The current state of PEEK implant osseointegration and future perspectives: a systematic review.

Polyetheretherketone (PEEK) has been considered as an alternative to replace surgical metal implants. Several medical applications, including dental and orthopaedic implants, need confirmed osseointegration before functional loading. The present study aims at providing a comprehensive systematic review of the evidence on PEEK implants' osseointegration. A systematic search was conducted using Cochrane library, MEDLINE (PubMed), Ovid MEDLINE, Web of Science and EMBASE databases. Publications were identified in accordance with specific inclusion and exclusion criteria. Eligibility screening, data extraction and quality assessment were performed. The review protocol was registered in PROSPERO (CRD42018116061). A total of 55 articles were reviewed and 29 of the most relevant that met the inclusion criteria were selected. Heterogeneity was identified among the included studies. Several approaches have been applied to enhance PEEK osseointegration, with most in vivo studies conducted on small-scale animal models but no study evaluating the osseointegration of PEEK under cyclic loading. However, PEEK modifications are demonstrated to enhance osseointegration preclinically. Collectively, the present review shows a shortage of evidence, including a lack of comprehensive assessment of osseointegration, the need for large-animal-model tests, the need to assess the effect of loading on the implants and the lack of randomised controlled clinical trials.

A novel approach for planning orthognathic surgery: the integration of dental casts into three-dimensional printed mandibular models.

A method of producing a composite model consisting of a three-dimensional printed mandible bearing plaster teeth is presented. Printed models were obtained from cone beam computed tomograms (CBCT) of dry human mandibles. The plaster casts of the teeth were obtained from impressions of the teeth of the dry mandibles. The distorted teeth of the printed models were removed and replaced by the plaster casts of the teeth using a simple transfer jig. The accuracy of the composite models obtained from six mandibles was assessed from laser scans. The scans of the dry mandibles and the composite models were superimposed and the magnitude of the discrepancies at six points on the dentition and six on the mandible were obtained. It was concluded that the errors of the method were small enough to be clinically significant. The use of the composite models is illustrated in two clinical cases.

Digital replacement of the distorted dentition acquired by cone beam computed tomography (CBCT): a pilot study.

During cone beam computed tomography (CBCT) scanning, intra-oral metallic objects may produce streak artefacts, which impair the occlusal surface of the teeth. This study aimed to determine the accuracy of replacement of the CBCT dentition with a more accurate dentition and to determine the clinical feasibility of the method. Impressions of the teeth of six cadaveric skulls with unrestored dentitions were taken and acrylic base plates constructed incorporating radiopaque registration markers. Each appliance was fitted to the skull and a CBCT performed. Impressions were taken of the dentition with the devices in situ and dental models were produced. These were CBCT-scanned and the images of the skulls and models imported into computer-aided design/computer-aided manufacturing (CAD/CAM) software and aligned on the registration markers. The occlusal surfaces of each dentition were then replaced with the occlusal image of the corresponding model. The absolute mean distance between the registration markers in the skulls and the dental models was 0.09±0.02mm, and for the dentition was 0.24±0.09mm. When the method was applied to patients, the distance between markers was 0.12±0.04mm for the maxilla and 0.16±0.02mm for the mandible. It is possible to replace the inaccurate dentition on a CBCT scan using this method and to create a composite skull which is clinically acceptable.

The virtual human face: superimposing the simultaneously captured 3D photorealistic skin surface of the face on the untextured skin image of the CBCT scan.

The aim of this study was to evaluate the impact of simultaneous capture of the three-dimensional (3D) surface of the face and cone beam computed tomography (CBCT) scan of the skull on the accuracy of their registration and superimposition. 3D facial images were acquired in 14 patients using the Di3d (Dimensional Imaging, UK) imaging system and i-CAT CBCT scanner. One stereophotogrammetry image was captured at the same time as the CBCT and another 1h later. The two stereophotographs were individually superimposed over the CBCT using VRmesh. Seven patches were isolated on the final merged surfaces. For the whole face and each individual patch: maximum and minimum range of deviation between surfaces; absolute average distance between surfaces; and standard deviation for the 90th percentile of the distance errors were calculated. The superimposition errors of the whole face for both captures revealed statistically significant differences (P=0.00081). The absolute average distances in both separate and simultaneous captures were 0.47 and 0.27mm, respectively. The level of superimposition accuracy in patches from separate captures was 0.3-0.9mm, while that of simultaneous captures was 0.4mm. Simultaneous capture of Di3d and CBCT images significantly improved the accuracy of superimposition of these image modalities.

Nicotine replacement lozenges: abuse-related hyperkeratosis of the lateral border of the tongue. A case report.

A case of a white patch on the right lateral border of the tongue, found to be hyperkeratosis induced by long-term habitual placement of nicotine replacement lozenges (NiQuitin CQ) in the right lingual sulcus, is presented. The lesion became less evident once the patient varied the intraoral location and reduced his consumption of these tablets.

Ligneous alveolar gingivitis in the absence of plasminogen deficiency.

A case of localized, longstanding, asymptomatic ligneous gingivitis affecting the crest of the edentulous lower left posterior alveolar ridge (ligneous alveolar gingivitis) of a middle-aged Caucasian woman is presented. This patient did not have any associated ophthalmic lesions (ligneous conjunctivitis) and did not have a plasminogen deficiency.