician. Twenty-two percent (n=20) of the cleft group were caries free compared to 41% (n=41) in the control group. The combined dmf/DMF for the cleft group was 2.09 compared to 1.50 for the control (P<0.05). Separate analysis of the dmf and DMF between the two groups indicated that the difference lay in the caries found in the deciduous dentition of the cleft group. The first dental visit was at 4 years of age for the cleft group. CONCLUSIONS: Cleft affected children in the region did not receive adequate and regular dental care at the appropriate time. In view of the significantly greater risk of dental disease in clefting, particularly in the deciduous dentition, all cleft affected children should be referred for comprehensive and continued preventive dental care from the first year of life.

The reliability of 3 sagittal reference planes in the assessment of Class I and Class III treatment.

The objective of this study was to test the reproducibility and validity of 3 sagittal reference planes with the use of the Wits analysis. Measurements made to the functional occlusal plane, the bisected occlusal plane, and the maxillomandibular bisector were compared with each other and with the angular measurement of the ANB angle. The angular relationship of these reference planes to the postmaxillary vertical reference plane was also studied. The data were collected from pretreatment (T1), posttreatment (T2), and 2-year postretention (T3) lateral cephalograms of 35 Class I and 10 Class III subjects. Nonextraction treatment for these patients was performed with full fixed orthodontic appliances in the permanent dentition. Cephalometric data were compared with 39 Class I and 9 Class III control subjects. The serial lateral cephalograms of untreated control subjects that were analyzed were taken at ages approximating those of the treated groups at T1, T2, and T3. The maxillomandibular bisector was determined to be an easily identifiable and reproducible reference plane that exhibited greater stability over time with both growth and treatment than either the functional occlusal plane or bisected occlusal plane. The mean values for the maxillomandibular bisector Wits result for Class I and III populations were distinct and, when combined with previous Class II data, yielded a triphasic distribution that may be a useful clinical tool for patient assessment.

Comparison of bond strength of three adhesives: composite resin, hybrid GIC, and glass-filled GIC.

The objective of this study was to compare 3 orthodontic adhesives in the areas of shear-peel bond strength, location of adhesive failure, and extent of enamel cracking before bonding and after debonding of orthodontic brackets. The adhesives included a composite resin control (Transbond XT; 3M/Unitek, St Paul, Minn), a resin-modified glass ionomer cement (Fuji Ortho LC; GC America Corp, Alsip, Ill), and a polyacid-modified composite resin under dry and saliva-contaminated conditions (Assure; Reliance Orthodontic Products Inc, Itasca, Ill). Metal brackets were bonded to the buccal surfaces of 160 (4 groups of 40) human premolars. The bonded teeth were stored in deionized water at 37 degrees C for 30 days and thermocycled for 24 hours before debonding with a Universal Instron (Instron Corp, Canton, Mass) testing machine. The extent of cracking in the buccal surfaces was evaluated under 16x magnification before bonding and after debonding. Although the bond strength of the composite resin control (20.19 MPa) was significantly greater (P <.05) than that of the adhesives in the other groups, clinically acceptable shear-peel bond strengths were found for all adhesives (Fuji Ortho LC = 13.57 MPa, Assure-dry = 10.74 MPa, Assure-wet = 10.99 MPa). The bond strength for the Assure adhesive was not significantly affected by saliva contamination. The sample of extracted premolars used in this study displayed a greater frequency of buccal surface enamel cracking (46.7%) than that reported in the literature for in vivo premolars (7.8%-10.2%), which was possibly due to the extraction process. The frequency of enamel cracking in a subset of this sample (n = 34) increased from 46.4% at prebonding to 62.4% at postdebonding as a result of the forces of debonding.

A comparison of shear-peel band strengths of 5 orthodontic cements.

The objective of this study was to compare the shear-peel band strength of 5 orthodontic cements using both factory and in-office micro-etched bands. The 5 orthodontic cements evaluated were a zinc phosphate (Fleck's Cement), 2 resin-modified glass ionomer cements (RMGI)(3M Multicure glass ionomer and Optiband), and 2 polyacid-modified composite resin cements (PMCR)(Transbond Plus and Ultra Band Lok). Salivary contamination was examined with a polyacid-modified composite resin (Transbond Plus). Two hundred and eighty extracted human molar teeth were embedded in resin blocks and each was randomly assigned to the following 7 groups: 6 groups with factory etched bands, 5 cement groups and salivary contaminated group, and 1 in-office micro-etched group. The cemented teeth were put in deionized water at 37 degrees C for 30 days and thermocycled for 24 hours. The force required to break the cement bond was used as a measure of shear-peel band retention. With the use of an Instron testing machine, a shear-peel load was applied to each cemented band. Data were analyzed with a one-way analysis of variance (ANOVA) with a Tukey test for the multiple comparisons. The RMGIs and PMCRs demonstrated significantly greater shear-peel band strengths compared to the zinc phosphate cement. No statistically significant differences were noted between the RMGI cement and PMCR cements and within the RMGI groups, however, there was a statistically significant difference within the PMCR groups. Significantly lower band strengths were noted with the saliva contaminated PMCR cement group (Transbond Plus) and the inpractice sandblasted PMCR group. Both RMGIs and PMCRs were found to demonstrate favorable banding qualities. The lower band strength with saliva-contaminated bands suggests that moisture control is critical when using a PMCR. The variability noted in the in-office micro-etched bands might be technique related.

Polymerization with the argon laser: curing time and shear bond strength.

The objective of this study was to determine the efficiency of an argon laser in polymerizing a light-cured orthodontic adhesive. Metal brackets were bonded to 185 premolars, divided into 5 different protocol groups of 37 each as follows: light 40-second buccal, light 40-second lingual, laser 5-second lingual, laser 10-second lingual, and laser 15-second lingual. All bonded specimens were placed in distilled water for 30 days at 37 degrees C followed by thermal cycling for 24 hours. Brackets were detached using a shearpeel load delivered by an Instron machine. The site of bond failure was examined under 10x magnification. The difference in the shear-peel bond strength between the light 40-second buccal (13.31 MPa) and the light 40-second lingual (11.95 MPa) groups was not statistically significant. The mean shear-peel bond strengths for the laser cured groups were quite similar for the 5-, 10- and 15-second laser groups (10.86, 11.32, and 10.80 MPa). The difference in mean lingual bond strength between the light 40-second and laser 5-second groups was not statistically significant (t = 1.26; P = .212). The adhesive remnant index analysis revealed principally cohesive bond failures. An increased frequency of enamel fractures at debond was noted in the lingual light-cured and 10-second laser-cured groups, at 35.1% (13/37) and 21.6% (8/ 37), respectively. All other groups displayed enamel fractures of 16.2% (6/37). A 5-second cure using an argon laser produced bond failure loads comparable to those obtained after 40 seconds of conventional light cure, with less than half the frequency of enamel fracture at debond.

The management of traumatic ankylosis during orthodontics: a case report.

Dental ankylosis may be a significant complication in orthodontic clinical practice. This case report describes the management of a malocclusion, complicated by an ankylosed maxillary central incisor, which arose during orthodontic treatment, following an acute traumatic injury. The use of the ankylosed incisor in successfully managing the significant Class II division 1 malocclusion is described.

Premature dental eruption: report of case.

This case report reviews the variability of dental eruption and the possible sequelae. Dental eruption of the permanent teeth in cleft palate children may be variable, with delayed eruption the most common phenomenon. A case of premature dental eruption of a maxillary left first premolar is demonstrated, however, in a five-year-old male. This localized premature dental eruption anomaly was attributed to early extraction of the primary dentition, due to caries.

The use of a deprogramming appliance to obtain centric relation records.

The purpose of this study was to investigate the effect of an anterior flat plane deprogramming appliance (Jig) in 40 subjects for whom centric relation (CR) records were obtained before and after the use of the appliance. Incisal overbite and overjet dimensions and three-dimensional instrument condylar representation using the Panadent condylar path indicator (CPI) were recorded from maximum intercuspation and centric relation. Subjects were assessed subjectively to determine the degree of difficulty manipulating the mandible to obtain the centric relation record. The mean overbite difference from maximum intercuspation (MI) to centric relation without (CR) and with (CRJ) the appliance were statistically significant and decreased 1.58 mm and 2.23 mm, respectively. The mean overjet values from MI to CR and CRJ were statistically significant and increased .44 mm and .57 mm, respectively. Significant differences were determined on the Panadent articulator for the absolute vertical (Z) and absolute horizontal (X) values for centric relation with and without the appliance. The number of subjects who exceeded the threshold values of 2 mm for CPI recordings in either the horizontal or vertical direction was 7 (18%,) from MI to CR and 16 (40%) from MI to CRJ. The Lucia-type jig deprogramming appliance provides a centric relation record with greater displacement from MI than a centric relation record alone. This appliance may be a useful adjunct in a patient where mandibular manipulation in taking a centric relation bite registration is deemed not easy.

A comparison of the shear bond strengths of two glass ionomer cements.

The objective of this study was to determine the in vitro shear bond strength (in megapascals) and location of bond failure with two light-cured glass ionomer resin systems. One system was a hybrid glass ionomer cement with resin (GC Orthodontics, Aslip, Ill), and the other system a glass-filled resin system (Reliance Orthodontic Products, Inc, Itasca, Ill). These systems, Fuji Ortho LC (GC Orthodontics) and Ultra Band Lok (Reliance), respectively, were compared to a light-cured composite resin. Maxillary premolar brackets (n = 200) were bonded to the facial surface of human premolar teeth. The two glass ionomer resin systems were each evaluated by two protocols, one according to the manufacturers' direction plus a variation of their respective technique. The five distinct groups (n = 40) were stored in 37 degreesC distilled water for 30 days and subjected to thermocycling before shear bond strength testing. The findings indicated that large variations existed between the bond strengths of the materials tested. The laboratory shear bond strength of the glass-filled resin glass ionomer cement (Reliance), whether tested in a dry or moist field, was similar to the composite control with all of the previous materials being significantly (P <.01) higher than both the hybrid glass ionomer cement groups (Fuji Ortho LC). However, the hybrid glass ionomer cement with enamel conditioner demonstrated a clinically acceptable mean megapascal value. The Adhesive Remnant Index values ranged from 0.53 to 1.62. The hybrid glass ionomer cement without enamel conditioning recorded the lowest mean adhesive remnant index score and the lowest mean megapascal score. Although both products are glass ionomer resin systems, their individual chemistries vary; this affects their clinical performance. Clinically, it may be suggested that glass ionomers used in a dry field may be beneficial for orthodontic bonding, and that glass ionomer resin systems used in a moist environment need an enamel conditioner.

Direct bonding to Adlloy-treated amalgam.

The purpose of this study was to test the bond-enhancing effect by modifying amalgam surfaces with Adlloy (a gallium-tin liquid alloy) and bonding brackets by using two different resin systems. Bond strength and location of bond failure was assessed by using (1) Concise (3M Dental Products) and (2) C&B Metabond (Parkell) systems with and without the use of Adlloy alloy. Class V buccal amalgam restorations (n = 132) were subjected to one of two surface treatments: (1) sandblasting or (2) sandblasting plus Adlloy treatment. Mandibular premolar brackets were bonded with Concise composite resin or C&B Metabond (adhesive) to amalgam surfaces. All specimens were stored in 37 degrees C water for 10 weeks and subjected to thermocycling before bond strength testing. The laboratory shear bond strength of Concise material to amalgam was not improved after Adlloy modification. However, Adlloy-treated amalgam significantly increased the laboratory shear bond strength of orthodontic brackets bonded with C&B Metabond material. The majority (58%) of the bond failures of C&B Metabond bonded to non-Adlloy treated-amalgam occurred at the amalgam-adhesive interface, whereas the majority (58%) of the bond failure of C&B Metabond bonded to Adlloy-treated amalgam failed within the adhesive. Fracture within the amalgam during debonding was observed with C&B Metabond bonded to sandblasted amalgam (21%) and Adlloy-treated amalgam (15%). Regardless of Adlloy treatment, C&B Metabond would appear to provide adequate orthodontic bonding to amalgam; however, there may exist a potential risk of amalgam restoration fracture upon debonding.

The reliability of three sagittal reference planes in the assessment of Class II treatment.

This investigation evaluated the reliability and validity of three anteroposterior skeletal measurements using the maxillary-mandibular (MM) Bisector, the functional occlusal plane (FOP), and the bisected occlusal plane (BOP) as reference planes in the assessment of anteroposterior discrepancies. Comparisons were made between these measurements in both treated and control samples of Class II Division 1 patients. The data were collected from pretreatment, posttreatment, and 2 years posttreatment lateral cephalograms of 36 Class II Division 1 subjects whose treatment was nonextraction with low or straight pull headgears. Comparisons were made to an untreated control group of 15 Class II Division 1 subjects. The MM Bisector was found to be a highly reproducible reference plane whose greater stability was demonstrated by a lack of change in its cant during growth or during growth and treatment, compared with the BOP or FOP. With the ANB angle used as a standard, and MM Bisector anteroposterior measure was a more reliable and valid indicator of the skeletal anteroposterior relationship of the jaws, especially longitudinally during growth and treatment, than the Wits appraisals made with either the FOP or BOP.

Bond strengths of two ceramic brackets using argon laser, light, and chemically cured resin systems.

The present study compared tooth-bracket bond strengths using two types of ceramic brackets and three methods of polymerization: argon laser, conventional light, and chemical. Ninety extracted human premolars were prepared for bonding with pumice and gel etchant. Using single crystal alumina brackets with silanated bases, three groups of 15 teeth were bonded with one of the three polymerization methods. Similarly, three groups of 15 teeth were bonded with polycrystal alumina brackets with nonsilanated bases. Each bonded bracket was tested on an Instron tensile testing machine in shear mode to determine shear debonding strength. Fracture sites were recorded. Results demonstrated that (1) all combinations produced shear bond strengths greater than those considered clinically acceptable, (2) the mean shear bond strengths of the single crystal alumina brackets with silanated bases were significantly higher than those of the polycrystal alumina brackets with nonsilanated bases, and (3) no enamel fractures were found on debonding the chemically cured brackets while the light and laser groups exhibited a 10% rate of enamel fracture on debonding.

Orthodontic bonding to Adlloy-treated type IV gold.

Adlloy surface treatment of noble alloys has been shown to increase the bond strength of composite to gold alloys. The purpose of this study was to test the bond strength of Adlloy-treated type IV gold surfaces and orthodontic brackets bonded with self-curing composite resin, and compare it with sandblasted gold and etched enamel. Data were derived from a control sample of 40 human premolars and two experimental groups of Adlloy-treated and sandblasted gold surfaces. "A"-Company premolar brackets were bonded with Concise self-curing composite resin. The specimens were submerged in water for 30 days and thermocycled 1500 times before being subjected to shear bond tests. Statistically significant differences were found in the mean values of the three groups (F = 124.04; df = 2,117; P < .001). Bonds on the adlloy-treated gold were twice as strong as those found on microetched gold. Adlloy surface treatment of type IV gold will permit adequate bond strength; however, FDA approval is required for intraoral use.

Soft tissue profile changes in late adolescent males.

The purpose of this study was to document soft tissue profile changes in late adolescent skeletal Class I males from 14 to 20 years of age and to compare these changes with those of the underlying hard tissues. Using serial lateral cephalograms from a sample of 33 untreated Class I adolescent males, 26 soft and hard tissue parameters were assessed at ages 14 to 16, 16 to 18, and 18 to 20 years. The concept that differential facial growth occurs from nasion to pogonion was substantiated by these data. The hard tissue chin moved forward more than A-point, which in turn moved forward more than nasion, resulting in the hard and soft tissue profile being flattened or reduced in convexity. Horizontal soft tissue thickening of 1.0 mm overlying the hard tissue surfaces from midface to chin was observed at 14-16 years. Continued change of the soft tissue profile from 16 to 20 was thus the result of underlying skeletal growth. Nasal tip increased significantly over all age periods, and underwent the largest growth change of all measurements assessed (approximately 8.0 mm). This growth increase declined by approximately one-half over each successive age period. Although variable, continued soft tissue movements throughout the 14- to 20-year age period affect treatment planning, maintenance of the posttreatment profile, and posttreatment occlusal retention requirements.

The management of premolar supernumeraries in three orthodontic cases.

This paper reviews the incidence, etiology and location of supernumerary teeth with emphasis on premolar supernumeraries and examines the management of supernumerary premolars of three patients undergoing orthodontics. These cases demonstrate that the management of premolars is assessed individually and treatments based on potential complications, which may occur during the orthodontic and surgical management of the dentition. Progress and posttreatment radiographs are recommended for the assessment of late forming supernumerary teeth.

Management of lower incisor crowding in the early mixed dentition.

This paper describes normal and problem development in lower incisor positioning and offers options for management of crowded cases. The following guidelines were recommended, (1) lower incisor crowding of 2 mm or less and with an intercanine width greater than 28mm will usually resolve spontaneously, (2) lower incisor crowding of 3-4 mm is best managed by discing of the primary dentition, (3) crowding assessment of 5-9 mm requires extraction of primary teeth with probable placement of a supportive lingual arch and, (4) crowding greater than 10 mm requires fixed appliance therapy and careful orthodontic management with attention to the severity of the malocclusion.

Orthodontic retention.

This article briefly describes several factors that should be considered during orthodontic retention. These factors may influence occlusal stability following the completion of the active phase of orthodontic therapy. Orthodontic retention is an important part of orthodontic treatment. It should always be considered and included in the initial stages of treatment planning, rather than added on at the end of treatment as an after-thought.

Facial growth in females 14 to 20 years of age.

The objective of this study was to determine the magnitude and the direction of postpubertal mandibular and maxillary facial growth in females. The sample consisted of 37 untreated subjects who had Class I skeletal and dental characteristics and whose lateral cephalograms were taken at 14, 16, and 20 years of age. Mandibular growth was determined to be significant for the age periods of 14 to 16 years and 16 to 20 years. Overall mandibular growth as measured from Co-Gn was approximately twice that of the overall maxillary growth as measured from Co-A. Correlation analysis revealed a statistically significant relationship between the estimates of incremental mandibular growth from either articulare or condylion. The mandibular growth rate was found to be twice as large for age period 14 to 16 years as for age period 16 to 20 years. The increase in posterior vertical face height was slightly more than the increase in anterior vertical face height. The mandibular plane angle decreased 1.1 degrees during the age period of 14 to 20 years, suggesting a tendency for a closing rotation of the mandible. Mandibular incisors appeared to tip labially with advancing age. Although variable, the potential for significant maxillary and mandibular facial growth in females during late adolescent has been demonstrated.