A newly designed resonance frequency analysis device for dental implant stability detection

Resonance frequency (RF) analysis technology was used to design a new dental implant stability detector. To calibrate and test the performance of this novel apparatus, in vitro and in vivo models, respectively, were used. The RF values of the test implants detected using our new device and a commercially available analogous device (Osstell) were compared. Further, implant stability status was also detected clinically using our device at 2, 4, 8, and 12 weeks after surgery. A high correlation was demonstrated between the values measured with the two devices (y = 0.31x-12.45; R2 = 0.98, p < 0.05). In our clinical tests, an initial RF value above 10.0 kHz indicated that the implant was ready to accept functional loading, while values in the 4.0-10.0 kHz range reflected the need for further osseointegration. In conclusion, these results indicated that our new device might be useful in a clinical setting for evaluating the healing status of a placed implant.     

Immunoglobulins in milk from cows immunized with oral strains of Actinomyces, Prevotella, Porphyromonas, and Fusobacterium.

Immunization of pregnant cows with bacteria leads to the presence of high concentrations of specific antibodies in colostrum and milk. A total of 14 cows was immunized with single strains of heat-killed oral bacteria or pools of strains of Actinomyces, Porphyromonas, Prevotella, and Fusobacterium. Two cows were treated with adjuvant alone. The mean percentages of IgG1, IgG2, IgM, and IgA in all of the milks were 83.8, 3.8, 9.3, and 3.1, respectively. ELISA and whole cell agglutination assays demonstrated high titers in the milks from the cows immunized with either individual strains or the bacterial pools. The highest titers determined by ELISA belonged to the IgG1 isotype and in several milks were 64-fold greater than titers in milk from cows treated with adjuvant alone. The concentrations of all antibodies and the titers determined by ELISA and whole cell agglutination assays markedly decreased from the first to the sixth milkings. The functional specificity of the antibodies was demonstrated by agglutination tests against a wide range of bacteria including members of Actinomyces, Fusobacterium, Porphyromonas, Prevotella, Streptococcus, Eubacterium, Propionibacterium, Peptostreptococcus, Bacteroides, Actinobacillus, Haemophilus, Capnocytophaga, and Wolinella. Minimal cross-reactions with bacteria in other genera were observed with all of the milks. High-titer milk preparations have been obtained from immunized cows, and the capacity of the bovine antibodies to agglutinate target bacteria indicates their potential usefulness in oral passive immunization studies.     

Progressive dysphagia in an elderly male

Dysphagia can result from a variety of causes, including central nervous and peripheral nervous system, myogenic, and structural disorders. A 76-year-old man underwent anterior cervical disketomy and fusion 10 years ago, with progressive dysphagia noted 2 years ago. Endoscopy showed an oropharyngeal tumor, and lateral plain film evaluation of the neck revealed a cervical plate extrusion. Removal of the instrumentation and tumor with primary closure of the pharyngeal perforation was performed, and dysphagia was resolved postoperatively. We report the case of an unusual presentation in the pharynx. We should not neglect this rare diagnosis, because it can progress to a life-threatening outcome.     

Assessing the relationship between children's oral health status and that of their mothers

BackgroundThe authors conducted a study to describe the relationship between the oral health of young children and that of their mothers.MethodsUsing data from the Third National Health and Nutrition Examination Survey and a related birth certificate–linked file, the authors compiled a sample of 1,184 mother/child pairs for children aged 2 through 6 years. The authors performed logistic and cumulative logistic regression analyses by using children's caries experience and untreated caries status as dependent variables. They evaluated the mothers' untreated caries status and tooth loss status along with other covariates, including age, race/ethnicity and poverty status.ResultsChildren of mothers who had high levels of untreated caries were more than three times as likely (odds ratio [OR], 3.5; 95 percent confidence interval [CI], 2.0–6.2) to have higher levels of caries experience (treated or untreated dental caries) compared with children whose mothers had no untreated caries. A similar relationship was observed between mothers' tooth loss and caries experience among their children. The children of mothers with high levels of tooth loss were more than three times as likely (OR, 3.3; 95 percent CI, 1.8–6.4) to have higher levels of caries experience compared with children of mothers with no tooth loss; for mothers with moderate tooth loss, the OR was 2.3 (95 percent CI, 1.5–3.5).ConclusionsMothers' oral health status is a strong predictor of the oral health status of their children.Practice ImplicationsPreventive plans for children should be based on a caries risk assessment. The results of this study demonstrate that basic information obtained from the child's mother regarding her oral health status is valuable in helping the dentist determine the child's caries risk.     

Repeated oral hygiene instructions alone, or in combination with metronidazole dental gel with or without subgingival scaling in adult periodontitis patients: a one-year clinical study

The aims of the present study were to evaluate the clinical efficacy of, and to monitor microbiologically, repeated oral hygiene instructions alone or in combination with metronidazole 25% gel or subgingival scaling with or without metronidazole gel in treatment of new, residual or recurrent periodontal pockets in previously treated adult periodontitis patients. Ten suitable patients were included in this randomized single-blind clinical study with an intra-individual design. Clinical parameters were measured before and at 1, 3, 6, 9 and 12 months after treatment. Subgingival plaque samples were taken at every examination from one selected site in each quadrant. Smears from plaque samples were silver-stained and differential counting was performed under light microscopy at 1000X magnification. Four treatment modalities: (i) oral hygiene instruction (OHI) alone; (ii) OHI and metronidazole dental gel; (iii) OHI and subgingival scaling; (iv) OHI and subgingival scaling plus metronidazole gel, were randomly assigned to one quadrant of each patient. At the 12-month examination, the mean reductions in probing pocket depth were 2.6 mm after OHI alone, 2.8 mm after OHI and metronidazole gel, 3.3 mm after OHI and subgingival scaling and 2.6 mm after oral OHI and subgingival scaling plus metronidazole gel. The mean gains in probing attachment level were 2.2 mm, 1.9 mm, 2.7 mm and 1.6 mm, respectively. Although there were statistically significant differences in treatment responses between some treatment modalities at some time points, these were not considered to be clinically significant. Differential counts showed a shift towards a healthy microflora in response to all treatment modalities. From the 12-month results, it was concluded that the metronidazole 25% gel produced positive effects on the clinical parameters and on the subgingival plaque microbiological composition in new, residual or recurrent pockets in previously treated chronic periodontitis patients. However, the metronidazole gel alone or in combination with scaling does not seem to have any additional clinically significant therapeutic effects over and above those derived from improved oral hygiene resulting from monthly recalls, with or without subgingival scaling.     

Group distal movement of teeth using microscrew implant anchorage

The purpose of this study was to quantify the treatment effects of distalization of the maxillary and mandibular molars using microscrew implants. The success rate and clinical considerations in the use of the microscrew implants were also evaluated. Thirteen patients who had undergone distalization of the posterior teeth using forces applied against microscrew implants were selected. Among them, 11 patients had mandibular microscrew implants and four patients had maxillary implants, including two patients who had both maxillary and mandibular ones at the same time. The maxillary first premolar and first molars showed significant distal movement, with no significant distal movement of the anterior teeth. The mandibular first premolar and first and second molars showed significant distal movement, but no significant movement of the mandibular incisor was observed. The microscrew implant success rate was 90% over a mean application period of 12.3 +/- 5.7 months. The results might support the use of the microscrew implants as an anchorage for group distal movement of the teeth.     

Reposition of intruded permanent incisor by a combination of surgical and orthodontic approach: a case report

This report presents a case of a completely intrusive luxation of an immature permanent central incisor in a 7 years 9 months-old girl. Because there are severe intrusive trauma and cortical alveolar bone fracture, it was impossible to reposition with orthodontic or surgical method alone. The intruded tooth was repositioned to healthy alveolar bone level by using surgical extrusion and stabilization with sutures and periodontal pack. After healing of adjacent bone, the intruded maxillary central incisor erupted orthodontically by removable orthodontic appliance. It was moved from a high position to level of adjacent tooth in about 7 months. A radiograph was taken 6 months after ceasing forced eruption, which demonstrated minor root resorption, but the alveolar bone height had increased.     

Transverse molar movements during growth

The purpose of this study was to evaluate changes in molar crown torque and intermolar arch width from the time of permanent first molar eruption to early adulthood. Molar crown torque and intermolar arch width were measured in 36 untreated subjects with Class I occlusion from the Iowa Facial Growth Study at approximate ages 7.5, 10.3, 12.9, 16.5, and 26.4 years. On average, the mandibular first and second molars uprighted buccally by 5.0 degrees and 7.5 degrees, respectively. Mandibular first and second molar intermolar width increased by 2.2 and 0.78 mm, respectively. On average, maxillary first and second molars uprighted lingually by 3.3 degrees and 5.9 degrees, respectively. Maxillary first and second intermolar width increased by 2.8 and 2.0 mm, respectively. Results of statistical analysis by the Wilcoxon signed rank test indicate that (1) maxillary molars erupt with buccal crown torque and upright with age, whereas mandibular molars erupt with lingual crown torque and upright with age (P <.01), and (2) molar crown torque changes are accompanied by concurrent increases in maxillary and mandibular intermolar width (P <.01).     

Bone changes in the mandible following botulinum neurotoxin injections

In this study, botulinum neurotoxin type A (BoTx/A) was injected into the temporalis and masseter muscles of growing rats to induce masticatory hypoactivity. Sixty, 30-day-old, male Long-Evans rats were randomly divided into four groups. BoTx/A was bilaterally injected in the masseter muscles in group I, in the temporalis muscles in group II, and into both the masseter and the temporalis muscles in group III. Group IV served as the control in which saline was bilaterally injected into both muscles. Forty-five days after the injections, the rats were sacrificed. Observation of cortical bone thickness from bone biopsies of the right halves of the mandibles, evaluation of the volume of masseter and temporalis muscles with a plethysmometer, and scanning of bone mineral density (BMD) of the skull and mandibular bone structure with dual-energy X-ray absorptiometry were performed. One-way analysis of variance was employed to analyse measurements of muscle volume, BMD, and cortical bone thickness among the groups. The least square difference was then used to determine significance. Reduced cortical bone thickness and BMD of the skull and mandibular bone structure were observed. The volumes of the temporalis and masseter muscles injected with BoTx/A were smaller. Masticatory hypofunction affects bone structure during development.