Antimicrobial properties of hydrogen peroxide and sodium bicarbonate individually and in combination against selected oral, gram-negative, facultative bacteria

The topical application of hydrogen peroxide (H2O2) and sodium bicarbonate (NaHCO3), individually and in combination, has been used empirically in the treatment of periodontal diseases. In this study, we examined both minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of these disinfectants individually and in combination against selected facultative, Gram-negative oral bacteria in a microtiter dilution assay. The bacteria studied included Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Eikenella corrodens, and Capnocytophaga gingivalis. These bacteria exhibited MBC (one hr) values ranging from 75 mumol/L to greater than 10 mmol/L and MIC from less than 5 to 500 mumol/L for H2O2. The tested bacteria exhibited MIC values for NaHCO3 of from 23 to 182 mmol/L, and the MBC (one hr) exceeded 728 mmol/L for most of the strains examined. At sublethal (sub-MIC) concentrations, sodium bicarbonate antagonized the ability of H2O2 to inhibit bacterial growth in MIC assays, but sublethal concentrations of H2O2 had no effect on the MIC values of NaHCO3. Lethal concentrations of H2O2 and NaHCO3 exhibited synergistic antimicrobial activity in combination in one-hour bactericidal assays. Since the bactericidal properties of these antimicrobial agents are synergistic, we conclude that it may be rational to use them in combination to treat certain forms of periodontal disease. Also, lower and perhaps safer concentrations of H2O2 can be used in combination with NaHCO3 when oxidative antimicrobial chemotherapy is indicated.     

Esophageal adenocarcinoma metastatic to the maxilla

Although metastatic malignant lesions in the maxilla are exceedingly rare, case reports of such lesions do appear occasionally in the literature. This article describes the clinical and pathologic features of an esophageal adenocarcinoma metastatic to the maxilla. The initial maxillary appearance of the tumor mimicked primary dental pathosis and, in addition, was the presenting sign of malignant disease in the patient. The relevant literature is reviewed, and the processes by which metastases form are discussed.     

Odontogenic infection leading to cervical emphysema and fatal mediastinitis

A case of fatal mediastinitis following an odontogenic infection has been presented. The anatomic pathways through fascial planes from the mouth to the mediastinum have been reviewed. The causes of cervical emphysema when the oral cavity is an entry site have been discussed. Usually this process is benign, but the possibility that gas-forming anaerobes could be present in the emphysema and that insidious mediastinitis could concurrently occur is stressed. The presence of Bacteroides asaccharolyticus in the anaerobic cultures from the submandibular and chest abscesses, and the recovery of aerobic organisms, leads to speculation about a synergistic action between these organisms.     

Influence of a parafunctional oral habit on root fracture development after trauma to an immature tooth

Root fractures in immature teeth are rare because the resilience of the alveolar bone is more favorable to the occurrence of luxation. This article reports a case of traumatic injury in an immature permanent tooth that progressed to root fracture, having a parafunctional oral habit as the possible modifying factor of case evolution. A 12-year-old boy presented for treatment complaining of a defective restoration and mild pain on the maxillary right central incisor. The patient had a history of crown fracture in this tooth due to trauma 2 years before. The clinical examination showed healthy gingival tissues and no abnormal tooth mobility, whereas radiographic projections revealed healthy periradicular tissues, incomplete root formation, and no visible root fracture. As pulp necrosis was diagnosed, calcium hydroxide therapy was started for canal disinfection and subsequent obturation. However, after 4 weeks of treatment, a horizontal fracture line was observed radiographically in the root's middle third. The patient denied a new traumatic injury, but revealed the habit of chewing on a pencil. Refraining from the deleterious oral habit was strongly advised, and root canal filling with mineral trioxide aggregate was performed to treat the root fracture. After 4 years of follow-up, the tooth has normal function and no abnormal mobility. Images suggestive of remodeling at the apical end of the coronal segment and replacement resorption of the apical segment are seen radiographically. This case demonstrates the need of following cases of dental trauma and the possible influence of parafunctional oral habits as modifying factors of case progression.     

Dental implants placed in extraction sites implanted with bioactive glass: human histology and clinical outcome

PURPOSE: To evaluate the clinical outcome of implants placed into sites grafted with bioactive glass. MATERIALS AND METHODS: Seventeen consecutively treated patients were referred to a private specialist surgical practice for the repair of dentoalveolar defects, and/or ridge maintenance at the site of extraction sockets, prior to implantation. Bioactive glass available in 1 of 2 forms was utilized as an alloplastic grafting material. Bone cores were trephined out at the time of implantation and processed and examined to evaluate the tissue response under the light microscope. Implant mobility, marginal bone levels, and soft tissue health were all evaluated over a 2- to 3-year follow-up period to determine treatment success. RESULTS: A total of 40 Astra Tech dental implants were placed. The overall success rate at the end of the study was 88.6% for implants that were in function for a mean period of 29.2 months (22 to 24 months). One patient with 5 successful implants died at 18 months after functional loading. At that time the cumulative success rate was 90%. Another patient who was diagnosed with cancer of the large bowel lost 3 implants. If this patient were excluded from the data, the cumulative success rate increases to 96.8%. Mean marginal bone loss measured 0.5 mm mesially and 0.4 mm distally over a maximum follow-up of 36 months. Human histology demonstrated that connective tissue was seen to exist without any inflammatory response, for up to 6 months. Increasing evidence of bone formation was seen in direct relation to the bioactive glass material beyond this time frame. DISCUSSION: The need to repair and augment dentoalveolar defects necessitates the use of autogenous bone or a substitute that may be seen to avoid the additional morbidity of a donor site procedure and without risk of cross infection. The use of bioactive glass has been proposed as a viable bone substitute. The current study draws attention to the long healing time required to achieve even a small amount of new bone incorporation into the graft, as seen histologically. However, the high rate of osseointegration and continued medium-term function of implants placed into these grafted sites would indicate that the use of bioactive glass does not prohibit osseointegration. However, it is likely that the initial integration will have derived from those areas in contact with native bone. CONCLUSION: Implants will survive for up to 3 years in sites grafted with bioactive glass, even when such grafts appear to only slowly conduct new bone growth.     

Teaching of all-ceramic restorations in central European dental schools: a survey

The teaching of all-ceramic restorations in Central European dental schools in the mid 1990s has been surveyed. Based on a 65% response, the findings indicate that the majority of undergraduate (pre-doctoral) students receive instruction in all-ceramic restorations with >75% gaining clinical experience in the use of such restorations prior to graduation. When clinical experience was not received, formal instruction, either in the regular curriculum or in elective studies was generally available. All the schools, with one exception, anticipated that the importance of teaching all-ceramic restorations would increase or at least stay the same. In general, the findings were similar to those reported in studies of the teaching of all-ceramic restorations in North America, Scandinavia, and the UK and Ireland, especially in relation to luting systems, contraindications and finishing instrumentation. However, clinical requirements for all-ceramic restorations in Central European dental schools were more common than in dental schools in North America, Scandinavia and the UK and Ireland.