Custom made onlay implants in peek in maxillofacial surgery: a volumetric study

PURPOSE

Facially malformed patients often present a variable degree of facial imbalance even after basal bone correction, and resolution of the residual hard- and soft-tissue deficiencies and asymmetries of the face are of great importance for achieving a satisfactory post-implant procedure result. The use of polyether ether ketone (PEEK) implants for maxillofacial reconstruction has been documented in the literature, but the number of patients who have received them is limited. The aim of this study was to evaluate the overall volumetric results in patients with facial imbalance after onlay custom implant positioning for mandible and fronto-orbital reconstructions. Analysis was performed by confronting volumes with the use of three-dimensional (3D) photogrammetry.

METHODS

Fifteen patients were eligible for PEEK implant placements, eight for mandibular angle reconstruction, and seven for fronto-orbital reconstruction. Pre- and post-surgical 3D images of each patient's face were acquired. Facial asymmetry was analyzed by comparing each face with its mirrored copy.

RESULTS

Three-dimensional analyses have shown that some degree of volume imbalance was still present in the patients with only 1.32 ± 1.02 mm residual discrepancy after treatment.

CONCLUSION

Results of the study were found to fall within clinically acceptable limits since an asymmetry rate of < 3 mm is considered to fall into the norm.

Osteoperiosteal free fibula flap as an effective preprosthetic reconstructive option in severe jaw atrophy and oncological resection

The gold standard in modern surgical treatment of patients with severe maxillo-mandibular atrophy must include the aim to achieve restoration of function and aesthetics with immediate reconstruction of the oro-mandibular defects. The medical records of 14 patients who were treated in a 5-year period (2010-2014) at our department with severe maxillary and mandibular atrophy, and reconstructed by vascularised free fibula flap were reviewed. Among the former, a total of 14 patients underwent maxillary and mandibular reconstruction using the osteoperiosteal fibula free flap. No major complications were reported. The main advantage of this technique is that it allows the formation of keratinised gengiva, which provides the best implantological options. The only disadvantage of the technique is that the wounds have to heal for second intention, and for this reason patients have to undergo strict follow-up for the first months after the operation. The aim of this article is to evaluate the efficiency of the technique in bone reconstruction after jaw resection or severe atrophy.

Risks in surgery-first orthognathic approach: complications of segmental osteotomies of the jaws. A systematic review

OBJECTIVE

To date, no systematic review has been undertaken to identify the complications of segmental osteotomies. The aim of the present systematic review was to analyze the type and incidence of complications of segmental osteotomies, as well as the time of subjective and/or clinical onset of the intra- and post-operative problems.

MATERIALS AND METHODS

A search was conducted in two electronic databases (MEDLINE - Pubmed database and Scopus) for articles published in English between 1 January 2000 and 30 August 2015; only human studies were selected. Case report studies were excluded. Two independent researchers selected the studies and extracted the data. Two studies were selected, four additional publications were recovered from the bibliography search of the selected articles, and one additional article was added through a manual search.

RESULTS

The results of this systematic review demonstrate a relatively low rate of complications in segmental osteotomies, suggesting this surgical approach is safe and reliable in routine orthognathic surgery.

CONCLUSIONS

Due to the small number of studies included in this systematic review, the rate of complication related to surgery first approach may be slightly higher than those associated with traditional orthognathic surgery, since the rate of complications of segmental osteotomies must be added to the complication rate of basal osteotomies. A surgery-first approach could be considered riskier than a traditional one, but further studies that include a greater number of subjects should be conducted to confirm these findings.

Lipofilling as refinement procedure in maxillo-mandibular malformations

Maxillo-mandibular asymmetry has numerous aetiologies: congenital, traumatic, iatrogenic and post-oncologic. Patients with congenital dentofacial malformations are generally submitted to orthognathic surgery and/or additional procedures (genioplasty, alloplastic implants) with satisfactory results. However, despite achieving skeletal symmetry, noticeable facial asymmetry may persist.This study was performed in 45 patients (29 women and 16 men) operated between December 2012 and June 2014. All patients were affected by maxilla-mandibular asymmetry and underwent orthognatic surgery for hard tissue correction of the deformity. Residual facial alterations were then treated with lipofilling refinement proceure. In all cases good integration of the grafted fat was observed in the recipient sites. Retrospective analysis of photographic documentation showed progressive volumetric decrease for up to approximately 6 months after surgery; after that graft volume remained relatively stable. There were no significant surgical complications, either from the fat harvest site or the reconstructed site. Mild oedema and bruising were frequent during the first post-operative week. No haematomas, infections, vascular or nervous injuries were recorded. Twenty-four patients felt the need to have a second procedure. A second fat transfer was performed in 22 cases, and a third in 2 (total of 69 procedures). Based on the observations of our study, fat grafting is a simple, effective and reproducible technique, with a high satisfaction rate and few disadvantages or complications. We demonstrated that the success of lipofilling is dependent on the treated aesthetic subunits of the face. The malar and lateral cheek regions seem to be highly favourable for fat grafting, unlike the upper and lower lips subunits. Composite procedures using orthognathic surgery and autologous fat provide the surgeon with an additional, more customisable option for patients with maxillo-mandibular malformations.

One-pot reaction to obtain N,N'-disubstituted guanidines of pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine scaffold as human A3 adenosine receptor antagonists

In this paper we describe an extension SAR study of pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine nucleus as A3AR antagonist. Our initial aim was to replace the phenylcarbamoyl moiety at the 5 position of PTP nucleus with a thiourea functionality to evaluate the contribution of new structural modification against the A3AR. The synthesized 12-25 were not characterized by the predicted side chain but by a 1,3-disubstituted guanidine and are shown to be interesting A3AR antagonists.

Design, synthesis, and biological evaluation of novel 2-((2-(4-(substituted)phenylpiperazin-1-yl)ethyl)amino)-5'-N-ethylcarboxamidoadenosines as potent and selective agonists of the A2A adenosine receptor

Stimulation of A2A adenosine receptors (AR) promotes anti-inflammatory responses in animal models of allergic rhinitis, asthma, chronic obstructive pulmonary disease, and rheumatic diseases. Herein we describe the results of a research program aimed at identifying potent and selective agonists of the A2AAR as potential anti-inflammatory agents. The recent crystallographic analysis of A2AAR agonists and antagonists in complex with the receptor provided key information on the structural determinants leading to receptor activation or blocking. In light of this, we designed a new series of 2-((4-aryl(alkyl)piperazin-1-yl)alkylamino)-5'-N-ethylcarboxamidoadenosines with high A2AAR affinity, activation potency and selectivity obtained by merging distinctive structural elements of known agonists and antagonists of the investigated target. Docking-based SAR optimization allowed us to identify compound 42 as one of the most potent and selective A2A agonist discovered so far (Ki hA2AAR = 4.8 nM, EC50 hA2AAR = 4.9 nM, Ki hA1AR > 10 000 nM, Ki hA3AR = 1487 nM, EC50 hA2BAR > 10 000 nM).

Bisphosphonate-Related Osteonecrosis of the Jaw: A Retrospective Study on the Role of Dental Prophylaxis

Clinicians use bisphosphonates in neoplastic and metabolic bone diseases. Osteonecrosis is the main complication of the maxillary bones, along with late mucosal healing with necrotic bone exposure, pain, burning sensation, paresthesia, and is commonly associated with osteonecrosis. In the dental unit of our department, we checked 181 patients, and divided them into three groups: patients who had not undergone therapy, patients who were currently undergoing bisphosphonate therapy, and those who had completed bisphosphonate therapy (but who had not been followed-up). For clinical management, patients were treated with a dental prophylaxis protocol or drug therapy, involving topical and/or systemic administration, and then underwent surgical resections when the osteonecrosis did not improve with any treatment. Variability with the percent of complications was statistically significant in the three groups. Despite the limited number of patients in this study, which will require further investigation, our experience demonstrated that preventive strategies in relation to complications are crucial. At this point, a satisfactory treatment for this pathology does not exist.

Discovery of 7-oxopyrazolo[1,5-a]pyrimidine-6-carboxamides as potent and selective CB(2) cannabinoid receptor inverse agonists

We recently described the medicinal chemistry of a new series of heteroaryl-4-oxopyridine/7-oxopyrimidines as CB2 receptor partial agonists, showing that the functionality of these ligands is controlled by the nature of the heteroaryl function condensed with the pyridine ring. We describe herein the design and synthesis of the 7-oxopyrazolo[1,5-a]pyrimidine-6-carboxamides, structural isomers of our previously reported pyrazolo[3,4-b]pyridines. All of the new compounds showed high affinity and selectivity for the CB2 receptor in the nanomolar range. In 3,5-cyclic adenosine monophosphate (cAMP) assays, the novel series shows stimulatory effects on forskolin-induced cAMP production acting as inverse agonists.

Use of irradiate animal pericardium membrane for prevention of Frey's syndrome after parotidectomy

BACKGROUND

Frey syndrome is a common complication that appears few months after parotid surgery with flushing and sweating of the parotid-temporal area during mastication. It presumably originates from an aberrant nervous regeneration in which the parasympathetic fibers of the parotid gland would combine themselves with the sympathetic fibers of the sweat glands and with the cutaneous vessels.

AIM

In the present study we analyze the effectiveness of a collagenous membrane derived from animal pericardium (APM) to prevent Frey's syndrome after parotidectomy.

MATERIALS AND METHODS

We studied a total of 40 patients with benign tumors of the parotid gland, including 30 patients with pleomorphic adenoma, 7 patients with Warthin tumor and 3 with basal cells adenoma. The patients were divided into 2 groups: group 1 (experimental n=20) executed superficial parotidectomy with replacement of bovine pericardial matrix (BPM); group 2 (control n=20) underwent superficial parotidectomy followed by reposition of superficial musculoaponeurotic system (SMAS) flap. All patients were questioned over their subjective symptom and tested with Minor's test after 12 months from the intervention and introduced in a follow-up of 3 years.

RESULTS

Subjectively Frey syndrome was referred in 5% of patients in group 1 and in 10% in group 2, while 0 cases were observed in group 1 after the starch-iodine test, 2 cases in group 2 (10%).

CONCLUSIONS

Considering the present results, although this study needs further implementation, we can affirm that BPM is a valid option in preventing Frey's syndrome whereas SMAS flap is not available.

Water-soluble pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines as human A₃ adenosine receptor antagonists

A relevant problem of the pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine nucleus, an attractive scaffold for the preparation of adenosine receptor antagonists, is the low water solubility. We originally functionalized the C(5) position with a salifiable 4-pyridylcarbamoyl moiety that conferred good water solubility at low pH (<4.0) but poor solubility at physiologic pH, indicative of the dissociation of the pyridinium species. Here we replaced the pyridin-4-yl moiety with a 1-(substituted)piperidin-4-yl ring to exploit the higher basicity of this nucleus and for the the possibility to generate stable, water-soluble salts. The hydrochloride salt of the 1-(cyclohexylmethyl)piperidin-4-yl derivative (10, K(i)(hA(3)) = 9.7 nM, IC(50)(hA(3)) = 30 nM, K(i)(hA(1)/hA(3)) = 351, K(i)(hA(2A)/hA(3)) > 515, IC(50)(hA(2B)) > 5 μM) showed a solubility of 8 mg/mL at physiological pH and gave a stable aqueous system suitable for intravenous infusion. Molecular modeling studies were helpful in rationalizing the available structure-activity relationships and the selectivity profile of the new ligands.

Novel 1,3-dipropyl-8-(3-benzimidazol-2-yl-methoxy-1-methylpyrazol-5-yl)xanthines as potent and selective A₂B adenosine receptor antagonists

Molecular modeling studies, including the comparative molecular field analysis (CoMFA) method, on 52 antagonists of the A(2B) adenosine receptor with known biological activity were performed to identify the three-dimensional features responsible for A(2B) adenosine receptor antagonist activity. On the basis of these and previous results on the potent antagonist effect of 8-pyrazolyl-xanthines at human A(2B)AR, a new series of compounds was synthesized and evaluated in binding studies against the human A(1), A(2A), A(3), and A(2B)ARs. A remarkable improvement in selectivity with respect to the previous series, maintaining the potency at human A(2B) receptor, was achieved, as exemplified by the 8-[3-(4-chloro-6-trifluoromethyl-1H-benzoimidazol-2-yl-methoxy)-1-methyl-1H-pyrazol-5-yl]-1,3-dipropyl-3,7-dihydro-purine-2,6-dione derivative 66: K(i) A(2B) = 9.4 nM, IC(50) hA(2B) = 26 nM hA(1)/hA(2B) = 269, hA(2A)/hA(2B) > 106, hA(3)/hA(2B) >106. This study also led to the identification of a series of pyrazole-xanthine compounds with a simplified structure, exemplified by 8-(3-hydroxy-1-methyl-1H-pyrazol-5-yl)-xanthine 80 displaying very high affinity at A(2B)AR with good selectivity over AR subtypes (K(i) = 4.0 nM, IC(50) hA(2B) = 20 nM hA(1)/hA(2B) = 183, hA(2A),hA(3)/hA(2B) > 250).

Pyrrolo- and pyrazolo-[3,4-e][1,2,4]triazolo[1,5-c]pyrimidines as adenosine receptor antagonists

The discovery and development of adenosine receptor antagonists have represented for years an attractive field of research from the perspective of identifying new drugs for the treatment of widespread disorders such as inflammation, asthma and Parkinson's disease. The present work can be considered as an extension of our structure-activity relationship studies on the pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine (PTP) nucleus, extensively investigated by us as a useful template, in particular, for the identification of A(2A) and A(3) adenosine receptor antagonists. In order to explore the role of the nitrogen at the 7-position, we performed a new synthetic strategy for the preparation of pyrrolo[3,4-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives which can be considered as 7-deaza analogues of the parent PTPs. We also synthesised a novel series of pyrazolo[3,4-e][1,2,4]triazolo[1,5-c]pyrimidines as junction isomers of the reference compounds. In both cases we obtained some examples of potent antagonists (K(i) in the low nanomolar range) with variable selectivity profiles in relation to the nature of substituents introduced at the C(5)-, N(8)- and/or N(9)-positions. The pyrrolo-triazolo-pyrimidine derivative 9b appeared to be a potent A(3) adenosine receptor antagonist (K(i)=10 nM) with good selectivity over hA(1) (74-fold) and hA(2A) (20-fold) adenosine receptors combined with low activity at the hA(2B) subtype (IC(50)=906 nM). Moreover, some examples of high-affinity A(1)/A(2A) dual antagonists have been identified in both series. This work constitutes a new and important contribution for the comprehension of the interaction between PTPs and adenosine receptors.

New 2-heterocyclyl-imidazo[2,1-i]purin-5-one derivatives as potent and selective human A3 adenosine receptor antagonists

A series of 4-allyl/benzyl-7,8-dihydro-8-methyl/ethyl-2-[(substituted)isoxazol/pyrazol-3/5-yl]-1H-imidazo[2,1-i]purin-5(4H)-ones has been synthesized and evaluated in radioligand binding assays to determine their affinities at the human A(1), A(2A), and A(3) adenosine receptors. Efficacy at the hA(2B) AR and antagonism of selected ligands at the hA(3) AR were also assessed through cAMP experiments. All of the synthesized molecules exhibited high affinity at the hA(3) AR (K(i) values ranging from 1.46 to 44.8 nM), as well as remarkable selectivity versus A(1), A(2A), and A(2B) AR subtypes. Compound (R)-4-allyl-8-ethyl-7,8-dihydro-2-(3-methoxy-1-methyl-1H-pyrazol-5-yl)-1H-imidazo[2,1-i]purin-5(4H)-one (R-33) was found to be the most potent and selective ligand of the series (K(i) hA(3) = 1.46 nM, K(i) hA(2A)/K(i) hA(3) > 3425; IC(50) hA(2B)/K(i) hA(3) > 3425; K(i) hA(1)/K(i) hA(3) = 1729). Molecular modeling studies were helpful in rationalizing the available structure-activity relationships along with the selectivity profiles of the new series of ligands.

Clinical experience with spiramycin in bisphosphonate-associated osteonecrosis of the jaw

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) consists of an exposure of the jaw bone that persists for over 8 weeks in patients with positive history for bisphosphonates. Symptomatology is characterized by dull and ceaseless pain, and in advanced stages, the exposure of necrotic bone is evident, which is frequently associated with purulent secretions and faetor oris. Despite many different studies on BRONJ, there are no general guidelines to treat this disease. In this work, the authors present their experience in BRONJ conservative therapy with spiramycin by comparing the results achieved with amoxicillin and clavulanic acid. From January 1, 2008 to June 30, 2008, our department received 25 patients who were affected by osteonecrosis secondary to bisphosphonates. Thirteen had taken bisphosphonates for osteoporosis and 12 for malignancies. We divided the 25 patients into two groups: those who had not received any treatment and those who had received treatment. The first group of 13 patients had been treated only with spiramycin (S). The results from this group were only evaluated to test the efficacy of spiramycin and were not considered in the study. The second group of 12 patients had not undergone any previous treatment. This group was further divided in two groups of 6 patients each; one group was treated with spiramycin and the other with amoxicillin and clavulanic acid (ACA). The following criteria were used to evaluate the results of the study: pain, sensibility deficits, purulent secretion and bone exposure. All group results were evaluated according to the criteria chosen, and positive results were achieved in both groups S and ACA, such as reduction or disappearance of pain, sensibility deficits and purulent secretion and healing of bone exposition, although spiramycin showed itself to be more effective than the combination of amoxicillin and clavulanic acid. Spiramycin is a macrolide antibiotic with a wide spectrum of activity against Streptococci, Pneumococci, Diplococci, Gonococci and Staphylococci, which are typical in BRONJ. No resistance was indicated. Administration of the antibiotics can be intravenous, intramuscular, rectal or oral, which remains the most frequently used since spiramycin elimination also occurs with saliva and the antibiotic reaches high concentrations in the oral cavity where BRONJ is situated. Good compliance to the spiramycin regimen was observed in all three groups, with a general improvement in all of the parameters considered. In only two cases did patients have to undergo surgical curettage. The results showed that spiramycin can be a first choice drug in the treatment of BRONJ, and it should be strongly considered for patients where previous antibiotic therapy did not prove to be effective.

Structure-activity relationship studies of a new series of imidazo[2,1-f]purinones as potent and selective A(3) adenosine receptor antagonists

We recently described the synthesis of 1-benzyl-3-propyl-1H,8H-imidazo[2,1-f]purine-2,4-diones, new potent and selective A(3) adenosine receptor antagonists containing a xanthine core. The present work can be considered an extension of our SAR studies on related structures in which the effect of different kind of substitutions at the 1-, 3- and 8-positions has been evaluated in order to improve both the potency and the hydrophilicity of the originally synthesised molecules. The A(3) binding disposition of these compounds was also investigated through docking and 3D-QSAR studies.

N(6)-[(hetero)aryl/(cyclo)alkyl-carbamoyl-methoxy-phenyl]-(2-chloro)-5'-N-ethylcarboxamido-adenosines: the first example of adenosine-related structures with potent agonist activity at the human A(2B) adenosine receptor

A new series of N(6)-[(hetero)aryl/(cyclo)alkyl-carbamoyl-methoxy-phenyl]-(2-chloro)-5'-N-ethylcarboxamido-adenosines (24-43) has been synthesised and tested in binding assays at hA(1), hA(2A) and hA(3) adenosine receptors, and in a functional assay at the hA(2B) subtype. The examined compounds displayed high potency in activating A(2B) receptors with good selectivity versus A(2A) subtypes. The introduction of an unsubstituted 4-[(phenylcarbamoyl)-methoxy]-phenyl chain at the N(6) position of 5'-N-ethylcarboxamido-adenosine led us to the recognition of compound 24 as a full agonist displaying the highest efficacy of the series (EC(50) hA(2B)=7.3 nM). These compounds represent the first report about adenosine-related structures capable of activating hA(2B) subtype in the low nanomolar range.