Stock Prosthesis Research Articles

CUSTOMISED OCULAR PROSTHESIS FABRICATION - A CASE SERIES

Loss of an eye, whether due to trauma or medical necessity, can lead to significant physical and psychological distress This article delves into the profound impact of ocular prosthetics in alleviating the physical and psychological repercussions of eye loss. Acrylic resin has been identified as an optimal material for its durability, aesthetic fidelity, and biocompatibility in fabricating ocular prostheses. Beyond restoring facial symmetry and enhancing aesthetics, these prostheses significantly bolster patient self-confidence and overall quality of life. The series comprehensively examines four distinct methods for iris positioning and prosthesis characterization, crucial for imparting natural vitality to the prosthetic eye. Each case underscores the importance of personalized care in ocular prosthetics, emphasizing the advantages over standard stock prostheses.

Virtual Surgical Planning for Temporomandibular Joint Reconstruction with Stock TMJ Prostheses: Pilot Study.

The temporomandibular joint (TMJ) is one of the most complex joints in the human anatomy. In advanced degenerative stages, conservative or minimally invasive surgical therapies have failed to restore joint function, and joint replacement with prostheses has been required. Stock prostheses, compared to custom-made prostheses, are much less expensive and require less pre-operative preparation time. Four patients followed for years for temporomandibular dysfunction and previously operated on by arthroscopy or open joint surgery that have been reconstructed with stock TMJ prostheses (STMJP) through virtual surgical planning (VSP) and an STL model with surgical and positioning guides were included. The median follow-up was 15 months; the median number of previous TMJ surgeries was 2. The mean preoperative MIO was 24.6 mm and at longest follow-up was 36.4 mm. The median preoperative TMJ pain score was 8, and the median postoperative TMJ pain was 3. All patients have improved their mandibular function with a clear improvement of their initial situation. In conclusion, we believe that stock TMJ prostheses with virtual surgical planning and surgical guides are a good alternative for TMJ reconstruction at the present time. Nonetheless, prospective and randomized trials are required with long-term follow up to assess their performance and safety.

Novel Use of Virtual Reality and Augmented Reality in Temporomandibular Total Joint Replacement Using Stock Prosthesis

This technical innovation demonstrates the use of ImmersiveTouch Virtual Reality (VR) and Augmented Reality (AR)-guided total temporomandibular joint replacement (TJR) using Biomet stock prosthesis in 2 patients with condylar degeneration. TJR VR planning includes condylar resection, prosthesis selection and positioning, and interference identification. AR provides real-time guidance for osteotomies, placement of prostheses and fixation screws, occlusion verification, and flexibility to modify the surgical course. Radiographic analysis demonstrated high correspondence between the preoperative plan and postoperative result. The average differences in the positioning of the condylar and fossa prosthesis are 1.252±0.269mm and 1.393±0.335mm, respectively. The main challenges include a steep learning curve, intraoperative technical difficulties, added surgical time, and additional costs. In conclusion, the case report demonstrates the advantages of implementing AR and VR technology in TJR's using stock prostheses as a pilot study. Further clinical trials are needed prior to this innovation becoming a mainstream practice.

Computational modelling of the fossa component fixation associated with alloplastic total temporomandibular joint replacements

The alloplastic total temporomandibular joint (TMJ) replacement is a complex surgical approach to end-stage TMJ disorders. The fixation of TMJ prostheses remains a critical issue for implant design and performance. For the fossa component, it is generally considered to use fixation screws to achieve tripod stability. However, the fossa may still come loose, and the mechanism remains unknown. A computational framework, consisting of a musculoskeletal model for calculating muscle and TMJ forces, and a finite element model for the fossa fixation simulation, was developed. A polyethylene (PE) fossa with stock prosthesis design was analyzed to predict contact pressures at the fixation interfaces, and stresses/strains in the fossa implant and bone during the static loading of normal chewing bite and maximum-force bite. The predicted maximum von Mises stresses were 33 MPa and 44 MPa for the bone, 13 MPa and 28 MPa for the PE fossa, and 131 MPa and 244 MPa for the screws, for the normal and maximum bites, respectively; the peak minimum principal strain was in the range of -2514 ∼ -3545 με for the bone. The results show that the sufficient initial mechanical strength of the fossa component fixation can be established using the screws in combination with bone support. The functional loads applied through the prosthetic TMJ bearing can be largely transferred to supporting bone without causing high level stresses. Tightening fixation screws with a pretension of 100 N can reduce transverse load to the screws and help prevent screw loosening. Further research is recommended to accurately quantify the transverse load and its influence on screw loosening during dynamic loading, and the frictional properties at the bone-implant interface.

Heterotopic ossification after alloplastic temporomandibular joint replacement: a case cohort study

BackgroundHeterotopic ossification (HO) is one of the serious complications leading to the failure of alloplastic temporomandibular joint replacement (TJR). However, there was few research on its exact incidence and occurrence. Severe HO might result in pain and limited mouth opening after surgery. Therefore, it is necessary to clarify its clinical and imaging manifestations. The purpose of this study was to study the occurrence and classify HO after the alloplastic TJR.MethodPatients who underwent standard TJR (Zimmer Biomet stock prostheses or Chinese stock prostheses) with fat graft and at least 1-year-follow-up were included. HO was classified into 4 types according to postoperative computed tomography (CT) scans. Type and occurrence in different TMJ disease were compared. Joint space within 1 week after operation was measured and compared between HO and non-HO TJRs. Maximum incisal opening (MIO), pain, and quality of life (QoL) were recorded and their relevance with HO was analyzed statistically.Result81cases with 101 joints were included in the study. The mean follow-up time was 22.9 months (12 ~ 56 months). Among the 48 joints, 27 (56.3%) were type I (bone islands); 16 (33.3%) were type II (bone spurs from the mandibular ramus); 3 (6.3%) were type III (bone spurs from the fossa); and 2 (4.2%) were type IV (bone spurs from both the mandibular ramus and fossa). In HO patients, joint space in type IV was smaller than the other 3 types. Pain scores in HO were significantly greater than non-HO patients before and after operations (p < 0.05). 1 patient in Type IV HO developed ankylosis and had prosthesis revision which accounted for 2.1% in HO patients and 1.0% in all TJR patients.ConclusionHO after alloplastic TJR with fat graft was not severe except for type IV, which was easy to cause ankylosis. Preserving sufficient TJR space was important for ankylosis prevention.

Comparative clinical outcomes between stock vs custom temporomandibular total joint replacement systems

With the evolution of temporomandibular (TMJ) prosthetic total joint replacement, there has been much debate around the advantages of custom over stock prostheses. The aim of this study is to compare the clinical outcomes of a TMJ stock prosthesis (Zimmer-Biomet) to a custom prosthesis (OMX).Clinical data from 139 prosthetic joints placed in 117 patients was retrospectively collected and analysed. All patients were diagnosed with end-stage joint osteoarthritis and were treated by a single surgeon. Minimum follow up was 2 years post-surgery.The cohort was divided into 2 groups, 60 stock prosthetic joints in 54 patients and 79 custom prosthetic joints in 63 patients. This comprised of 110 males and 7 females. The average age at the time of surgery was 53.4yr ± 12.7yr. There was no statistical difference in pre-operative MIO and pain scores between the two groups. Post-operatively, patients fitted with a custom prosthesis showed statistically significant (P = 0.013) improvement in Maximum Interincisal Opening (MIO) (+6.33 mm vs +2.53 mm) and fewer complications. Following surgery, no difference noted in pain scores and patient satisfaction between the two groups.In experienced hands, both stock and custom TMJ implants work well. However, the added advantages of custom prostheses together with growing access to digital technology is likely to result in custom devices dominating the market in TMJ total joint replacement systems.

Classification and surgical management of temporomandibular joint ankylosis: a review.

The paper reviews various classifications and surgical techniques for the treatment of temporomandibular joint ankylosis. PubMed, EBSCO, Web of Science, and Google Scholar were searched using a combination of keywords. Articles related to classification, resection-reconstruction of the temporomandibular joint, and management of airway obstruction were considered and categorized based on the objectives. Seventy-nine articles were selected, which included randomized clinical trials, non-randomized controlled cohort studies, and case series. Though several classifications exist, most classifications are centered on the radiographic extent of the ankylotic mass and do not include the clinical and functional parameters. Hence there is a need for a comprehensive staging system that takes into consideration the age of the patient, severity of the disease, clinical, functional, and radiographic findings. Staging the disease will help the clinician to adopt a holistic approach in treating these patients. Interpositional arthroplasty (IA) results in better maximal incisal opening compared with gap arthroplasty, with no significant difference in recurrent rates. Distraction osteogenesis (DO) is emerging as a popular technique for the restoration of symmetry and function as well as for relieving airway obstruction. IA, with a costochondral graft, is recommended in growing patients and may be combined with or preceded by DO in cases of severe airway obstruction. Alloplastic total joint replacement combined with fat grafts and simultaneous osteotomy procedures are gaining popularity. A custom-made total joint prosthesis using CAD/CAM can efficiently overcome the shortcomings of stock prostheses.

Rehabilitating an Ocular Defect with a Custom Made Ocular Prosthesis: A Clinical Report

An ocular prosthesis is a replacement of the ocular part of the eye in patients due to trauma, benign ormalignant lesion or congenital anomaly, there is the loss of the eye. Prosthetic rehabilitation with a customizedocular prosthesis that is proportioned and similar in appearance to that of the contralateral natural eye isneeded. This maintains the volume of the orbital socket and also helps create an illusion of the presence ofa healthy eye. It provides the individual confidence to adapt to a normal lifestyle and prevent them fromgoing into psychological distress. Various techniques have been advocated for the fabrication of the ocularprosthesis comprising the use of the stock prosthesis, custom made prosthesis and micro-implants for therehabilitation of the ocular part of the eye. A cosmetically approvable and pleasing ocular prosthesis arethose which reproduces the colour, appearance and orientation of the iris to that of the contralateral naturaleye. This clinical report describes a simple, economical and time-saving method for the fabrication of thecustomised ocular prosthesis in a patient with the ocular defect.

Evaluation of fit feasibility of stock total joint replacement in temporomandibular joint ankylosis patients

Long standing adult temporomandibular joint ankylosis (TMJA) results in smaller ramal height, and warped and undulated ramus. Despite the efforts made to standardise the sizes available in stock joint (Zimmer Biomet®), the system causes fit challenges in TMJA patients. The aim of the study was to evaluate the virtual feasibility of stock prostheses in TMJA patients. The data included amount of bone contouring for fossa placement, available ramal length, length discrepancy if placed straight, angulation of mandibular component required to adapt to the bone, and mediolateral fit discrepancy. CT data of 50 TMJA patients (71 joints; unilateral, n=29; bilateral, n=21; male, n=33; female, n=17) with mean age of 24.26±8.88 years were included. 53 joints required more than 3mm lateral bone reduction for fossa placement. The ramal length were categorised into ranges 35–40mm (n=15), 41–45mm (n=14), 46–50mm (n=28) and >50mm (n=14). Correlation between the age of occurrence of ankylosis and ramal length using the Pearson correlation coefficient revealed a positive correlation (r=0.38, p=0.001). Length discrepancy, angulation of mandibular component, and mediolateral fit discrepancy decreases as the ramal length increases. Only 14 joints had appropriate fit of stock prostheses while the remaining 57 joints warranted compromised placement. Even the smallest available stock mandibular component (45mm) had a compromised fit in terms of length and adaptability on the lateral aspect of ramus. The study concludes that a short ramus is mostly limiting factor in using stock prosthesis in TMJA patients. There is a need for still smaller size stock prostheses.

Evaluation of fit feasibility of TJR standard stock prosthesis in TMJ ankylosis patients of Indian population – a radiographic study

Introduction: Stock alloplastic temporomandibular joint (TMJ) replacement is challenging particularly in TMJ ankylosis patients due to the limited ramus height, undulating lateral ramus and root of zygomatic arch. Despite efforts made to standardize the sizes in available stock joint (BIOMET LORENZ), this system throw challenges in the ankylosis patients of Indian population. It limits the applicability as the system was designed based on the anatomy of American population.

Alloplastic Total Temporomandibular Joint Reconstruction: A 10-Year Experience of the University of the Witwatersrand, Johannesburg.

This study aimed to retrospectively analyze our 10-year experience with total alloplastic reconstruction of the temporomandibular joint prostheses. Indications and clinical outcomes were also evaluated.Methodology: This was a cross-sectional study in which 31 patients who had alloplastic total Temporomandibular Joint prosthesis implanted between 2007 and 2017 were reviewed. Outcomes (maximum mouth opening distance and occlusion), subjective outcomes (pain, diet consistency and chewing, quality of life), and complications were evaluated. There were 16 females and 15 males with a mean age of 36.94 years (range 11-72 years). In total, 51 prostheses (20 bilateral, 11 unilateral) were implanted. The stock prostheses were used in 28 patients (90.32%) and only 3 (9.68%) were of custom-made type. Fifty-eight percent of patients were diagnosed with temporomandibular joint ankylosis, 22.58% had degenerative conditions, 9.68% had pathology (hemifacial microsomia, synovial chondromatosis, and osteochondroma), and 9.68% had malocclusion.The results showed that there was a significant improvement in maximum mouth opening distance (P-value < 0.0001), particularly in patients who had ankylosis.There was improvement in diet consistency (P-value < 0.0001) and quality of life (P-value 0.013). Postoperative complications ranged from facial nerve injuries (n = 4), keloids (n = 2), and heterotopic bone formation (n = 2). TMJ alloplasts provide satisfactory clinical and functional outcomes for patients with end-stage TMJ diseases, evidenced by overall improvement in maximum mouth opening, chewing ability and quality of life and reduction in pain. Previously operated joints and a preoperative diagnosis of ankylosis increase the risk of occurrence of complications postimplantation of total alloplastic joints.

How Does a Unilateral Temporomandibular Joint Replacement Affect Bilateral Masseter and Temporalis Muscle Activity?—A Prospective Study

Total alloplastic temporomandibular joint replacement (TMJR) requires the detachment of the masseter muscle (MM) at its insertion to the lateral ramus and often the resection of the coronoid process (insertion of the temporalis muscle). There is little literature on how a detachment affects the muscles. The present study evaluates the long-term masticatory muscle activities and maximum voluntary bite force (MVC) in patients with unilateral TMJR. Surface electromyography of the MM and anterior temporalis muscle during bite force testing and MVC were evaluated bilateral preoperatively (T0), 1 (T3), 2 (T4), 3 (T5), and 4years (T6) postoperatively. The percentage overlapping coefficient (index of the symmetric distribution of muscular activity) was calculated. Differences between stock or custom devices were evaluated. Fourteen patients were enrolled, 4 males and 10 females, age 47.3±14.3years at TMJR placement. In 11 patients, the coronoid process was resected, 5 patients received stock, and 9 custom prostheses. After surgery, a trend in the improvement of bilateral surface electromyography activities and MVC was found without statistical significance for the side comparison or the time of the investigation. The percentage overlapping coefficient values showed postoperatively relative (>72%) symmetry in both muscles. Up to T5 on the TMJR side, MM showed higher activity when custom prostheses were used. There was no significant difference between stock and custom prostheses. The vertical (anterior) fibers of the temporalis muscle are preserved despite the resection of the coronoid process. The anterior temporalis muscle, as a synergist of the MM on the TMJR side, postoperatively partially assumes its abduction function. The detached MM appears to reattach. Generally, the bilateral increase in muscle activity and MVC of both muscles suggests regeneration of the investigated muscles. Custom prostheses seem to have an initial advantage for the reattachment of the MM compared with stock prostheses.

Will they fit? Determinants of the adaptability of stock TMJ prostheses where custom TMJ prostheses were utilized

Currently only two alloplastic temporomandibular joint (TMJ) total joint replacement (TJR) systems are available in the United States. The aim of this study was to define variables that determine whether a Biomet stock prosthesis could have been used to reconstruct a TMJ previously reconstructed with a TMJ Concepts patient-fitted prosthesis. All of the TMJ Concepts prostheses placed between 2010 and 2018 at the University of Texas – Health at San Antonio were analyzed retrospectively. There were 128 cases (241 joints) with intact stereolithographic models analyzed for successful adaptation of the Biomet stock TMJ prosthesis. Anatomical, demographic, etiological, and perioperative data were gathered for each joint to investigate possible causes of failure of stock adaptation. The majority of joints, 74% (178/241), could have had a stock prosthesis adapt. All joints with ≥40mm gap arthroplasty failed stock prosthesis adaptation. Only 50% (32/64) of the joints with at least one previous open TMJ surgery and 60% (58/96) of the joints with concomitant orthognathic surgery could have had a stock TMJ prosthesis. The stock prosthesis could not be adapted for any of the patients requiring TMJ replacement for congenital disorders or those requiring TMJ salvage. Overall, the majority of cases treated with a patient-specific TMJ TJR could have been treated with a stock prosthesis.

Total Temporomandibular Joint Replacement: Stick to Stock or Optimization by Customization?

This article aims to compare the difference in postoperative results in patients treated with either a patient-specific (PSI) or a stock temporomandibular total joint replacement system. The investigators performed a systematic review concerning postoperative results after placement of either a stock total joint replacement system or a PSI. PubMed Central, Web of Science, Cochrane Library Plus, Wiley Online Library, and EMBASE were used to conduct this search. All articles up to August 15, 2018, were scrutinized. All included articles were nonrandomized cohort studies. Maximal mouth opening (MMO) and Visual Analog Scale (VAS) scores for pain and diet before and after surgery were evaluated. The Methodological Index for NonRandomized Studies scale was used for quality assessment. Weighted mean difference was calculated and pooled by meta-analysis using random-effect models. The search identified 1581 articles, of which 15 were included. The average risk of bias was low. Both systems achieved significant increases in MMO and decreased VAS pain scores at 1, 2, and 3 years after surgery. No significant difference was found between the system types. Both achieved significant improvements in dietary VAS scores, with a more significant improvement for stock implants. Due to the lack of detailed diagnostic evaluation tools allowing proper start-point categorization, there is a significant risk for selection bias in the pooled data. The PSI is more frequently chosen for cases with more significant joint degeneration, skewing postoperative results. A patient-fitted implant can provide significant operative and patient-centered advantages over a stock implant, which will likely be confirmed when observational cohort studies have included indications like the ones for stock prostheses. Furthermore, while current US Food and Drug Administration-approved stock implants contain cobalt -chromium -molybdenum, the newly manufactured PSI are made of titanium alloy, diminishing the risks of morbidity and implant failure.

Prospective study of five-year outcomes and postoperative complications after total temporomandibular joint replacement with two stock prosthetic systems.

To evaluate and compare outcomes and complications associated with reconstruction of the temporomandibular joint (TMJ), we prospectively analysed the data of 70 patients who had their joints replaced with stock prostheses during the period 2004-14 and who had been followed up for five years. We used two types of stock prostheses: the metal-on-metal Christensen system (CS), and the ultra-high-molecular-weight-polyethylene-on-metal Biomet® system (BS). Data were collected at 3, 6, 12, 24, 36, 48, and 60 months postoperatively and compared with preoperative measurements. Five years after the replacement there was an increase in mean (SD) mouth opening from 2.0 (0.6) to 4.0 (0.5cm) (p=0.012) in the CS, and from 2.5 (1.0) cm to 4.1 (0.6) cm (p=0.018) in the BS. The mean (SD) reductions in visual analogue pain scores were from 6.9 (1.6) to 2.0 (1.4) (p=0.001) in the CS, and 6.5 (1.4) to 1.5 (1.1) (p=0.001) in the BS. There were no significant differences in improvements in mouth opening or reduction in pain between the two groups. However, there were differences in the number of implants that failed, which led to removal and replacement of 2/14 prostheses in the CS group and 3/77 in the BS group (p=0.06). The results supported the placement of stock prostheses, as evidenced by a low incidence of complications and adverse events, and a long-term improvement in function and reduction in pain in the TMJ. The BS group had significantly fewer prosthetic failures than the CS group.

Total joint reconstruction using computer-assisted surgery with stock prostheses for a patient with bilateral TMJ ankylosis

BackgroundsThe purpose of this study is to discuss the total joint reconstruction surgery for a patient with recurrent ankylosis in bilateral temporomandibular joints (TMJs) using three-dimensional (3D) virtual surgical planning, computer-aided manufacturing (CAD/CAM)-fabricated surgical guides, and stock TMJ prostheses.Case presentationA 66-year-old female patient, who had a history of multiple TMJ surgeries, complained of severe difficulty in eating and trismus. The 3D virtual surgery was performed with a virtual surgery software (FACEGIDE, MegaGen implant, Daegu, South Korea). After confirmation of the location of the upper margin for resection of the root of the zygoma and the lower margin for resection of the ankylosed condyle, and the position of the fossa and condyle components of stock TMJ prosthesis (Biomet, Jacksonville, FL, USA), the surgical guides were fabricated with CAD/CAM technology. Under general anesthesia, osteotomy and placement of the stock TMJ prosthesis (Biomet) were carried out according to the surgical planning. At 2 months after the operation, the patient was able to open her mouth up to 30 mm without complication.ConclusionFor a patient who has recurrent ankylosis in bilateral TMJs, total joint reconstruction surgery using 3D virtual surgical planning, CAD/CAM-fabricated surgical guides, and stock TMJ prostheses may be an effective surgical treatment option.

Surgical outcomes and challenges in stock alloplastic total joint replacement (TJR) in adult temperomandibular joint ankylosis (TMJA)

Background: The stock prosthesis used to treat adult TMJA is not without its inherent problems

Reconstruction of the temporomandibular joint: a comparison between prefabricated and customized alloplastic prosthetic total joint systems

The implantation of an alloplastic total temporomandibular joint (TMJ) prosthesis is an innovative approach for the treatment of end-stage TMJ disorders. Two types of system exist: prefabricated (stock) and customized computer-aided design/computer-aided manufacturing (CAD/CAM) devices. A clinical study was performed to evaluate the effectiveness of these two designs. Twenty-eight patients treated between 2015 and 2017 were included and assigned to two groups: stock prostheses (group 1) and customized CAD/CAM prostheses (group 2). Clinical evaluations were performed at five time-points up to 6 months postoperative. Parameters included maximum interincisal opening, pain, diet, complications, and subjective well-being at the end of follow-up. Differences between pre-surgery and 6-month post-surgery values were highly significant (P<0.001). No patient required a liquid diet at the end of treatment, and 66% of group 1 patients and 100% of group 2 patients reported improved well-being. Complications were observed in 32% of patients and included temporary paralysis of the facial nerve. In conclusion, clinical outcomes of stock and CAD/CAM prostheses suggested great improvements in mouth opening and reduction of pain as a result of the rehabilitation of TMJ function. Results showed comparable data for the two types of prosthesis design at 6 months postoperative.

Preliminary clinical study of Chinese standard alloplastic temporomandibular joint prosthesis

PurposeTo evaluate the preliminary clinical outcomes on the Chinese standard temporomandibular joint (TMJ) prostheses. Patients and methodsPatients who underwent Zimmer Biomet and Chinese standard prostheses by one surgeon between January 1st 2016 and June 30th 2017 were included in the study. Maximum incisal opening (MIO), pain, diet, and joint function were measured; CT scans were taken before and after the operation and during at least a 12-months follow-up for evaluation. ResultsThirty-five patients including 12 with Chinese standard prostheses and 23 with Biomet stock prostheses participated in the study. After an average of 14.3 months follow-up, both types of prostheses could significantly improve MIO, diet, and joint function, and relieve pain (p < 0.05). There were no significant differences in diet, pain level and joint function either before or after the operation between the two types of prostheses, whereas after the operation, the MIO with Chinese standard prostheses was significantly larger than with the Biomet stock prostheses (p < 0.05). However, there was no significant difference before operation (p > 0.05). A computed tomography (CT) scan showed that no prostheses dislocated or broke, no screws loosened, and ectopic bone formation appeared around the alloplastic condyle. ConclusionChinese standard TMJ prostheses are effective and stable in clinical application. They can significantly improve mouth opening, diet, and joint function and relieve pain.

Comparison of bone adaptation after modification in biomet standard alloplastic temporomandibular joint prostheses

PurposeThe aim of the study was to compare bone adaptation after design modification in Biomet stock prostheses. Materials and methodsComputed tomography (CT) data of the patients treated with a Biomet TMJ replacement from 2010 to 2016 were recruited. Fossa prosthesis with a bulge and 4 types of condyle-ramus angle prostheses were virtually designed and implanted by computer-assisted simulation. The amount of bone trimming including fossa, mandibular ramus and bone graft were measured by ProPlan CMF 1.4 software. The differences between the original and modified prostheses were compared by SPSS 17.0 software for statistical analysis. ResultsThere were 54 patients’ CT data included in the study. The amount of fossa bone trimming was 150.20 mm3 in the modified prosthesis and 281.82 mm3 in the original one. The amount of ramus bone trimming was 103.86 mm3 in the modified prosthesis and 229.45 mm3 in the original one. The amount of fossa bone grafting was 95.88 mm3 in the modified prosthesis and 263.03 mm3 in the original one. There were significant differences between them (p = 0.000). ConclusionsThe modified Biomet prostheses design requires less bone trimming and grafting for implantation.