Immediate placement and loading of implants with laser-microgrooved collar in combination with an anorganic porcine bone mineral matrix in the esthetic zone. Twelve-month results of a prospective multicenter cohort study.

BACKGROUND: Many techniques have been proposed to address post-extraction ridge resorption, which often represents a concern, especially in the esthetic region. PURPOSE: The purpose of the present, prospective, multicenter, single cohort study was to investigate, up to 1 year of function, the effectiveness of a protocol for alveolar ridge preservation involving implants with laser-microgrooved surface immediately placed in fresh extraction sockets. MATERIALS AND METHODS: Twenty eight patients candidate to tooth extraction in the esthetic zone (site 15-25 and 35-45) were treated by immediate placement of a single laser-microgrooved implants with the adjunct of a highly porous anorganic porcine bone mineral matrix and a collagen wound dressing. Peri-implant marginal bone level (MBL) was evaluated at time of loading, 3 and 12 months after loading. Gingival index, plaque index, probing depth, and bleeding on probing were measured at 3, 6, and 12 months after loading. Dimensional changes at implant sites were digitally evaluated using the best-fit superimposition of pre-and post-socket preservation models. Implant aesthetic score (IAS) as well as patients' post-operative quality of life were also evaluated at 12 months. Comparisons between data relative to thick and thin gingival phenotypes were made using Student's t-test or Mann-Whitney test, as appropriate. The significance level was set at p = 0.05. RESULTS: No patient dropped out, and 28 implants were evaluated at 12 months post-loading. The overall MBL was found to be 0.92 ± 1.11 mm. Volumetric analysis of superimposed models showed an alveolar bone tissue displacement at the buccal aspect of -0.57 ± 0.52 mm in thin phenotypes and -0.46 ± 0.31 mm in thick phenotypes (p = 0.58, unpaired Student's t-test). No signs of soft tissue recession or esthetically unpleasant buccal gingiva were reported. CONCLUSIONS: The clinical protocol herein employed showed benefits in maintaining marginal bone levels and soft tissue contour around post-extraction implants in the esthetic zone.

Osteo-regeneration personalized for children by rapid maxillary expansion: an imaging study based on synchrotron radiation microtomography.

BACKGROUND: Personalized maxillary expansion procedure has been proposed to correct maxillary transversal deficiency; different protocols of stem cell activation have been suggested and rapid maxillary expansion (RME) is the most commonly used among clinicians. The present study aimed to quantify in three-dimensions (3D) the osteo-regeneration of the midpalatal suture in children submitted to RME. METHODS: Three patients (mean age 8.3 ± 0.9 years) were enrolled in the study to preform biopsy of midpalatal suture. Two patients (subjects 1 and 2) were subjected to RME before biopsy. The third patient did not need maxillary expansion treatment and was enrolled as control (subject 3). Midpalatal suture samples were harvested 7 days after RME in subject 1, and 30 days after RME in subject 2. The samples were harvested with the clinical aim to remove bone for the supernumerary tooth extraction. When possible, maxillary suture and bone margins were both included in the sample. All the biopsies were evaluated by complementary imaging techniques, namely Synchrotron Radiation-based X-ray microtomography (microCT) and comparative light and electron microscopy. RESULTS: In agreement with microscopy, it was detected by microCT a relevant amount of newly formed bone both 7 days and 30 days after RME, with bone growth and a progressive mineralization, even if still immature respect to the control, also 30 days after RME. Interestingly, the microCT showed that the new bone was strongly connected and cross-linked, without a preferential orientation perpendicular to the suture's long axis (previously hypothesized by histology), but with well-organized and rather isotropic 3D trabeculae. CONCLUSIONS: The microCT imaging revealed, for the first time to the authors' knowledge, the 3D bone regeneration in children submitted to RME.

Digital Dynamic 3D Monitoring of Lower Incisors Intrusion in Lingual Orthodontics.

OBJECTIVE: The aim of the present study is to propose a 3-dimensional evaluation of lower intrusion obtained with lingual orthodontics considering not only the crowns but also dental roots. METHODS: 9 adult patients underwent fixed lingual orthodontic treatment with i-TTя lingual brackets system for the correction of crowding in the lower arch associated with a deep overbite. Initial records, consisting of photos, CBCTs and intraoral scans were collected. Threshold segmentation of the CBCT was performed to generate a three-dimensional virtual model of each the teeth of the lower arch, superimposed with the crown of the same teeth obtained by intraoral scan models to generate a complete set of digital composite lower arch The same procedure was performed to monitor one key step of the i-TTЯ technique consisting in lower incisors intrusion (T2). T1-T2 three-dimensional superimposition and color displacement maps were generated to measure and evaluate the movements obtained at the lower arch. RESULTS: The root displacement of the incisors during their intrusion in the early stage was totally "bone-safe" in the 88.9% (8 of 9) of the cases observed. No significant extrusion of the premolars used as anchorage unit was measured. CONCLUSION: This method has proved to be an accurate and reliable approach to dynamically visualize the 3-dimensional positions of the teeth, including their roots, with no additional radiation for in-progress treatment monitoring. The 3-dimensional evaluation showed that the employed lingual appliance allowed to obtain significant lower incisors intrusion with negligible undesired extrusion of premolars employed as anchorage teeth.

Prediction of Class II improvement after rapid maxillary expansion in early mixed dentition.

BACKGROUND: The aim of this study is to identify cephalometric pretreatment parameters for prediction of Class II improvement induced by rapid maxillary expansion. METHODS: Lateral cephalograms of 30 patients (mean age 8.3 ± 1.6 years old) showing Class II molar relationship and undergone to rapid maxillary expansion on the upper deciduous molars were traced before treatment, and molar relation changes were evaluated on dental casts before and after treatment. Overall treatment time lasted 10.2 ± 2 months. Good responders (18 subjects, 10 females and 8 males) showed improvement of at least 2.50 mm, and bad responders (12 subjects, 7 females and 5 males) showed no improvement, improvement less than 2.50 mm, or worsening of molar relationship after treatment. Student's t test was used to assess significance of differences between groups, and discriminant analysis allowed identification of predictive pretreatment variables. RESULTS: Articular angle, superior gonial angle, and mandibular dimensions (Co-Gn, S-Ar, Ar-Go, Go-Me) showed significant differences in the comparison between groups. Mandibular length Co-Gn and superior gonial angle were selected as significant predictive variable for discrimination. CONCLUSIONS: Patients with smaller mandibular length and more acute superior gonial angle are expected to have more chances to improve molar Class II after rapid maxillary expansion.