Platelet-derived growth factor stimulates bone fill and rate of attachment level gain: results of a large multicenter randomized controlled trial

BACKGROUND: Growth factors are generally accepted to be essential mediators of tissue repair via well-established mechanisms of action that include stimulatory effects on angiogenesis and cellular proliferation, ingrowth, differentiation, and matrix biosynthesis. The aim of this study was to evaluate in a large-scale, prospective, blinded, and randomized controlled clinical trial the safety and effectiveness of purified recombinant human platelet-derived growth factor (rhPDGF-BB) mixed with a synthetic beta-tricalcium phosphate (beta-TCP) matrix for the treatment of advanced periodontal osseous defects at 6 months of healing. METHODS: Eleven clinical centers enrolled 180 subjects, each requiring surgical treatment of a 4 mm or greater intrabony periodontal defect and meeting all inclusion and exclusion criteria. Subjects were randomized into one of three treatment groups: 1) beta-TCP + 0.3 mg/ml rhPDGF-BB in buffer; 2) beta-TCP + 1.0 mg/ml rhPDGF-BB in buffer; and 3) beta-TCP + buffer (active control). Safety data were assessed by the frequency and severity of adverse events. Effectiveness measurements included clinical attachment levels (CAL) and gingival recession (GR) measured clinically and linear bone growth (LBG) and percent bone fill (% BF) as assessed radiographically by an independent centralized radiology review center. The area under the curve (AUC), an assessment of the rate of healing, was also calculated for CAL measurements. The surgeons, clinical and radiographic evaluators, patients, and study sponsor were all masked with respect to treatment groups. RESULTS: CAL gain was significantly greater at 3 months for group 1 (rhPDGF 0.3 mg/ml) compared to group 3 (beta-TCP + buffer) (3.8 versus 3.3 mm; P = 0.032), although by 6 months, this finding was not statistically significant (P = 0.11). This early acceleration of CAL gain led to group 1 exhibiting a significantly greater rate of CAL gain between baseline and 6 months than group 3 as assessed by the AUC (68.4- versus 60.1-mm weeks; P = 0.033). rhPDGF (0.3 mg/ml)-treated sites also had significantly greater linear bone gain (2.6 versus 0.9 mm, respectively; P < 0.001) and percent defect fill (57% versus 18%, respectively; P < 0.001) than the sites receiving the bone substitute with buffer at 6 months. There was less GR at 3 months in group 1 compared to group 3 (P = 0.04); at 6 months, GR for group 1 remained unchanged, whereas there was a slight gain in gingival height for group 3 resulting in comparable GR. There were no serious adverse events attributable to any of the treatments. CONCLUSIONS: To our knowledge, this study is the largest prospective, randomized, triple-blinded, and controlled pivotal clinical trial reported to date assessing a putative periodontal regenerative and wound healing therapy. The study demonstrated that the use of rhPDGF-BB was safe and effective in the treatment of periodontal osseous defects. Treatment with rhPDGF-BB stimulated a significant increase in the rate of CAL gain, reduced gingival recession at 3 months post-surgery, and improved bone fill as compared to a beta-TCP bone substitute at 6 months.     

Bone formation after sinus augmentation with engineered bone

Objectives: The aim of the following investigation was to quantify the resorption rate of tissue-engineered bone grafts in the maxillary sinus using volume measurements. MATERIAL AND METHODS: Sinus floor augmentation using autologous bone grafts from the iliac crest (n=17, group 1) was compared with commercially produced transplants of human cells seeded on polyglycolid-polylactid (PLGA) scaffolds (Oral Bone) (n=14, group 2). RESULTS: The total resorption rate for autologous transplants 3 months post operation was 29%, while the tissue-engineered bone showed a resorption rate of 90%. The autologous bone had a bone density of up to 266-551 Hounsfield units (HU), while sufficient mineralization of tissue-engineered bone was found in only one case (152 HU). CONCLUSION: In this clinical study, the use of autologous cancellous bone grafts in sinus augmentation was more reliable than scaffolds containing cultured osteoblasts. Further tissue-engineered bone transplants should be examined to draw general conclusions about the use of tissue-engineered grafts compared with autologous bone grafts for maxillary sinus augmentation.     

Early intervention surveillance strategies (EISS) in dental student clinical performance: a mathematical approach

Graduating dental practitioners requires the mastery of a number of skills and a significant body of basic information. Dental education is a complex combination of didactic and physical skill learning processes. It is necessary to develop appropriate tools to measure student clinical performance to allow the provision of interventional strategies at the right time targeted at the right individuals. In this study, an approach to early intervention surveillance strategies was developed that is cost-effective, transparent, and robust based on mathematical predictions of student clinical achievements. Using a cohort of students' clinical activity profile, a polynomial pair was developed that represents the predictive function of low and high achieving students. This polynomial pair can then be applied to students to predict their final achievement based on their current status. The polynomial methodology is adaptable to local variation such as access to clinical facilities. The early intervention surveillance strategy developed in this study provides a simple, cost-effective, predictive risk assessment system that relies on data sets already collected in most dental schools and can be completed without the need for significant human intervention. The mathematical approach allows the focusing of educational support towards students that require the assistance, thus augmenting the better use of resources.     

Capacity for training in clinical research: status and opportunities

The ability to base patient care on scientific evidence depends in part on the results of translational and applied research. The shortage of trained clinical researchers identified by several sources limits the availability of clinical research studies upon which to base evidence-based therapeutics. This premise suggests that the dental profession needs to train more clinical researchers and faculty to conduct clinical research and to teach its applications to practice. Increasing opportunities for clinical research training in a variety of settings should eventually increase the numbers of clinical researchers, raise faculty involvement in clinical research, and promote science transfer. This paper reports on the current status of clinical research in dental schools, specifies the diverse groups involved in the clinical research enterprise, and identifies underutilized opportunities and partnerships for clinical research training. Data on federal and nonfederal funding of clinical research and training programs are presented. Existing and novel mechanisms for expanding clinical research training throughout and across traditional as well as unconventional environments are explored.     

Mucosal malignant melanomas in head and neck surgery: a retrospective study of six patients and review of the literature

Introduction

Of all malignant processes of the oral mucosa, 0.5% are malignant melanomas. Because of late diagnosis, pattern of growth, close proximity to the bone (particularly in palatinal localizations), and the correlated infiltration, malignant melanomas have a bad prognosis.

Patients and methods

In this retrospective study, six cases of patients with oral mucosal malignant melanoma are evaluated, and a critical review of the literature is presented. The female to male proportion was 1:1 with an average age of 60.2 years; all patients were treated between January 1999 and July 2007. A neck dissection was performed on two patients because of clinically positive lymph nodes; one patient received interleukin 2 therapy, and three patients received postoperative radiotherapy. Two male patients died.

Conclusions

We recommend biopsy on every growing lesion, pigmented or nonpigmented, for the required diagnosis and, in cases of malignant melanoma, wide excision as a second step. Neck dissections should be performed in patients with clinically positive lymph nodes. Concerning interleukin 2 therapy, further studies should be performed in order to evaluate a routine application.     

A 0.05% cetyl pyridinium chloride/0.05% chlorhexidine mouth rinse during maintenance phase after initial periodontal therapy

BACKGROUND: Chlorhexidine (CHX) mouth rinse/spray can still be considered the gold standard in the chemical prevention of plaque formation and development of gingivitis. The product unfortunately has some side effects, such as extrinsic tooth staining, poor taste, taste disturbance, sensitivity changes in tongue, pain and irritation because of the alcohol content. These side effects led to the search of new formulations. METHODS: In this double-blind, randomized, long-term, parallel study, 48 moderate periodontitis patients rinsed for 6 months (starting immediately after a "one-stage, full-mouth" disinfection) with one of the following products: CHX 0.2%+alcohol (Corsodyl), CHX 0.05%+ cetyl pyridinium chloride (CPC) 0.05% and no alcohol (Perio-Aid Maintenance, a new formulation), or the placebo of the latter. After 1, 3 and 6 months a series of clinical and microbiological parameters were recorded for the supra- and subgingival area as well as for saliva. RESULTS: Although there was a significant treatment impact (mechanical debridement) in all groups, both CHX solutions further decreased both plaque and gingivitis indices (p<0.001 and p<0.05, respectively), when compared with placebo. This was also reflected by additional reductions in the number of CFU/ml of aerobic and especially anaerobic species and by a suppression of Streptococcus mutans (versus an overgrowth for the placebo), in all niches. Differences between both CHX solutions were never encountered. The subjective ratings were slightly in favour of the new CHX-CPC formulation when compared with the other CHX-alcohol formulation, especially for taste of the product (p<0.05), but less impressive for the staining of teeth and tongue. CONCLUSIONS: The results of this study demonstrated the potential of a new CHX 0.05%+CPC 0.05% non-alcoholic formulation as an effective antiplaque agent for long-term use with reduced subjective side effects.     

Augmentation of faciolingual gingival dimensions with free connective tissue grafts before labial orthodontic tooth movement: an experimental study with a canine model.

PURPOSE: The aim of this study was to determine in an animal model whether any increase in gingival thickness after placement of free connective tissue autografts is maintained after labial orthodontic tooth movement. MATERIAL: In a split-mouth technique, the maxillary second and third incisors of 4 adult greyhounds were used as experimental, control, and sham-control teeth. The experimental teeth underwent gingival augmentation surgery. Two to 3 months later, the teeth were moved with a bonded orthodontic appliance over 2 to 3 months. Baseline and 2-month retention clinical measurements of gingival height were taken before the animals were killed. Histometric measurements recorded the free gingival height and the gingival thickness at 5 graduated levels down the teeth. RESULTS: Clinical measurements of changes in gingival margin position revealed a mean coronal shift of 0.44 mm over grafted teeth, with 50% of nongrafted teeth and 100% of the sham-control teeth experiencing small amounts of gingival recession. The histometric results showed that gingival thickness measurements for the grafted teeth were, on average, between 0.13 and 0.18 mm thicker at all levels of measurement than for the nongrafted teeth (P < .01). CONCLUSIONS: Free connective tissue grafts placed on the labial aspect of incisors might help prevent the faciolingual thinning of the gingival tissues that can occur as a result of labial orthodontic tooth movement. Further research is required to confirm these results in a larger sample and determine the long-term benefits of preorthodontic gingival augmentation to prevent gingival recession.     

Evolución del cierre de ileostomía en una unidad de cirugía colorrectal. Análisis comparativo según la técnica

Introduction

The objective of this study is to assess whether the results of loop ileostomy closure in terms of morbidity and hospital stay are influenced by the type of anastomosis and suture used.

Method

All patients who underwent loop ileostomy closure were reviewed. A retrospective cohort study comparing morbidity and hospital stay according to the type of anastomosis (TT/LL) and the type of suture (hand sewn/mechanical) was performed.

Results

From January 2003 to November 2011 a total of 167 loop ileostomy closures were analized. The groups were: type of anastomosis (TT 95/LL 72) and type of suture (manual 105/stapled 62). In 76% of the observed population the underlying disease was cancer. Mortality occurred in one case. The stratified morbidity analysis by type of complications showed no significant differences between the groups in terms of local (7.4% TT, LL 8.3%, 6.7% hand sewn, stapled 9.7%), general (TT 9.5%, 16.7% LL, hand sewn 6.7%, 6.5% stapled) and surgical (TT 15.8%, 19.4% LL, hand sewn 17.1%, 17.7% stapled) complications, nor in the rate of reoperations (TT 6.3%, 6.9% LL, hand sewn 6.7%, 6.5% stapled) and hospital stay in days (TT 7.8, 8 LL, hand sewn 8.6, stapled 6.7)

Conclusions

Closure of loop ileostomy can be performed regardless of the type of suture or anastomosis used, with the same rate of morbidity and hospital stay.