Successful minimally invasive management of primary maxillary central incisors after lateral luxation: a case report

Lateral luxation in primary maxillary incisors is a traumatic injury that can lead to darkening of the tooth, pulp necrosis, root resorption, and damage to the permanent teeth. Management of this kind of trauma typically includes pulpectomy or extraction in cases of root resorption. However, in young children, removal of the tooth may be psychological stressing, especially for the parents, while increased mobility can make immediate endodontic treatment difficult to perform. This article outlines a severe palatal luxation on the maxillary right central incisor treated with conservative management in a 2-year-old boy. At the one-year follow-up appointment, the surrounding bone was healthy, the roots displayed physiological resorption, the crowns showed color improvement, and there was no radiographically noticeable damage to the permanent teeth.     

Thickness of the anterior maxillary facial bone wall-a retrospective radiographic study using cone beam computed tomography

The purpose of this retrospective radiographic study was to analyze the thickness of the facial bone wall at teeth in the anterior maxilla based on cone beam computed tomography (CBCT) images, since this anatomical structure is important for the selection of an appropriate treatment approach in patients undergoing postextraction implant placement. A total of 125 CBCT scans met the inclusion criteria, resulting in a sample size of 498 teeth. The thickness of the facial bone wall in the respective sagittal scans was measured perpendicular to the long axis of the tooth at two locations: at the crest level (4 mm apical to the cementoenamel junction; MP1) and at the middle of the root (MP2). No existing bone wall was found in 25.7% of all teeth at MP1 and in 10.0% at MP2. The majority of the examined teeth exhibited a thin facial bone wall (< 1 mm; 62.9% at MP1, 80.1% at MP2). A thick bone wall (? 1 mm) was found in only 11.4% of all examined teeth at MP1 and 9.8% at MP2. There was a statistically significant decrease in facial bone wall thickness from the first premolars to the central incisors. The facial bone wall in the crestal area of teeth in the anterior maxilla was either missing or thin in roughly 90.0% of patients. Both a missing and thin facial wall require simultaneous contour augmentation at implant placement because of the well-documented bone resorption that occurs at a thin facial bone wall following tooth extraction. Consequently, radiographic analysis of the facial bone wall using CBCT prior to extraction is recommended for selection of the appropriate treatment approach.     

Prevalence of maxillary sinus septa in 1024 subjects with edentulous upper jaws: a retrospective study

Maxillary sinus floor augmentation has been routinely performed to optimize dental implant placement in the posterior maxilla. However, complications during a sinus grafting procedure, such as perforation of the Schneiderian membrane, have been reported. This complication is generally associated with the presence of maxillary septa. Therefore, the aim of this retrospective study was to evaluate the prevalence of maxillary sinus septae in completely edentulous subjects by means of panoramic radiography. A total of 1024 panoramic radiographs were evaluated by 3 calibrated examiners. From these radiographs, 307 maxillary septa were detected in 221 subjects (21.58%); 86 (8.40%) of the subjects showed maxillary septa in both maxillary sinuses. Logistic regression failed to detect any correlation between the presence of maxillary septa, age, and gender (P > .05). Within the limits of the study, the prevalence of maxillary septa in this Brazilian population was shown to be moderate, indicating that dentists must be aware of the presence of this anatomic structure during maxillary sinus elevation grafting.     

Immunohistochemical localization of alphavbeta3 integrin receptor during experimental tooth movement.

During orthodontic treatment, multinucleated clast cells carry out the resorption of mineralized tissues. Adhesion of clast cells to the mineralized tissues is mediated by transmembrane cell-surface glycoproteins called integrins, specifically by the alphavbeta3 integrin, which plays an important role in the process of bone resorption. The role of the alphavbeta3 integrin in bone resorption leading to osteoporosis has been demonstrated, but its role in alveolar bone and root resorption during orthodontic tooth movement is unknown. This study examined the expression of the alphavbeta3 integrin during experimental tooth movement. Tooth movement was achieved in 16 male Sprague-Dawley rats (each weighing 120-200 g) with elastic bands between their maxillary first and second molars. The molar-bearing segments were dissected and processed for histologic and immunohistochemical examination. The expression of alphavbeta3 integrin was examined with 2 primary antibodies: a polyclonal anti-alphav integrin subunit antibody and a polyclonal anti-beta3 integrin subunit antibody. Negative controls were similarly processed but without incubation with primary antibodies. The alphavbeta3 integrin was expressed both by osteoclasts associated with alveolar bone resorption and by odontoclasts associated with root resorption during experimental tooth movement. Furthermore, the beta3 integrin subunit was expressed by the epithelial rests of Malassez in the periodontal ligament. Negative controls did not show immunolabeling. The alphavbeta3 integrin adhesion receptor is expressed during experimental tooth movement and might be involved in the process of mineralized tissue resorption and the functions of the epithelial rests of Malassez.     

Biodistribution of a carborane-containing porphyrin as a targeting agent for Boron Neutron Capture Therapy of oral cancer in the hamster cheek pouch

Boron Neutron Capture Therapy (BNCT) is a bimodal cancer treatment based on the selective accumulation of 10B in tumors and concurrent irradiation with thermalized neutrons. The short-range, high-LET radiation produced by the capture of neutrons by 10B could potentially control tumor while sparing normal tissue if the boron compound targets tumor selectively within the treatment volume. In previous studies, we proposed and validated the hamster cheek pouch model of oral cancer for BNCT studies, proved that absolute and relative uptake of the clinically employed boron compound boronophenylalanine (BPA) would be potentially therapeutic in this model and provided evidence of the efficacy of in vivo BPA-mediated BNCT to control hamster oral mucosa tumors with virtually no damage to normal tissue. We herein present the biodistribution and pharmacokinetics of a lipophilic, carborane-containing tetraphenylporphyrin (CuTCPH) in the hamster oral cancer model. CuTCPH is a novel, non-toxic compound that may be advantageous in terms of selective and absolute delivery of boron to tumor tissues. For potentially effective BNCT, tumor boron concentrations from a new agent should be greater than 30 ppm and tumor/blood and tumor/normal tissue boron concentration ratios should be greater than 5/1 without causing significant toxicity. We administered CuTCPH intraperitoneally (i.p.) as a single dose of 32 microg/g body weight (b.w.) (10 microg B/g b.w.) or as four doses of 32 microg/g b.w. over 2 days. Blood (Bl) and tissues were sampled at 3, 6, 12, 24, 48, and 72 h in the single-dose protocol and at 1-4 days after the last injection in the multidose protocol. The tissues sampled were tumor (T), precancerous tissue surrounding tumor, normal pouch (N), skin, tongue, cheek and palate mucosa, liver, spleen, parotid gland and brain. The maximum mean B ratios for the single-dose protocol were T/N: 9.2/1 (12h) and T/Bl: 18.1/1 (72 h). The B value peaked to 20.7+/-18.5 ppm in tumor at 24h. The multidose protocol maximum mean ratios were T/N: 11.9/1 (3 days) and T/Bl: 235/1 (4 days). Absolute boron concentration in tumor reached a maximum value of 116 ppm and a mean value of 71.5+/-48.3 ppm at 3 days. The fact that absolute and relative B values markedly exceeded the BNCT therapeutic threshold with no apparent toxicity may confer on this compound a therapeutic advantage. CuTCPH-mediated BNCT would be potentially useful for the treatment of oral cancer in an experimental model.     

Tooth loss in treated periodontitis patients responsible for their supportive care arrangements

AIM: To identify risk indicators associated with tooth loss and periodontitis in treated patients responsible for arranging supportive periodontal care (SPC). MATERIALS AND METHODS: Ninety-seven Chinese subjects (34-77 years) who showed favourable responses to periodontal therapy provided in a teaching hospital 5-12 years previously were recalled. They were advised to seek regular SPC on discharge. Background information, general health status, smoking, oral hygiene habits, follow-up dental care, tooth loss, and periodontal parameters were investigated. Multiple regression analysis was performed. RESULTS: Two hundred and fifty-six teeth had been lost, 195 because of self-reported periodontal reasons. Up to 26.8% sites were with pockets > or =6 mm. Positive correlations were found between total/periodontal tooth loss and (i) smoking pack-years, (ii) time spent on oral hygiene, (iii) years since therapy's conclusion, (iv) age, and negative correlations with (v) inter-dental brush use, and (vi) education levels. Tooth loss by arch was correlated with wearing of removable partial denture in that arch. Percentage sites with pockets > or =6 mm were significantly negatively correlated with percentage sites without bleeding on probing. CONCLUSIONS: Smokers, more elderly patients, removable partial denture wearers, and patients with lower education levels or not using inter-dental brushes ought to be targeted for clinic-based SPC.     

Respiratory outcome of mid-face advancement with distraction: a comparison between Le Fort III and frontofacial monobloc

Upper airway stenosis in patients with faciocraniosynostosis is very common and often severe. Mid-face advancement, either with a Le Fort III or concomitantly to a monobloc frontofacial advancement, may prevent a tracheotomy or result in its ablation. The amelioration of respiratory function appears to be much better if the mid-face advancement is combined with distraction osteogenesis, although large studies with long-term follow-up are rare. In this study we reviewed the respiratory outcome between Le Fort III with distraction and monobloc advancement with distraction in 55 faciocraniosynostotic patients. Early respiratory results of both procedures were very good and stable at long-term follow-up. The choice between a Le Fort III and a monobloc procedure is made based on presenting morphology, previous surgery, and age. Both can be expected to give a long-lasting improvement of upper airway obstruction.     

In vitro cytotoxic and non-genotoxic effects of gutta-percha solvents on mouse lymphoma cells by single cell gel (comet) assay

Chloroform and eucalyptol are widely used in clinical dentistry as gutta-percha solvents. However, these compounds may represent a hazard to human health, especially by causing injury to genetic apparatus and/or inducing cellular death. In this study, the genotoxic and cytotoxic potentials associated with exposure to chloroform and eucalyptol were assessed on mouse lymphoma cells in vitro by the single cell gel (comet) assay and trypan blue exclusion test, respectively. Both gutta-percha solvents proved to be cytotoxic at the same levels in concentrations of 2.5, 5 and 10 microL/mL (p<0.05). On the other hand, neither of the solvents induced DNA breakage. Taken together, these results suggest that although both tested compounds (chloroform and eucalyptol) are strong cytotoxicants, it seems that they are not likely to increase the level of DNA damage on mammalian cells.     

In vivo fracture resistance of implant-supported all-ceramic restorations

STATEMENT OF PROBLEM: Because of their specific mechanical properties, all-ceramic restorations demonstrate a lower fracture resistance than ceramic restorations supported by metal substructures. However, advances have been made in the fabrication of high-strength all-ceramic abutments for anterior implants. No previous study has compared the fracture loads between 2 different all-ceramic abutments restored by glass-ceramic crowns. PURPOSE: The purpose of this in vitro investigation was to quantify the fracture load of implanted-supported Al(2)O(3) and ZrO(2) abutments restored with glass-ceramic crowns. MATERIALS AND METHODS: Two ceramic abutments were tested: an Al(2)O(3) abutment (CerAdapt) and a ZrO(2) abutment (Wohlwend Innovative). The abutments (n = 10) were placed on Br?nemark dental implants and prepared for restoration with glass-ceramic crowns (IPS Empress). After fabrication, in accordance with the manufacturer's guidelines, the crowns were bonded to the all-ceramic abutments with a dual-polymerizing resin luting agent. The fracture loads (N) were determined by force application at an angle of 30 degrees by use of a computer-controlled universal testing device. The data were analyzed with the unpaired t test (alpha=.05). RESULTS: Statistical analysis showed significant differences between both groups (P=.001) of all-ceramic abutments, with mean fracture load values of 280.1 N (+/- 103.1) for the Al(2)O(3) abutments and 737.6 N (+/- 245.0) for the ZrO(2) abutments. CONCLUSION: Within the limitations of this study, both all-ceramic abutments exceeded the established values for maximum incisal forces reported in the literature (90 to 370 N). The ZrO(2) abutments were more than twice as resistant to fracture as the Al(2)O(3)-abutments.