Orthodontic Treatment of Palatally Impacted Maxillary Canines with the Use of a Digitally Designed and 3D-Printed Metal Device.

The purpose of this article is to present a computer designed and 3D-printed metal device, which was used for the surgical exposure and orthodontic treatment of maxillary palatally impacted canines. In two cases which presented a palatally impacted canine, a Cone-Beam Computed Tomography (CBCT) was acquired and an intraoral scanning was performed, to determine the exact location of the canine. Based on a digital model, a device leaning on the teeth and mucosa was designed to serve as a guiding tool for the oral surgeon to expose the crown of the canine and help the orthodontist to provide proper traction. The device was then 3D-printed in biocompatible dental alloy and placed in the patients' mouth. After the surgical exposure of the canine's crown in both cases, a gold chain apparatus was bonded on and it was mounted on the metal projection of the device through an elastic chain. Within 3 months of traction, the crown of the canines appeared in the patients' palate to the exact location that was predicted and guided. A 3D-designed and manufactured metal device, with information acquired by CBCT and intraoral scanning, can be used for the exposure and traction of palatally impacted canines.

Bimaxillary Dentoalveolar Protrusion Case Treated with Anchorage by Buccally Implemented Mini-Implants Using a 3D-Printed Surgical Guide.

The article presents a case of bimaxillary dentoalveolar protrusion treated by distalizing the upper and lower teeth, using anchorage from mini implants. A 16-year-old male patient presented with severe upper and lower incisor proclination with protruding lips and a convex profile, with a background of bimaxillary dentoalveolar protrusion. Instead of having four premolars extracted, retraction of the dentition was decided with absolute anchorage, provided by mini implants. In order to carry out the procedure in one stage, four mini-implants were inserted as close to the root of the 1st molars as possible. Implementation was facilitated by a surgical template which was created on a digital model and then 3D printed. Accurate placement was achieved and the case was successfully treated by significant uprighting of the incisors and retraction of the anterior dentition, closing the spaces in the upper and lower arch. Facial aesthetics were also improved. A digitally designed surgical guide was utilized in this case of bimaxillary dentoalveolar protrusion in order to facilitate the accurate placement of the mini implants which were used for a one-stage retraction of the dentition.

Accuracy of Mini-Implant Placement Using a Computer-Aided Designed Surgical Guide, with Information of Intraoral Scan and the Use of a Cone-Beam CT.

BACKGROUND: The purpose of the study was to investigate the accuracy of mini-implant placement with the use of a computer designed surgical guide derived by intraoral scanning alongside Cone-Beam Computed Tomography (CBCT) or the use of a 2D radiograph. METHODS: Thirty-five mini-implants (Aarhus® System: n = 20, Ø: 1.5 mm and AbsoAnchor®: n = 15, Ø: 1.3-1.4 mm) were placed in the maxilla and mandible of 15 orthodontic patients for anchorage purposes in cases where a CBCT was needed due to impacted teeth or for safety reasons. All were placed with the help of a computer designed surgical guide. One implant became loose and was excluded from the study. For 18 mini-implants (study group), CBCT and intraoral scanning were used for guide design, while for 16 (control group) only intraoral scanning and panoramic imaging information were used. Mini-implant position was recorded by angular and linear measurements on digital models created by combining Digital Imaging and Communications in Medicine (DICOM) and stereolithography (.stl) files. Accuracy in positioning was determined by comparing corresponding measurements for virtual and real positioned mini-implants on digital models before and after operation. The results were statistically analyzed with t-tests and the Mann-Whitney test. RESULTS: No significant statistical differences were found for pre- and post-operational angular measurements in the study group, while significant statistical differences occurred on the same measurements for the control group (coronal angle 13.6° pre-op and 22.7° post-op, p-value = 0.002, axial angle 13.4° pre-op and 15.9° post-op, p-value = 0.034). Linear measurements pre- and post-operational for either group presented no significant statistical differences. CONCLUSIONS: A 3D designed and manufactured surgical guide with information concerning CBCT and intraoral scanning ensures accuracy on mini-implant placement while design of the guide without the use of a CBCT is less accurate, especially on inclination of the implant.

Treatment of an Avulsed and Ankylosed Incisor through Single Tooth Alveolar Osteotomy and Conventional Orthodontic Mechanisms.

We present the treatment of an injured and avulsed incisor (which was afterwards ankylosed), by subapical osteotomy and conventional orthodontic mechanisms. A 9-year-old boy presented for orthodontic treatment with an injured and avulsed central incisor, which, after initial repositioning, ended up with ankylosis and severe root resorption. The case was treated by single tooth alveolar osteotomy and distraction osteogenesis through conventional orthodontics, advocating for the floating bone concept due to the short vertical distance by which the tooth alveolus part had to be relocated. Orthodontic treatment of the avulsed central incisor was completed after osteotomy and distraction osteogenesis, and the tooth was restored to its proper position, aiming to address issues of aesthetics and function for the time being. The patient was finally referred to a prosthodontist for future and final implant rehabilitation due to severe root resorption. Distraction osteogenesis after surgical procedures is a reliable solution for dealing with an ankylosed and submerged tooth.

Retrieval analysis of immediately loaded orthodontic mini-implants: material and tissue characterization.

OBJECTIVE: To investigate the morphological and compositional alterations of retrieved orthodontic mini-implants and the type of adjacent bone, in relation to loading period and anatomical region. MATERIALS AND METHODS: Seventy orthodontic mini-implants (Aarhus: n = 35 and AbsoAnchor: n = 35) were placed in the maxilla and mandible of 33 orthodontic patients for anchorage purposes. All mini-implants were immediately loaded for a period specified by treatment plan. Fifty-nine mini-implants were retrieved (Aarhus: n = 29 and AbsoAnchor: n = 30) and examined by stereomicroscopy, reflection Fourier transform infrared microspectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Tissue samples adjacent to the implants were histologically examined to identify the bone type. RESULTS: Changes in surface finish, formation of biological integuments, and compositional alterations mainly due to adsorption of proteinaceous material (rich in C, O, N, OH, NH, CH2/CH3, amide I, II, and III, and CH-OH) were identified in all mini-implants. In some cases, mineralized fragments were identified (rich in Ca, P, and Ca-P). In 25 out of the 59 histological sections examined, woven and lamellar bone types were detected. In 12 sections, only woven bone was detected, whereas in the residual 22, only lamellar bone was identified. A significant correlation was found between histological result and loading time but not between histology and region. CONCLUSION: Morphological and elemental alterations were found for both types of mini-implant surfaces. An increase of the loading period increased the possibility of lamellar bone development around mini-implants.