Bioactive substances may be used to enhance the rate and quantity of bone healing during osseointegration of titanium dental implants. A pilot observational study was undertaken to assess a novel keratin hydrogel in six adult sheep utilising the femoral condyles as the surgical site to assess osseointegration. Implants and osteotomy sites were coated with the keratin gel prior to implant placement (test implants) whereas the opposite knee received unmodified control implants in each animal. Fifty 3.5 mm 9 7 mm Neoss dental implants were surgically implanted with a range of 3-5 Neoss dental implants placed per surgical site in each knee and allowed to heal for 5 days or 2, 4, 8, 12 and 16 weeks prior to the sheep being sacrificed. Of the 50 placed implants, 24 were used for this study and analysed via resin-embedded, undemineralised sections from test and control implants to assess the range of healing around the unloaded dental implants. These dental implants were analysed using histomorphometric methods for the best 3 consecutive threads on each side and the percentage of bone to implant contact (%BIC) was used to determine the degree of osseointegration between test and control dental implants at each time point. All implants appeared osseointegrated at the time of sacrifice. One each of the pairs of control implants at 2, 4 and 12 weeks demonstrated minimal integration histologically, with %BIC\10 %. No test implants had %BIC \35 % at any time point. Mean %BIC for test implants was higher than controls at all time points except 5 days and 2 weeks. The range from 2 to 16 weeks healing was 39.7 % [SD 25.5 %] to 85.4 % [14.2 %] for test implants and 35.6 % [43.4 %] to 46.6 % [23.1 %] for controls. %BIC appeared to increase earlier in the test implants (from 4 weeks onwards) compared to controls. After 16 weeks, %BIC was almost twice as great in test implants as controls. This pilot observational study suggests that keratin hydrogel may promote earlier osseointegration around titanium dental implants. Further cross-sectional studies with larger sample sizes are warranted. The most marked difference between test and control implants was seen after 4 weeks. It is recommended that future studies in this model focus on healing after 4 weeks.

).Rapid prototyping, also known as three-dimensional (3D) printing, is an additive manufacturing technology that allows expedient and accurate reproduction of osseous anatomy. It was originally introduced in the mechanical engineering field during the 1980s and this technology has gained interest in craniomaxillofacial surgery as a tool for assessment and preoperative surgical planning.1,2 For orbital floor fractures, rapid prototyping can provide an accurate anatomical representation of the osseous defect, allowing the clinician to preoperatively adapt a titanium plate for reconstruction. This theoretically reduces the operative time required, risk of orbital plate malposition, poor anatomical contour, and trauma to soft tissues due to multiple insertions during trimming and adaptation of the titanium orbital plate. We propose that the use of rapid prototyping and preoperative plate adaptation can significantly reduce the operative time taken while improving patient outcome. MethodsComputed tomography (CT) data were processed via an imaging software program (e.g., 3D slicer, Osirix [OsirixPixmeo, Bernex, Geneva, Switzerland]), cropped and then exported as a stereolithographic file (.stl) (►Fig. 1) which was then used for fabrication of a 3D model via 3D printing. CT orbital parameters used were 0.5 mm slice thickness, The titanium orbital plate was sterilized before insertion and intraoperative CT imaging was used to assess final titanium plate position. Case 1A 59-year-old female presented to the maxillofacial outpatient department following a mechanical fall resulting in a left orbital floor fracture. Enophthalmos of 2 mm was present and a CT scan revealed a large floor defect (►Figs. 2 and 3). Diplopia was present on upward gaze. A rapid prototyping model was fabricated and a Synthes titanium orbital plate was further adapted preoperatively. The orbital floor was accessed via a mid-lid approach and the modified titanium orbital plate was inserted. No further adaptation of the plate was required and the time taken from insertion of the plate to final fixation was less than 1 minute, as no further adaptation was necessary. Position was confirmed with an intraoperative CT scan (O-arm, Medtronic [Medtronic, Minneapolis, MN]) (►Figs. 4-6). The patient's diplopia and enophthalmos had resolved 2 weeks postoperatively and no complications were noted at the 6th week follow-up. Keywords► rapid prototyping ► 3D printing ► orbital reconstruction AbstractRapid prototyping entails the fabrication of three-dimensional anatomical models which provide an accurate and cost-effective method to visualize complex anatomical structures. Our unit has been using this to assist in the diagnosis, planning, and preoperative titanium plate adaptation for orbital reconstruction surgery following traumatic injury. The aim of this article is to demonstrate the potential clinical and costsaving benefits of this technology.

In Christchurch Hospital, rapid prototyping (RP) and intraoperative imaging are the standard of care in orbital trauma and has been used since February 2013. RP allows the fabrication of an anatomical model to visualize complex anatomical structures which is dimensionally accurate and cost effective. This assists diagnosis, planning, and preoperative implant adaptation for orbital reconstruction. Intraoperative imaging involves a computed tomography scan during surgery to evaluate surgical implants and restored anatomy and allows the clinician to correct errors in implant positioning that may occur during the same procedure. This article aims to demonstrate the potential clinical and cost saving benefits when both these technologies are used in orbital reconstruction which minimize the need for revision surgery.

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