Craniofacial osseointegration

Active osseointegration in an ex vivo porcine bone model

Achieving osseointegration is a fundamental requirement for many orthopaedic, oral, and craniofacial implants. Osseointegration typically takes three to 6 months, during which time implants are at risk of loosening. The aim of this study was to investigate whether osseointegration could be actively enhanced by delivering controllable electromechanical stimuli to the periprosthetic bone. First, the osteoconductivity of the implant surface was confirmed using an in vitro culture with murine preosteoblasts. The effects of active treatment on osseointegration were then investigated in a 21-day ex vivo model with freshly harvested cancellous bone cylinders (n = 24; Ø10 mm × 5 mm) from distal porcine femora, with comparisons to specimens treated by a distant ultrasound source and static controls. Cell viability, proliferation and distribution was evident throughout culture. Superior ongrowth of tissue onto the titanium discs during culture was observed in the actively stimulated specimens, with evidence of ten-times increased mineralisation after 7 and 14 days of culture (p < 0.05) and 2.5 times increased expression of osteopontin (p < 0.005), an adhesive protein, at 21 days. Moreover, histological analyses revealed increased bone remodelling at the implant-bone interface in the actively stimulated specimens compared to the passive controls. Active osseointegration is an exciting new approach for accelerating bone growth into and around implants.

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

In recent years, the field of mandibular reconstruction has made great strides in terms of hardware innovations and their clinical applications. There has been considerable interest in using computer-aided design, finite element modelling, and additive manufacturing techniques to build patient-specific surgical implants. Moreover, lattice implants can mimic mandibular bone's mechanical and structural properties. This article reviews current approaches for mandibular reconstruction, their applications, and their drawbacks. Then, we discuss the potential of mandibular devices with lattice structures, their development and applications, and the challenges for their use in clinical settings.

The Latest Craniofacial Reconstructive Techniques Using Anchored Implants after Surgical Treatment of Nasal and Paranasal Sinuses Tumors

Reconstructive surgery after surgical treatment of neoplasms in the head and neck region is always a challenge. Many factors are responsible for the success of reconstruction. The anatomy of the facial region is complex, which significantly influences the aesthetic effect of the reconstruction. Moreover, many patients undergo postoperative radiotherapy after surgical treatment, which affects the range of reconstructive techniques. The aim of this study is to review current reconstructive methods in the craniofacial region, using bone-anchored implants to attach nasal prostheses. The article also comprises the authors' own experience with successful single-stage, Vistafix 3 osseointegrated implants for the attachment of an external nasal prosthesis in a 51-year-old man after surgical removal of squamous cell carcinoma of the nose and paranasal sinuses. The literature search for articles regarding implants in craniofacial reconstructions was performed using the three following databases: Scopus, Web of Science and MEDLINE (through PubMed), and follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA). A systematic literature search was set for 2018-2023 and retrieved 92 studies. From them, 18 articles were included in the review.

Comparison of passive versus active transcutaneous bone anchored hearing devices in the pediatric population

Objective

Transcutaneous bone anchored hearing devices (BAHDs) were introduced in an effort to avoid potential complications associated with the abutment of percutaneous BAHDs. Transcutaneous BAHDs can be active or passive. While studies have demonstrated good outcomes with both, a direct comparison of audiological and clinical outcomes of these devices in the pediatric population has not yet been studied.

Study design

Retrospective, multicenter study.

Setting

Two tertiary academic centers.

Methods

Between 2015 and 2019, all patients who received an active transcutaneous BAHD (Bonebridge, BB) at one center, and patients that received a passive transcutaneous BAHD (Attract, AT) at another center, were included in this study. Exclusion criteria included age > 18 years, and mixed hearing loss or single-sided deafness. Study outcomes included patient demographics, indications, complications and preoperative and one-year postoperative audiometric data.

Results

Eighteen BB and eight AT patients met the inclusion criteria. The age range was 5–16 years. There were no significant differences in complication outcomes. Both devices demonstrated similar mean improvements in hearing thresholds at frequencies of 250 Hz (38 dB Active vs. 38 dB Passive), 500 Hz (34 dB vs. 42 dB), 1000 Hz (34 dB vs. 40 dB) and 2000 Hz (31 dB vs. 22 dB). The BB was significantly more effective at frequencies of 4000 Hz (28 dB vs. 7 dB) and 8000 Hz (29 dB vs. 6 dB) (p < 0.05).

Conclusion

This is the first study comparing audiological outcomes between an active and a passive transcutaneous BAHD in the pediatric population. While both devices improved audiometric outcomes in the low and mid frequencies, the active BAHD demonstrated significantly better outcomes in the higher frequencies.

Graphical Abstract

Surgery Training System Supported by Organic Materials

The aim of the study was the qualitative assessment of new materials based on a polycarbonate matrix in terms of its use in 3D printing and its processing and geometric modification (cutting). Filaments made of the new material doped with talc in five different proportions were visually inspected with a microscope. The calibration and test models were made using the FFF (fused filament fabrication) technique. In addition, its susceptibility to the drill and the behavior of the shavings were assessed and the temperature changing during drilling was measured. The implant was inserted to measure its resonance stability in each of the holes made and translated into the value of the implant stability quotient (ISQ) ranging from 1 to 100. The results were compared to those obtained for the training model of the skull bone. The amount of filler has been shown to affect the composite. Moreover, due to the properties of talc, a compatibilizer (polyol) was used. Differences were observed between the model made of the commercial material, the model made of the dried, tested material, and the model made of the undried material. It was confirmed that the presence of water in the material during its processing is important.

Osseointegration of Extremity Prostheses: A Primer for the Plastic Surgeon

Interest in amputation surgery has increased in conjunction with rising public awareness about amputee care. To date, plastic surgeons have impacted the quality of life and functional potential of amputees through novel strategies for sensory feedback and prosthesis control and various techniques for neuroma treatment and prevention. Osseointegration, which involves the direct skeletal attachment of a prosthesis to bone, has the ability to further maximize amputee function. There exists a critical role for plastic surgeons to help optimize techniques for extremity osseointegration through improved wound care and soft-tissue management. An overview of current osseointegrated prostheses and their associated limitations, and potential avenues through which plastic surgeons can help mitigate these challenges, are discussed in this article.

Epithetic nasal reconstruction after total rhinectomy: Oncologic outcomes, immediate and long-term adverse effects, and quality of life

INTRODUCTION

Total rhinectomy for tumors of the nasal cavity substantially alters patients' appearance and requires local reconstruction. While full nasal epitheses are well-established for this purpose, potential long-term adverse effects and impact on patients' quality of life are not fully understood.

METHODS

Sixteen patients who underwent total rhinectomy with ensuing nasal reconstruction with a full nasal epithesis were included in the study. Oncologic outcomes were assessed, and adverse effects and quality of life analyses were performed based on a patient-reported outcomes tool.

RESULTS

In patients with squamous cell carcinomas of the nasal cavity, total rhinectomy led to excellent local tumor control. Immediate and long-term adverse effects of total rhinectomy and placement of a nasal epithesis were predominantly limited to the immediate nasal region. While patients were satisfied with their nasal appearance, they reported a worse assessment of their facial appearance and a measurable long-term effect on their psychological well-being.

CONCLUSION

Total rhinectomy and reconstruction with a full nasal epithesis is a safe and oncologically sound treatment approach. However, its effects on patients' overall appearance and psychological well-being need to be considered during treatment planning and follow-up.

Utilizing DICOM data to generate custom computer-aided designing and computer-aided machining polyetheretherketone healing abutments for an ear prosthesis

Soft tissue healing around implants may turn out to be the most decisive factor in the success or failure of the prosthesis. Dimension, configuration, and material of the healing abutments play a pivotal role in achieving optimal soft tissue architecture around implants. Digital imaging with computer-aided designing and computer-aided machining (CAD-CAM) technology, has made it easier to illustrate, design, replicate maxillofacial structures, and generate its supporting elements in a reliable, faster, and more convenient manner. This case report highlights the issue relevant to the implant-supported prosthetic replacement, on a site previously attempted for surgical reconstruction of the missing ear. Presurgical DICOM data were used to obtain custom CAD-CAM polyetheretherketone (PEEK) healing abutments on implants in a patient with an excessive amount of tissue in the missing right ear region. It is probably the first extraoral use of PEEK as a healing abutment in the workflow of implant retained maxillofacial prosthetics. No issue warranting the removal of the PEEK component was observed during the duration of its use.

[Prosthetic rehabilitation in the head and neck region]

Implant-retained craniofacial prostheses (or epitheses) made of silicone are state of the art for prosthetic rehabilitation of facial defects. With the modern extraoral implant systems, prostheses may be securely anchored to the bone regardless of size and location of the defect. Prerequisite for successful implantation is the classical atraumatic surgical technique with avoidance of any thermal trauma to the bone. The treatment intention may be a temporary measure, a rescue procedure after failed (re)construction, or a definitive treatment option. This article gives an overview of the strategies in various facial regions stratified according to the age of the patient and the etiology of the defect. Moreover, prosthetic rehabilitation offers additional options for septal perforations, distorted and leaky tracheostomies, and treatment-resistant tracheoesophageal fistula.

Application of totarol as natural antibacterial coating on dental implants for prevention of peri-implantitis

Peri-implantitis is the most important issue threatening the long-term survival rate of dental implants. Various efforts have been made to reduce implant surface plaque formation, which is one of the essential causes of peri-implantitis. In our study, we applied the natural antibacterial agent totarol as a coating on experimental silicon wafer and titanium implant surfaces. To analyze the interaction between the totarol coating and the oral primary colonizer S. gordonii and isolates of mixed oral bacteria, samples were incubated in a model system simulating the oral environment and analyzed by Live/Dead staining, crystal violet staining and scanning electron microscopy (SEM). After 4 d, 8 d, 12 d, 16 d, and 24 d salivary incubation, the stability and antibacterial efficiency of totarol coating was evaluated through SEM. The results indicated that totarol coatings on both silicon wafer and Ti surfaces caused efficient contact killing and an inhibition effect towards S. gordonii and mixed oral bacterial film growth after 4 h, 8 h, 24 h, and 48 h incubation. After longtime salivary incubation of 12 d, the bactericidal effect started to weaken, but the anti-adhesion and inhibition effect to biofilm development still exist after 24 d of salivary incubation. The application of a totarol coating on implant or abutment surfaces is a promising potential prophylactic approach against peri-implantitis.

Osteomyelitis Risk in Patients With Transfemoral Amputations Treated With Osseointegration Prostheses

BACKGROUND

Percutaneous anchoring of femoral amputation prostheses using osseointegrating titanium implants has been in use for more than 25 years. The method offers considerable advantages in daily life compared with conventional socket prostheses, however long-term success might be jeopardized by implant-associated infection, especially osteomyelitis, but the long-term risk of this complication is unknown.

QUESTIONS/PURPOSES

(1) To quantify the risk of osteomyelitis, (2) to characterize the clinical effect of osteomyelitis (including risk of implant extraction and impairments to function), and (3) to determine whether common patient factors (age, sex, body weight, diabetes, and implant component replacements) are associated with osteomyelitis in patients with transfemoral amputations treated with osseointegrated titanium implants.

METHODS

We retrospectively analyzed our first 96 patients receiving femoral implants (102 implants; mean implant time, 95 months) treated at our center between 1990 and 2010 for osteomyelitis. Six patients were lost to followup. The reason for amputation was tumor, trauma, or ischemia in 97 limbs and infection in five. All patients were referred from other orthopaedic centers owing to difficulty with use or to be fitted with socket prostheses. If found ineligible for this implant procedure no other treatment was offered at our center. Osteomyelitis was diagnosed by medical chart review of clinical signs, tissue culture results, and plain radiographic findings. Proportion of daily prosthetic use when osteomyelitis was diagnosed was semiquantitatively graded as 1 to 3. Survivorship free from implant- associated osteomyelitis and extraction attributable to osteomyelitis respectively was calculated using the Kaplan-Meier estimator. Indication for extraction was infection not responsive to conservative treatment with or without minor débridement or loosening of implant.

RESULTS

Implant-associated osteomyelitis was diagnosed in 16 patients corresponding to a 10-year cumulative risk of 20% (95% CI 0.12-0.33). Ten implants were extracted owing to osteomyelitis, with a 10-year cumulative risk of 9% (95% CI 0.04-0.20). Prosthetic use was temporarily impaired in four of the six patients with infection who did not undergo implant extraction. With the numbers available, we did not identify any association between age, BMI, or diabetes with osteomyelitis; however, this study was underpowered on this endpoint.

CONCLUSION

The increased risk of infection with time calls for numerous measures. First, patients should be made aware of the long-term risks, and the surgical team should have a heightened suspicion in patients with method-specific presentation of possible infection. Second, several research questions have been raised. Will the surgical procedure, rehabilitation, and general care standardization since the start of the program result in lower infection rates? Will improved diagnostics and early treatment resolve infection and prevent subsequent extraction? Although not supported in this study, it is important to know if most infections arise as continuous bacterial invasion from the skin and implant interface and if so, how this can be prevented?

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Osseointegrated Implants and Prosthetic Reconstruction Following Skull Base Surgery

Rehabilitation following ablative skull base surgery remains a challenging task, given the complexity of the anatomical region, despite the recent advances in reconstructive surgery. Remnant defects following resection of skull base tumors are often not amenable to primary closure. As such, numerous techniques have been described for reconstruction, including local rotational muscle flaps, pedicled flaps with skin paddle, or even free tissue transfer. However, not all patients are appropriate surgical candidates and therefore may instead benefit from nonsurgical options for functional and aesthetic restoration. Osseointegrated implants and biocompatible prostheses provide a viable alternative for such a patient population. The purpose of this review serves to highlight current options for prosthetic rehabilitation of skull base defects and describe their indications, advantages, and disadvantages.

Retention systems for extraoral maxillofacial prosthetic implants: a critical review

We describe the techniques available for retention of implant-supported prostheses: bar-clips, O-rings, and magnets. We present reported preferences and, although this is limited by the heterogeneity of methods used and patients studied, we hope we have identified the best retention systems for maxillofacial prosthetic implants. If practitioners know the advantages and disadvantages of each system, they can choose the most natural and comfortable prosthesis. We searched the PubMed and Scopus databases, and restricted our search to papers published 2001-13. MeSH terms used were Maxillofacial prosthesis and Craniofacial prosthesis OR Craniofacial prostheses. We found a total of 2630 papers, and after duplicates had been removed we analysed the rest and found 25 papers for review. Of these, 12 were excluded because they were case reports or non-systematic reviews. Of the remaining 13, 10 described group analyses and seemed appropriate to find practitioner's choices, as cited in the abstract (n=1611 prostheses). Three papers did not mention the type of prosthetic connection used, so were excluded. The most popular choices for different conditions were analysed, though the sites and retention systems were not specified in all 10 papers. The bar-clip system was the most used in auricular (6/10 papers) and nasal prostheses (4/10). For the orbital region, 6/10 favoured magnets. Non-osseointegrated mechanical or adhesive retention techniques are the least expensive and have no contraindications. When osseointegrated implants are possible, each facial region has a favoured system. The choice of system is influenced by two factors: standard practice and the abilities of the maxillofacial surgeon and maxillofacial prosthetist.

Prosthetics in Facial Reconstruction

Reconstruction of the head and neck can be a challenging undertaking owing to numerous considerations for successful rehabilitation. Although head and neck defects were once considered irretrievably morbid and associated with a poor quality of life, advances in surgical technique has immensely contributed to the well-being of these patients. However, all patients are not suitable surgical candidates and many have sought nonsurgical options for functional and cosmetic restoration. As such, the advent of prostheses has ameliorated those concerns and provided a viable alternative for select patient populations. Prosthetic reconstruction has evolved significantly over the past decade. Advances in biocompatible materials and imaging adjuncts have spurred further discovery and forward progress. A multidisciplinary approach to head and neck reconstruction focused on appropriate expectations and patient-centered goals is most successfully coordinated by a team of head and neck surgeons, maxillofacial surgeons, and prosthetic specialists. The aim of this article is to provide a comprehensive review of the current trends for prosthetic rehabilitation of head and neck defects, and further elaborate on the limitations and advancements in the field.

Ocular Reconstruction Using Bone-Anchored Implants in Irradiated Facial Deformities After Tumor Extirpation

BACKGROUND

Surgical resection of ocular malignancies can result in complex craniofacial defects that can be difficult to reconstruct with conventional reconstruction techniques. Craniofacial prosthesis supported by bone-anchored implants has evolved as a reliable alternative in such scenarios.

METHODS

The authors describe a patient who underwent extensive facial resection secondary to squamous cell carcinoma resulting in significant facial deformities. A bone-anchored osseointegrated implant was used to perform facial reconstruction.

RESULTS

The patient had successful reconstruction of her orbit with bone-anchored implant. However, her implant needed to be removed 10 months postoperatively secondary to infection. A second attempt at implant placement has been deferred due to osteonecrosis secondary to adjuvant radiotherapy.

CONCLUSION

Bone-anchored implants can provide an elegant alternative in the reconstruction of complex facial defects and provide direct access to surveillance for possible tumor recurrence. However, these bone-supported prosthetics should be used with caution in patients undergoing irradiation.

Survival and complications of implants to support craniofacial prosthesis: A systematic review

OBJECTIVE

To assess the survival rate of craniofacial implants (CIs) to support facial prosthesis/epithesis and the prevalence of surgical/biological complications based on previously published studies.

METHODS

An electronic search was undertaken in March/2016. Only studies with a minimum of 5 patients were included. Untransformed proportions of implant failures for different regions were calculated. A meta-analysis evaluated the influence of radiotherapy on the failure rates. A meta-regression was performed considering the follow-up period as covariate.

RESULTS

Seventy publications included 2355 patients and 8184 CIs (545 failures). The probability of a failure was 5.5% for all CIs (95%CI 4.5-6.5, P < 0.001), 1.2% for CIs in the auricular region (95%CI 0.8-1.5, P < 0.001), 12.2% for the nasal region (95%CI 9.0-15.5, P = 0.017), and 12.1% for the orbital region (95%CI 9.3-15.0, P < 0.001). Radiotherapy statistically affected the CIs rates (OR 5.80, 95%CI 3.77-8.92, P < 0.00001). There was no statistically significant influence of the follow-up time on the proportion of implant failures (P = 0.814). Soft tissue adverse reactions were the most common complications.

CONCLUSIONS

Implants placed in the auricular region have a lower probability of failure than those in the nasal and orbital regions. Soft tissue adverse reactions were the most common complications. Radiotherapy significantly affected the CIs failure rates.

Monoscopic photogrammetry to obtain 3D models by a mobile device: a method for making facial prostheses

Purpose

The aim of this study is to present the development of a new technique to obtain 3D models using photogrammetry by a mobile device and free software, as a method for making digital facial impressions of patients with maxillofacial defects for the final purpose of 3D printing of facial prostheses.

Methods

With the use of a mobile device, free software and a photo capture protocol, 2D captures of the anatomy of a patient with a facial defect were transformed into a 3D model. The resultant digital models were evaluated for visual and technical integrity. The technical process and resultant models were described and analyzed for technical and clinical usability.

Results

Generating 3D models to make digital face impressions was possible by the use of photogrammetry with photos taken by a mobile device. The facial anatomy of the patient was reproduced by a *.3dp and a *.stl file with no major irregularities. 3D printing was possible.

Conclusions

An alternative method for capturing facial anatomy is possible using a mobile device for the purpose of obtaining and designing 3D models for facial rehabilitation. Further studies must be realized to compare 3D modeling among different techniques and systems.

Clinical implication

Free software and low cost equipment could be a feasible solution to obtain 3D models for making digital face impressions for maxillofacial prostheses, improving access for clinical centers that do not have high cost technology considered as a prior acquisition.

Recommendations for implant-retained nasal prostheses after ablative tumor surgery: Minimal surgical aftercare, high implant survival, and satisfied patients

BACKGROUND

Nasal defects resulting from tumor resection are preferably rehabilitated with implant-retained nasal prostheses. Aftercare, clinical outcome of the implants, and patients' satisfaction with implant-retained nasal prostheses were assessed.

METHODS

Twenty-eight consecutive patients needing total rhinectomy because of tumor resection between 1998 and 2013 were treated according to a standardized protocol with 2 implants in the nasal floor. Surgical and prosthetic aftercare was scored using patient records. Finally in 2014, skin reaction, peri-implant bone loss, and patients' satisfaction were assessed in all 13 still living patients.

RESULTS

In total, 56 implants were inserted (median follow-up, 35.1 months; interquartile range [IQR], 8.9-63.3). Implant survival was 96.4%. Implant survival was independent of radiotherapy. Peri-implant skin was healthy and patients' satisfaction high. Longevity of the prostheses was limited.

CONCLUSION

Rehabilitation of nasal defects resulting from total rhinectomy with implant-retained nasal prostheses, according to our protocol, resulted in high patient satisfaction and favorable treatment outcome. © 2015 Wiley Periodicals, Inc. Head Neck 38: E-E, 2016.

Anaplastology in times of facial transplantation: Still a reasonable treatment option?

Optimum functional and aesthetic facial reconstruction is still a challenge in patients who suffer from inborn or acquired facial deformity. It is known that functional and aesthetic impairment can result in significant psychosocial strain, leading to the social isolation of patients who are affected by major facial deformities. Microvascular techniques and increasing experience in facial transplantation certainly contribute to better restorative outcomes. However, these technologies also have some drawbacks, limitations and unsolved problems. Extensive facial defects which include several aesthetic units and dentition can be restored by combining dental prostheses and anaplastology, thus providing an adequate functional and aesthetic outcome in selected patients without the drawbacks of major surgical procedures. Referring to some representative patient cases, it is shown how extreme facial disfigurement after oncological surgery can be palliated by combining intraoral dentures with extraoral facial prostheses using individualized treatment and without the need for major reconstructive surgery.

A porcine model: surgical anatomy of the orbit for maxillofacial surgery

Due to its similarity to humans, the pig has proven to be a suitable biomodel for both research purposes and for training medical professionals, particularly in surgical specializations. For example, new implant materials have been tested on pig jaws and pigs have also been used in the development of new surgical techniques. For optimizing the effectiveness of such research or training, detailed data on the anatomy of their particular features are needed. At present, however, only limited information related to surgical and imaging anatomy of the facial and orbital areas of the pig and its comparison to human structures from the experimental surgery point of view is available in the literature. The aim of this study was to obtain such data and to compare the morphological structures of the porcine and human orbital regions and to lay down the foundation for practical use in experimental surgery. Ten pig heads were examined using computed tomography (CT) and magnetic resonance imaging (MRI) and, subsequently, a dissection of the orbit was carried out. Attention was focused on the structure of the orbit (floor, rim and nerves) frequently affected by pathological processes in humans (such as trauma, infection or tumours) and which consequently are frequently the subject of maxillofacial surgery. The porcine orbit is suitable for use in experimental medicine. However, if used in experiments, its anatomical peculiarities must be taken into consideration. Our study presents a foundation of basic knowledge for researchers who plan to use the pig as a biomedical model to investigate alternative treatments in the head region.

Surgical and audiological evaluation of the Baha BA400

Objective:

Despite extensive soft tissue reduction, the most common complications associated with bone-anchored hearing aid systems, also known as bone-anchored hearing implants, are related to adverse skin reactions around the abutment. The necessary soft tissue reduction also adds complexity to the surgical procedure. This study aimed to evaluate the surgical and audiological outcomes of a new connective interface of the Cochlear™ Baha® BA400 device implanted using the one-stage surgical technique.

Method:

A multicentre, retrospective case series is presented, including data collected from three tertiary care institutions.

Results:

In total, 16 patients who had undergone bone-anchored hearing aid surgery over a 10- to 12-month period were assessed for hearing performance, implant stability and surgical complications.

Conclusion:

This case series indicates that new abutments with a hydroxyapatite coating can be implanted percutaneously without soft tissue reduction. Furthermore, device implantation using this surgical technique may have some advantages compared with a conventional device and procedure combination over 12- to 16-months of follow up.

Vibrotactile evaluation: osseointegrated versus socket-suspended transfemoral prostheses

This study investigated detection thresholds of vibrometric stimuli in patients with transfemoral amputation supplied with osseointegrated (OI) and socket-suspended prostheses. It included 17 patients tested preoperatively with socket-suspended prostheses and after 2 yr with OI prostheses and a control group (n = 17) using socket-suspended prostheses, evaluated once. Assessments on the prosthetic and intact feet were conducted at six frequencies (8, 16, 32, 64, 125, and 250 Hz). Furthermore, measurements were conducted to investigate how vibrometric signals are transmitted through a test prosthesis. The results showed that the OI group had improved ability to detect vibrations through the prosthesis at 125 Hz (p = 0.01) at follow-up compared with the preoperative measurement. Compared with the control group, the OI group at follow-up had better ability to detect high frequency vibrations through the prosthesis (125 Hz, p = 0.02; 250 Hz, p = 0.03). The vibrometric signal transmitted through the test prosthesis was reduced at 8, 125, and 250 Hz but was amplified at 16, 32, and 64 Hz. Differences between the OI and the control groups were found in the highest frequencies in which the test prosthesis showed reduction of the vibrometric signal. The study provides insight into the mechanisms of vibration transmission between the exterior and bone-anchored as well as socket-suspended amputation prostheses.

Modulation of Host Osseointegration during Bone Regeneration by Controlling Exogenous Stem Cells Differentiation Using a Material Approach

Stem cell-based tissue engineering for large bone defect healing has attracted enormous attention in regenerative medicine. However, sufficient osseointegration of the grafts combined with exogenous stem cells still remains a major challenge. Here we developed a material approach to modulate the integration of the grafts to the host tissue when exogenous bone marrow stromal cells (BMSCs) were used as donor cells. Distinctive osseointegration of bone grafts was observed as we varied the content of hydroxyapatite (HA) in the tissue scaffolds implanted in a mouse femur model. More than 80% of new bone was formed in the first two weeks of implantation in high HA content scaffold but lack of host integration while only less than 5% of the new bone was formed during this time period in the no HA group but with much stronger host integration. Cell origin analysis leveraging GFP reporter indicates new bone in HA containing groups was mainly derived from donor BMSCs. In comparison, both host and donor cells were found on new bone surface in the no HA groups which led to seamless bridging between host tissue and the scaffold. Most importantly, host integration during bone formation is closely dictated to the content of HA present in the scaffolds. Taken together, we demonstrate a material approach to modulate the osseointegration of bone grafts in the context of exogenous stem cell-based bone healing strategy which might lead to fully functional bone tissue regeneration.

Titanium fixtures for bone-conduction devices and the influence of type 2 diabetes mellitus

OBJECTIVE

The aim of this study is to evaluate whether diabetes mellitus (DM) is a risk factor for titanium fixture loss in bone-conduction devices (BCDs) because of osseointegration failure.

STUDY DESIGN

Retrospective case study.

SETTING

Tertiary referral center.

PATIENTS

All patients who received a BCD at Nijmegen between January 1, 1988, and December 31, 2007, were analyzed. The analyses were performed on 833 patients (993 implants) and a subpopulation of patients aged 40 years or older consisting of 641 patients (739 implants).

METHODS

Patients received a questionnaire asking about the presence of DM at the time of implantation. Data concerning implant loss were retrieved from medical records and the Nijmegen BCD database.

RESULTS

The total survival rate of the BCD implant in this population was 90.6%. The prevalence of DM was 9.3%. In the subpopulation of patients aged 40 years or older, the non-DM group lost 5.1% of their implants versus 14% of Type 2 DM patients, a statistically significantly difference (p = 0.003). Spontaneous loss, loss due to a Grade 4 Holgers skin reaction, and trauma accounted for 2.2% versus 4.7% (p = 0.13), 0.5% versus 2.3% (p = 0.1), and 0.6% versus 4.7% (p = 0.007), respectively, of implant losses in non-DM versus Type 2 DM patients.

CONCLUSION

The prevalence of DM among the Nijmegen BCD population is higher than the general Dutch prevalence. A statistically significantly higher implant loss was observed during the study period for Type 2 DM patients than non-DM BCD wearers.

Osseointegrated implant applications in cosmetic and functional skull base rehabilitation

This study discusses the indications, outcomes, and complications in patients that underwent osseointegrated implantation for skull base rehabilitation. We conducted a retrospective review of eight patients with skull base defects who had undergone implantation of a facial prosthetic retention device ± bone-anchored hearing aid at a tertiary academic referral center. Descriptive analysis of applications, techniques, outcomes, and complications were reviewed. The majority of patients were males (n = 6) with previously diagnosed skull base malignancy (n = 5) with an average age of 46 (range, 14 to 77). All patients received an implanted facial prosthetic device either for an aural (n = 7) or orbital (n = 1) prosthesis. There were only two complications that included infection (n = 1) and implant extrusion (n = 1). Osseointegrated implantation of abutments for anchoring prosthetic devices in patients for skull base rehabilitation provides an excellent cosmetic option with minimal complications.

The new Baha implant: a prospective osseointegration study

OBJECTIVES

To assess stability of a new-design titanium implant (Cochlear Baha BAI300) in bone-anchored hearing aid (Baha) recipients over time.

STUDY DESIGN AND SETTING

Prospective case series with planned data collection at a tertiary care institution. Twelve patients who underwent Baha surgery over 12 months were analyzed.

SUBJECTS

All patients (3 children, age range 6-10 years, mean 7.7 years, median 7.3 years; 9 adults, age range 34-73 years, mean 52.8 years, median 48 years) underwent the 1-stage procedure following the standard Brånemark technique. In all procedures, the single-skin incision was applied.

METHODS

The stability of the implant was measured with implant stability quotient (ISQ) measurement tests. All patients were tested at surgery and every week after for 1 year. Wound-healing time, degree of soft tissue reactions around the abutment, and need for revision surgery were examined. Two-tailed Student t test and χ(2) for all comparisons were calculated; P < .05 values were considered significant.

RESULTS

The new implant showed a steep increase of ISQ values over the first 2 weeks and reached stable ISQ values 3 weeks after surgery. Complete skin healing time was obtained in 8 days on average (range, 7-12 days; median 7.6 days). Neither implant extrusion nor skin revision surgery was observed in our patients during the first year of follow-up.

CONCLUSIONS

This new implant revealed stability and fast integration. The data from the present study suggest the new implant may be suitable for early loading protocols.

Extra-oral implants: insertion per- or post-ablation?

Although the benefit of extra-oral implants in the reconstruction of maxillofacial oncological defects is undisputable, some relevant issues need to be clarified. The purpose of this retrospective study was to evaluate the relationship between implants placed during ablation (DA-implants) and after ablation (AA-implants) of the tumor with respect to implant survival. In total, 103 implants were assessed: 44 nasal implants (17 patients) and 59 orbital implants (18 patients). All patients received their implant-retained maxillofacial epithesis between 1997 and 2010, with a mean follow-up of 35 months (range 8-156 months). The survival rate of DA-implants was 90.0% for the orbital region and 93.5% for the nasal region. The survival rate of the AA-implants for the orbital and the nasal region was 82.8% and 61.5%, respectively. This study shows a significant higher survival rate of extra-oral implants placed during ablative surgery compared to implants in a later stage (p=0.044), thereby stressing the importance of installing extra-oral implants during the ablative surgical session.

Implant survival rate in bone-anchored hearing aid users: long-term results

Objective:

To investigate the long-term survival rate of bone-anchored hearing aid implants, and to assess the number of patients who stop using their bone-anchored hearing aid.

Method:

Patients who underwent bone-anchored hearing aid surgery between September 1977 and December 1986 were identified from a prospective database. Data were collected from patient records.

Results:

During the study period, 143 patients were fitted with a bone-anchored hearing aid. Records from 132 patients were found, with a mean follow up of nine years. A total of 150 implants were installed in these patients. A total of 41 implants (27 per cent) were lost during follow up: 17 lost osseointegration, 16 were removed and eight were lost due to direct trauma. At the end of follow up, 119/132 (90 per cent) patients were still using their bone-anchored hearing aid.

Conclusion:

Despite a high incidence of implant loss over time, a large number of patients still continued to use their bone-anchored hearing aid.

Implant-retained craniofacial prostheses for facial defects

Craniofacial prostheses, also known as epistheses, are artificial substitutes for facial defects. The breakthrough for rehabilitation of facial defects with implant-retained prostheses came with the development of the modern silicones and bone anchorage. Following the discovery of the osseointegration of titanium in the 1950s, dental implants have been made of titanium in the 1960s. In 1977, the first extraoral titanium implant was inserted in a patient. Later, various solitary extraoral implant systems were developed. Grouped implant systems have also been developed which may be placed more reliably in areas with low bone presentation, as in the nasal and orbital region, or the ideally pneumatised mastoid process. Today, even large facial prostheses may be securely retained. The classical atraumatic surgical technique has remained an unchanged prerequisite for successful implantation of any system. This review outlines the basic principles of osseointegration as well as the main features of extraoral implantology.

[Craniofacial prostheses for facial defects]

Craniofacial prostheses (or epitheses) are artificial substitutes for facial defects. Today, prostheses made of silicone are state-of-the-art. They may be fixed anatomically (to already existing structures), mechanically (to spectacle frames), chemically (using adhesives), or surgically (to osseointegrated titanium implants). With the existing extraoral implant systems, prostheses may be securely anchored to the bone regardless of size and location of the defect. The classic atraumatic surgical technique has remained an unchanged prerequisite for successful implantation by avoidance of any heat trauma to the bone. This review outlines the indications and contra-indications as well as advantages and disadvantages of craniofacial prostheses and their retention methods in various facial regions. It summarizes the basic principles of extraoral implantology in respect to implant positioning and the management of children and radiated patients.

Postsurgical care for rehabilitation with implant-retained extraoral prostheses

The health of a peri-implant tissue is a critical factor for the long-term success of treatment with extraoral implants. However, infection and inflammation may occur and lead to implant loss and prostheses failure. Therefore, some postsurgical care as hygiene with soap and water, soft toothbrush, and Superfloss type dental floss and medication with anti-inflammatory and antibiotic are suggested to avoid complications. In addition, a thin and smooth layer of subcutaneous tissue in the peri-implant area should be preserved during implant insertion to favor the assistance recommended in this phase.

Retrospective study of treatment outcomes with implant-retained extraoral prostheses: survival rates and prosthetic complications

STATEMENT OF PROBLEM

Implant-retained extraoral prostheses are an acceptable solution for patients with facial defects. However, these prostheses have a limited service life. Little has been reported on survival periods of implant-retained extraoral prostheses and prosthetic complications of this treatment modality.

PURPOSE

The purpose of this study was to estimate the survival rates of implant-retained extraoral prostheses and to analyze the frequency of prosthetic complications.

MATERIAL AND METHODS

Seventy patients were treated with implant-retained extraoral prostheses. Each patient was examined with respect to the prosthesis appearance and abutment and attachment component complications at 6-month intervals over a period of 10 to 46 months. The Kaplan-Meier survival estimation method was used for the first and subsequent prostheses. The reasons for remaking prostheses were recorded. Complications of the abutment and attachment components and the prostheses were recorded. Frequency of complications was evaluated. Data were analyzed using the Fisher exact test (alpha=.05).

RESULTS

Thirty-two auricular, 25 orbital, and 13 nasal prostheses were evaluated. The Kaplan-Meier analysis revealed an estimated mean survival time of 14.5 months for the patients' first prostheses. The survival times for the first implant-retained auricular, orbital, and nasal prostheses were 14.1, 13.4, and 17.6 months, respectively. The survival times for the second implant-retained auricular, orbital, and nasal prostheses were 14.4, 15.3, and 14.0 months, respectively.

CONCLUSIONS

Implant-retained extraoral prostheses had limited survival rates. The primary reasons for making new prostheses were discoloration, tearing, and mechanical failures of the acrylic resin substructure or retentive elements. Common complications were the need for clip activation, loosening of bar screws and abutments, and loss of attachment between silicone and the acrylic resin substructure. (J Prosthet Dent 2010;103:118-126).

Survival rates and periimplant soft tissue evaluation of extraoral implants over a mean follow-up period of three years

STATEMENT OF PROBLEM

The use of implants with extraoral prostheses provides excellent support, stability, and retention, thereby offering the potential for improving a patient's appearance and quality of life. However, few studies have examined cumulative survival rates of extraoral implants, nor have these reports documented long-term aspects of treatment, such as soft tissue health around abutments.

PURPOSE

The purpose of this study was to evaluate the survival rates and the periimplant soft tissue responses of extraoral implants used to retain facial prostheses.

MATERIAL AND METHODS

Thirty-three patients with auricular, nasal, and orbital anatomical compromise were treated with 98 craniofacial and dental implants. Of the 33 patients, 14 had auricular, 9 had nasal, and 10 had orbital defects. After a 3-month osseointegration period, implant-retained prostheses were fabricated. Following completion of treatment, each patient was seen at 6-month intervals. These examinations were recorded for this patient cohort from 25 to 50 months. Data were analyzed using Kaplan-Meier survival analysis. A 5-point scale was used to record the health of periimplant soft tissues. The unit of measure as a visit/site unit was assigned for each instance and implant site. Periimplant soft tissue reactions were assessed for auricular, nasal, and orbital defects, for each implant site used for these patients' treatments.

RESULTS

The overall cumulative survival rates were 100% for auricular, 83.3% for nasal, and 77.4% for orbital implants, respectively. The survival rates of the implants were 72.7% for those placed in irradiated sites treated without adjunctive HBO therapy, and 93.4% for implants placed in nonirradiated sites. To evaluate the response of the periimplant soft tissues to the implants, a total of 524 visits/sites were recorded. Absence of inflammation (grade 0) of the periabutment soft tissues was observed in 73.3% of the visits/sites.

CONCLUSIONS

The anatomical site into which the implant is placed has an effect on success rate. The auricular site is the most predictable implant site. Survival rates of nasal and orbital implants were found to offer promising results in achieving reliable implant prognoses in these regions. Regardless of the implant site, a decreased survival rate was observed in the irradiated sites. Periimplant soft tissue reactions were most commonly associated with lapses in hygiene.

Bone-anchored titanium implants for auricular rehabilitation: case report and review of literature

CONTEXT AND OBJECTIVE

Osseointegrated implants have acquired an important role in the prosthetic rehabilitation of patients with craniofacial defects. The main indications are lack of local tissue for autogenous reconstruction, previous reconstruction failure and selection of this technique by the patient. This paper presents a clinical case and discusses indications and advantages of the osseointegrated implant technique for retention of auricular prostheses.

TYPE OF STUDY

Case report, Universidade Federal de São Paulo (UNIFESP).

METHODS

A female patient received three auricular implants after surgical resection of a hemangioma in her left ear. The time taken for osseointegration of the temporal bone was three months. After fabrication of the implant-retained auricular prosthesis, the patient was monitored for 12 months.

RESULTS

The clinical parameters evaluated showed good postoperative healing, healthy peri-implant tissue, good hygiene and no loss of implants. Good hygiene combined with thin and immobile peri-implant soft tissues resulted in minimal complications. Craniofacial implant integration appears to be site-dependent; increasing age affects osseointegration in the temporal bone. The frequency of adverse skin reactions in peri-implant tissues is generally low.

CONCLUSION

The surgical technique for rehabilitation using implant-retained auricular prostheses seems to be simple. It is associated with low rates of adverse skin reactions and long-term complications. Prostheses anchored by osseointegrated implants seem to provide better retention than do prostheses supported on spectacle frames, less risk of discoloration through the use of adhesives and better esthetic results than do prostheses anchored in the surgical cavity.

Can keratinocytes cause failure of osseointegration?

AIM

Bone-anchored hearing aids are well established, implanted devices. We present two patients who suffered mixed hearing loss and who underwent titanium implant placement in the temporal bone to enable attachment of bone-anchored hearing aids. Osseointegration is necessary for such implants to function. We report these two cases to highlight how such osseointegration may be disrupted.

METHOD

Attached tissue from the explanted or removed titanium implants was examined by transmission electron microscopy and histopathological analysis.

RESULTS

Attached tissue from both implants showed the presence of keratinocytes at the titanium implant and living bone interface. This was confirmed by histopathological analysis. In one case, there was frank keratinocyte proliferation, which had led to osseointegration failure; in the other case, such proliferation was present but not so advanced.

CONCLUSION

These findings suggest that, in the cases reported, keratinocytes implanted between the titanium and the living bone, leading to disruption of osseointegration.

Alternative strategy to reconstruct the nose after excision: extra-oral implant anchored to bone

Reconstruction of the nose is a two-step process; first, the implant is positioned, and secondly a prosthesis is made to be implanted within three months. This ensures a better cosmetic result from only two operations; the prosthesis may be better placed; and the position can be corrected. Our results suggest that a craniofacial prosthesis anchored to bone is a viable alternative to conventional prosthetic surgery, and offers considerable benefits compared with existing support systems.