Next-generation sequencing reveals the mutational landscape of clinically diagnosed Usher syndrome: copy number variations, phenocopies, a predominant target for translational read-through, and PEX26 mutated in Heimler syndrome.

BACKGROUND: Combined retinal degeneration and sensorineural hearing impairment is mostly due to autosomal recessive Usher syndrome (USH1: congenital deafness, early retinitis pigmentosa (RP); USH2: progressive hearing impairment, RP). METHODS: Sanger sequencing and NGS of 112 genes (Usher syndrome, nonsyndromic deafness, overlapping conditions), MLPA, and array-CGH were conducted in 138 patients clinically diagnosed with Usher syndrome. RESULTS: A molecular diagnosis was achieved in 97% of both USH1 and USH2 patients, with biallelic mutations in 97% (USH1) and 90% (USH2), respectively. Quantitative readout reliably detected CNVs (confirmed by MLPA or array-CGH), qualifying targeted NGS as one tool for detecting point mutations and CNVs. CNVs accounted for 10% of identified USH2A alleles, often in trans to seemingly monoallelic point mutations. We demonstrate PTC124-induced read-through of the common p.Trp3955* nonsense mutation (13% of detected USH2A alleles), a potential therapy target. Usher gene mutations were found in most patients with atypical Usher syndrome, but the diagnosis was adjusted in case of double homozygosity for mutations in OTOA and NR2E3, genes implicated in isolated deafness and RP. Two patients with additional enamel dysplasia had biallelic PEX26 mutations, for the first time linking this gene to Heimler syndrome. CONCLUSION: Targeted NGS not restricted to Usher genes proved beneficial in uncovering conditions mimicking Usher syndrome.

Age-dependent three-dimensional microcomputed tomography analysis of the human midpalatal suture.

AIM: The success of rapid maxillary expansion is hard to predict in patients from the age of 20. There are as yet no reliable parameters enabling us to define success or failure a priori. The aim of this study was thus to use micro-CT techniques to quantify suture morphology three-dimensionally, and investigate its relation to age. MATERIAL AND METHODS: The morphology of the midpalatal suture was evaluated by documenting 28 human-palate specimens from individuals aged 14-71 using computed tomography. The software AMIRA 3.00 was used for 3D (three-dimensional) reconstruction of the datasets. Sutural morphology was quantified and examined for age-dependent morphological characteristics with the software Image Tool 3.00. To that end, the specimens were assigned to three age groups (< 25 years, 25 years to < 30 years, >/= 30 years) and the following parameters were considered: obliteration index in the frontal plane, and suture length, linear sutural distance, and interdigitation index in the horizontal plane, as well as bone density (BV/TV [%]) in the sagittal plane. RESULTS: Significant differences between age groups were only found for bone density in sagittal dimension. The middle-aged group exhibited the highest bone density (53.2%). In comparison to that group, bone density was significantly lower in the youngest and the oldest age groups. The mean obliteration index exhibited substantial inter-individual variation, was generally low, and did not correlate with chronological age. The extent of interdigitation was independent of age. CONCLUSIONS: The necessity for surgical weakening can neither be explained by sutural interdigitation increasing with age nor by a higher obliteration index. Sutural bone density (hence the fracture resistance increasing with age) seems to be the parameter limiting conservative RME.

Value of two cone-beam computed tomography systems from an orthodontic point of view.

AIM: Since its introduction in dental radiology in 1998, cone-beam computed tomography (CBCT) has found increasing acceptance in clinical routine. The aim of this study was thus to evaluate this imaging modality from an orthodontic point of view. MATERIALS AND METHODS: Two systems formed the basis of this investigation: the NewTom 9000 (NewTom Germany AG, Marburg, Germany), in use at the University Medical Center Hamburg-Eppendorf since October 2002, and the mobile Arcadis Orbic 3D system (Siemens Medical Solutions, Erlangen, Germany), which was introduced in February 2005. Two independent examiners evaluated a total of 68 NewTom and 15 Arcadis Orbic 3D images involving orthodontic indications. The images were categorized according to their indications and diagnostic value assessed according to a predefined and quantifiable protocol. Information obtained from the CBCT was also compared to that gleaned from conventional radiographs. RESULTS: The indication for the NewTom images in cleft patients as well as for all Arcadis Orbic 3D images was considered justified. The osseous morphology of the cleft and position of osteosynthetic screws and plates were particularly well visualized. CBCT implementation in cases of tooth impaction or for assessing third molars was considered justified, although its value was judged differently by the two examiners. CBCT did not provide more information than conventional imaging regarding cartilaginous joint structures. CONCLUSIONS: In complex orthodontic cases in which 3D imaging is mandatory, CBCT is the method of choice. Furthermore, in cleft patients and those undergoing combined orthodontic and maxillofacial therapy, CBCT proved advantageous, providing more information than conventional images.

Associations between orthopaedic disturbances and unilateral crossbite in children with asymmetry of the upper cervical spine.

The objective of the present study was to detect possible associations between unilateral crossbite and orthopaedic disturbances in children with asymmetry of the upper cervical spine. Fifty-five children aged 3-10 years (22 girls and 33 boys) with a unilateral crossbite and 55 gender- and age-matched children with a symmetric occlusion but no crossbite, who served as the control group, were selected from an orthopaedic cohort of 240 patients. In all children, asymmetry of the upper cervical region was confirmed by radiographs and palpation. The following orthopaedic aspects were investigated: oblique shoulder and pelvis, scoliosis, functional leg length difference, and laxity of ligaments of the foot. The differences between the groups were analysed by means of an unpaired t-test. An increased occurrence of orthopaedic parameters in the frontal plane was observed in children with a unilateral malocclusion. A unilateral crossbite was not necessarily combined with a pathological orthopaedic variable, but statistically, children with a unilateral malocclusion showed more often an oblique shoulder (P = 0.004), scoliosis (P = 0.04), an oblique pelvis (P = 0.007), and a functional leg length difference (P = 0.002) than children with symmetry. The results suggest that a unilateral crossbite in children with asymmetry of the upper cervical spine is associated with orthopaedic disturbances. There is no evidence of a causal link.

Fluoride-releasing adhesive and antimicrobial self-etching primer effects on shear bond strength of orthodontic brackets.

OBJECTIVE: To determine whether the combination of a new antimicrobial primer and a fluoride-releasing adhesive will affect the shear bond strength (SBS) and the bracket/adhesive failure mode. MATERIALS AND METHODS: A total of 120 extracted human teeth were randomly divided into three groups of 40 specimens each (20 incisors, 20 premolars). Transbond XT was used in group 1, a fluoride-releasing adhesive (Kurasper F) was used in group 2, and a new antimicrobial self-etching primer (Clearfil Protect Bond) was applied in combination with Kurasper F in group 3. A universal testing machine was used to determine the SBS, and the adhesive remaining after debonding was assessed. RESULTS: No enamel fractures were detected in any of the specimens. SBS values for incisors and premolars were 11.40 +/- 4.65 MPa and 10.37 +/- 3.36 MPa in group 1, 14.50 +/- 4.22 MPa and 13.06 +/- 5.13 MPa in group 2, and 14.79 +/- 4.10 MPa and 14.60 +/- 3.55 MPa in group 3. Statistically significant difference (P = .001) was found in the premolars in group 3 revealing the highest mean SBS. Significantly lower adhesive remnant index (ARI) values (median ARI value of 1) were detected in group 3 when compared with groups 1 and 2. CONCLUSIONS: Considering the acceptable bond strength and the mode of failure, the combination of the new antimicrobial primer with the fluoride-releasing adhesive is recommended for clinical use.

Distraction osteogenesis of ankylosed front teeth with subsequent orthodontic fine adjustment.

OBJECTIVE: Conventional therapeutic approaches to correct ankylosed anterior teeth in infraposition require compromises involving esthetics and function. The combined approach of distraction and early orthodontic fine adjustment, not yet established as a routine, promises better results concerning the bone conditions and gingival development. CASE HISTORIES: Both female patients had suffered a trauma to the front teeth during early mixed dentition resulting in ankylosed central incisors in infraposition. At the ages of 14 years and 2 months and 15 years and 2 months, respectively, we carried out segment distraction by means of a bone-supported internal distractor followed by orthodontic fine adjustment after having shortened the consolidation phase. Both ankylosed front teeth could be successfully aligned, leading to an increase in bone and harmonization of the gingival margin in the dental arch. At ten and 14 months after the conclusion of treatment, we observed only few deviations in the dental situation compared to posttherapeutic findings. CONCLUSION: From a functional and esthetic point of view, therapy involving combined orthodontics and surgery is superior to conventional therapy. Orthodontic fine adjustment should be considered as a continuation of the distraction procedure.

Clinical profile of rapid maxillary expansion--outcome of a national inquiry.

BACKGROUND: Rapid maxillary expansion (RME) is a therapeutic orthodontic option with a long history, and there are many reports in the literature reporting widely divergent results concerning the appliance efficacy and many different treatment protocols. We aimed to evaluate the treatment protocols and clinical experiences with RME via a national inquiry of orthodontists to identify the status quo of RME in clinical daily routine. METHOD: Within the framework of an anonymous questionnaire, 2003 orthodontists and members of the German Orthodontic Society (DGKFO) were asked to report on their clinical experiences with RME. The standardized questionnaire covered clinical indications, dentition period at the time of insertion, mode of activation, retention time, observed side effects, and the reasons for requiring surgical assistance. RESULTS: The data from 487 questionnaires could be evaluated. The only indication for RME named by a large majority of responders was transversal maxillary deficiency. The average extent of the transversal deficiency amounted to 5.29 +/- 2.25 mm (median 5 mm). Most orthodontists (87.7%) employed RME in the permanent dentition of adolescents; it was significantly less frequently applied in the primary dentition or adults. Answers regarding the mode of activation varied greatly. The most frequent mode of activation was "1-2 activations a day" independent of the dentition period. 64.5% of the orthodontists reported buccal tipping of the anchorage teeth. No correlation was detected between mode of activation, time of insertion and observed side effects. 60% of the orthodontists reported a retention period of between 3 and 6 months (median 4.5 months). With an average age of 19.28 years, 79.3% assessed chronological age as a limiting factor for conventional RME. It was not possible to identify a homogeneous diagnostic procedure for the indication of surgical assistance. CONCLUSIONS: Although RME has a long clinical history, no standardized treatment protocols exist. Randomized clinical trials are necessary to make clear-cut clinical recommendations on the use of RME, as required by the tenets of evidence-based medicine and quality assurance.

Orofacial myofunctional disorders in children with asymmetry of the posture and locomotion apparatus.

352 children radiologically identified with asymmetry in the occipito-cervical region were assessed on a number of myofunctional measures. In all children an orthopedic examination was conducted including a functional test of the upper cervical spine and the iliac joint, the postural test by Matthiass, as well as gait analysis. During a second examination the orofacial myofunctional status was recorded. In general, about 70% of the children revealed orofacial myofunctional disorders. Correlational analysis was conducted in order to determine whether specific myofunctional variables were associated with postural and orthopedic alterations. A weak body posture correlated statistically significantly with all assessed myofunctional variables. On the other hand, all orthopedic items correlated significantly with a reclined head position. A blockade of the iliac spine correlated significantly with persistent habits, articulation disorders and tongue dysfunction, whereas functional asymmetry of the upper cervical spine correlated significantly with incompetent lips. A finding of at least five statistically significant correlations within each orofacial variable underlined the complex symptomatology of myofunctional disorders, so that consideration needs to be given to adequate treatment approaches. The data generated by the present study stress the importance of early interdisciplinary screening in children to ensure a physiological development of the orofacial region and the still growing vertebral column. To help understand the complexity of symptoms influencing orofacial development, an explanatory model of the "interactive functional box system" is given.

Cephalometric evaluation of children with Down syndrome after early intervention with the stimulating plate.

The aim of stimulating plate therapy in patients with trisomy 21 is to correct orofacial dysfunctions and prevent the establishment of subsequent morphological characteristics such as protrusion of the incisors and pseudoprognathia. This study investigated the effectiveness of this type of therapy in improving skeletal traits of patients with Down syndrome. The lateral cephalograms of 22 consecutive juveniles with Down syndrome, whose orofacial dysfunctions had been successfully treated with a stimulating plate according to Castillo Morales in infancy (17 months +/- 24 months), were examined 136 months on average (minimum of 78 months, maximum of 231 months) after initiation of treatment. In 16 of the 22 patients, the anomaly-typical bialveolar protrusion of the anterior teeth was diagnosed. The cephalometric results indicated larger values of cephalometric parameters concerning cranial base and maxilla, and markedly larger mandibular cephalometric values when compared to untreated children with Down syndrome. These results show that a stimulating plate may not always be indicated in patients with Down syndrome with a skeletal Class III pattern and minor orofacial findings.

Correlations between dentition anomalies and diseases of the of the postural and movement apparatus--a literature review.

From anatomic and functional aspects the stomatognathic system and the upper cervical spine are closely interlinked. Together with complex neuromuscular relationships, this gives rise to an important field of cooperation between orthodontics and orthopedics. The literature appeals for close interdisciplinary cooperation for patients with syndromes and for those with torticollis and scoliosis. Since orthopedic points of contact are obvious in these special cases, orthopedic aspects are now being taken increasingly into account in farther-reaching studies. With the rising popularity of manual medicine, these aspects are being recognized from the orthopedic point of view too in terms of functional correlations and are being increasingly debated at international congresses and in the literature. Although relevant publications were initially confined to studies of moderate scientific interest or case reports, potential correlations have undergone scientific investigation in recent interdisciplinary studies. Despite the many clinical studies, no unequivocal recommendation can be given for basic conditions under which an orthopedist is bound to be consulted on patients with orthodontic findings. This literature review is aimed at providing an introduction to this still hotly debated issue.

Orofacial development in children with Down's syndrome 12 years after early intervention with a stimulating plate.

BACKGROUND: Orofacial regulation therapy for children with Down's syndrome was introduced to Europe in Munich in 1978. Since then, many clinical studies have provided scientific evidence that this therapeutic approach enhances the orofacial function and facial appearance of children with trisomy 21. Only few long-term results have been published to date. PATIENTS AND RESULTS: In the present study, 20 children with trisomy 21 were examined more than 12 years after starting treatment in infancy with a Castillo Morales stimulating plate. The follow-up examination showed that the improved orofacial appearance resulting from the early treatment had remained stable in most cases. Although the mechanical stimulus of the stimulating plate was absent during the follow-up period, some patients revealed a lip and tongue posture superior to that recorded at baseline. CONCLUSION: According to the results of the present study, the orofacial status in early childhood is decisive for the subsequent development of the orofacial region and the long-term stability of the achieved improvements: Children with a pronounced orofacial dysfunction showed a greater stimulation-plate-induced improvement than those with initially moderate orofacial findings. This observation was confirmed by the findings of the 12-year follow-up: Children with Down's syndrome and initially slight orofacial impairment displayed only slight improvements or unchanged findings.

Evaluation of a new concept of myofunctional therapy in children.

This prospective study was designed to evaluate a new concept of myofunctional therapy in comparison with conventional myofunctional therapy. 45 children aged three to sixteen years in need of myofunctional therapy were randomly divided into two groups: 19 children were referred to myofunctional therapy in private practices in Hamburg and served as controls. The remaining 26 children were treated with face former therapy at the Department of Orthodontics by a medical assistant specializing in myofunctional therapy. The overall observation time was six months. Every three months an overall clinical assessment was performed at the Department of Orthodontics by a speech pathologist and an orthodontist, who documented the clinical situation. The clinical examination included measurement of lip strength, palatography to document the swallowing pattern, logopedic diagnosis, and an orthodontic examination with reference to a standardized diagnostic sheet. In all children's orofacial function could be improved. Children treated with the Face Former showed a statistically significantly improvement in palatal tongue position during swallowing. They achieved stronger lip pressure within a shorter time than children who did not use the Face Former. However, at the end of the observation time there was no statistically significant difference in lip strength between the two groups. Habitual mouth closure was also achieved within a shorter time for children treated with the FaceFormer than children with myofunctional therapy. Face Former therapy seems to offer a good alternative to conventional myofunctional therapy. Longitudinal studies will follow to judge whether the established orofacial balance could be stabilized, i.e. the established physiological orofacial function becomes automatic.

Plasma arc curing of ceramic brackets: an evaluation of shear bond strength and debonding characteristics.

The aim of this in vitro investigation was to evaluate bond strength and debonding characteristics when a xenon plasma arc curing light is used to bond polycrystalline and monocrystalline ceramic brackets. Brackets were bonded to 240 extracted bovine mandibular incisors with a composite adhesive. Curing intervals of 1, 3, and 6 seconds were chosen for curing with the plasma arc light, and the control group was cured at 10 seconds per bracket with a conventional halogen light. Debonding was performed on a universal testing machine and according to the bracket manufacturers' recommendations. Both the polycrystalline and the monocrystalline brackets consistently debonded at the bracket-adhesive interface, regardless of debonding method, curing interval, or curing light. No enamel fractures were observed after debonding. Bracket fractures were rare and did not affect debonding. Bond strength was significantly higher for the monocrystalline brackets (P <.0001): mean shear bond strength ranged between 9.68 +/- 2.17 MPa (plasma arc curing light, 1 sec curing interval) and 10.73 +/- 3.22 MPa (halogen light, 10 sec curing interval) for the polycrystalline brackets and between 19.85 +/- 2.97 MPa (plasma arc curing light, 1 sec curing interval) and 22.94 +/- 3.20 MPa (plasma arc curing light, 3 sec curing interval) for the monocrystalline brackets. Significant differences were also found for the curing methods used (P =.047). A curing interval of 3 seconds with the plasma arc curing light is recommended for both polycrystalline and monocrystalline ceramic brackets.

Plasma arc curing lights for orthodontic bonding.

Xenon plasma arc lights were introduced recently for light-cured orthodontic bonding. Compared with a conventional tungsten-quartz-halogen light source, these high-intensity lights promise a dramatic reduction in curing time. The purpose of this in vitro investigation was to evaluate bond strength with 2 commercially available plasma arc lights and reduced curing intervals. Brackets were bonded to 150 extracted human teeth (75 premolars, 75 incisors) with a composite adhesive. Intervals of 2 and 6 seconds were used for curing with the plasma arc lights; a control group was bonded with a halogen light source and 20 seconds of light exposure per bracket. Bond strength testing was performed with a universal testing machine. A substantial reduction in curing time was possible with both plasma arc units. Significantly lower bond strength values were found for premolar brackets bonded with plasma arc curing lights and the shortest curing interval of 2 seconds compared with the longer curing time of 6 seconds or the standard curing time with the halogen light. Although 2 seconds of curing might be adequate to achieve acceptable bond strength values for the incisors, the Weibull analysis indicated a higher probability of bond failure for premolar brackets in particular. Six seconds of curing time is recommended for bonding stainless steel brackets with xenon plasma arc light sources.

Enamel conditioning for orthodontic bonding with a single-step bonding agent.

AIM: In-vitro evaluation of an alternative method to the conventional acid etch technique. MATERIAL AND METHOD: 240 human anterior and posterior teeth were divided into 16 groups of 15 teeth each. Group variables were: tooth type, enamel conditioning technique (Prompt L-Pop((R)): 3M Espe, Seefeld, Germany, or 37% phosphoric acid and bonding), adhesive (Transbond trade mark XT: 3M Unitek, Monrovia, CA, USA and ENlight((R)): Ormco, Orange, CA, USA), and testing procedure (shear and tensile bond strength). Upper lateral incisors and premolar brackets (Mini-Diamond((R)): Ormco, Orange, CA, USA) were used. Intergroup differences were analyzed by an analysis of variance. The enamel surface and the failure mode of debonded specimens were investigated with light and scanning electron microscopy. RESULTS: Despite a tendency towards a higher bond strength after phosphoric acid conditioning, no statistically significant differences were found between the enamel conditioning methods. Statistically significant differences were recorded for the different adhesives: bond strength with Transbond trade mark XT was higher than with Enlight((R)). CONCLUSION: The single-step bonding agent sems to provide an acceptable bond strength between adhesive and enamel. No enamel fractures were detected. In vivo studies will be conducted to investigate the clinical performance of the new material.