Three-dimensional numerical simulation of stress induced by different lengths of osseointegrated implants in the anterior maxilla

Lower survival rates were observed for the implant placed in the anterior maxilla. The purpose of this study was to investigate the influence of different implant lengths on the stress distribution around osseointegrated implants under a static loading condition in the anterior maxilla using a three-dimensional finite element analysis. The diameter of 4.0 mm external type implants of different lengths (8.5 mm, 10.0 mm, 11.5 mm, 13.0 mm, 15.0 mm) was used in this study. The anterior maxilla was assumed to be D3 bone quality. All the material was assumed to be homogenous, isotropic and linearly elastic. The implant–bone interface was constructed using a rigid element for simulating the osseointegrated condition. Then, 176 N of static force was applied on the middle of the palatoincisal line angle of the abutment at a 120°angle to the long axis of abutment. The von Mises stress value was measured with an interval of 0.25 mm along the bone–implant interface. Incremental increase in implant length causes a gradual reduction of maximum and average von Mises stress at the labial portion within the implant. In the bone, higher stress was concentrated within cortical bone area and more distributed at the labial cortex, while cancellous bone showed relatively low stress concentration and even distribution. An increase in implant length reduced stress gradients at the cortical peri-implant region. Implant length affects the mechanisms of load transmission to the osseointegrated implant. On the basis of this study the biomechanical stress-based performance of implants placed in the anterior maxilla improves when using longer implants.     

Reconstruction of the edentulous mandible with fresh frozen bone grafts and implants: a 4-year report of a prospective clinical study

Allogen bones from tissue bank are often used in dentistry although the data analyzing the long-term success in mandible are scarce. This study evaluated by computed tomography scans (CTS) the bone resorption around the implants installed on fresh frozen bone (FFB) previously grafted, after 4 years of occlusal rehabilitation. Six subjects were grafted with blocks in posterior mandible using FFB. After 6 months, 27 implants were placed and after further 4 months the prostheses were delivered. Following 4 years of the final rehabilitation procedures, another CTS was done in order to measure the resorption in periimplant bone crest at the proximal implant surfaces. It was observed a 100 % survival rate of the implants after 4 years of the fixture installation. The marginal bone resorption after 48 months was 2.82 ± 1.63 mm and no statistical significant difference was observed along the region where the implants were fixed when compared with the interimplantar space. In addition there was no significant correlation regarding the length of the implant used and the amount of marginal bone resorption. The conclusion is that grafted areas with FFB are suitable to implant installation in the posterior mandible.     

Multi-factorial analysis of variables influencing the bone loss of an implant placed in the maxilla: Prediction using FEA and SED bone remodeling algorithm

The aim of this study was to investigate the interactions of implant position, implant–abutment connection and loading condition influencing bone loss of an implant placed in the maxilla using finite element (FE) analysis and mathematical bone remodeling theory. The maxilla section contours were acquired using CT images to construct FE models containing RS (internal retaining-screw) and the TIS (taper integrated screwed-in) implants placed in SC (along the axis of occlusal force) and RA (along the axis of residual ridge) positions. The adaptive strain energy density (SED) algorithm was combined with FE approach to study the preliminary bone remodeling around implant systems under different load conditions. The simulated results showed that the implant position obviously influenced the bone loss. An implant placed in the RA position resulted in substantially increased bone loss. Implant receiving a lateral load slightly increased bone loss compared with an axial load. The implant type did not significantly influence bone loss. It was found that buccal site suffered the most bone loss around the implant, followed by distal, lingual and mesial sites. The implant position primarily influenced bone loss and it was found most obviously at the buccal site. Implant placed along the axial load direction of a proposed prosthesis could obtain less bone loss around the implant. Attaining proper occlusal adjustments to reduce the lateral occlusal force is recommended in implant–bone–prosthesis system. Abutments of internal engagement with or without taper-fit did not affect the bone loss in the surrounding bone.     

Functional rehabilitation of the atrophic mandible and maxilla with fibula flaps and implant-supported prosthesis

Historically, nonvascularized bone grafts have been the standard treatment for severe mandibular and maxillary atrophy, followed by immediate or delayed implant placement. Extreme atrophy is an unfavorable biological and mechanical location for nonvascularized autologous bone transplants. The authors present the results of a multidisciplinary treatment protocol for rehabilitation of extreme mandibular and maxillary atrophy by use of the vascularized fibular flap. This protocol includes bone augmentation, implant surgery, soft-tissue management, and prosthetic restoration. Since 1993, 18 patients with a mean age of 47.5 years presented with extreme mandibular and/or maxillary atrophy and underwent alveolar crest augmentation with vascularized fibular flaps. Bone healing was achieved in 17 of the 18 patients. Seventy-three osteointegrated implants were inserted in 12 of 17 fibular flaps. Altogether, 62 implants were loaded and 11 dental prostheses were made. Average follow-up of the loaded implants was 41 months. The success rate of loaded implants was 100 percent. The authors strongly recommend the use of the fibular bone flap when dealing with extreme atrophy of the mandible and maxilla and suggest the protocol outlined in this review.     

The use of metallic implants in the study of facial growth in children: method and application

On the basis of experience gained over a number of years, an account is given of the technique for insertion of the implants, the radiographic method, and the graphic procedure for preparation of growth tracings. Small pins of hard tantalum are hammered into the bone under local analgesia with a pencil-shaped instrument, in the tip of which the implant is placed. No surgical exposure is necessary. Because of remodeling resorption of the bone and eruption of the teeth, the implants can be placed only in certain places in the maxilla and mandible. In implant studies it is necessary to observe a high level of reproducibility in positioning the head in the cephalostat. An X -ray cephalostat with a built-in image intensifier has been designed which enables the position to be monitored by televison. In the graphic procedure, drawings of the arches from dental casts are incorporated in tracings of profile radiographs; the paths of eruption of the teeth and development or the arches can then be examined with the metallic implants as references.     

Placement of endosteal implants in the zygoma after maxillectomy: a Cadaver study using surgical navigation

Endosteal implants facilitate obturator prosthesis fixation in tumor patients after maxillectomy. Previous clinical studies have shown, however, that the survival of implants placed into available bone after maxillectomy is generally poor. Nevertheless, implants positioned optimally in residual zygomatic bone provide superior stability from a biomechanical point of view. In a pilot study, the authors assessed the precision of VISIT, a computer-aided surgical navigation system dedicated to the placement of endosteal implants in the maxillofacial area. Five cadaver specimens underwent hemimaxillectomy. The cadaver head was matched to a preoperative high-resolution computed tomograph by using implanted surgical microscrews as fiducial markers. The position of a surgical drill relative to the cadaver head was determined with an optical tracking system. Implants were placed into the zygomatic arch, where maximum bone volume was available. The results were assessed using tests for localization accuracy and postoperative computed tomographic scans of the cadaver specimens. The localization accuracy of landmarks on the bony skull was 0.6 +/- 0.3 mm (average +/- SD), as determined with a 5-df pointer probe; the localization accuracy of the tip of the implant burr was 1.7 +/- 0.4 mm. The accuracy of the implant position compared with the planned position was 1.3 +/- 0.8 mm for the external perforation of the zygoma and 1.7 +/-1.3 mm for the internal perforation. Eight of 10 implants were inserted with maximal contact to surrounding bone, and two implants were located unfavorably. Reliable placement of implants in this region is difficult to achieve. The technique described in this article may be very helpful in the management of patients after maxillary resection with poor support for obturator prostheses.     

Long-term use of polyurethane breast prostheses: a 14-year experience

I have used polyurethane prostheses for the past 14 years, implanting 220 implants into 130 patients who desired breast reconstruction after subcutaneous mastectomy or cancer ablation or simply breast augmentation. I theorize that a polyurethane-covered implant resists contracture, retaining its compressibility because the fibroblasts proliferate into the polyurethane in many different directions. When the fibrils contract, the forces of contracture counterbalance one another, resisting contracture. However, when smooth prostheses are implanted, fibrils are directed in a circular fashion around the implant and naturally contract, leading to firmer breasts. There were 115 prostheses inserted following subcutaneous mastectomy, and 22 percent developed contracted capsules. Seven implants became exposed because of skin necroses; one was removed because of a Staphylococcus infection; and two patients developed a combination of polyurethane and silicone granulomas. These developed only with the earlier implant, where there was shedding of the polyurethane sponge layer and silicone bled from the low-viscosity silicone used in the earlier implants. No granulomas were noted with the currently used Surgitek Replicon implant. Eighty-five breasts were reconstructed after cancer ablation with polyurethane implants, and the contracture rate was 2.3 percent. Other complications were minimal. A smaller group of patients had augmentation mammaplasty, and 20 prostheses were placed in 10 patients. A 15 percent contracture rate was noted in this group. In this study, 82 percent of patients were followed for up to 14 years. Capsular contractures occurred in 30 implants between 1 and 11 years, for an average recurrence at 6.3 years. The overall contracture rate was 13 percent. Other complications were minimal. All implants were placed subcutaneously or subglandularly, and all were drained.     

The potential benefits of dental implants on the oral health quality of life of people with Parkinson’s disease

Objective: To investigate how dental implants impact on the oral health quality of life of people with Parkinson’s disease (PD). Background: PD is a progressive neurological disorder that can result in a number of oral health care challenges, including denture difficulties. Lack of evidence related to use of implants in PD prompted this study to investigate their use in this group of people. Materials and methods: Nine people with PD were provided with either fixed or removable prostheses using Astra‐Tech implants. Participants completed the socio‐dental questionnaire, ‘The Dental Impact on Daily Living Assessment’ (DIDL) prior to implant surgery, and at 3 and 12 months after provision of the final prosthesis. DIDL comprises two components – the Oral Health Quality of Life Inventory (OH‐QoL) and the Self‐Reported Assessment of Oral Health and Functional Status (SROH). Results: Nine people (with an age range of 54–77 years) had implants placed. The implant success rate was 85 and 81% in the maxilla and mandible, respectively. The OH‐QoL and SROH results (analysed using the one‐way analysis of variance and pairwise multiple comparisons) demonstrated a significant improvement in the domains of eating and satisfaction with the prosthesis after 3 months, which was maintained at the twelve month review. The OH‐QoL indicated a gradual improvement in oral well‐being over the 12‐month period. Conclusion: The oral health quality of life of people with PD was improved by the use of dental implants, indicating this as a viable treatment option.     

Treatment of midfacial defects using prostheses supported by ITI dental implants

The purpose of this study was to evaluate retrospectively the use of ITI dental implants used for anchoring facial prostheses in the restorative treatment of midface defects. The authors analyzed the clinical data of 26 patients with orbital defects (n = 11), orbitonasal defects (n = 4), orbitonasomaxillary defects (n = 3), and nasal defects (n = 8). Data included age, sex, primary disease, implant position, implant length, implant failure, prosthetic attachment, radiation therapy, and peri-implant skin reactions. Follow-up was at 1, 3, 6, and 12 months and then on a yearly basis. The authors noted the status of healing and complications, if any. In total, 62 implants were placed as follows: 27 (43.5 percent) for orbital prostheses, 12 (19.4 percent) for orbitonasal prostheses, 14 (22.6 percent) for orbitonasomaxillary prostheses, and nine (14.5 percent) for nasal prostheses. Thirty-eight implants (61.3 percent) were placed in previously irradiated areas in 18 patients (69.2 percent). Mild skin reactions together with mild accumulation of sebaceous crusting around implants were recorded in 14.2 percent of the skin observations. No patient experienced severe inflammation requiring administration of systemic antibiotics or surgical revision. Implant success was 100 percent in both irradiated and nonirradiated patients. In conclusion, ITI dental implants result in a high rate of success in retaining midface prostheses and offer good stability and aesthetic satisfaction.     

自体颏部骨移植并种植体修复前牙槽骨缺损的应用研究

目的:评价自体颏部骨移植方法在前牙槽骨缺损植骨及种植的效果。方法:对16例前牙骨缺损的患者进行自体颏部骨移植,分别于植骨12～16周后植入种植体,共植入18枚种植体,术后16～20周完成修复治疗。结果:16例自体骨移植患者中,1例出现术后感染,经局部冲洗换药后后愈合良好,其余患者移植骨均已成活,修复后种植体至今均无脱落,局部外形良好。结论:自体颏部骨移植能有效恢复局部牙槽外形,为前牙美学修复提供良好的基础。     

Present clinical applications of osseointegrated percutaneous implants

Altogether, 389 screws of commercially pure titanium have been inserted at various locations in the facial skeleton of 174 patients. The indications for treatment have been stable anchorage of an external hearing aid or a facial episthesis, in the latter case to restore the facial contours after congenital disorders or status after trauma or cancer surgery. All implants have been inserted in a two-stage procedure, the first being anchorage of the titanium elements in the bone, the second, minimally 3 months later, being establishment of a permanent skin penetration. The outcome of every inserted implant has been analyzed. Only six implants failed to become integrated in bone and had to be removed. Five of these failures occurred in previously irradiated bone, where the success rate was estimated to 85.3 percent. In nonirradiated bone, 354 of 355 inserted implants became osseointegrated, i.e., anchored in bone in a stable manner. The soft tissues were without any adverse reactions in 92 percent of the 951 clinical observations, whereas potentially serious skin complications were observed in only 2.8 percent. Presently, the longest clinical follow-up is 8 years, and 37 implants have been followed for more than 5 years. We believe that this clinical material is the first in which an uneventful bone anchorage and skin penetration have been demonstrated in consecutively operated upon clinical cases. The implants used for anchoring an external hearing aid were also successful in the sense that the patients gained 15 dB (average) in hearing threshold and showed a significantly improved discrimination score. The implants inserted to hold facial epistheses resulted in considerably improved retention and a good cosmetic outcome for the patients.     

Breast reconstruction using tissue expanders and implants in Hodgkin's patients with prior mantle irradiation.

Women treated for Hodgkin's disease with mantle irradiation have an increased risk for developing breast cancer. Typically, breast malignancy in Hodgkin's patients presents bilaterally in a younger age group. Skin flap ischemia, poor skin expansion, implant extrusion, capsular contracture, and poor cosmesis are common sequelae of tissue expander/implant breast reconstruction after breast irradiation for failed breast conservation therapy. This has led most surgeons to favor autologous tissue reconstruction in this setting. This study was performed to determine the efficacy of tissue expander/implant breast reconstruction in breast cancer patients who have been treated with prior mantle irradiation for Hodgkin's disease. A retrospective analysis of all breast cancer patients with a history of Hodgkin's disease and mantle irradiation treated with mastectomy and tissue expander/implant reconstruction between 1992 and 1999 was performed. There were seven patients, with a mean age of 35 years (range, 28 to 42 years). The average interval between mantle irradiation and breast cancer diagnosis was 16 years (range, 12 to 23 years). All patients underwent two-stage reconstruction. Textured surface tissue expanders were placed in a complete submuscular position at the time of mastectomy. Expansion was initiated 2 weeks after insertion and continued on a weekly basis until completion. Expanders were replaced with textured surface saline-filled implants as a second stage. Patients were evaluated for skin flap ischemia, infection, quality of skin expansion, implant extrusion, capsular contracture, rippling, symmetry, and final aesthetic outcome. Breast cancer was bilateral in five patients and unilateral in two. Two patients did not undergo simultaneous bilateral breast reconstruction because of metachronous cancer development. One of the patients had an initial transverse rectus abdominis muscle flap breast reconstruction, followed by a tissue expander/implant reconstruction of the opposite breast. The average follow-up was 3 years. Complications were limited to one case of cellulitis after implant placement that resolved with intravenous antibiotics. There were no cases of skin flap ischemia, poor skin expansion, or implant extrusion. Overall patient satisfaction was high and revisions were not requested or required. Symmetry was best achieved with bilateral implants. This study demonstrates the efficacy of tissue expander/implant breast reconstruction in patients treated with prior mantle irradiation. In this series, tissue expansion was reliable with low morbidity. Second-stage placement of permanent implants yielded good aesthetic results without significant capsular contracture. Mantle irradiation did not appear to compromise the prosthetic breast reconstruction. Tissue expander/implant breast reconstruction should remain a viable option in this category of irradiated patients.     

Simulated bone remodeling around tilted dental implants in the anterior maxilla

Dental implants have to be placed with the long axis in different angulations due to the change in bone morphology. The objective of this study was to investigate the different bone remodeling response induced by the tilted dental implants and to assess whether it could lead to bone loss and implant failure. In this study, bone remodeling due to palato-labially inclined dental implants placed in the anterior maxillary incisor region was simulated. CT-based finite element models of a maxillary bone with dental implants were created herein. Five dental implants were placed at \(+10^{\circ }\), \(+5^{\circ }\), \(0^{\circ }\), \(-5^{\circ }\) and \(-10^{\circ }\), respectively. The remodeling progression was recorded and compared. Model \(-10^{\circ }\) (palatal side) shows the highest bone density values, but the inclined implant at \(+10^{\circ }\) (labial side) leads to significant bone loss. From a biomechanical perspective, it is speculated that a palatally inclined implant is more likely to enhance the bone density in the maxillary anterior region, but labial inclination of implant could jeopardize its stability.     

The biomaterial influences the ossification after sinus floor elevation using tissue-engineered bone grafts

Sinus floor elevation is the standard procedure that allows dental implant insertion in the atrophic posterior maxilla. Instead of autogenous bone, tissue-engineered bone grafts can be used, but clear comparative clinical studies also assessing the influence of the biomaterial are missing. In six patients, tissue-engineered bone grafts were used in eight sinus floor elevations. After culturing osteoblast-like cells from biopsies of the maxilla, they were seeded on scaffolds made either from demineralised bovine bone matrix (DBBM) or from solvent-dehydrated mineralised bone (SDBB), and grafted. In all patients primary wound healing was without complications, except for one patient in the SDBB group. After 12 months, implant insertion was possible only in the SDBB group; in the DBBM group, fibrous connective tissue was found in an attempt of implant insertion. After 5 months, implant placement was performed in one patient of each group. However, the two implants inserted in the DBBM group were lost after 6 weeks. Histology of the bone cores in the DBBM group at 5 months showed lamellar bone and osteoid, and at 12 months showed fibrous connective tissue. Inflammation and some resorption of the scaffold was found 5 months after SDBB grafting, and after 12 months cancellous bone formation encapsulating SDBB remnants were observed. These preliminary data suggest that the preparation method of the bovine bone matrix, in particular the mineral content, and therefore the mechanical stability may have some influence on the generation of new bone.     

Stability of dental implants in microvascular osseous transplants

Microvascular iliac crest and scapula transplants have been used in reconstruction of the lower jaw following tumor surgery. It has only been with the insertion of dental implants that a satisfactory prosthetic rehabilitation of the patient has been achieved. For this study, a follow-up of 38 patients with lower jaw tumors was carried out. The patients had been treated with partial resection of the lower jaw and neck dissection with microvascular iliac crest transplants (n = 20) or microvascular scapula transplants (n = 18); this was followed with dental implants (n = 143) in the region of the transplants or the local lower jaw. One hundred thirty-nine of the 143 dental implants were loaded by prosthetic superstructures. In all patients, the implant situation was evaluated on average 2 years 5 months after implantation. Periotest values, periimplant probing depths, and contact bleeding were registered, and the extent of periimplant bone loss was defined radiographically. The clinical situation in the region of the implant was compared for both types of implants and also with the nonresected lower jaw. The average Periotest values were within the normal range for all groups. In one scapula implant, however, a better average of Periotesting, -3.3, was found compared with implants of the iliac crest with Periotest values of -0.7. A measurement of -2.1 was found for the local lower jaw, similar to that of scapula implants. Pathologic probing depths were found for all three compared groups. The radiographically determined vertical loss of bone was the same for all three groups, on average 1 mm at 27 months postoperatively. The highest incidence of sulcus bleeding was found in the scapula implant group. Thus, it can be stated that the scapula transplants provide a similar transplant site to local lower jaw bone, whereas implants in iliac crest transplants show lesser bony stability. Periimplant soft-tissue conditions are worse for both types of transplants compared with local tissue of the lower jaw.     

Prognosis of implant longevity in terms of annual bone loss: a methodological finite element study

Dental implant failure is mainly the consequence of bone loss at peri-implant area. It usually begins in crestal bone. Due to this gradual loss, implants cannot withstand functional force without bone overload, which promotes complementary loss. As a result, implant lifetime is significantly decreased. To estimate implant success prognosis, taking into account 0.2 mm annual bone loss for successful implantation, ultimate occlusal forces for the range of commercial cylindrical implants were determined and changes of the force value for each implant due to gradual bone loss were studied. For this purpose, finite element method was applied and von Mises stresses in implant–bone interface under 118.2 N functional occlusal load were calculated. Geometrical models of mandible segment, which corresponded to Type II bone (Lekholm & Zarb classification), were generated from computed tomography images. The models were analyzed both for completely and partially osseointegrated implants (bone loss simulation). The ultimate value of occlusal load, which generated 100 MPa von Mises stresses in the critical point of adjacent bone, was calculated for each implant. To estimate longevity of implants, ultimate occlusal loads were correlated with an experimentally measured 275 N occlusal load (Mericske-Stern & Zarb). These findings generally provide prediction of dental implants success.     

Saline-filled breast implant safety and efficacy: a multicenter retrospective review

Our center undertook an industry-funded, outcomes-based, multicenter, retrospective review to evaluate the safety and efficacy of saline-filled breast implants. Our review was part of a pre-market approval review process mandated by the U.S. Food and Drug Administration. The design of our review was modeled on a Plastic Surgery Educational Foundation outcomes study previously conducted by our center. For this study, several significant changes were made to our previous protocol, including improved patient tracking, stronger biostatistical support, and a mandatory 10-year minimum patient follow-up period. Physician-reported and patient-reported data on 450 patients with 882 saline-filled breast implants placed between January 1, 1980, and June 30, 1986, were obtained. Mean patient follow-up period was 13.0 years. Most implants (93.9 percent) were placed for breast augmentation. Seventy-four percent were placed in a submammary position; 25.6 percent, subpectorally; and 0.2 percent, subcutaneously. The overall complication rate was 20.2 percent. Reoperation for capsular contracture or implant deflation was necessary in 104 of 450 patients (23.1 percent). Deflation occurred in 73 implants (8.3 percent) and was underreported according to the physicians' record review alone. This deflation rate is higher than the 5.5 percent previously reported by our center. However, 26 of these 73 deflations (35.6 percent) occurred in a single cohort of patients at one center using Surgitek saline implants. If this cohort is excluded, the deflation rate drops to 5.8 percent, a figure more consistent with data published in the literature and found in our previous study. Of the 73 deflations, spontaneous deflation was reported for 50 (74.6 percent), and the remainder were iatrogenic. Actuarial survival of the non-Surgitek implants was 98.4 percent to 99.8 percent at 5 years and 96.9 percent to 98.9 percent at 10 years (95 percent confidence interval). Risk factors for implant deflation included the use of Surgitek saline-filled implants (odds ratio = 17.5, p < 0.01), use of Heyer-Schulte and Mentor model 1800 implants (odds ratio = 3.0, p < 0.01), and implant size greater than 450 cc (odds ratio = 1.01, p < 0.02). Risk factors for capsular contracture included submammary implant position (odds ratio = 2.05, p = 0.03) and implant size greater than 450 cc (odds ratio = 1.01, p < 0.01). Overall, satisfaction was high: 93 percent of patients were "satisfied" or "very satisfied" with their implants. As in our earlier study, risk factors for patient dissatisfaction were reconstruction after mastectomy (odds ratio = 7.6, p = 0.011), significant breast firmness (odds ratio = 6.2, p < 0.001), and patient desire for smaller implants (odds ratio = 3.0, p = 0.020). In conclusion, our review provides additional outcomes-based evidence that saline-filled breast implants remain a safe, effective alternative to silicone gel-filled models.     

Breast cancer after augmentation mammaplasty: treatment by skin-sparing mastectomy and immediate reconstruction

Breast conservation has been associated with poor cosmetic outcome when used to treat breast cancer in patients who have undergone prior augmentation mammaplasty. Radiation therapy of the augmented breast can increase breast fibrosis and capsular contraction. Skin-sparing mastectomy and immediate reconstruction are examined as an alternative treatment.Six patients with prior breast augmentation were treated for breast cancer by skin-sparing mastectomy and immediate reconstruction. One patient underwent a contralateral prophylactic skin-sparing mastectomy. Silicone gel implants had been placed in the submuscular location in five patients and in the subglandular position in one patient a mean of 10.2 years (range, 6 to 20 years) before breast cancer diagnosis. The mean patient age was 41.3 years (range, 33 to 56 years). Four independent judges reviewed postoperative photographs to grade the aesthetic results in comparison with the opposite native or reconstructed breast.The American Joint Committee on Cancer staging was stage 0 in one patient, stage I for four patients, and stage II for one patient. Five of the six patients presented with a palpable breast mass. Latissimus dorsi flap reconstruction was performed in four patients (bilaterally in one) and a transverse rectus abdominis muscle (TRAM) flap was used in two patients. Three patients were treated by skin-sparing mastectomy with preservation of the breast implant (two patients with latissimus flaps, and one patient with a TRAM flap). The tumor location necessitated the removal of implants in two patients (one patient with a latissimus flap and one with a TRAM. A saline implant was placed under the latissimus flap after gel implant removal. The patient who underwent bilateral skin-sparing mastectomies desired explantation and placement of saline implants. No remedial surgery was performed on the opposite breast to achieve symmetry. Complications occurred in two patients at the latissimus dorsi donor site (seroma in one patient, and seroma and infection in one). Five patients underwent complete nipple reconstructions. The mean duration of follow-up was 33.6 months (range, 15.5 to 70.3 months), and there were no recurrences of breast cancer. The aesthetic results were judged to be good to excellent in all cases.Skin-sparing mastectomy and immediate reconstruction can be used in patients with prior breast augmentation, with good to excellent cosmetic results. Depending on the tumor and implant location, the implant may be preserved without compromising local control.     

Aesthetic augmentation of the malar-midface structures

Based on extensive experience with bone grafts for augmentation of the midface-malar region, an implant design has been developed using Proplast. After careful preoperative assessment, a very specific surgical method, described herein, allows precise implant positioning without the need for suture fixation. In many instances, the 6-mm implant can be inserted unchanged. One-hundred and six patients have been operated on using 176 implants over the past 6 years. There were four unilateral infections (2.3 percent of implants and 3.8 percent of patients). None had permanent motor or sensory nerve problems. Fifteen implants (8.5 percent) in 12 patients (11.3 percent) were either removed or repositioned. In those having augmentation for entirely aesthetic reasons, 3 of 60 patients (5.0 percent) required implant removal or repositioning. The incidence of needing to remove or reposition implants has decreased as the technique has evolved.     

Retrospective cephalometric analysis of mandibular bone absorption under silicone rubber chin implants.

A longitudinal study was conducted on 85 patients who received silicone rubber implants to the chin. Over half of these patients were found to have some absorption of the bone beneath the implants, and much other information was obtained. There were no concomitant changes in the soft tissue profile in the patients who demonstrated bone absorption under their implants. It appeared that the bone absorption was less when the implant was placed over the hard bone of the lower part of the mandible, rather than higher or over alveolar bone.