For 3-dimensional (3D) imaging of a tissue, 3 methodological steps are essential and their successful application depends on specific characteristics of the type of tissue. The steps are 1° clearing of the opaque tissue to render it transparent for microscopy, 2° fluorescence labeling of the tissues and 3° 3D imaging. In the past decades, new methodologies were introduced for the clearing steps with their specific advantages and disadvantages. Most clearing techniques have been applied to the central nervous system and other organs that contain relatively low amounts of connective tissue including extracellular matrix. However, tissues that contain large amounts of extracellular matrix such as dermis in skin or gingiva are difficult to clear. The present survey lists methodologies that are available for clearing of tissues for 3D imaging. We report here that the BABB method using a mixture of benzyl alcohol and benzyl benzoate and iDISCO using dibenzylether (DBE) are the most successful methods for clearing connective tissue-rich gingiva and dermis of skin for 3D histochemistry and imaging of fluorescence using light-sheet microscopy.

BackgroundFixed orthodontic appliances (FOA) temporarily interfere with periodontal health of patients, as the appliance complicates oral hygiene. The use of aligners in orthodontic therapy increased strongly during the last decade. In the literature, the reports about effects of aligner treatment on oral hygiene and gingival conditions are scarce. This cross-sectional study evaluated oral hygiene and patient’s satisfaction during orthodontic treatment of patients with FOA or Invisalign®.Methods100 patients (FOA = 50, Invisalign® = 50) were included who underwent orthodontic treatment for more than 6 months. Clinical examinations were performed to evaluate patients’ periodontal condition and were compared with clinical data at the beginning of the orthodontic treatment. Oral hygiene, patients’ satisfaction and dietary habits were documented by a detailed questionnaire. For statistical analysis, the Mann–Whitney U-Test and Fisher’s Exact Test were used; as multiple testing was applied, a Bonferroni correction was performed.ResultsAt the time of clinical examinations, patients with FOA were in orthodontic therapy for 12.9 ± 7.2 months, whereas patients with Invisalign® were in orthodontic therapy for 12.6 ± 7.4 months. Significantly better gingival health conditions were recorded in Invisalign® patients (GI: 0.54 ± 0.50 for FOA versus 0.35 ± 0.34 for Invisalign®; SBI: 15.2 ± 7.6 for FOA versus 7.6 ± 4.1 for Invisalign®), whereas the amount of dental plaque was also less but not significantly different (API: 37.7 % ± 21.9 for FOA versus 27.8 % ± 24.6 for Invisalign®). The evaluation of the questionnaire showed greater patients’ satisfaction in patients treated with Invisalign® than with FOA.ConclusionPatients treated with Invisalign® have a better periodontal health and greater satisfaction during orthodontic treatment than patients treated with FOA.Electronic supplementary materialThe online version of this article (doi:10.1186/s12903-015-0060-4) contains supplementary material, which is available to authorized users.

CAF and MMTT with the additional use of a graft are equally successful in covering gingival recessions of Miller class I and II, with high aesthetic results. All patients indicated their willingness for further periodontal surgery.