Faculty Bibliography

BACKGROUND: Robin sequence (RS) is defined as a triad of retrognathia, glossoptosis, and airway obstruction. Although several studies have reported on the efficacy of mandibular distraction, the risks associated with this operation remain unclear. An outcomes analysis focusing on complications is reported here. METHODS: A 7-year retrospective review of all patients with RS treated with mandibular distraction was performed. Recorded variables included associated medical comorbidities, improvement in apnea/hypopnea index, need for tracheostomy, repeat distraction, and complications. Complications associated with mandibular distraction were categorized as major, moderate, or minor. They included surgical site infection (SSI), device failure, temporomandibular joint ankylosis, facial nerve injury, hypertrophic scarring, self-extubation premature ossification, and fibrous nonunion. RESULTS: Fifty patients were identified. Four patients (8%) required tracheostomy following distraction, and 3 required repeat distraction. There were 0% major, 12% moderate, and 18% minor complications. Moderate complications were device failure (2%), SSI requiring return to the operating room (2%), and SSI requiring intravenous antibiotics (8%). Minor complications were SSI managed with oral antibiotics (12%), self-extubation (4%), and transient facial nerve palsy (2%). The most common complication was SSI (22%), of which 90.9% were successfully treated by antibiotics alone. There was a 0% rate of temporomandibular joint ankylosis. CONCLUSIONS: Mandibular distraction is a safe and effective treatment option for infants with RS and severe airway obstruction. The most common complication is infection; the majority of cases are successfully treated with antibiotics alone.

Bacterial biofilms have emerged as potential critical triggers in the pathogenesis of bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) or BRONJ. BRONJ lesions have shown to be heavily colonized by oral bacteria, most of these difficult to cultivate and presents many clinical challenges. The purpose of this study was to characterize the bacterial diversity in BRONJ lesions and to determine host immune response. We examined tissue specimens from three cohorts (n=30); patients with periodontal disease without a history of BP therapy (Control, n=10), patients with periodontal disease having history of BP therapy but without ONJ (BP, n=5) and patients with BRONJ (BRONJ, n=15). Denaturing gradient gel electrophoresis of polymerase chain reaction (PCR)-amplified 16S rRNA gene fragments revealed less bacterial diversity in BRONJ than BP and Control cohorts. Sequence analysis detected six phyla with predominant affiliation to Firmicutes in BRONJ (71.6%), BP (70.3%) and Control (59.1%). Significant differences (P<0.05) in genera were observed, between Control/BP, Control/BRONJ and BP/BRONJ cohorts. Enzyme-linked immunosorbent assay (ELISA) results indicated that the levels of myeloperoxidase were significantly lower, whereas interleukin-6 and tumor necrosis factor-alpha levels were moderately elevated in BRONJ patients as compared to Controls. PCR array showed significant changes in BRONJ patients with downregulation of host genes, such as nucleotide-binding oligomerization domain containing protein 2, and cathepsin G, the key modulators for antibacterial response and upregulation of secretory leukocyte protease inhibitor, proteinase 3 and conserved helix-loop-helix ubiquitous kinase. The results suggest that colonization of unique bacterial communities coupled with deficient innate immune response is likely to impact the pathogenesis of ONJ.International Journal of Oral Science advance online publication, 8 August 2014; doi:10.1038/ijos.2014.46.

BACKGROUND: Reconstruction in the setting of prior breast irradiation is conventionally considered a higher-risk procedure. Limited data exist regarding nipple-sparing mastectomy in irradiated breasts, a higher-risk procedure in higher-risk patients. METHODS: The authors identified and reviewed the records of 501 nipple-sparing mastectomy breasts at their institution from 2006 to 2013. RESULTS: Of 501 nipple-sparing mastectomy breasts, 26 were irradiated. The average time between radiation and mastectomy was 12 years. Reconstruction methods in the 26 breasts included tissue expander (n = 14), microvascular free flap (n = 8), direct implant (n = 2), latissimus dorsi flap with implant (n = 1), and rotational perforator flap (n = 1). Rate of return to the operating room for mastectomy flap necrosis was 11.5 percent (three of 26). Nipple-areola complex complications included one complete necrosis (3.8 percent) and one partial necrosis (3.8 percent). Complications were compared between this subset of previously irradiated patients and the larger nipple-sparing mastectomy cohort. There was no significant difference in body mass index, but the irradiated group was significantly older (51 years versus 47.2 years; p = 0.05). There was no statistically significant difference with regard to mastectomy flap necrosis (p = 0.46), partial nipple-areola complex necrosis (p = 1.00), complete nipple-areola complex necrosis (p = 0.47), implant explantation (p = 0.06), hematoma (p = 1.00), seroma (p = 1.00), or capsular contracture (p = 1.00). CONCLUSION: In the largest study to date of nipple-sparing mastectomy in irradiated breasts, the authors demonstrate that implant-based and autologous reconstruction can be performed with complications comparable to those of the rest of their nipple-sparing mastectomy patients.

AIMS: It has been accepted that bone damage and subsequent resorption occurs in cases of adverse interfacial bone strain. Fractured implants represents an important opportunity for evaluating the bone response to overstrain. The objective of the study was to analyze the bone morphology and morphometry around retrieved fractured implants in humans. Five fractured implants retrieved after 22.4 (+/- 2.8) years were used in the present study. The investigation was conducted in a transmitted brightfield and circularly polarized light Microscope. The parameters considered were the total bone area, total bone remodeling area, bone-remodeling rate (BRR), and bone transverse collagen fibers orientation (CFO). FINDINGS: For grouped samples, the BRR was 51.9% (+/- 10) while the transverse CFO was 13.0% (+/- 9.7). The interthread BRR was 58.1% (+/- 4.0) for level 1 and 40.4% (+/- 12.8) for level 2 with a significant decrease in BRR (p = 0.019) as a function of depth along the implant length. CONCLUSIONS: Both bone level and bone quality attains stability to a certain level with respect to implant neck fracture following physiologic interaction between mechanical and biological inputs. The BRR significantly decrease as function of threads depth. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1342-1352, 2014.

Several histologic studies regarding peri-implant soft tissues and biological width around dental implants have been done in animals. However, these findings in human peri-implant soft tissues are very scarce. Therefore, the aim of this case series was to compare the biological width around unloaded one- and two-piece implants retrieved from human jaws. Eight partially edentulous patients received 2 test implants in the posterior mandible: one-piece (solid implants that comprise implant and abutment in one piece) and two-piece (external hexagon with a healing abutment) implants. After 4 months of healing, the implants and surrounding tissue were removed for histologic analysis. The retrieved implants showed healthy peri-implant bone and exhibited early stages of maturation. Marginal bone loss, gaps, and fibrous tissue were not present around retrieved specimens. The biologic width dimension ranged between 2.55 +/- 0.16 and 3.26 +/- 0.15 to one- and two-piece implants, respectively (P < 0.05). This difference was influenced by the connective tissue attachment, while sulcus depth and epithelial junction presented the same dimension for both groups (P > 0.05). Within the limits of this study, it could be shown that two-piece implants resulted in the thickening of the connective tissue attachment, resulting in the increase of the biological width, when compared to one-piece implants.

Purpose: This study aimed to evaluate the survival probability of four narrow-diameter implant systems when subjected to fatigue loading. Materials and Methods: Seventy-two narrow-diameter implants to be restored with single-unit crowns were divided into four groups (n = 18): Astra Tech (3.5-mm diameter), with a standard connection (ASC); BioHorizon (3.4-mm diameter), with a standard connection (BSC); Intra-Lock (3.4-mm diameter), with a standard multilobular connection (ISC); and Intra-Lock (3.4-mm diameter), with a modified square connection (IMC). The corresponding abutments were screwed onto the implants, and standardized metal crowns (maxillary central incisors) were cemented and subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and reliability for 100,000 cycles at 150 and 200 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used to access the failure modes. Results: The calculated survival probability for 100,000 cycles at 150 N was approximately 93% in group ASC, 98% in group BSC, 94% in group ISC, and 99% in group IMC. At 200 N, the survival rate was estimated to be approximately < 0.1% for ASC, 77% for BSC, 34% for ISC, and 93% for IMC. Abutment screw fracture was the main failure mode for all groups. Conclusions: Although the probability of survival was not significantly different among systems at a load of 150 N, a significant decrease was observed at 200 N for all groups except IMC.