An Osteotomy Tool That Preserves Bone Viability: Evaluation in Preclinical and Clinical Settings.

The main objectives of this work were to assess the efficiency, ease-of-use, and general performance of a novel osseoshaping tool based on first-user clinical experiences and to compare these observations with preclinical data generated in rodents using a miniaturized version of the instrument. All patients selected for the surgery presented challenging clinical conditions in terms of the quality and/or quantity of the available bone. The presented data were collected during the implant placement of 15 implants in 7 patients, and included implant recipient site (bone quality and quantity) and ridge evaluation, intra-operative handling of the novel instrument, and the evaluation of subsequent implant insertion. The instrument was easy to handle and was applied without any complications during the surgical procedure. Its use obviated the need for multiple drills and enabled adequate insertion torque in all cases. This biologically driven innovation in implant site preparation shows improvements in preserving vital anatomical and cellular structures as well as simplifying the surgical protocol with excellent ease-of-use and handling properties.

Clinical reliability of CAD/CAM cross-arch zirconia bridges on immediately loaded implants placed with computer-assisted/template-guided surgery: a retrospective study with a follow-up between 3 and 5 years.

PURPOSE: The purpose of this study is to retrospectively evaluate the implant and prosthetic survival and success rates of zirconia-based, implant-supported, screw-retained, cross-arch restorations up to 5 years after placement. MATERIALS AND METHODS: Twenty-two consecutive edentulous patients (11 males and females, each; mean age 68.3 years) received 26 CAD/CAM cross-arch zirconia implant bridges (NobelProcera™ Implant Bridge Zirconia; Nobel Biocare AG, Zurich, Switzerland) supported by 4 to 10 implants each. All patients were followed for at least 3 years (range 36-60 months, mean 42.3 months). Clinical assessments were scheduled every 4 months during hygiene maintenance. Outcomes were implant and prosthetic survival rates, prosthetic success rate, any observed clinical complications, patient satisfaction, and soft tissue parameters. Fisher's exact test was used to assess associations between categorical variables. RESULTS: No dropouts occurred. The overall implant and prostheses survival rate up to 5 years was 100%. Three out of 26 restorations (five out of three hundred forty eight dental units) showed an adhesive chip-off fracture of the veneering ceramic, scoring a cumulative prosthetic success rate of 88.5% at the prosthetic level and 98.6% at the unit level. All 22 patients were functionally and aesthetically highly satisfied with their restorations. Successful soft tissue parameters were found around all implants. CONCLUSIONS: Industrially manufactured, zirconia-based, implant-supported, screw-retained, cross-arch restorations are a viable alternative to conventionally manufactured porcelain-fused-to-metal restorations for rehabilitating the edentulous patient.

Retrieval analysis of different orthodontic brackets: the applicability of electron microprobe techniques for determining material heterogeneities and corrosive potential

OBJECTIVE: The objective of this study was to investigate the applicability of micro-analytical methods with high spatial resolution to the characterization of the composition and corrosion behavior of two bracket systems. MATERIAL AND METHODS: The surfaces of six nickel-free brackets and six nickel-containing brackets were examined for signs of corrosion and qualitative surface analysis using an electron probe microanalyzer (EPMA), prior to bonding to patient's tooth surfaces and four months after clinical use. The surfaces were characterized qualitatively by secondary electron (SE) images and back scattered electron (BSE) images in both compositional and topographical mode. Qualitative and quantitative wavelength-dispersive analyses were performed for different elements, and by utilizing qualitative analysis the relative concentration of selected elements was mapped two-dimensionally. The absolute concentration of the elements was determined in specially prepared brackets by quantitative analysis using pure element standards for calibration and calculating correction-factors (ZAF). RESULTS: Clear differences were observed between the different bracket types. The nickel-containing stainless steel brackets consist of two separate pieces joined by a brazing alloy. Compositional analysis revealed two different alloy compositions, and reaction zones on both sides of the brazing alloy. The nickel-free bracket was a single piece with only slight variation in element concentration, but had a significantly rougher surface. After clinical use, no corrosive phenomena were detectable with the methods applied. Traces of intraoral wear at the contact areas between the bracket slot and the arch wire were verified. CONCLUSION: Electron probe microanalysis is a valuable tool for the characterization of element distribution and quantitative analysis for corrosion studies.

Digitizing implant position locators on master casts: comparison of a noncontact scanner and a contact-probe scanner.

PURPOSE: Although several investigations of the fit of computer-aided design/computer-assisted manufactured implant restorations have been reported in the literature, very limited information is available on the accuracy of dental scanners for surface data acquisition. The objective of this research project was to investigate the accuracy and repeatability of a three-dimensional noncontact laser scanning system based on conoscopic holography recording the spatial orientation of an implant in vitro. MATERIALS AND METHODS: One master cast containing five nonparallel implant replicas with scan abutments (implant position locator [IPL], Nobel Biocare) was repeatedly digitized by two commercially available dental scanners and an industrial highprecision coordinate measuring machine as a reference. Repeated measurements of the center point and vector analysis were applied to determine the accuracy and repeatability of IPL orientation. The Wilcoxon signed rank test modified for equivalence was applied to determine whether the systems were equally accurate based on given threshold limits of 0.010, 0.005, and 0.001 mm. RESULTS: All between-system tests identified significant differences, although most differences were very small in absolute terms. Tests for equivalence based on difference windows were exploratorily significant for 0.010 and 0.005 mm. CONCLUSION: Conoscopic holography scan technology is a valid option to supplement dental touch-probe scanners for laboratory digitization of implant master casts.

Dental aspects in patients with DiGeorge syndrome.

DiGeorge syndrome, which is caused by a microdeletion of 1.5 to 3.0 megabases on the long arm of chromosome 22, has an incidence of approximately 1:4,000 to 1:5,000 live births. The phenotypic spectrum of this disorder includes congenital heart defects, immunodeficiency due to thymic hypoplasia or aplasia, transient or permanent hypocalcemia due to parathyroid hypoplasia or aplasia, developmental retardation, and psychiatric disorders. Dental aspects in these patients include skeletal malformations, velopharyngeal insufficiency with or without cleft palate, small mouth, and hypotonus orofacial musculature, as well as impaired salivary flow. Enamel aberrations related to hypocalcemia may result in a higher frequency of dental caries. Based on a series of five patients, the medical and dental aspects that have to be considered in the care of patients with DiGeorge syndrome are presented.

Prosthodontic treatment of a patient with bisphosphonate-induced osteonecrosis of the jaw using a removable dental prosthesis with a heat-polymerized resilient liner: a clinical report.

Bisphosphonate-induced osteonecrosis of the jaws (BONJ) is reported frequently in patients receiving oral or intravenous bisphosphonates. To minimize potential complications, dental treatment must be performed with care. There are invasive and noninvasive treatment options for patients with active BONJ or a history of this complication. This clinical report describes the prosthodontic treatment of a patient who developed BONJ after receiving intravenous bisphosphonates (pamidronate). Because of the recurrent incidence of BONJ, noninvasive prosthetic therapy with telescopic overdentures and a heat-polymerized resilient liner was provided. After 2 years, there were no biological or technical complications.

Prosthetic considerations for orthodontic implant site development in the adult patient.

Proper site development is a key factor for long-term clinical success of dental implants. Whereas surgical and restorative techniques have been refined to ensure predictable functional and esthetic outcome, individual clinical prerequisites do not always allow proper placement of implants when prosthetic and material properties are considered. Orthodontic tooth movement may be a viable and nonsurgical site development treatment option. With the introduction and advancements of minimal invasive and less visible orthodontic appliances, a growing number of adult patients are willing to obtain orthodontic treatment. The spectrum of modern appliances is broad and ranges from clear aligners to lingual brackets. Skeletal anchorage devices such as orthodontic mini-implants often eliminate unpopular external anchorage devices (ie, headgear) in adult patients, This article discusses the selection of an appropriate pretreatment approach by taking patient-specific criteria into account.

Zirconia abutments for single-tooth implants--rationale and clinical guidelines.

Clinical success of an endosseous implant to replace a single tooth is not only defined by its survival. Esthetic parameters have become integral aspects in defining success and failure. All-ceramic abutments have started to play a major role in achieving an esthetically successful result. The material itself, however, is not the exclusive determinant for esthetic success. It is the appropriate design and proper handling of the material and the abutment that enables the clinician to achieve esthetic outcomes that were not possible with traditional metal alloys. This article explores the rationale for using zirconia for prosthetic implant components, explains specific material properties, and discusses strategies and guidelines for the design and successful clinical implementation of CAD/CAM-fabricated zirconia implant abutments.

Blood transfusion in bimaxillary orthognathic operations: need for testing of type and screen.

We prospectively evaluated the incidence of blood transfusion in 105 consecutively treated patients (45 men and 60 women) having bimaxillary orthognathic operations, to find out whether type and screen testing are adequate in clinical practice. All patients had Le Fort I osteotomy combined with bilateral sagittal split osteotomy of the ramus. The preoperative routine was restricted to type and screen testing and verification of ABO/Rhesus (Rh) status. Autologous blood donation or routine cross-matching of allogeneic units of blood was not done. Intraoperative haemoglobin concentrations and the need for blood transfusion in patients having bimaxillary osteotomies were recorded in a prospective database. The mean duration of operation was 196 min (range 115-325). The median length of hospital stay was 8 days (range 4-16). The mean (SD) reduction in haemoglobin during operation was 34 (16)g/L in men and 32 (10)g/L in women (p=0.32). No patients had an allogeneic blood transfusion. We found that type and screen testing and verification of ABO/Rh status seems to be an adequate precaution to manage blood loss. As reflected by the low rate of transfusion in the present study, severe haemorrhage that requires transfusion of allogeneic blood has become the exception rather than the rule in bimaxillary orthognathic operations.

Diagnostic potential of 3D-data-based reconstruction software: an analysis of the rare disease pattern of cherubism.

Cherubism is an autosomal-dominant syndrome characterized by bilateral maxillomandibular bony degeneration, fibrous connective tissue hyperplasia, and displacement of permanent tooth germs. Reossification of the cystic lumen occurs spontaneously, but dislocated teeth must be realigned orthodontically. Advancements in virtual 3D reconstruction of anatomic structures based on computed tomography (CT) or cone beam CT data have provided for more predictable individual treatment planning. We evaluated two software programs for making densitometry and volume measurements of cystic areas in the mandibles, and for 3D visualization of permanent tooth germs within the cystic lumen, in two siblings with cherubism.

[Psychological and dental considerations in the prosthetic rehabilitation of children. Child prothesis--part I]. / Psychologische und zahnmedizinische Aspekte bei der prothetischen Versorgung von Kindern. Kinderprothesen--Teil I.

The fabrication of a prosthesis for a child requires an extensive diagnostic process together with a detailed medical and dental history. The treatment modalities for children and adults are different. By young patients attention must be paid in order to establish a feeling of trust and close cooperation between the dentist and the patient. The aim of the treatment with removable denture prosthesis is the re-establishment of aesthetic, phonetic and function while assuring at the same time a high standard of oral hygiene and periodontal maintenance. The continuous jaw growth and the dentition changes of a child must be closely monitored. Therefore, frequent (3-6 months recall intervals) follow-up examinations and denture adjustments are needed.

Comparative study on interactive computer-aided-learning and computer-aided-testing in patient-based dental training in maxillofacial surgery.

AIM: The objective of this comparative study was to validate, through empirical data, the use of interactive, problem-oriented computer-aided-learning (CAL) and computer-aided-testing (CAT) in dental studies by directly comparing these methods with conventional teaching. METHOD: A total of 95 students from the third and fourth clinical semesters participated in an interdisciplinary seminar on oral maxillofacial implantology; 47 of these were taught using conventional teaching methods, while the remaining 48 students were taught using mobiTED, a CAL/CAT-based interactive communication system that can be used patient- and problem-oriented. An examination was given at the end of the course to evaluate student learning. A student's interest/attentiveness, involvement, knowledge gain, and the course attractiveness and quality were evaluated with visual analogue scales (VAS) in a subjective experience protocol. RESULTS: The study group taught using the CAL/CAT-based interactive communication system showed statistically significant better results in the examination, with a median score of 89.2%, while the conventional teaching study group achieved a median score of 76.0%. A VAS-based analysis of subjective experiences also revealed statistically significant differences between the two study groups. CONCLUSION: Use of the CAL/CAT system for interactive, problem-oriented learning in patient-based dental training led to increased levels of attentiveness, of student acceptance and of the perceived attractiveness of the seminar. CAL/CAT-mediated instruction also led to increased communication, with a subsequent improvement in the qualitative and quantitative parameters of knowledge transfer and cognitive knowledge assimilation. Use of CAL/CAT also facilitated the acquisition, appraisal, and understanding of complex medical data.

CAD/CAM and telescopic technology: design options for implant-supported overdentures.

There are many options with respect to materials, construction methods, and design concepts for the technical implementation of implant-supported dental prostheses. Different methods of anchorage can be used to attach removable superstructures to implants. Telescopic crowns make it possible to fabricate inexpensive superstructures with precise and passive fit. Computer-aided design/computer-assisted manufacture (CAD/CAM) technology allows copings to be fabricated from materials such as zirconia or titanium. Moreover, CAD/CAM crown copings can serve as a base for fabricating customized ceramic replacement teeth. Different veneering techniques, such as pressed-on ceramics for zirconia cores, ensure a fast and economic work process. With the use of electroforming it is possible to manufacture highly precise secondary structures that ensure passive seating of the prosthesis in a stable position. This article demonstrates a restorative treatment option using current techniques with the aim of rehabilitation with an esthetic and functional implant-supported removable denture.

Precision for computer-guided implant placement: using 3D planning software and fixed intraoral reference points.

PURPOSE: The aim of this article is to describe the application of screws as fixed intraoral reference points for stable, precise, and repeatable positioning of diagnostic and surgical templates for implant placement. MATERIALS AND METHODS: Currently available software programs in combination with computed tomography data allow 3-dimensional treatment planning in demanding clinical situations prior to implant placement. One drawback of most systems is the lack of stability and support of both radiographic and surgical templates in edentulous patients. The characteristics and application of a new screw system in combination with computer assisted 3-dimensional implant placement are specified. RESULTS: Implants were placed exactly as projected without impairment of the mandibular nerve despite close proximity of the mental foramen. CONCLUSION: Precision and accuracy of computer-based or -supported implant placement is valuable only if an exact transfer to the intraoral situation is granted. Depending on the clinical patient situation, fixed intraoral reference points can improve precision in an efficient manner.

Prosthodontic considerations for predictable single-implant esthetics in the anterior maxilla.

Long-term functional and esthetic success with implant-supported single-tooth restorations requires a comprehensive and interdisciplinary treatment approach. Important parameters include the initial clinical situation, the surgical approach, the provisional phase, and the choice of abutment material and design as well as the definitive restoration. This article presents the main aspects of current treatment protocols and discusses material options and clinical techniques to achieve predictable outcomes.