Faculty Bibliography

BACKGROUND:Successful osseointegration of endosteal dental implants has been attributed to implant design, including the macro-, micro- and nano- geometric properties. Based on current literature pertaining to implant design, the resultant cellular and bone healing response is unknown when the thread thickness of the implants is increased, resulting in an increased contact area in implants designed with healing chambers. The aim of this study was to evaluate the effect of two implant designs with different thread profiles on the osseointegration parameters and implant stability at 3- and 6-weeks in vivo using a well-established preclinical dog model. MATERIAL AND METHODS/METHODS:A total of 48 type V Ti alloy implants were divided in two groups according to their thread design (D1= +0.1x/mm and D2= +0.15x/mm) and placed in an interpolated fashion into the radii of six beagles. Insertion torque was measured at time of placement, radii were extracted for histological processing following 3- and 6-week healing intervals. Histologic and histomorphometric analyses were performed in terms of bone to implant contact (%BIC) and bone area fraction occupancy within implant threads (%BAFO). Statistical analyses were performed through a linear mixed model with fixed factors of time and implant thread design. RESULTS:Surface roughness analysis demonstrated no significant differences in Sa and Sq between D1 and D2 implant designs, which confirmed that both implant designs were homogenous except for their respective thread profiles. For insertion torque, statistically significant lower values were recorded for D1 in comparison to D2 (59.6 ± 11.1 and 78.9 ± 10.1 N⋅cm, respectively). Furthermore, there were no significant differences with respect to histological analysis and histomorphometric parameters, between D1 and D2 at both time points. CONCLUSIONS:Both thread profiles presented equivalent potential to successfully osseointegrate in the osteotomies, with D2 yielding higher mechanical retention upon placement without detrimental bone resorption.

PURPOSE/OBJECTIVE:To evaluate the effect of short curing time using a high-radiant emittance light on polymerization shrinkage vectors in different consistency bulk-fill composites (BFRCs) using micro-computed tomography. METHODS AND MATERIALS/METHODS:Radiopaque zirconia fillers were homogeneously incorporated and functioned as radiopaque tracers into two regular-paste: TBFill (Tetric EvoCeram Bulk Fill) and TPFill (Tetric PowerFill), and two flowable (n=6): TBFlow (Tetric EvoFlow Bulk Fill) and TPFlow (Tetric PowerFlow) resin composites. Class I cavities (4 mm depth × 4 mm length × 4 mm width) were 3D-printed and filled in a single increment: TBFill and TBFlow were light-activated using a Bluephase Style 20i (10 seconds in high-mode); TPFill and TPFlow were light-activated using a Bluephase PowerCure (three seconds). The same adhesive system (Adhese Universal) was used for all groups. Microcomputed tomography scans were obtained before and after light-activation. Filler particle movement was identified by polymerization shrinkage vectors at five depths (from 0-4 mm): top, top-middle, middle, middle-bottom and bottom. RESULTS:TPFlow showed the lowest total vector displacement, followed by TBFlow, TBFill and TPFill, significantly different among each other (p<0.05). Generally, BFRCs showed decreased vector displacement with increased depth, and higher displacement at the top-surface (p<0.05). Qualitative analysis showed a similar pattern of vector magnitude and displacement for groups TBFill and TPFill, with displacement vectors on occlusal (top) surfaces toward the center of the restoration from the top to middle areas, and relatively limited displacement at the bottom. TBFlow and TPFlow showed more displacement on the occlusal (top). CONCLUSIONS:Short curing time with high-radiant emittance on fast-curing BFRCs was shown to be a feasible option in terms of vector displacement. Flowable BFRCs presented lower vector displacement than their regular-viscosity versions.

Sphenoorbital meningiomas are a challenge to access and reconstruct. Although there is much neurosurgical literature on resection of such tumors, there is little discussion on the best methods for the reconstruction of consequent defects, which are often extensive due to large areas of hyperostosis requiring resection. We performed a retrospective analysis of patients who underwent resection and reconstruction of a sphenoorbital meningioma by the senior authors (C.S. and D.A.S.) between 2010 and 2020. Surgical access in all cases included an orbitozygomatic osteotomy. The study cohort consisted of 23 patients (20 female, 3 male) with an average age of 50 (range: 37-72) years at the time of surgery. Most patients had progressive proptosis before the ablative operation. Orbital reconstruction was with a combined titanium-Medpor implant in 18 patients, split calvarial bone graft in 3 patients, and a Medpor implant in 2 patients. Calvarial reconstruction was performed with titanium mesh in 21 patients, split calvarial bone graft and titanium mesh in 1 patient, and craniotomy bone and titanium plate in 1 patient. Reoperation was required in 7 patients due to hypoglobus or enophthalmos (N=2), orbital implant malposition (N=1), abscess (N=1), pain (N=1), intracranial fat graft modification (N=1), and soft tissue deformities (N=2). Our experience demonstrates that sphenoorbital meningiomas can require broad areas of resection of the skull base and calvarium and necessitate comprehensive reconstruction of the anterior cranial fossa, orbital walls, and cranium. Collaboration between craniofacial surgeons and neurosurgeons can achieve optimal results.

Agnathia-otocephaly complex (AOC), a first branchial arch defect, is characterized by mandibular hypoplasia or aplasia, ear abnormalities, microstomia, and macroglossia and is a rare and often fatal diagnosis. Herein, the technical considerations and details of mandibular reconstruction using virtual surgical planning (VSP) and a vascularized free fibula flap for further mandibular reconstruction in a 10-year-old boy are presented. The patient's preoperative examination was consistent with agnathia (absence of mandibular symphysis, bilateral mandibular bodies, condyles, coronoids, rami, and temporomandibular joint), severe microstomia, and a Tessier # 30 cleft (maintained to allow oral access until later in treatment). Virtual surgical planning was utilized to plan a 3-segment fibula for the reconstruction of the mandibular symphysis and bilateral body segments, and bilateral costochondral grafts were planned for the rami. To the authors' knowledge, this represents the first application of virtual surgical planning for mandibular reconstruction with a vascularized free fibula flap in a pediatric patient with severe agnathia-otocephaly complex.

Lambdoid craniosynostosis (CS) is a congenital anomaly resulting from premature fusion of the cranial suture between the parietal and occipital bones. Predominantly sporadic, it is the rarest form of CS and its genetic etiology is largely unexplored. Exome sequencing of 25 kindreds, including 18 parent-offspring trios with sporadic lambdoid CS, revealed a marked excess of damaging (predominantly missense) de novo mutations that account for ~ 40% of sporadic cases. These mutations clustered in the BMP signaling cascade (P = 1.6 × 10^-7), including mutations in genes encoding BMP receptors (ACVRL1 and ACVR2A), transcription factors (SOX11, FOXO1) and a transcriptional co-repressor (IFRD1), none of which have been implicated in other forms of CS. These missense mutations are at residues critical for substrate or target sequence recognition and many are inferred to cause genetic gain-of-function. Additionally, mutations in transcription factor NFIX were implicated in syndromic craniosynostosis affecting diverse sutures. Single cell RNA sequencing analysis of the mouse lambdoid suture identified enrichment of mutations in osteoblast precursors (P = 1.6 × 10^-6), implicating perturbations in the balance between proliferation and differentiation of osteoprogenitor cells in lambdoid CS. The results contribute to the growing knowledge of the genetics of CS, have implications for genetic counseling, and further elucidate the molecular etiology of premature suture fusion.

INTRODUCTION/BACKGROUND:Simultaneous Le Fort III/I (LF III/I) osteotomies are often performed when a differential advancement of the upper and lower midface is needed. This study aims to evaluate midface position preoperative and 1 week postoperative in patients with severe midface hypoplasia. In addition, this study aims to compare the planned surgical movements to the actual postoperative movements. MATERIALS AND METHODS/METHODS:A retrospective review was conducted using cephalometry for patients treated with a simultaneous LF III/I osteotomy at a single institution. Osteotomies were performed during 1980-2018 on skeletally mature patients with a craniofacial syndrome, with clinical and radiographic follow-up available. RESULTS:Twelve patients met the inclusion criteria with a mean age of 20.2±6.4 years. Treatment resulted in statistically significant anterior movements related to Orbitale, anterior nasal spine, A Point, and the upper incisor tip, and inferior movements related to anterior nasal spine, A Point, upper and lower incisor tips, B point, and pogonion. Stability after 1 year showed only statistically significant changes at ANB. The predictable error for planned movements versus actual movements was greater in the vertical plane than the horizontal plane. CONCLUSIONS:A simultaneous LF III/I osteotomy significantly improved the midface position and occlusal relationship in syndromic patients with midface hypoplasia in a predictable manner. Further multicenter studies with larger sample sizes are needed to validate the conclusions.

BACKGROUND/PURPOSE/OBJECTIVE:This paper describes the changes in maxillary arch morphology in infants with bilateral cleft lip and palate (BCLP) following nasoalveolar molding (NAM) and with follow up to assess the need for secondary alveolar bone grafting (ABG) and premaxillary repositioning surgery at preadolescence. METHODS/DESCRIPTION/UNASSIGNED:Treatment records of infants with BCLP treated with NAM between 2003 and 2013 were reviewed. Patients with complete BCLP who underwent NAM and had complete sets of maxillary casts at T 0 pre-NAM (mean = 27 days), T 1 post-NAM (mean = 6 months and 5 days), and T 2 before palate surgery (mean = 11 months and 15 days) were included. The sample comprised 23 infants (18 male, 5 female). Casts were digitized and analyzed using three dimensional software. The need for secondary ABG and premaxillary repositioning surgery was assessed at preadolescent follow-up (mean = 8.3 years). RESULTS:Cleft width was reduced on average by 4.73 mm (SD ± 3.15 mm) and 6.56 mm (SD ± 4.65) on the right and left sides, respectively. At T 1, 13 (56.52%) patients underwent bilateral gingivoperiosteoplasty (GPP), 8 (34.78%) patients unilateral GPP, and 2 patients (8.7%) did not undergo GPP. 34/46 clefts sites (73.91%) underwent GPP while 12 (26.08%) did not. At preadolescent follow-up of 19 patients, 7 patients (36.84%) did not need ABG on either side, 8 (42.10%) needed ABG on 1 side, and 4 (21.05%) needed ABG on both sides. None of the patients needed premaxillary repositioning surgery. CONCLUSIONS:Nasoalveolar molding treatment significantly improves the position of the premaxilla before primary repair, and there is a significant reduction in the need for secondary ABG and premaxillary repositioning surgery at preadolescence.

The calvaria (top part of the skull) is made of pieces of bone as well as multiple soft tissue joints called sutures. The latter is crucial to the growth and morphogenesis of the skull, and thus a loss of calvarial sutures can lead to severe congenital defects in humans. During embryogenesis, the calvaria develops from the cranial mesenchyme covering the brain, which contains cells originating from the neural crest and the mesoderm. While the mechanism that patterns the cranial mesenchyme into bone and sutures is not well understood, function of Lmx1b, a gene encoding a LIM-domain homeodomain transcription factor, plays a key role in this process. In the current study, we investigated a difference in the function of Lmx1b in different parts of the calvaria using neural crest-specific and mesoderm-specific Lmx1b mutants. We found that Lmx1b was obligatory for development of the interfrontal suture and the anterior fontanel along the dorsal midline of the skull, but not for the posterior fontanel over the midbrain. Also, Lmx1b mutation in the neural crest-derived mesenchyme, but not the mesoderm-derived mesenchyme, had a non-cell autonomous effect on coronal suture development. Furthermore, overexpression of Lmx1b in the neural crest lineage had different effects on the position of the coronal suture on the apical part and the basal part. Other unexpected phenotypes of Lmx1b mutants led to an additional finding that the coronal suture and the sagittal suture are of dual embryonic origin. Together, our data reveal a remarkable level of regional specificity in regulation of calvarial development.