Age-related changes in the midpalatal suture: Comparison between CBCT staging and bone micromorphology

The age-related maturation of the human midpalatal suture is challenging to predict, but critical for successful non-surgical rapid maxillary expansion (RME). While cone-beam computed tomography (CBCT) can be used to categorize the suture into stages, it remains unclear how well the stages predict the actual micromorphology of the palate. To address this clinically relevant question, we used CBCT together with three-dimensional micro-computed tomography (μCT) analysis on 24 human palate specimens from individuals aged 14-34 years. We first classified the specimens into stages (A-E) using CBCT images and then correlated the results with our comprehensive μCT analysis. Our analysis focused on several factors, including bone volume fraction (BV/TV), sutural width, volume, interdigitation, ossification, and their associations with age, CBCT stage, and sex. Our μCT analysis revealed a decrease in sutural width and volume after the age of 20 years, accompanied by sutural closure beginning in the palatal segment. The overall rate of ossification remained low but increased after the age of 20 years. No significant differences were found between males and females. Importantly, we also found no correlation between individual age and CBCT stages. Furthermore, there was no association between CBCT stages and patalal suture volume, ossification and interdigitation. Taken together, our findings cast doubt on the reliability of CBCT stage as a means of predicting skeletal maturity of the palatal suture, as it appears to lack the precision required to accurately assess the true micromorphology of the palatal suture. Future investigations should explore whether alternative CBCT parameters may be more useful in addressing the challenging question of whether RME requires surgical bone weakening.

[Assessment of carious dental lesions and treatment options: comparison of the knowledge of dental students and orthodontic assistants]

In order to optimize dental education, established procedures for caries diagnosis and therapy, such as the International Caries Classification and Management System (ICCMS), should be integrated into the curriculum. In preparation, the level of knowledge of dental students on caries detection and management was surveyed in order to specifically address deficits in dental teaching. In addition, the data were compared with the knowledge of clinically experienced dentists. The results are presented in this report and possible consequences for dental teaching are discussed.Twenty-six sixth semester dental students and six assistant dentists at the Department of Orthodontics (Philipps University of Marburg, Germany) were available for the written survey during the winter semester 2018/2019. For 12 anonymized orthodontic patient cases, the clinical findings, caries risk, and adequate treatment were to be determined for each defined tooth. The consensus decision of two experienced dentists served as the reference value. As a result, agreement with the reference ranged from 40.7% to 51.3% for students and from 56.9% to 75.0% for assistant dentists. The extent of caries and the resulting necessary treatment were mostly underestimated.In addition to theoretical knowledge, clinical experience is another prerequisite for adequate caries diagnosis and its management. The underestimation of caries extent and necessary treatment should be taken into account when teaching content. Procedures such as the ICCMS should be integrated into the dental curriculum at an early stage, so that orthodontic patients can also receive effective care.

Detection of Erosive Changes on Smooth Surfaces with and without Orthodontic Brackets Using an Intraoral Scanner-An In Vitro Study

BACKGROUND

Consumption of acidic beverages favours development of erosions. Modern diagnostic methods are required to detect erosions at an early stage. This study aimed to evaluate the suitability of an intraoral scanner (IOS) for detection of erosive changes on smooth surfaces adjacent to orthodontic brackets.

METHODS

Orthodontic metal brackets were attached to the buccal surfaces of 58 extracted permanent human teeth. Teeth were randomly divided into groups: A = 6% citric acid, B = Coca-Cola, C = Redbull, D = Powerade, E = Control, no acid exposure. Teeth were exposed to acid in three erosion cycles, followed by rinsing and brushing. Scans of teeth were performed at baseline and after each erosion cycle and enamel loss was measured. Quantitative light-induced fluorescence (QLF) measurements were performed as reference standard.

RESULTS

Significant substance loss was measured in all acid groups after the second and third erosion cycle (p < 0.0001). Correlation between scans and QLF were significant (p = 0.001).

CONCLUSIONS

With IOS, it was possible to detect and quantify enamel erosion at smooth surfaces with and without orthodontic brackets after a short exposure time. Considering the limitations of in vitro results, the use of IOS can be a promising digital tool to detect and monitor erosive enamel changes during fixed orthodontic treatment.

Ability of a Blue Hemoglobin-Based Liquid as a Novel Technology to Stain Initial Enamel Demineralization: A Proof-of-Concept in vitro Study

During orthodontic treatment, enamel demineralization can occur. Its early detection is the basis for efficient preventive measures to arrest or remineralize lesions. In the present study, the application of a novel blue hemoglobin-based liquid (BlueCheck) was evaluated as proof of concept for detection of artificially demineralized smooth surfaces. 60 samples from extracted human posterior teeth were randomly assigned to four groups (15 per group). In 30 of these samples (groups A and B), superficial enamel was removed to create a ground surface. On the surface of other 30 samples (group C and D), orthodontic metal brackets were bonded. On each surface, BC liquid was applied and rinsed with water after 3 min (baseline). All surfaces were checked by two independent observers for presence of blue areas. On each sample, one side was covered by nail varnish to protect this enamel part from demineralization. The samples were demineralized with lactic acid (pH 4.6) for 7 days (group A and C) and 14 days (group B and D), respectively. Mineral loss was determined using quantitative light-induced fluorescence after demineralization. BlueCheck dye was again applied on the samples and evaluated for presence of stained areas. Histological sections were prepared from randomly selected samples and lesion depth was measured. Kruskal-Wallis test was used for group comparison (α = 0.05). After demineralization, median ΔF value for all samples was -8.25% indicating the presence of an initial demineralization. The difference of ΔF values was not statistically significant between samples at 7 or 14 days of demineralization, nor for samples with and without orthodontic brackets (p = 0.13). At baseline, none of the sample surfaces showed discoloration, whereas a distinctive blue color was visible after demineralization in all samples exposed to acid-exposed areas, corresponding to 100% sensitivity. The internal control surfaces (without demineralization) did not show any staining, corresponding to 100% specificity. Histologically measured lesion depths ranged between 200 and 254 μm. In this in vitro study, staining of demineralized enamel surface areas were shown to be reliable. Based on our results, this easily applicable product seems useful to be an adjuvant method to clinical examination to monitor oral health during an orthodontic treatment on tooth surfaces after removal of dental biofilm.

[Why the Wittenberg anatomist and scientist Konrad Victor Schneider (1614-1680) is also important for pneumologists]

The Wittenberg physician Konrad Victor Schneider (1614-1680) was the first to prove that mucus is not formed in the brain, nor is it secreted into the nasal cavity via the ethmoid bone. He recognised that there is no open anatomical connection between the brain and the nasal air space. Schneider discovered the sinonasal mucosa as the production site of mucus and thus refuted the hypothesis of cerebral mucus production and secretion by Hippocrates, Galen and Vesal. The nasal mucosa was named "membrana Schneideria" in honour of Schneider.

Remineralisation capability of silver diamine fluoride in artificial enamel lesions on smooth surfaces using quantitative light-induced fluorescence measurements in-vitro

Enamel demineralisation can develop on smooth surfaces as an undesirable side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the ability of 38% silver diamine fluoride in remineralisation (as estimated by fluorescence gain) of artificial initial lesions in smooth surfaces of human enamel. The smooth surfaces of 50 human tooth samples were artificially demineralised and 45 samples were allocated randomly into three groups receiving a single treatment with a varnish: group I: Riva Star (silver diamine fluoride, SDF), group II: Bifluorid 12 (NaF, CaF₂), and group III: Cervitec F (CHX, CPC, NH₄F). Five samples were assigned as a negative control group without treatment. All samples were exposed to pH-cycling for 28 days. Fluorescence behavior was measured using Quantitative light-induced fluorescence before and after demineralisation and up to four weeks on a weekly basis. Analysis of variance (ANOVA) with Tukey–Kramer post-hoc tests and repeated measures ANOVA were used for statistical evaluation (α = 0.05). After demineralisation, all samples showed mean ΔF of − 16.22% ± 4.35, without significance differences between the fluorescence behaviour of the samples (p = 0.251). After 28 days group comparison showed a statistically significant difference (p = 0.034) for ΔF values: the lowest fluorescence values were found in group I (SDF, mean ΔF − 16.47 ± 6.08) with a significant difference compared to group III (Cervitec F, mean ΔF − 11.71 ± 4.83). In group II (Bifluorid 12) mean ΔF value was − 15.55 ± 2.15) without statistically significant differences to groups I and III. The fluorescence behaviour of SDF varnish on smooth surfaces with artificial initial enamel lesions was significantly lower compared to Cervitec F varnish after short time use.

Knowledge of undergraduate dental students regarding management of caries lesions

Objectives

Understanding of lifelong control of disease processes associated with caries and its management is an essential part of dental education. This study evaluated the dental students’ knowledge of caries diagnosis and management using the International Caries Classification and Management System (ICCMS).

Methods

A survey was conducted among undergraduate dental students at two dental schools, attending the sixth (centre 1) and seventh semester (centre 2), respectively. Medical histories, clinical images and radiographs of 12 patients were compiled as anonymous cases. For each case, a specific lesion was to be assessed. In addition, the students should determine the patient’s caries risk and select a treatment option. An expert report (consensus decision) was used as the reference standard. For statistical analysis, kappa statistics and binomial tests were used.

Results

A total of 46 students participated in this study. The percentage of agreement of responses to the reference was: centre 1: 40.7–51.3%, centre 2: 57.9–67.9%. The corresponding Kappa values were: centre 1: 0.073–0.175, centre 2: 0.315–0.432. Overall, students tended to underestimate the codes compared to the reference standard (p < 0.001).

Conclusion

Introducing systematic content about caries diagnosis and management such as ICDAS and ICCMS in the learning objectives of undergraduate dental students can be proposed. However, in order to improve diagnosis and enable a more reliable choice of treatment options, attention should also be given to the way they are didactically taught.

Impact of rapid maxillary expansion on palatal morphology at different dentition stages

Objective

Rapid maxillary expansion (RME) is an established and frequently used procedure to overcome maxillary constriction. In-depth studies about morphological changes of the alveolar process and its immediate surroundings are missing. Therefore, the aim of the present study was to examine the treatment effects of a dentally anchored, rapid maxillary expander at different dentition stages upon palatal width, height and shape.

Material and methods

The dental casts of 114 patients—taken immediately before and after RME—were three-dimensionally analysed. Depending on the dentition stage, the patients were divided into two groups (each n = 57, group 1, early mixed dentition; group 2, late mixed or permanent dentition).

Results

The width increases were highly significant, both in the overall and in the individual groups (p < 0.001). While the width increase was greater in the posterior area than anteriorly in the early group, the widening in the late group happened significantly greater anteriorly than posteriorly. Palatal height increased anteriorly and posteriorly in both groups to a significant extent (p < 0.001). The height increase was more pronounced in the anterior region than in the posterior region in the late group. The palatine index according to Kim revealed a change in palatal morphology both anteriorly and posteriorly in the early group but only anteriorly in the late group.

Conclusions

Maxillary expansion occurs more parallel in early treatment compared to V-shaped opening in the later treatment approach.

Clinical relevance

RME is more advantageous in an early dentition.

Use of bioluminescence measurements for detection of artificial demineralization adjacent to orthodontic brackets

PURPOSE

Enamel demineralization can occur as a side effect during orthodontic treatment with fixed appliances and should be detected as early as possible. A new approach to assess demineralization is a system consisting of a photosensitive protein that binds to free calcium ions at the enamel surface. A camera is then used to visualize the bioluminescence spots. This in vitro study aimed to evaluate the ability of the bioluminescence technology to assess artificially demineralized enamel adjacent to various orthodontic brackets.

METHODS

In all, 108 human enamel samples were allocated randomly to groups with different orthodontic bracket material: stainless steel, titanium, ceramic. Initial lesions were created adjacent to the brackets. The samples were assessed by bioluminescence before and after demineralization. Images were assessed for presence of bioluminescence spots (yes/no). To quantify the bioluminescence measurements, the images' pixel values (P) were calculated within a defined area (F) adjacent to each bracket before and after demineralization. Quantitative light-induced fluorescence measurements (ΔF, ΔQ) were performed as the reference standard for demineralization.

RESULTS

After demineralization, bioluminescence spots were visible (yes/no decision) in 87% of the samples. The pixel analysis of the bioluminescence spots showed significantly higher pixel values after demineralization compared to baseline (p < 0.0001). The bracket material had no influence on the bioluminescence measurements. All samples showed fluorescence loss with a median ΔF of -9.52% (±3.15) and a median ΔQ of -1.01% × mm² (±3.34), respectively.

CONCLUSION

The bioluminescence technology is a promising tool to demonstrate demineralization adjacent to different orthodontic brackets in vitro.

Impact of self-assembling peptides in remineralisation of artificial early enamel lesions adjacent to orthodontic brackets

Enamel demineralisation can occur as a side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the efficacy of the self-assembling peptide P11-4 for remineralisation combined with fluorides, compared to application of fluoride varnish alone. De- and remineralisation was assessed by Quantitative light-induced fluorescence (QLF). Orthodontic brackets were bonded on 108 human enamel samples and white spot lesions were created. The samples were allocated randomly into three groups: Group I received no treatment, group II had a single application of fluoride varnish (22,600 ppm), and group III was treated with P11-4 following a single application of fluoride varnish. Quantitative light-induced fluorescence (QLF) measurements were performed at baseline, after demineralisation and after storage in remineralisation solution for 7 and 30 days. Non-parametric tests (Kruskal-Wallis test and Friedman test) were used for further analysis. After demineralisation, all samples showed a median ΔF -9.38% ± 2.79. After 30 days median ΔF values were as followed: group I = -9.04% ± 2.51, group II = -7.89 ± 2.07, group III = -6.08% ± 2.79). The median ΔF values differed significantly between all groups at all investigation times (p < 0.00001). Application of P11-4 with fluoride varnish was superior to the use of fluorides alone for remineralisation of enamel adjacent to brackets.

Effects of 445-nm Diode Laser-Assisted Debonding of Metallic Brackets on Shear Bond Strength and Enamel Surface Morphology

Objective: To evaluate the effect of a 445-nm diode laser on the shear bond strength (SBS) of metallic brackets before debonding. Background: Due to the new blue laser technology, very few studies are available in this context. Methods: Seventy metallic brackets (Discovery; Dentaurum, Ispringen, Germany) were bonded to the frontal enamel surfaces of 70 caries-free bovine incisors in a standardized way. Each sample was randomly assigned to the control or laser group, with 35 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue^®; Sirona, Bensheim, Germany) on three sides of the bracket bases for 5 s each (lateral-coronal-lateral, a total of 15 s) immediately before debonding. SBS values were evaluated for the control group and laser group. Micrographs of the enamel surface were taken with 10 × magnification to assess the adhesive remnant index (ARI) and the degree of enamel fractures after debonding. Results: There were no statistically significant differences in SBS in the laser group in comparison with the control group (p > 0.05). The distribution of ARI scores was also not statistically significantly different in the laser group in comparison with the control group (p > 0.05). Three enamel fractures occurred in the control group and one in the laser group after debonding. Conclusions: Irradiation of metallic brackets with the 445-nm diode laser before debonding does not significantly reduce the SBS values and does not influence the remaining amount of adhesive on the enamel surface. The risk of enamel fractures during debonding is therefore not clinically affected.

Nasal soft- and hard-tissue changes following tooth-borne and hybrid surgically assisted rapid maxillary expansion: A randomized clinical cone-beam computed tomography study

PURPOSE

The aim of this study was to assess the effects of tooth/bone-borne (hybrid) and tooth-borne (TB) surgically assisted rapid maxillary expansion (SARME) on the width of the nasal soft and hard tissue.

PATIENTS AND METHODS

Twenty skeletally mature patients (nine males and 11 females; mean age 19.4 years) with transverse maxillary hypoplasia were randomly assigned to hybrid or TB devices. The patients had undergone SARME operations, performed by the same surgical team using the same procedure (Le Fort I osteotomy with pterygomaxillary dysjunction, midline osteotomy, and no down-fracture). Nasal soft- and hard-tissue changes were analyzed using CBCT preoperatively (T0), at the end of the active expansion phase (T1), and after 6 months of retention (T2). The study was approved by the relevant ethics committee.

RESULTS

The skeletal and soft-tissue nasal parameters increased significantly in the T0-T1 and T0-T2 periods in both groups (P < 0.05). No statistically significant differences between the groups were observed. The mean piriform aperture width increased from 1.26 mm in T0-T1 to 0.97 mm in T1-T2 and 2.17 mm in T0-T2 (P < 0.008). In the soft tissue, the alar base width increased to 2.78 mm and the alar width to 2.95 mm in T0-T2 (P = 0.001). There was a positive correlation (63.6%) between the changes in skeletal and soft-tissue values.

CONCLUSION

The hybrid and TB devices led to similarly significant widening effects in nasal soft and hard tissues in both the short term and 6 months after SARME.

Influence of Photobiomodulation Therapy on Gingivitis Induced by Multi-Bracket Appliances: A Split-Mouth Randomized Controlled Trial

OBJECTIVE

The objective of this split-mouth trial was to investigate the influence of photobiomodulation therapy (PBMT) on adjuvant treatment of gingivitis induced by multi-bracket appliances, after bracket debonding and professional tooth cleaning.

MATERIALS AND METHODS

Thirteen patients (mean age 16.15 years; standard deviation ±2.12 years) who had completed active orthodontic treatment with fixed orthodontic appliances in an orthodontic clinic were included on a randomized basis. At time point T0, after bracket debonding and professional tooth cleaning, the papilla bleeding index (PBI) and bleeding on probing (BOP) were assessed in the upper jaw by the blinded investigator (M.S.), who was not aware at any time of which quadrant received PBMT. The study was based on a patient-blinded split-mouth design. In each patient, PBMT was administered by a practitioner (S.S.) in one upper quadrant (wavelength: 660 nm; Power: 100 mW; Power density: 100 mW/cm²; Energy density per application point = 2 J/cm²; Energy per application point = 2 J; Total dose = 52 J/cm²; Total energy = 52 J; Irradiation time: 26 × 20 sec), while the other upper quadrant received a simulated laser application with the laser system turned off. Randomized equal allocation of the sides was accomplished. The second PBI and BOP assessment followed 4-6 days after laser irradiation (T1) by M.S.

RESULTS

No statistical differences were observed between the sides with regard to PBI and BOP values at T0 (p > 0.05). The PBI and BOP values decreased significantly between T0 and T1 on both sides (p < 0.05). At T1, the PBI and BOP values were significantly lower in the laser side in comparison with the control side (p < 0.05).

CONCLUSIONS

On the basis of these results and study parameters, adjuvant PBMT is able to accelerate the healing process in patients with gingivitis induced by multi-bracket appliances.

Inhibition of bone resorption by bisphosphonates interferes with orthodontically induced midpalatal suture expansion in mice

OBJECTIVES

Craniofacial sutures are important growth sites for skull development and are sensitive to mechanical stress. In order to determine the role of bone resorption in stress-mediated sutural bone growth, midpalatal suture expansion was performed in mice receiving alendronate, an anti-resorptive bisphosphonate.

MATERIALS AND METHODS

The midpalatal sutures of 8-week-old C57BL/6 mice were expanded by orthodontic wires over the period of 2 weeks. Mice with maxillary expansion without drug treatment as well as untreated animals served as controls. Skulls were analyzed with micro-computed tomography (micro-CT), immunohistochemistry and histology.

RESULTS

Maxillary expansion in mice without drug treatment resulted in an increase of TRAP-positive osteoclasts. In contrast, no increase in osteoclasts was observed in expanded sutures of mice with bisphosphonate treatment. Double calcein labeling demonstrated rapid bone formation on the oral edges of the expanded sutures in mice without bisphosphonate treatment. Less bone formation was observed in bisphosphonate-treated mice after expansion. Histology revealed that the sutural architecture was reestablished in expanded sutures of mice without bisphosphonate treatment. In contrast, the sutural architecture was disorganized and the cartilage had an irregular form, following expansion in bisphosphonate-treated mice. Finally, micro-CT imaging demonstrated that the total amount of maxillary expansion was significantly lower in mice with bisphosphonate treatment as compared to those of mice without drug treatment.

CONCLUSIONS

In conclusion, our results indicate that osteoclast-mediated bone resorption is needed for maxillary suture expansion and reorganization of sutural architecture.

CLINICAL SIGNIFICANCE

Orthodontic palatal expansion can be complicated in patients with inherited or drug-induced diseases of osteoclast dysfunction.

Intrapulpal Temperature Increases Caused by 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets During Simulated Pulpal Fluid Circulation

OBJECTIVE

This study investigated temperature increases in dental pulp resulting from laser-assisted debonding of ceramic brackets using a 445-nm diode laser.

MATERIALS AND METHODS

Eighteen ceramic brackets were bonded in standardized manner to 18 caries-free human third molars. Pulpal fluid circulation was simulated by pumping distilled water at 37°C through the pulp chamber. The brackets were irradiated with a 445-nm diode laser. Temperatures were measured using a thermal camera at points P1 (center of the pulp) and P2 (in the hard dental tissue) at the baseline (T0), at the start and end of laser application (T1 and T2), and the maximum during the sequence (T_max).

RESULTS

Significant differences in the temperatures measured at P1 and P2 were observed among T0, T1, T2, and T_max. Significant increases in temperature were noted at points P1 and P2, between T1 and T2, T1 and T_max, and T2 and T_max. The maximum P2 values were significantly higher than at P1. The maximum temperature increase measured in the pulp was 2.23°C, lower than the critical threshold of 5.5°C.

CONCLUSIONS

On the basis of the laser settings used, there is no risk to the vitality of dental pulp during laser-assisted debonding of ceramic brackets with a 445-nm diode laser.

445-nm diode laser-assisted debonding of self-ligating ceramic brackets

Objectives:

This study determined the influence of irradiation on aesthetic ceramic brackets with a novel 445-nm diode laser prior to debonding on the bracket failure mode.

Materials and methods:

Thirty ceramic brackets (In-Ovation® C, GAC) were standard-bonded to the oral and buccal planed and polished enamel surfaces of 15 caries-free human 3

Results:

In the laser group, the ARI-score was statistically significantly reduced (p<0.05) at 10-fold and 20-fold magnifications compared to the conventional group, while enamel fractures were not found at any magnification in either group at T1. Enamel fractures and grinding marks were increasingly found in the conventional group by SEM at T2.

Conclusion:

Irradiation with the novel diode laser prior to debonding of ceramic brackets significantly changes bonding failure in terms of less remaining adhesive. This is of clinical importance as the risk of enamel fractures and chair time can be reduced.

Effects of 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets on Shear Bond Strength

OBJECTIVE

The aim of this study was to measure the effect of irradiation with a novel 445-nm diode laser on the shear bond strength (SBS) of ceramic brackets before debonding.

MATERIALS AND METHODS

Thirty ceramic brackets (In-Ovation^® C, GAC) were bonded in standard manner to the planed and polished buccal enamel surfaces of 30 caries-free human third molars. Each tooth was randomly allocated to the laser or control group, with 15 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue^®; Sirona) on three sides of the bracket bases for 5 sec each (lateral-coronal-lateral, a total of 15 sec) immediately before debonding. SBS values were measured for the laser group and control group. To assess the adhesive remnant index (ARI) and the degree of enamel fractures, micrographs of the enamel surface were taken with 10-fold magnification after debonding.

RESULTS

The SBS values were significantly lower statistically in the laser group in comparison with the control group (p < 0.05). The ARI scores were also significantly lower statistically in the laser group in comparison with the control group (p < 0.05). No bracket fractures or enamel fractures occurred in either group after debonding.

CONCLUSIONS

Irradiation of ceramic brackets with the novel diode laser before debonding significantly reduces the SBS values. This is of clinical importance, as it means that the risk of damage to the teeth, bracket fractures, and the overall treatment time can be reduced.

Pain reduced by low-level laser therapy during use of orthodontic separators in early mixed dentition

OBJECTIVE

The purpose of this work was to investigate whether low-level laser therapy (LLLT) applied at a defined distance from the gingiva has a pain-reducing effect in young patients undergoing orthodontic separation during the early mixed-dentition stage.

MATERIALS AND METHODS

A total of 40 children in early mixed dentition (mean age 8.05 years) who required separation of molars were included. The study comprised a group of 20 patients whose treatment included laser application on the day of separation and a control group of 20 patients not receiving LLLT. All patients recorded their maximum pain intensities on the day of separation (day 1) and on the following 4 days.

RESULTS

Compared to the control group, pain perception was significantly reduced (p < 0.05) in the LLLT group on day 1 and continued to be reduced on day 2. Equivalent pain levels were recorded in both groups on days 3-5.

CONCLUSION

Given our findings of a pain-reducing effect in young patients undergoing orthodontic separation during the early mixed-dentition stage, LLLT is an interesting alternative option of providing analgesia even in very young patients.

Novel lingual retainer created using CAD/CAM technology: evaluation of its positioning accuracy

OBJECTIVES

Permanent retention is currently the method of choice to stabilize orthodontic treatment results. Frequently, permanent retention schemes are adopted to prevent posttreatment changes in the esthetic zone of the anterior teeth. With increasingly prolonged times of intraoral device use, and retention to be provided in the maxilla despite limited space, the demands placed on well-planned and precise retainer positioning are becoming more exacting. The aim of the present study was to analyze the intraoral precision of lingual retainers made using computer-aided design and machining (CAD/CAM).

MATERIALS AND METHODS

A custom manufacturer (Retaintechnology; Cologne, Germany) employing innovative CAD/CAM technology was commissioned to fabricate 16 lingual retainers. Following intraoral insertion using the manufacturer's recommended transfer system, impressions of the intraoral situations were taken and scanned for digitization. On this basis, the intraoral retainer positions were compared to the preceding virtual setups by superimposition with the manufacturer's datasets. Three-dimensional processing software (Geomagic Qualify 2012; Geomagic) was used to analyze the retainers, based on a total of 80 interproximal sites, for deviations from their planned positions along the horizontal (x-), sagittal (y-), and vertical (z-) axes. These deviations of the achieved from the intended positions were considered clinically relevant if ≥ 0.5 mm and, based on this premise, were subjected to a t-test with statistical software (Prism; GraphPad).

RESULTS

The intraoral retainer positions were found to correlate closely with the preceding virtual setups (i.e., the positions as they had been planned by the custom manufacturer). Positional deviations were significantly less than 0.5 mm. They were very small in the horizontal and sagittal planes and moderately larger in the vertical plane.

CONCLUSION

Highly precise intraoral results may be achieved by transferring three-dimensional virtual setups for lingual retainers to the actual patients. This CAD/CAM strategy of making retainers can offer high predictability even in anatomically demanding regions and in the presence of limited space.

Rapid-maxillary-expansion induced rhinological effects: a retrospective multicenter study

Conventional dental-borne rapid maxillary expansion (RME) leads to a widening of the airways, followed by improved nasal breathing. Although combined skeletal-dental appliances are nowadays being inserted increasingly often and provide a force at the center of resistance in the nasomaxillary complex, no study exists so far that shows whether this treatment may improve the expansionary effect on the airways. In this study, low-dose computed tomography (CT) images from 31 patients (average age 14.63 ± 0.38 years) were examined retrospectively. Both records (T0 = before expansion and T1 = immediately after maximum expansion) were taken in a time interval of 25 days to avoid growth influence. Five patients were treated with Hyrax RME, 6 patients with Hybrid RME, and 20 patients with acrylic cap RME. The total airway volume increased highly significantly (mean +7272.6 mm(3); P < 0.001, power = 0.998), representing an average airway expansion of +11.54 % (2.35 %/mm activation). While the nasopharynx and oropharynx showed highly significant expansion (P < 0.000, power = 0.999), the airway at the laryngopharynx did not change significantly (P > 0.779, power = 0.05). Although the patients were significantly older in the Hybrid RME group (P = 0.006), the positive rhinological effects were comparable within all groups of different appliances (P > 0.316). Hybrid RME may, therefore, be an advisable procedure in patients with nasomaxillary impairment and pronounced patient's age.

Density of the midpalatal suture after RME treatment - a retrospective comparative low-dose CT-study

Introduction

Rapid maxillary expansion (RME) is a common technique to improve the dental and skeletal transverse width in cases of constricted maxillary arches. Although retention after RME has been widely examined, there is still no clear statement about the minimal retention time in postpubertal patients and many practitioners have retention concepts varying between three and six months.

Methods

This retrospective study consisted of 14 patients who were either treated with a Haas-type RME (6 patients) or a Hybrid-RME (8 patients). The average age was 15.8 years (min. 13.5 years, max. 23.0 years).

Low-dose CT scans were taken initially before placement of the RME (T0), directly after maximal activation (T1) and (in six cases) also in retention after 6 months (T2). Using a 3D-software (“OnDemand3D”/Cybermed Inc.) in analogy to the method published by Franchi et al. (AJODO Volume 137/ Number 4) all values were measured twice at an interval of 1 month to assess the method error and the intraoperator reliability.

Statistical analysis was performed using SPSS 21 for Mac. Possible influences of the RME-type were assessed using the univariate ANOVA. Changes in the sutural density between the different points of time were examined using paired t-tests.

Results

The density of the suture decreased significantly after expansion (T0-T1) with both types of RME (p = 0.000). In the retention period there was a significant increase of the sutural density (p = 0.007) although it did not achieve the initial level (p = 0.002).

Conclusions

1. The midpalatal suture was opened in all analysed patients.

2. In postpubertal patients a retention time of six months does not allow sufficient reorganization of the suture.

3. Therefore, a retention period longer than six months seems to be beneficial to prevent relapses in postpubertal patients.