In-house three-dimensional printing within the digital orthodontic workflow.

Intraoral scanning techniques, and the associated software, have revolutionized model acquisition, analysis, and virtual planning in orthodontics. Three-dimensional printing is the final aspect of this digital workflow, converting these virtual models and simulations of the tooth and occlusal movements into physical reality. This article provides an insight into how in-house three-dimensional printing is now a feasible and transformative reality for many orthodontic settings and how this empowers orthodontists to optimize their patient care.

The accuracy of maxillary positioning using digital model planning and 3D printed wafers in bimaxillary orthognathic surgery.

OBJECTIVE: Orthognathic wafers may be made using digital model movements and CAD-CAM technology. This paper analysed the accuracy of maxillary movements using this new process. DESIGN: Retrospective study of pre and post-operative cephalograms. PARTICIPANTS: Thirty consecutive orthognathic patients undergoing bimaxillary osteotomies in a UK hospital. METHODS: Jaw movements were planned using cephalometric and Orthoanalyzer™ software. The resultant intermediate and final wafer occlusal relationships were used for wafer fabrication by 3D printing of the inter-occlusal space. Pre- and post-operative lateral cephalograms were compared in terms of maxillary antero-posterior and vertical movements. Statistical analyses including the paired t-test, two-sample t-test and Fisher's exact test. RESULTS: Wide individual variation was observed between the planned and actual movements. Thirteen cases (43%) had a 2 mm discrepancy in at least one variable. Statistically significant differences between the planned and actual maxillary vertical movements were observed for the molar (U6y: p < 0.0001) and anterior maxillary (Ay: p < 0.01) differences. Analysis of a subgroup with primarily impaction movements demonstrated a statistically significant bias towards excessive maxillary advancement (U1x: p < 0.01) and incisor impaction (U1y: p < 0.01) in this group. CONCLUSIONS: This new digital surgical wafer technique achieves a similar level of accuracy to the conventional facebow and model surgery process.

A 3D printed surgical analogue to reduce donor tooth trauma during autotransplantation.

Surgical trauma and prolonged extra-alveolar exposure of the donor tooth's root sheath are both complicating factors during tooth autotransplantation surgery. This case report describes a 12-year-old female patient who underwent surgical transplantation of a maxillary second premolar to a central incisor site. A three-dimensional printed analogue of the donor tooth was fabricated from a cone beam (CBCT) scan of the tooth in order to minimise the extra-oral (exposure) time and frequency of trial insertions of the donor tooth into the recipient socket. The laboratory and clinical aspects of this novel technique are described.

Dentoskeletal changes following mini-implant molar intrusion in anterior open bite patients.

OBJECTIVE: To evaluate skeletal and dental changes after intrusion of the maxillary molars in subjects with anterior open bite. MATERIALS AND METHODS: This retrospective cephalometric study evaluated skeletal and dental changes resulting from the use of maxillary orthodontic mini-implants in 31 consecutively treated patients. Radiographs were taken at the start and end of maxillary molar intrusion to evaluate the associated changes. Statistical analysis was performed using a one-sample t-test. RESULTS: The mean treatment observation time was 1.31 years (SD  =  2.03). The maxillary first molars (P  =  0.0026) and second molars (P  =  0.039) were intruded. However, the mandibular first molars (P  =  0.0004) and second molars (P  =  0.003) erupted in adolescent patients. Both the maxillary and mandibular first molars inclined distally (P  =  0.025 and P  =  0.044, respectively). The mandibular plane angle decreased (P  =  0.036), lower facial height decreased (P  =  0.002), and the occlusal plane angle increased (P  =  0.009). The overbite increased (P < .0001). The ANB angle decreased (P < .0001). Mandibular dental and skeletal changes were more apparent in adolescents, while adults tended toward maxillary changes. CONCLUSIONS: Vertical traction from orthodontic mini-implants reduces the maxillary posterior dentoalveolar height, thereby assisting orthodontic closure of anterior open bite. However, simultaneous eruption or extrusion of the mandibular molars should be controlled. Adolescent patients tend to demonstrate more favorable effects of mandibular autorotation than do adults.

Molar intrusion in the management of anterior openbite and 'high angle' Class II malocclusions.

Orthodontic correction of anterior openbite has conventionally involved extraction therapy or an adjunctive maxillary impaction osteotomy. However, bone anchored molar intrusion treatments have been reported in recent years as a less invasive alternative for such patients. This paper describes the concepts and treatment processes involved with mini-implant molar intrusion to correct anterior openbite and reduce patients' excessive vertical facial proportions.

Mini-implant applications in orthognathic surgical treatment.

Orthognathic surgical treatment conventionally relies on the use of full arch fixed orthodontic appliances. However, the introduction of orthodontic mini-implants has altered surgical options in terms of providing an alternative to fixation (intermaxillary fixation, IMF) screws and even to maxillary osteotomy. This paper describes the integration of mini-implants within orthognathic treatments in terms of 'surgery first' treatments and by introducing the concept of the conversion of bimaxillary cases into mandible-only surgery treatments.

Correction of the occlusal and functional sequelae of mandibular condyle fractures using orthodontic mini-implant molar intrusion.

We report on the non-surgical management of an adult female whose bilateral mandibular condylar fractures had resulted in a clockwise (posterior) mandibular rotation, limitation of mandibular movements and increased occlusal loading on the molar teeth. She refused maxillary surgery and was treated with a minimally-invasive approach, involving orthodontic fixed appliances and mini-implant intrusion of the maxillary molar teeth. This provided both occlusal and functional improvements, including a significant increase in the inter-incisal distance, which were stable after one year of retention.

Digital model planning and computerized fabrication of orthognathic surgery wafers.

Conventional orthognathic wafers are made by a process involving manual movement of stone dental models and acrylic laboratory fabrication. In addition, a facebow record and semi-adjustable articulator system are required for maxillary osteotomy cases. This paper introduces a novel process of producing both intermediate and final orthognathic surgical wafers using a combination of computerized digital model simulation and three-dimensional print fabrication, without the need for either a facebow record or the additional ionizing radiation exposure associated with cone beam computerized tomography.

Spontaneous resolution of a periapical lesion during orthodontic treatment: a case report.

UNLABELLED: Teeth with periapical lesions can undergo successful orthodontic treatment, but conventional protocols indicate that such teeth should be endodontically stabilized prior to such treatment. A case report is presented where such endodontic stabilization was not possible, yet a chronic periapical lesion resolved as orthodontic treatment progressed. This paper will discuss the possible causes of the initial lesion, and reasons why it resolved without endodontic treatment. CLINICAL RELEVANCE: This report illustrates the possible combined roles of trauma, occlusion and periodontal disease in the development of a perio-endo lesion, and how orthodontic treatment potentially relieved some of the exacerbating factors, thus enabling resolution of the infection without endodontic treatment.

Treatment time and occlusal outcome of orthognathic therapy in the East of England region.

OBJECTIVES: To evaluate the process of combined orthognathic and orthodontic care. To identify factors that affect treatment time and percentage Peer Assessment Rating (PAR) reduction, and the PAR efficiency factor for such cases. DESIGN AND SETTING: Retrospective multi centre study of patients who underwent orthognathic treatment in the East of England region. METHODS: Analysis of consecutive cases that underwent orthognathic surgery in 2008. Inclusion criteria included pre- and post-surgery orthodontic treatment. RESULTS: Ten orthodontic units submitted data for a total of 118 patients. Within the sample, 64% were class III, 35% class II/1 and 1% class II/2. Overall extraction rate, excluding third molars, was 58%. Median age at bond up was 17 years. Mean total number of orthodontic attendances was 23. Median length of pre-surgical orthodontics was 23 months and post-surgical orthodontics was 7 months. Median length of total treatment was 29 months. Mean wait for surgery was 3·6 months. Diagnosis of incisor relationship and skeletal base, transfer of operator, total number of visits, tooth extraction and treatment unit affected treatment duration. Median pre- and post-treatment PAR scores were 43 and 4, respectively. Median change in PAR score was 38·5. Median per cent reduction in PAR was 90·6%. The median PAR efficiency factor (reduction in PAR score divided by treatment time in months) was 1·24. Diagnosis of incisor relationship and skeletal base correlated with percentage reduction in PAR score. CONCLUSIONS: Combined orthognathic treatment was effective. Factors affecting treatment duration and percentage reduction in PAR have been established.

An in vitro study of factors affecting the primary stability of orthodontic mini-implants.

OBJECTIVES: To evaluate the effects of mini-implant features (length, design, core diameter), insertion technique (insertion angle, cortical punch), and cortical bone depth and density on mini-implant primary stability. The effect of mini-implant reinsertion was also investigated. MATERIALS AND METHODS: Two hundred and sixty Infinitas mini-implants of two lengths (9 mm and 6 mm), two core diameters (0.8 mm and 0.9 mm) for an external diameter of 1.5 mm, and four designs (two tapered, external diameter 1.5 mm; two cylindrical, external diameters 1.5 mm and 2.0 mm) were inserted into synthetic bone blocks, and the maximum insertion torque (MIT) was recorded. The cortical layer of the blocks varied in density (30 and 50 lb per cubic foot) and depth (1 mm and 2 mm). Three angles of insertion (90°, 75°, and 60°) and two methods of insertion (direct and cortical punch) were tested. Forty mini-implants were also removed and reinserted. RESULTS: A significant increase in the average MIT occurred when cortical bone density increased and when mini-implants were reinserted. The 1.5 mm diameter cylindrical design had significantly lower MIT than the 1.5 mm tapered and the 2.0 mm cylindrical designs. The other variables did not have a significant effect on MIT. CONCLUSIONS: Mini-implants achieved greater primary stability in higher-density cortical bone, and the 1.5 mm diameter tapered and 2.0 mm cylindrical designs offered greater primary stability than the 1.5 mm cylindrical design. Reinserting mini-implants resulted in significantly increased MIT, possibly because of blunting of the threads.

A clinical strategy for maxillary molar intrusion using orthodontic mini-implants and a customized palatal arch.

Orthodontic mini-implants are a valuable adjunct in orthodontics and potentially expand the orthodontic treatment envelope. In particular, their use may revolutionize the treatment of anterior openbites through the application of direct molar intrusion. Clinical protocols for mini-implant usage are just beginning to evolve and this paper describes the basis for a new clinical approach and future research, for the orthodontic treatment of anterior openbites.

Current products and practice: bone anchorage devices in orthodontics.

Bone anchorage is a promising new field in orthodontics and already a wide variety of bone anchorage devices (BADs) are available commercially. This review aims to assist clinicians by outlining the principles of bone anchorage and the salient features of the available systems, especially those that may influence the choice of a specific BAD for anchorage reinforcement.