Gian Andrea Pelliccioni

Effectiveness of three different retreatment techniques in canals filled with compacted gutta-percha or Thermafil: a scanning electron microscope study.

INTRODUCTION This study evaluated the root canal wall morphology under scanning electron microscopy magnification after removal of 2 types of root canal fillings by using ultrasonic tips, nickel-titanium (NiTi) rotary instruments, and hand K-files. METHODS Thirty-six extracted roots were filled by using AH Plus (DeTrey-Dentsply, Konstanz, Germany) as a sealer with Thermafil (Tulsa Dental Products, Tulsa, OK) (18 roots) or warm vertically condensed gutta-percha (18 roots). All fillings were removed up to the middle third by using Gates Glidden drills. The retreatment was completed by using K-files (group 1), M-Two NiTi rotary instruments (group 2), or ESI ultrasonic tips (group 3) in 12 roots each. Root canals were irrigated by using 10% ethylenediaminetetraacetic acid and 2.5% NaOCl. The samples were split longitudinally and observed by scanning electron microscopy (100-2000x). The presence of smear layer, filling debris, and the surface profile was evaluated in each picture. Kruskal-Wallis (analysis of variance) and Mann-Whitney tests were used to evaluate the differences between the obturation techniques, the 3 retreatment methods, and the canal thirds (P < .05). RESULTS Resin sealer tags were observed inside dentinal tubules. No statistical differences (P > .05) were found among the 3 retreatment methods. No statistical differences were observed between Thermafil and vertically compacted warm gutta-percha for each group or between the coronal third used as control, middle, and apical thirds. CONCLUSIONS All retreatment techniques showed similar performances in terms of smear layer morphology, debris, and surface profile. None of them completely removed filling debris from dentinal tubules of apical third.

Evaluation of osteoblast-like cell response to Proroot MTA (mineral trioxide aggregate) cement

Some endodontic sealers have been shown to cause local and systemic effects, mainly due to microleakage of chemicals from the sealer. To avoid the risk of toxic effects in vivo, the biological compatibility of filling materials has to be assessed. In vitro compatibility of Proroot™ MTA cement in comparison with two different fillers used in clinical practice, was examined by testing the adherence, viability, proliferation and secretion of collagen of osteoblast-like cells. In our experimental system, Saos-2 cells challenged with Proroot™ MTA for 24 and 72 h showed a better behaviour than the cells exposed to the other compounds under assay. We found that the cells attached to the rough surface of Proroot™ MTA cement and spread onto the rough surface. Moreover, the cells on Proroot™ MTA were viable, grew, and released some collagen even at 72 h, while cell metabolism and growth was dramatically reduced onto sEBA and amalgam surfaces. A parallel behaviour was found after the cells were challenged with extracts of the different fillers. In conclusion, according to our in vitro study, Proroot™ MTA showed a good interaction with bone-forming cells: such behaviour may partially account for its satisfying clinical performance.

A prospective clinical trial for assessing the efficacy of a minimally invasive protocol in patients with bisphosphonate-associated osteonecrosis of the jaws

OBJECTIVE The objective of this study was to assess whether a minimally invasive protocol can be effective in the long-term control of necrotic areas and pain in patients suffering osteonecrosis of the jaw associated with the use of bisphosphonate drugs (BRONJ). STUDY DESIGN Thirty-four consecutive patients (14 male, 20 female) with BRONJ under treatment with zoledronate, pamidronate, or alendronate were enrolled. All of the patients received professional oral hygiene treatment and antiseptic oral rinses, and if in pain they assumed an antibiotic therapy with amoxicillin/clavulanate potassium and metronidazole for ten days. At the baseline visit, as well as at each 3-month recall, the size of the osteonecrotic lesions were measured and the pain level assessed with a visual analog scale. RESULTS The results from the general linear model showed a statistically significant (F = 16.1; P < .01; r(2) = 0.95) time-related decrease in the size of exposed bone areas during the nonsurgical therapy (from 12.5 ± 12.0 mm to 8.8 ± 10.3 mm). CONCLUSIONS This conservative protocol seems to provide successful treatment in the vast majority of patients.

Radiographic assessment of the mandibular retromolar canal using cone-beam computed tomography

Abstract Objective. The ‘retromolar’ nerve is a collateral branch of the inferior alveolar nerve. Cone-beam computed tomography (CBCT) provides higher resolution images. This CBCT study reports the frequency of the retromolar nerve. Materials and methods. From 2007–2010 the CBCT study of 233 hemi-mandibles have been examined. The CBCT study was obtained from an investigation of the posterior mandibular region in 187 patients suffering from different pathologies and it was aimed at detecting in patients the presence of a retromolar canal and foramen. Results. Thirty-four retromolar canals with a foramen were detected on 233 CBCT (14.6%) in 30 out of 187 patients (16%). In the 46 patients who underwent CBCT bilaterally, the retromolar canal was found in nine subjects (19.6%) and was present bilaterally in four subjects, for an incidence of 8.7%. Conclusions. The results suggest that the radiological frequency of the retromolar nerve is notable, with a possible relevance in the surgical approach of the mandibular retromolar area. The presence of a retromolar canal, well detected with CBCT, may warn clinicians about the possibility of inadequate pre-surgical anaesthesia, local intra-operative bleeding and post-operative alterations of the sensation in the third molar area.

Prescriptions of NSAIDs to patients undergoing third molar surgery : an observational, prospective, multicentre survey.

Background and objectives:Surgical extraction of an impacted third molar is generally followed by acute post-operative pain that has been shown to be primarily inflammatory. Thus, use of NSAIDs in this context is appropriate and has been shown to be effective. Several drugs are employed for this purpose, but no information exists on the reasons why preference is given to one rather than another. The principal objective of this study was to evaluate the pattern of administration of NSAIDs in patients undergoing surgery for impacted third molar extraction. The study also aimed to collect information on the efficacy, onset and duration of the analgesic effect of routinely prescribed NSAIDs and to assess the duration of treatment with these drugs and their tolerability.Methods:This was an observational, multicentre, prospective survey. A total of 616 patients (38% male and 62% female) from the Italian Stomatology Clinics of the Universities of Bologna, Brescia, Cagliari, Chieti, Pavia, Pisa, Siena and Varese and from the Department of Oral and Maxillo-Facial Surgery of Semmelweis University, Budapest, were eligible for the study. Patients were evaluated over the 7 days following surgical extraction. NSAIDs were prescribed according to the normal prescribing habits of the centre and physician involved. The main outcomes of interest in the survey were the efficacy, onset and duration of analgesic effect, duration of therapy, and tolerability of the NSAIDs prescribed.Results:Nimesulide was the most prescribed NSAID (68%), followed by diclofenac, ketoprofen and ibuprofen. Because of the low proportion of patients receiving other NSAIDs, these patients were considered a single treatment group for evaluation purposes. Nimesulide, especially when given before patients started experiencing pain after surgery, was more effective than other NSAIDs in reducing the severity of pain on the day of surgery, in delaying the time to maximum intensity of pain, in providing complete pain relief and in prolonging the duration of analgesic effect on the day of surgery. These results are consistent with the known anti-inflammatory and analgesic actions of nimesulide and with the important role of inflammation in the onset of pain after this type of surgery.Conclusion:These results confirm nimesulide as an effective reference drug for the treatment of post-operative dental pain and show that it has a positive benefit/risk profile in this setting.

A latex membrane, as an alternative device in the GTR technique: preliminary report on its biocompatibility

Polymeric materials are of widespread use for many clinical applications, including dentistry. Periodontal guided tissue regeneration (GTR) is a technique developed to treat periodontal disease: it implies that new connective tissue attachment and bone regeneration are achieved, whereas epithelial migration is prevented by the placement of a barrier membrane. This study has focused on the toxicity in vitro of different polymeric membranes, either commercial or experimental, with a latex rubber membrane being of special interest for use as an implant material in guided tissue regeneration in periodontology. A cell culture system tested by quantitative assay methods offered a reliable tool which provided meaningful results on the first level biocompatibility of such membranes.

A Laboratory Based Investigation of a New Elastic Toothbrush Head

Purpose. To demonstrate the noninferiority of a new toothbrush head with retractile bristles compared to traditional toothbrush heads on dental models. Methods. The new toothbrush head, mounted on manual and electrical handles, presents retractile bristle groups that can singularly retract over its entire length and offer calibrated resistance. Fourteen gypsum models of dental arches, twelve with and two without anatomical impairments, were spread with a “plaque simulator.” Each arch was brushed twice with each of the four toothbrushes, one minute by the same operator, blinded to the study. The plaque index (PI) was recorded at the end of each brushing session. GLM for repeated measures analysed the data. Results. On all the casts, the manual prototype and the electric prototype, removed 11% and 14% more “plaque simulator” compared to the standard toothbrush. In presence of dental anomalies, the prototypes removed 13% and 16% more plaque, respectively, compared to standard toothbrushes (P = 0.04). In both situations, the 95% confidence intervals of PI did not include −10% (the minimal margin of clinical relevance). Conclusions. The prototype is more effective in removing plaque from the casts with anomalies. The noninferiority of the prototype with respect to the standard toothbrushes was demonstrated.

SIRT1/HERC4 Locus Associated With Bisphosphonate‐Induced Osteonecrosis of the Jaw: An Exome‐Wide Association Analysis

Osteonecrosis of the jaw (ONJ) is a rare, but serious drug side effect, mainly associated with the use of intravenous (iv) bisphosphonates (BPs). The purpose of this study was to identify genetic variants associated with ONJ in patients of European ancestry treated with iv BPs using whole‐exome sequencing (WES). The WES phase 1 included 44 multiple myeloma patients (22 ONJ cases and 22 controls) and WES phase 2 included 17 ONJ patients with solid tumors. Multivariable logistic regression analysis was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CI), adjusting for age, sex, and principal components for ancestry. Meta‐analysis of WES phase 1 and 2 was performed to estimate the combined ORs. In silico analyses were then performed to identify expression quantitative loci (eQTL) single‐nucleotide polymorphisms (SNPs) that are in high linkage disequilibrium (LD) with the top SNPs. The associations of the potentially functional SNPs were replicated and validated in an independent case‐control study of 48 patients of European ancestry treated with iv BPs (19 ONJ cases and 29 controls). The top SNPs in the exome‐wide association meta‐analysis were two SNPs on chromosome 10: SIRT1 SNP rs7896005 and HERC4 SNP rs3758392 with identical OR of 0.07 (0.01–0.46; p = 3.83 × 10−5). In the in silico functional analyses, two promoter region SNPs (rs7894483 and rs3758391) were identified to be in high LD with the index SNPs and are eQTLs for SIRT1 gene in whole blood in the GTEx database. The ORs were 0.30 (0.10–0.88), 0.26 (0.12–0.55), and 0.26 (0.12–0.55) for the WES top SNP rs7896005 and two promoter SNPs rs7894483 and rs3758391, respectively, in the replication sample. In summary, we identified the SIRT1/HERC4 locus on chromosome 10 to be associated with iv BP‐induced ONJ and two promoter SNPs that might be the potential genetic markers for this association.

Delayed onset infections after lower third molar germectomy could be related to the space distal to the second molar

The onset of delayed infection after lower third molar germectomy is influenced by the amount of distal space. This retrospective study aimed to determine whether the incidence of delayed onset infection is related to the space distal to the second molar. The ratio between the distal space and the crown width, measured according to the Ganss protocol on panoramic radiographs, was obtained for 218 surgical germectomies performed for orthodontic reasons in 134 patients. A delayed onset infection occurred following 20 germectomies at between 2 and 8 weeks after surgery; purulent exudates from the alveolus and swelling were present. In 16 of the 20 cases of infection, a Ganss ratio of <0.5 showed the almost complete absence of space distal to the second molar. This study found that the distal space was significantly and inversely correlated with delayed onset infection (P=0.004). From a clinical point of view, it is important for the surgeon to be aware that a higher Ganss ratio may indicate that a delayed onset infection is less likely to occur and that a lower Ganss ratio could indicate a greater likelihood of this type of infection, so that the patient can be properly informed.

Minimally Invasive Surgical Treatment

Minimally invasive surgery refers to all surgical procedures in which there is only a small incision or no incision at all. It is possible to distinguish between preventive surgery, aimed at removing actual causes that could worsen the patient’s quality of life, and palliative surgery, aimed, for example as discussed herein, at removing part of the osteonecrosis. Marsupialization of cystic lesions is appropriate if a cyst has already eroded the cortical bone. The procedure involves an incision to expose the fenestration followed by the insertion of a small Teflon tube for draining the lesion and reducing the endocystic pressure. This creates favorable conditions for neo-apposition of the bone inside the lacunae. Apicoectomy can be performed when endodontic therapy is not sufficient to treat a granuloma; as in marsupialization, this technique is possible only if the radiographic examinations confirm the presence of a fenestration of the cortical bone. Debridement is specifically carried out to treat stage 2 lesions, in patients who experience pain due to an inflammation of the surrounding soft tissues, or when there are sharp bone spicules. Sequestrectomy is viable only if the surgeon verifies the sequestrum’s mobility; it can be performed by removing the fragment atraumatically, using surgical forceps. Drug holiday is useful in patients receiving oral bisphosphonates and requiring oral surgery. Suspension of these drugs increases bone activity, which can be monitored by significant increases in CTX levels over time. A lower limit of >150 pg/ml is recommended to proceed with surgery. Piezosurgery is another minimally invasive treatment for removing necrotic tissues, creating regular bony borders. A prerequisite for these procedures is a good control of oral hygiene and antibiotic prophylaxis.