Faculty Bibliography

ABSTRACT: The incidence of postoperative complications in cleft care is low. In this 19-year retrospective analysis of cleft lip and palate patients treated with preoperative nasoalveolar molding, we examine the incidence of postoperative oronasal fistulae. The charts of 178 patients who underwent preoperative nasoalveolar molding by the same orthodontist/prosthodontist team and primary cleft lip/palate repair by the same surgeon over a 19-year period were reviewed. Millard, Mohler, Cutting, or Mulliken-type techniques were used for cleft lip repairs. Oxford-, Bardach-, or von Langenbeck-type techniques were used for cleft palate repairs. One nasolabial fistula occurred after primary cleft lip repair (0.56% incidence) and was repaired surgically. Four palatal fistulae (3 at the junction between soft and hard palate and 1 at the right anterior palate near the incisive foramen) occurred, but 3 healed spontaneously. Only 1 palatal fistula (0.71%) required surgical repair. All 5 fistulae occurred within the first 8 years of the study period, with 4 (80%) of 5 occurring within the first 3 years. Although fistula rate may be related to surgeon experience and the evolution of presurgical techniques, nasoalveolar molding in conjunction with nasal floor closure contributes to a low incidence of oronasal fistulae.

Craniofacial vascularized composite allotransplantation is especially challenging when bony components are required. Matching the complex three-dimensional anatomy of the donor and recipient craniofacial skeletons to optimize bony contact and dental occlusion is a time-consuming step in the operating room. Currently, few tools exist to facilitate this process. The authors describe the development of a virtual planning protocol and patient-specific device design to efficiently match the donor and recipient skeletal elements in craniofacial vascularized composite allotransplantation. The protocol was validated in a cadaveric transplant. This innovative planning method allows a "snap-fit" reconstruction using custom surgical guides while maintaining facial height and width and functional occlusion. Postoperative overlay technology in the virtual environment provides an objective outcome analysis.

Nipple-sparing mastectomy (NSM) as a therapeutic or prophylactic procedure for breast cancer is rapidly gaining popularity as the literature continues to support it safety. The lateral inframammary fold (IMF) approach provides adequate exposure and eliminates visible scars on the anterior surface of the breast, making this incision cosmetically superior to radial or periareolar approaches. We reviewed 55 consecutive NSMs performed through a lateral IMF incision with immediate implant-based reconstruction, with or without tissue expansion, between June 2008 and June 2011. Prior to incision, breasts were lightly infiltrated with dilute anesthetic solution with epinephrine. Sharp dissection, rather than electrocautery, was used as much as possible to minimize thermal injury to the mastectomy flap. When indicated, acellular dermal matrix was placed as an inferolateral sling. Subsequent fat grafting to correct contour deformities was performed in select patients. Three-dimensional (3D) photographs assessed changes in volume, antero-posterior projection, and ptosis. Mean patient age was 46 years, and mean follow-up time was 12 months. Twelve mastectomies (22%) were therapeutic, and the remaining 43 (78%) were prophylactic. Seven of the nine sentinel lymph node biopsies (including one axillary dissection) (78%) were performed through the lateral IMF incision without the need for a counter-incision. Acellular dermal matrix was used in 34 (62%) breasts. Average permanent implant volume was 416 cc (range 176-750 cc), and average fat grafting volume was 86 cc (range 10-177 cc). In one patient a positive intraoperative subareolar biopsy necessitated resection of the nipple-areola complex (NAC), and in two other patients NAC resection was performed at a subsequent procedure based on the final pathology report. Mastectomy flap necrosis, requiring operative debridement, occurred in two breasts (4%), both in the same patient. One of these breasts required a salvage latissimus dorsi myocutaneous flap to complete the reconstruction. Three nipples (6%) required office debridement for partial necrosis and operative reconstruction later. No patient had complete nipple necrosis. No statistically significant differences existed between therapeutic and prophylactic mastectomies for developing partial skin and/or nipple necrosis (p = 0.35). Three episodes (5%) of cellulitis occurred, which responded to antibiotics without the need for explantation. Morphological outcomes using 3D scan measurements showed reconstructed breasts were larger, more projected, and less ptotic than the preoperative breasts (196 versus 248 cc, 80 versus 90 mm, 146 versus 134 mm, p < 0.01 for each parameter). Excellent results can be achieved with immediate implant-based reconstruction of NSM through a lateral IMF incision. NAC survival is reliable, and complication rates are low.

PURPOSE: This study evaluated the reliability and failure modes of anterior implants with internal-hexagon (IH), external-hexagon (EH), or Morse taper (MT) implant-abutment interface designs. The postulated hypothesis was that the different implant-abutment connections would result in different reliability and failure modes when subjected to step-stress accelerated life testing (SSALT) in water. MATERIALS AND METHODS: Sixty-three dental implants (4 x 10 mm) were divided into three groups (n = 21 each) according to connection type: EH, IH, or MT. Commercially pure titanium abutments were screwed to the implants, and standardized maxillary central incisor metallic crowns were cemented and subjected to SSALT in water. The probability of failure versus number of cycles (95% two-sided confidence intervals) was calculated and plotted using a power-law relationship for damage accumulation. Reliability for a mission of 50,000 cycles at 150 N (90% two-sided confidence intervals) was calculated. Polarized-light and scanning electron microscopes were used for failure analyses. RESULTS: The beta values (confidence intervals) derived from use-level probability Weibull calculation were 3.34 (2.22 to 5.00), 1.72 (1.14 to 2.58), and 1.05 (0.60 to 1.83) for groups EH, IH, and MT, respectively, indicating that fatigue was an accelerating factor for all groups. Reliability was significantly different between groups: 99% for MT, 96% for IH, and 31% for EH. Failure modes differed; EH presented abutment screw fracture, IH showed abutment screw and implant fractures, and MT displayed abutment and abutment screw bending or fracture. CONCLUSIONS: The postulated hypothesis that different implant-abutment connections to support anterior single-unit replacements would result in different reliability and failure modes when subjected to SSALT was accepted.

ABSTRACT: Despite significant advances in cleft lip and palate treatment, anatomical controversies remain. Some have proposed that the width of the cleft is due to alveolar segmental displacement. Others suggest that the width is due to palatoalveolar hypoplasia. Improving our understanding of cleft anatomy may have implications for presurgical orthopedics and tissue engineering therapies. Palatoalveolar impressions of 17 noncleft children and 11 children with complete (alveolar, primary, and secondary) unilateral cleft palates were taken. Maxillary tuberosity positions and maxillary volumes were compared. Tuberosity position was determined by facebow transfer of palatoalveolar casts into geodetic datum boxes, and identification of the Cartesian coordinates (x, y, z) of the tuberosities relative to the box surfaces and Frankfurt horizontal. Maxillary volume was determined by immersing the palatoalveolar casts and measuring sand displacement. A significant difference was noted in the average tuberosity to contralateral tuberosity distance between cleft and noncleft cohorts. On average, cleft palate tuberosities were laterally displaced 8.7 mm compared with noncleft palates (P < 0.05). There was neither statistically significant alveolar segment elevation nor retroversion. A significant difference was noted in the average palatoalveolar volumes. The cleft palatoalveolar volume was 5.7 cm, and the noncleft palatoalveolar volume was 7.2 cm (P < 0.05). A palatal cleft is due to both alveolar tissue displacement and deficiency. Therefore, ideal cleft palate care should involve the correction of a displaced and deficient alveolus.

Although the use of zirconia abutments for implant-supported restorations has gained momentum with the increasing demand for esthetics, little informed design rationale has been developed to characterize their fatigue behavior under different clinical scenarios. However, to prevent the zirconia from fracturing, the use of a titanium connection in bi-component aesthetic abutments has been suggested. OBJECTIVE: Mechanical testing of customized thin-walled titanium-zirconia abutments at the connection with the implant was performed in order to characterize the fatigue behavior and the failure modes for straight and angled abutments. MATERIAL AND METHODS: Twenty custom-made bi-component abutments were tested according to ISO 14801:2007 either at a straight or a 25 degrees angle inclination (n=10 each group). Fatigue was conducted at 15 Hz for 5 million cycles in dry conditions at 20 degrees C+/-5 degrees C. Mean values and standard deviations were calculated for each group. All comparisons were performed by t-tests assuming unequal variances. The level of statistical significance was set at p