Histological and histomorphometric study of human palatal mucosa: Implications for connective tissue graft harvesting.

AIMS: To analyse the histological structure and histomorphometric characteristics of human hard palatal mucosa in order to determine the donor site of choice for connective tissue grafts from a histological point of view. MATERIALS AND METHODS: Palatal mucosa samples from six cadaver heads were harvested at four sites: incisal, premolar, molar and tuberosity. Histological and immunohistochemical techniques were performed, as was histomorphometric analysis. RESULTS: In the current study, we found that the density and size of cells were higher in the superficial papillary layer, whereas the thickness of the collagen bundles increased in the reticular layer. Excluding the epithelium, the mean percentage of lamina propria (LP) and submucosa (SM) was 37% and 63%, respectively (p < .001). LP thickness showed similar values in the incisal, premolar and molar regions, and a significantly greater thickness in tuberosity (p < .001). The thickness of SM increased from incisal to premolar and molar, disappearing in the tuberosity (p < .001). CONCLUSIONS: As dense connective tissue of LP is the tissue of choice for connective tissue grafts, the best donor site from a histological point of view is tuberosity because it is composed only of a thick LP without the presence of a loose submucosal layer.

Pseudoepitheliomatous hyperplasia after diode laser oral surgery. An experimental study.

BACKGROUND: to examine the process of epithelial reparation in a surgical wound caused by diode laser. MATERIAL AND METHODS: An experimental study with 27 Sprage-Dawley rats was undertaken. The animals were randomly allocated to two experimental groups, whose individuals underwent glossectomy by means of a diode laser at different wattages, and a control group treated using a number 15 scalpel blade. The animals were slaughtered at the 2nd, 7th, and 14th day after glossectomy. The specimens were independently studied by two pathologists (blinded for the specimens' group). RESULTS: at the 7th day, re-epithelisation was slightly faster for the control group (conventional scalpel) (p=0.011). At the 14th day, complete re-epithelization was observed for all groups. The experimental groups displayed a pseudoepitheliomatous hyperplasia. CONCLUSIONS: it is concluded that, considering the limitations of this kind of experimental studies, early re-epithelisation occurs slightly faster when a conventional scalpel is used for incision, although re-epithelisation is completed in two weeks no matter the instrument used. In addition, pseudoepitheliomatous hyperplasia is a potential event after oral mucosa surgery with diode laser. Knowledge about this phenomenon (not previously described) may prevent diagnostic mistakes and inadequate treatment approaches, particularly when dealing with potentially malignant oral lesions.

In vivo antiplaque effect of three edible toothpastes.

OBJECTIVES: The objective of this study was to analyse the antibacterial and antiplaque activity of three edible toothpastes with the widest worldwide distribution: KidScents™, which contains essential oils; Browning B& B™, with medicinal plants; and Wysong Probiodent™, which contains probiotics. STUDY DESIGN: The study group was formed of twenty healthy volunteers (dental students) with a good oral health status. Using a balanced randomisation system, all volunteers performed toothbrushing with four products (the three edible toothpastes and water) at intervals of one week. Bacterial vitality in the saliva was analysed by epifluorescence microscopy and plaque regrowth was evaluated using the Turesky-Quigley-Hein plaque index. RESULTS: Bacterial vitality in the saliva was significantly higher after toothbrushing with water (positive control) than with the three toothpastes (P=0.002, P=0.003 and P<0.001, respectively). The plaque index was significantly higher after using these three toothpastes than after toothbrushing with water (P=0.047, P=0.032 and P<0.001, respectively). CONCLUSIONS: The three edible toothpastes analysed have some antimicrobial activity but favour plaque regrowth.

In vivo substantivity of 0.12% and 0.2% chlorhexidine mouthrinses on salivary bacteria.

The in vivo antimicrobial activity of 0.12% and 0.2% chlorhexidine (CHX) on the salivary flora up to 7 h after its application, using epifluorescence microscopy with the SYTO 9/propidium iodide dual staining, was evaluated. Fifteen volunteers performed a single mouthrinse with sterile water (SM-water), a single mouthrinse with 0.12% CHX (0.12% SM-CHX) and a single and double mouthrinse with 0.2% CHX (0.2% SM-CHX and 0.2% DM-CHX). Samples of saliva were taken at 30 s, and 1, 3, 5, and 7 h after each application. In comparison with SM-water, 0.2% CHX (SM and DM) showed a significant antibacterial effect up to 7 h after the mouthrinse, whereas this effect only persisted up to 5 h after the 0.12% SM-CHX mouthrinse. On comparing the two concentrations of CHX, significantly higher percentages of bacterial vitality were observed in all the saliva samples after the use of 0.12% CHX than after 0.2% CHX. On comparison of the 0.2% SM-CHX and 0.2% DM-CHX, significantly higher percentages of live bacteria were observed in the saliva samples taken at 1, 3, 5, and 7 h after the single mouthrinse compared with the double mouthrinse. The 0.2% CHX mouthrinse had the greatest antimicrobial activity on the salivary flora up to 7 h after its application, with a progressive recovery in bacterial vitality. The differences observed with respect to the 0.12% CHX mouthrinse demonstrate the influence of the concentration on its immediate antimicrobial activity and substantivity.

The effect of dentist experience on the treatment of individuals with disability under general anesthesia.

AIMS: The aim of the present work was to assess in patients with severe disability operated under general anesthesia whether the progressive acquisition of experience by the dental team affects the type of procedure performed and the duration of operations. METHODS AND RESULTS: A study group of 911 patients who underwent dental treatment under general anesthesia between 1997 and 2014 was conformed. Information was collected from every patient including: dental diagnosis, dental procedures and duration of the operating times. To analyze the impact of the operators' experience, the study period was divided into three 6-year periods. The most prevalent systemic diagnosis was "mental disease and behavior disorders" (42.9%). The most common dental procedures were extractions and fillings. Fewer extractions were performed during the third 6-year period (p = .000). Compared with the other two periods, during the first period fewer composite fillings (p = .000 and p = .000, respectively) and more fissure sealants (p = .001 and p = .023, respectively) were performed. The number of amalgam fillings decreased progressively (p = .000). There was a statistically significant reduction in the mean duration of the operations between the first and third period (p = .002). CONCLUSION: The dental team's experience entailed a significant reduction in the duration of operations.

Brief Report: Estimating the Dental Age of Children with Autism Spectrum Disorders.

Determining a patient's dental age is essential from the dental standpoint but can also have connotations of a forensic, anthropological and medicolegal nature. In this study, we assessed the correspondence between dental age and chronological age in a group of 50 children with autism spectrum disorders, with a chronological age range of 3-17 years. The dental age was calculated using panoramic radiography images, applying linear regression models derived from the classical indices by Nolla and Demirjian. In 2 of every 3 boys, the dental age was ahead of the chronological age, and in almost 1 of every 3 cases, the difference was ≥ 12 months. In the girls, conversely, we found no significant differences between dental age and chronological age.

Effect of chewing an apple on dental plaque removal and on salivary bacterial viability.

OBJECTIVES: Studies on dental plaque removal by chewing an apple are scarce and dated, with conflicting findings. This study aimed to determine whether chewing an apple produced mechanical removal of dental plaque or had any effect on salivary bacterial viability. METHODS: The study group consisted of 20 healthy adults with good oral health status who were randomly assigned to brush their teeth or eat an apple. After 2 weeks, the experiment was repeated with the order reversed. Plaque index (PI) and the bacterial viability (BV) in a sample of whole saliva (spit) were determined before brushing or apple eating (baseline, B), immediately afterward (A) and 24 hours afterward (24). RESULTS: After chewing an apple, PI-A was significantly higher than both PI-B (P < .001) and PI-24 (P < .001). BV-A was significantly lower than BV-B (P < .001), with a return to baseline values at the BV-24 measurement. CONCLUSIONS: Chewing an apple does not remove dental plaque, and may favor plaque regrowth during the first 24 hours, but it does produce an immediate reduction in salivary bacterial viability similar to that after tooth brushing.

Oral health status in patients with moderate-severe and terminal renal failure.

AIMS: To evaluate the oral health status of patients with moderate-severe chronic renal failure (CRF) and with terminal renal failure (TRF). DESIGN: The study group was formed of 50 patients: 22 (44%) with moderate-severe CRF and 28 (56%) with TRF included in a haemodialysis programme. The controls (n=64) presented similar characteristics with regard to sex, age, weight and educational level. A single dentist performed an intraoral examination on all the subjects, gathering information on: number of decayed, missing or filled teeth; supragingival plaque accumulation; calculus deposits; periodontal pockets in the Ramfjord teeth; and depth of loss of insertion. RESULTS: No significant differences were detected in the values of the DMF index between the two groups. The mean number of decayed teeth was lower in the patients than in the controls, showing a tendency to statistical significance (p=0.052). The mean number of missing teeth was higher in the patients than in the controls (p=0.002). Twelve patients and seven controls were completely edentate. The mean number of filled teeth was significantly lower in the patients than the controls (p<0.001). Supragingival plaque accumulation and the loss of insertion were significantly greater in the patients than in the controls (p=0.006 and p<0.001, respectively). No significant differences were found with respect to the calculus deposits or to the presence of periodontal pockets in the two groups. The value of the DMF index, the mean number of teeth with caries and the number of filled teeth were significantly higher in the patients with moderate-severe CRF than in the patients with TRF (p=0.004, p=0.030 and p=0.006, respectively). CONCLUSIONS: Patients with CRF have a lower prevalence of caries, more supragingival plaque, more teeth with a loss of insertion and more missing teeth than the healthy controls. The prevalence of caries is affected by the severity of the renal failure and/or by haemodialysis treatment.

Unsuspected foreign body aspiration.

Aspiration of foreign bodies is a serious complication that may occur during the course of dental treatment. A case report of a 60-year-old man with recurrent pneumonia is presented. One year after the onset of his initial symptoms, a hard substance that made a complete mold of the bronchial tree at the inferior right lobe was extracted with a rigid bronchoscopy. This green material of elastic consistency was dental impression material (polyvinylsiloxane). On careful questioning, the patient indicated that he had dental impressions taken 2 months before the onset of the symptoms. Surgery was indicated and lobectomy of the inferior right lobe was performed without incident. To avoid this complication, some preventive precautions such as identifying high-risk patients; using rubber dam; tethering any small instrument with a ligature; placing a gauze screen to protect the oropharynx in sedated patients; and using custom impression trays to minimize the amount of impression material required have been suggested. In case of a suspected aspiration, the patient must be referred to appropriate medical care.

Chlorhexidine substantivity on salivary flora and plaque-like biofilm: an in situ model.

OBJECTIVE: To evaluate the in situ antibacterial activity of a mouthrinse with 0.2% Chlorhexidine (M-0.2% CHX) on undisturbed de novo plaque-like biofilm (PL-biofilm) and on salivary flora up to 7 hours after its application. METHODS: A special acrylic appliance was designed, with 3 inserted glass disks on each buccal side, allowing for PL-biofilm growth. Fifteen healthy volunteers wore the appliance for 48 hours and then performed an M-0.2% CHX; disks were removed at 30 seconds and 1, 3, 5 and 7 hours after the mouth-rinsing. Applying a washout period, saliva samples were collected from each volunteer at 30 seconds and 1, 3, 5 and 7 hours after performing an M-0.2% CHX. The PL-biofilm and saliva samples were analysed by confocal laser scanning and epifluorescence microscopes, respectively. RESULTS: At 30 seconds after M-0.2% CHX, the levels of viable bacteria detected in saliva were significantly lower than those observed in PL-biofilm. The difference in the percentage of live bacteria detected in saliva was significantly higher than that observed in PL-biofilm at 5 and 7 hours after M-0.2% CHX. CONCLUSION: After a single mouthrinse of the 0.2% CHX formulation tested in the present study, the 2-day PL-biofilm presented a significantly higher resistance to this antiseptic in situ than that observed in salivary flora. However, this 0.2% CHX formulation showed a higher substantivity on PL-biofilm than on salivary flora at 5 and 7 hours after mouth-rinsing, which could be related to the slower growth rate of PL-biofilm and the possible reservoir function for antimicrobial agents associated with the undisturbed de novo PL-biofilm.

In situ chlorhexidine substantivity on saliva and plaque-like biofilm: influence of circadian rhythm.

BACKGROUND: The aim of the present study is to assess in situ substantivity of a single mouthrinse with 0.2% chlorhexidine (CHX) on saliva and on undisturbed de novo plaque-like biofilm (PL-biofilm), differentiating between two times of application: 1) CHX mouthrinse in the morning; and 2) CHX mouthrinse at night. METHODS: The study participants were 10 healthy volunteers who wore an individualized splint with glass disks for 48 hours to boost the growth of PL-biofilm. Saliva samples were collected, and two disks were removed from each volunteer's splint at 8, 10, and 12 hours after performing a mouthrinse with 0.2% CHX at 7:00 am (M-0.2% CHX-diurnal) and 1:00 am (M-0.2% CHX-nocturnal). The saliva and plaque samples were analyzed by epifluorescence and confocal laser scanning microscopy, respectively, using a green fluorescent nucleic acid stain/propidium iodide staining. RESULTS: With M-0.2% CHX-diurnal, the frequency of vital bacteria in saliva was significantly higher than in the PL-biofilm at 8, 10, and 12 hours after mouthrinse. After M-0.2% CHX-nocturnal, the frequency of vital bacteria in saliva was significantly lower than in the PL-biofilm at 8 hours and higher than in the PL-biofilm at 12 hours after mouthrinse. CONCLUSION: These results support the more active physiologic dynamics of the salivary flora and the possible reservoir function associated with the structure of undisturbed de novo PL-biofilm.

Membrane perforation in sinus floor elevation - piezoelectric device versus conventional rotary instruments for osteotomy: an experimental study.

PURPOSE: Sinus membrane perforation is the most common intraoperative complication of maxillary sinus floor elevation (MSFE) procedures and frequently causes postoperative problems. Piezoelectric devices have been claimed to reduce the frequency of membrane perforations although no clear evidence supports this view. MATERIALS AND METHODS: Ten surgeons with different expertise levels performed 80 MSFEs in selected lamb heads, with rotary and piezoelectric instruments following standard protocols. After the procedures, specimens were coded and perforations or tears determined through a microscope. RESULTS: No significant differences in terms of thickness either of the sinus lateral wall (xi -xj = 73.2; 95% confidence interval [CI] = 45.3-191.8) or the membrane (xi -xj = 24.2; 95% CI = -29.4 to 77.9) were identified between the specimens allocated to each group. Nine membrane perforations (11.2%) occurred during the study, all within the lower expertise group. Membrane elevation by hand instruments caused five perforations (40%) in the rotary instrument group and one in the piezoelectric group. Expert surgeons produced no membrane perforations, the size of the antrostomy that was smaller in the piezoelectric group being the only significant difference between the rotary and piezoelectric groups. CONCLUSIONS: The use of piezoelectric material for MSFE reduces the frequency of membrane perforation among surgeons with a limited experience.

Lamb ex vivo model for training in maxillary sinus floor elevation surgery: a comparative study with human standards.

BACKGROUND: Many models have been suggested for surgical training in sinus floor elevation (SFE), but information on key features that provide feedback to the trainee is scarce. The aim of this study is to compare the thickness of the lateral wall of the maxillary sinus (TLWMS) and the thickness of the Schneiderian membrane (TSM) between an animal model and the human standard. METHODS: The observational study used 20 fresh lamb heads. Cone-beam computed tomography (CT) was performed for recording the following: TLWMS, sinus lateral floor width, distance from the lateral border of the anteroposterior bone crest to the sinus wall, and height of lateral maxillary sinus. Thirty human radiologic exploration cone-beam CTs were used for comparisons. The sinus membrane thickness was measured at three points per section and compared to those of 10 formalin-preserved human membranes. RESULTS: TLWMS in the animal model scored 2.25 ± 0.3 mm and was thicker than that of humans with subsinusal edentulism (Xi - Xj = 0.3; 95% confidence interval = 0.1 to 0.4), although this difference was not considered clinically relevant. The average thickness of the sinus membrane was 485.5 ± 137.1 µm with no significant differences between sides (P = 0.12) or between the thickness of human and lamb Schneiderian membranes. CONCLUSIONS: The model based on lambs is potentially useful for training in SFE techniques because of the similarities in the TLWMS and particularly the TSM. Additional studies are needed to validate this model within a teaching environment.

Evaluation of the substantivity in saliva of different forms of application of chlorhexidine.

OBJECTIVE: To evaluate the in vivo antimicrobial activity of different forms of application of chlorhexidine digluconate (CHX). METHOD AND MATERIALS: A group of 10 volunteers performed mouth rinsings with a 0.2% and 0.12% solution of CHX and applied CHX in the form of a 0.2% gel, a 0.2% and a 0.12% spray and a swab impregnated with a 0.2% solution. Samples of saliva were taken at baseline; 30 seconds; and 1, 3, 5, and 7 hours after each application. An epifluorescence microscopy technique (BacLight Live/Dead stain) was used to evaluate bacterial vitality. RESULTS: Bacterial vitality under basal conditions was 92%. At 30 seconds after CHX application, the lowest levels of viable bacteria were detected with the 0.2% and 0.12% solutions (1% and 8%, respectively). After 3 hours, the percentage of live bacteria achieved with the gel and sprays was similar to the basal figures (80% to 91%). At 7 hours, bacterial vitality recovered basal percentages, except with the 0.2% solution (77%). CONCLUSION: The 0.2% solution of CHX had the greatest sustained antimicrobial effect on the salivary flora, confirming the influence of the concentration and form of application on CHX substantivity.