A comparison of different sealants preventing demineralization around brackets.

AIM: Aim of the study was to compare how six different sealants resisted thermal, mechanical, and chemical loading in vitro. MATERIALS AND METHODS: In all, 120 extracted human, nondecayed molars were divided into six groups (20 samples each) and embedded in resin blocks. The buccal surfaces of the tooth samples were polished and divided into three areas. Area A contained the product to be analyzed, area B was covered with colorless nail varnish (negative control), and area C remained untreated (positive control). The samples were stored in 0.1% thymol solution. To simulate a 3-month thermomechanical load, the samples were subjected to thermal cycling and a cleaning device. After 7 days incubation in a ten Cate demineralization solution (pH value: 4.6), the samples were dissected using a band saw and the lesion depths and demineralization areas were evaluated and compared microscopically. RESULTS: The tooth surfaces treated with PRO SEAL® showed no demineralization. Mean lesion depths of 108.1, 119.9, 154.9, 149.2, and 184.5 µm were found with Alpha-Glaze®, Seal&Protect®, Tiefenfluorid®, Protecto®, and Fluor Protector, respectively. There was a significant difference between PRO SEAL® and the other products (p > 0.0001). There was no significant difference between the other products. CONCLUSION: PRO SEAL® resisted thermal, mechanical, and chemical loading in vitro, providing protection against white spot lesions.

Precision of implementing virtual setups for orthodontic treatment using CAD/CAM-fabricated custom archwires.

OBJECTIVES: The SureSmile® process (OraMetrix®; Richardson, TX, USA) utilizes computer-aided design and computer-aided manufacturing (CAD/CAM). A virtual setup is created for treatment planning and chairside implementation using custom archwires fabricated by robots. The objective of this study was to determine the precision of this implementation. METHODS: The setup models of 26 consecutive patients were compared to models of the final outcome. Using a virtual matching process, the planned and the achieved tooth positions were superimposed and the differences between them calculated along three translational planes and three rotational axes, thus, yielding six deviation values for each tooth. RESULTS: The median deviations were 0.19-0.21 mm based on translational movements and 1.77°-3.04° based on rotational movements. The precision of implementing the setups decreased from anterior to posterior, with incisors showing the best outcomes. CONCLUSION: Virtual setups can be implemented in a clinically successful fashion with custom archwires fabricated by CAD/CAM in accordance with the SureSmile® process.

Effect of untreated and treated temporomandibular joint arthritis on mandibular volume development in growing rabbits.

OBJECTIVES: The goal of this work was to investigate the volume development of the mandible in growing rabbits with bilaterally induced temporomandibular joint (TMJ) arthritis that was either left untreated or treated with the tumor necrosis factor-alpha (TNF-α) antagonist etanercept. METHODS: A total of 18 New Zealand White rabbits aged 8 weeks were randomized to three groups of 6 animals each. Two of these groups were used as arthritis groups by sensitizing the 12 animals to ovalbumin (OA) at 10 weeks, followed by intraarticular OA injections to induce bilateral TMJ arthritis and repeating these injections every 3 weeks to maintain the inflammation. One of the two arthritis groups was treated by weekly subcutaneous etanercept injections, whereas the other group was left untreated. The remaining 6 animals served as controls. Maxillofacial CT scans were obtained at 3-week intervals (from week 10 of the rabbits' lives to the end of the experiment at 22 weeks) to volumetrically track the development of the mandibles after segmentation. RESULTS: The mandibles did not grow at a continuous rate, but the rate of development was found to decrease in all groups over the course of the study (weeks 10-22). The most extensive volume increases were noted during weeks 10-13. Severe growth deficiencies, especially of the condylar processes, were observed in the arthritis group not receiving treatment. The arthritis group treated with etanercept showed better rates of growth without, however, reaching the normal range of the control group. CONCLUSION: Antigen-induced TMJ arthritis was found to involve severe problems of growth similar to those in juvenile idiopathic arthritis. Etanercept can improve the volume development but does not reestablish an entirely normal rate of growth.

Investigation of bone conditions for orthodontic anchorage plates in the anterior mandible.

OBJECTIVES: The clinical success of orthodontic anchorage plates depends on the stability of the miniscrews used for fixation. For good stability, the application site must provide bone of good quantity and quality. This study was performed to analyze bone quantity for orthodontic anchorage plates in the anterior mandible. PATIENTS AND METHODS: A total of 51 computed tomography (CT) scans of fully dentate patients (mean age 24.0±8.1 years; 27 men and 24 women) were evaluated. Measurements were taken to analyze the total orovestibular and vestibular cortical thickness of the mandibular jawbone at different anterior locations and levels. RESULTS: Vestibular cortical thickness is generally thinnest within the incisor area on the apex level. Its thickness increases in basal and distal directions. The total orovestibular thickness is also the least on the level of the anterior mandibular apices, becoming thicker toward more basal levels and the posterior teeth. CONCLUSION: We can reasonably assume that the stability of anchorage plates can be optimized by selecting a position well basal to the apices of the lower incisors, as this area offers enhanced cortical and total jawbone thickness.

Precision of indirect bonding of lingual brackets using the Quick Modul System (QMS)®.

OBJECTIVES: Almost all common laboratory procedures for lingual orthodontic appliances use indirect bonding of brackets via transfer trays. Ensuring precise transfer of these bracket positions to the oral cavity is especially important, as subsequent manual adjustments are challenging in lingual orthodontics and even minor errors of bracket placement may result in considerably deviating tooth positions. The purpose of this study was to evaluate in vivo the precision of indirect bonding of lingual brackets using the "Quick Modul System" (QMS®; Halbich Lingualtechnik, Berlin, Germany). MATERIALS AND METHODS: The study included eight consecutive patients treated with lingual brackets. After placing the brackets on a setup cast, the resultant positions were digitized with an optical scanner (OraScanner®; OraMetrix, Richardson, TX, USA). Individual transfer copings (QMS®) were used to transfer the brackets to the mouth, followed by intraoral scanning and virtual superimposition to analyze how much the intraoral bracket positions deviated from the positions on the cast. RESULTS: Translational deviations added up to a mean transfer error of 0.12 mm in the mesiodistal, 0.13 mm in the orovestibular, and 0.10 mm in the vertical planes. Mean deviations in rotational directions amounted to 2.20° of inclination, 3.21° of angulation, and 2.29° of rotation. CONCLUSION: The transfer system investigated in this study is capable of transferring bracket positions with good clinical precision. No differences between the bracket types and both modifications of the transfer copings were noted.

Shear bond strength and enamel fracture behavior of ceramic brackets Fascination® and Fascination®2.

OBJECTIVE: The purpose of this study was to compare the shear bond strength and incidence of enamel fractures of the ceramic brackets Fascination® and Fascination®2. MATERIALS AND METHODS: A total of 360 teeth (180 first upper bicuspids and 180 lower incisors) were stored in 96% ethanol, while 360 other teeth (180 first upper bicuspids and 180 lower incisors) were stored in 0.1% thymol. All 720 teeth were bonded one-half each with Fascination® and Fascination®2 brackets using three different adhesives and three different light curing units. The teeth were debonded with a debonding-device according to DIN EN ISO 10477 using a universal testing machine with a crosshead speed of 1 mm per minute. The enamel surface was then examined stereomicroscopically (10x and 40x magnification). The non-parametric Mann-Whitney U test was used, since the data were not normally distributed. RESULTS: The Fascination®2 brackets provided significantly lower shear bond strength than Fascination® brackets (p = 0.003). Fascination® brackets demonstrated significantly fewer, smaller enamel fractures than Fascination®2 brackets (p = 0.012). CONCLUSION: The lower shear bond strength of the Fascination®2 brackets is clinically acceptable, but our study's experimental design did not enable us to prove whether this is clinically associated with a lower risk of enamel fracture.

Comparison between logopedic and MRI findings in evaluating tongue function.

INTRODUCTION AND AIM: The logopedic examination according to Kittel (1998) is a method frequently used to diagnose tongue dysfunction. There has been a lack of reliable parameters to confirm this analysis. MR images visualize resting position and tongue movement as well as surrounding structures relevant to oral function. The aim of this study was to compare logopedic and MRI findings in evaluating tongue function and to assess whether MRI findings can replace logopedic examination for diagnostic purposes. MATERIAL AND METHODS: 56 subjects were examined by the following methods: - Logopedic examination according to Kittel (1998) - MR images of the tongue resting position (T1-weighted) and deglutition process (2D-FIESTA technique) - MRI analysis according to Fujiki et al. (2000) RESULTS: We observed marked differences between the logopedic and MRI findings, yet there were no significant correlations between the logopedic outcome and distances measured via MRI in tongue resting position and swallowing patterns. CONCLUSION: We noted little concordance between logopedic findings according to Kittel and MRI analysis according to Fujiki et al. Which of these findings correctly reflects the actual clinical situation remains unclear.

Validity and reliability of logopedic assessments of tongue function.

OBJECTIVE: This study investigated the validity and reliability of logopedic assessments of tongue function. MATERIALS AND METHODS: At two practices for myofunctional therapy, diagnosis of tongue dysfunction according to Kittel (1984, 1996, 2008) was carried out in 52 subjects (aged 5 to 63 years) by three speech pathologists at each practice. RESULTS: The agreement of the logopedic assessments was mostly satisfactory at one of the two practices but was unsatisfactory in most cases at the other practice. CONCLUSION: The inconsistent agreement between the logopedic assessments does not permit a definitive statement about the actual clinical situation.

Abrasive effect of air-powder polishing on smoothsurface sealants.

AIM: To prevent decalcification during orthodontic treatment using fixed appliances, many orthodontists use sealants to protect the enamel surface around the brackets. If the patients' oral hygiene is insufficient, air polishing devices are often used to clean the teeth. The aim of this study was to investigate the effects of air polishing on the sealant. MATERIAL AND METHODS: Three sealants (Pro Seal, OrthoSolo, and Seal&Protect((R)) were used in this study. Each was applied on the surface of 30 extracted human teeth. The enamel surfaces of 10 teeth each were then air polished with the sodium-bicarbonate-based powder (Air-Flow((R))) 5 or 10 seconds, or the glycine-based powder (Clinpro Prophy) for 10 seconds. RESULTS: The sealant had become thinner, revealing minor defects after 5 seconds of air polishing using the sodium-bicarbonate-based powder, practically disappearing after 10 seconds. Use of the glycine-based powder allowed longer air-polishing times, but the sealant surface also showed minor defects thereafter. CONCLUSION: Reliable protection against demineralization may be seriously compromised after sealed tooth surfaces are cleaned with air-polishing devices. This finding correlates with the type of powder and air-polishing time.

Remodeling along the bone-screw interface.

OBJECTIVE: The stability of cortical miniscrews depends on the contact between bone and implant. The aim of this study was to compare bone remodeling along the contact surface between the screw and bone with and without pre-drilling. MATERIALS AND METHODS: Twenty-four FAMI miniscrews (length 10 mm, diameter 2 mm) were inserted into the mandibular alveolar process apical to the premolars of four miniature pigs. Each pig received six screws, three on the one side with pre-drilling, three on the other side without pre-drilling. Polychrome fluorescent labels were used to assess the bone remodeling. After 12 weeks of osseointegration, all 24 screws and surrounding bone were removed. Microsections were prepared and analyzed histomorphometrically and under fluorescent microscopy. Differences between the groups were determined using the t test with a significance level of 5%. RESULTS: All the screws osseointegrated without any complications. Those without pre-drilling revealed a bone-screw contact of 64 +/- 11%, and those subjected to pre-drilling 63 +/- 12%. This difference was not significant. The mineral apposition rate, 1.6 +/- 0.4 microm/d and 1.7 +/- 0.4 microm/d, respectively, also failed to demonstrate any significant differences between the groups, while the portion of newly-formed bone in the pre-drilled group was significantly higher (59 +/- 9% vs. 27 +/- 6%). CONCLUSION: Significant differences in the bone-to-screw contact between the two groups are no longer in evidence after three months due to new bone formation. The minor extent of bone remodeling in the not pre-drilled group rules out substantial bone damage, which might have occurred during screw placement as a result of "cracks" or an excessive increase in pressure along the interface. The similar rate of new bone formation in both groups speaks against a stimulating effect of pre-drilling. Despite the absence of quantitative differences, it remains unclear whether the mechanical quality of the newly-formed bone resembles that of preexisting bone. Our findings seem to be applicable to the human mandible, however, its thinner cortical layer means less screw-to-bone contact is likely. We must reckon with less bone contact in the maxilla for the same reason.

Chlorhexidine in cleft lip and palate patients with multibracket appliances. Results of a prospective study on the effectiveness of two different chlorhexidine preparations in cleft lip and palate patients with multibracket appliances.

AIM: The aim of this study is to reduce the caries risk in cleft lip and palate (CLP) patients with multibracket appliances via a compliance-independent method. PATIENTS, MATERIALS AND METHODS: Sixty-eight CLP patients with multibracket appliances were submitted to professional tooth cleaning at 4-week intervals. After randomization, patients in group A wore a splint filled with chlorhexidine (CHX) gel (Chlorhexamed) for 15 minutes (3 x 5 min) every 12 weeks. Patients in group B were treated with CHX varnish (EC40) every 12 weeks. Fluoride varnish (Fluoridin) was applied to all teeth 4 and 8 weeks after the respective CHX treatments. Regular salivary bacteria counts (CRT) were carried out to determine therapeutic effectiveness. Initial DMFS values were compared to the final ones. RESULTS: Initial findings of the salivary test and DMFS index confirmed the high caries risk. The DMFS value increased dramatically in both groups despite this systematic prophylaxis program. The bactericidal effect of both CHX preparations turned out to be markedly weaker than that described in the literature. CONCLUSIONS: Though the CHX and fluoride application had a limited effect (at least in this test population), one should keep in mind that it is precisely this population that requires very intensive prophylaxis, and that no antibacterial adjuvant is more effective than CHX. However, the application interval should be individually adapted to the bacteria count.