Andreas Filippi

Tooth discoloration induced by endodontic materials: a laboratory study

AIM To investigate the discoloration potential of endodontic materials using a bovine tooth model. METHODOLOGY Two hundred and 10 dentine-enamel cuboid blocks (10 × 10 × 3.5 mm) were prepared out of the middle thirds of bovine tooth crowns. Standardized cavities were prepared in the walls of the pulp chamber leaving 2 mm of enamel and dentine on the labial wall of the crown. The specimens were randomly assigned to 14 groups (n = 15). Endodontic materials were placed into the cavities as follows: group A: empty, group B: blood, group C: calcium hydroxide, group D: ApexCal, group E: Ultracal XS, group F: Ledermix, group G: triple antibiotic paste (3Mix), group H: grey MTA(GMTA), group I: GMTA + blood, group J: white MTA (WMTA), group K: WMTA + blood, group L: Portland cement (PC), group M: PC + blood and group N: AH Plus. The cavities were sealed with composite and stored in water. Standardized colour measurement (VITA Easyshade compact) was performed at the following intervals: prior to (T0) and after placement of the filling (T1), 1 week (T2), 1 month (T3), 3 months (T4), 6 months (T5) and after 1 year (T6). Colour change (ΔE) values were calculated. A two-way analysis of variance was used to assess significant differences between the endodontic materials. The mean values of all groups were compared using the Tukey multiple comparison test (α = 0.05). RESULTS Significant differences were detected amongst the experimental groups after 12 months (P < 0.0001). The lowest colour change values were observed in the groups N (AH Plus, 3.2 ± 1.5), A (empty, 3.8 ± 1.4), L (PC, 4.1 ± 1.7), C (calcium hydroxide, 4.7 ± 1.5), E (Ultracal XS, 5.1 ± 1.9) and J (WMTA, 7.9 ± 6.7). The most discoloration was measured in groups G (3Mix, 66.2 ± 9.9) and F (Ledermix, 46.2 ± 11.6). PC showed the best colour stability amongst the Portland cement-based materials; however, when contaminated with blood (group M), a significantly higher ΔE value (13.6 ± 4.2) was detected (P = 0.032). CONCLUSION Materials used in endodontics may stain teeth. Therefore, the choice of material should not rely solely on biological and functional criteria, but also take aesthetic considerations into account.

Dental injuries resulting from tracheal intubation – a retrospective study

Even though it is known that dental injuries may occur in connection with tracheal intubation, the topic has hardly been evaluated in literature so far. Thus, this retrospective study was conducted including the data of 115-151 patients. All patients involved had been exposed to general anesthesia between 1995 and 2005. The resulting tooth injuries were assessed according to the following parameters: age, kind of hospital conducting treatment, intubation difficulties, pre-existing tooth damage, type and localization of tooth, type of tooth damage, and the number of teeth injured. At least 170 teeth were injured in 130 patients, while patients 50 years of age and older were especially affected. In contrast to older patients where in the majority of cases the periodontium (lateral dislocation) was injured, in younger patients dental hard tissue (crown fracture) was more likely to be affected. It was calculated that patients from the cardiothoracic surgery clinic were showing the highest risk of tooth damage. In more than three-fourth of all cases the anterior teeth of the maxilla, especially the maxillary central incisors, were affected. Pre-existing dental pathology like caries, marginal periodontitis and tooth restorations were often distinguishable prior to operation. Mouthguards in connection with tracheal intubation are not generally recommended as preventive device, due to the already limited amount of space available. Instead, pre-existing risk factors should be thoroughly explored before the induction of intubation narcosis.

Antimicrobial activity of Streptococcus salivarius K12 on bacteria involved in oral malodour

OBJECTIVE To investigate the antimicrobial activity of the bacteriocin-producing strain Streptococcus salivarius K12 against several bacteria involved in halitosis. DESIGN The inhibitory activity of S. salivarius K12 against Solobacterium moorei CCUG39336, four clinical S. moorei isolates, Atopobium parvulum ATCC33793 and Eubacterium sulci ATCC35585 was examined by a deferred antagonism test. Eubacterium saburreum ATCC33271 and Parvimonas micra ATCC33270, which have been tested in previous studies, served as positive controls, and the Gram-negative strain Bacteroides fragilis ZIB2800 served as a negative control. Additionally, the occurrence of resistance in S. moorei CCUG39336 to S. salivarius K12 was analysed by either direct plating or by passage of S. moorei CCUG39336 on chloroform-inactived S. salivarius K12-containing agar plates. RESULTS S. salivarius K12 suppressed the growth of all Gram-positive bacteria tested, but the extent to which the bacteria were inhibited varied. E. sulci ATCC35585 was the most sensitive strain, while all five S. moorei isolates were inhibited to a lesser extent. Natural resistance seems to be very low in S. moorei CCUG39336, and there was only a slight decrease in sensitivity after exposure to S. salivarius K12 over 10 passages. CONCLUSION Our studies demonstrate that S. salivarius K12 has antimicrobial activity against bacteria involved in halitosis. This strain might be an interesting and valuable candidate for the development of an antimicrobial therapy for halitosis.

Dental injuries in mountain biking : a survey in Switzerland, Austria, Germany and Italy

Mountain biking is considered an extreme sport, causing not only head and neck injuries, but also injuries to every part of the body. Using standardised interview, the aim of this work was to survey the frequency of dental injuries in mountain biking, as well as the behaviour of athletes after experiencing dental trauma, depending on their intensity level. Furthermore, habits of wearing helmets and mouthguards as well as knowledge about the tooth rescue kit were investigated. A total of 423 male mountain bikers from Germany, Italy, Austria and Switzerland were surveyed for this study, including 50 juniors from Switzerland. 27 athletes (5.7%) had endured tooth accidents in mountain biking. Only 246 (52%) were aware of the fact that avulsed teeth can be replanted, and only 30 individuals knew about the tooth rescue kit (6.3%). 71.9% (n=340) were familiar with mouthguards; however, only 21 individuals (4.4%) used mouthguards while mountain biking. The results show that where mountain biking is concerned, more information about prevention is required.

The antimicrobial activity of alpha-bisabolol and tea tree oil against Solobacterium moorei, a Gram-positive bacterium associated with halitosis

OBJECTIVE To investigate the antimicrobial effect of alpha-bisabolol and tea tree oil alone and in combination against the halitosis-associated Gram-positive bacillus Solobacterium moorei. DESIGN The inhibitory activity of alpha-bisabolol and tea tree oil against the reference strain S. moorei CCUG39336 and four clinical S. moorei isolates was investigated by a direct exposure test. Additionally, the ability of alpha-bisabolol to increase the sensitivity of S. moorei was tested by pretreating the bacteria with sublethal concentrations prior to the administration of tea tree oil. RESULTS A dose-dependent killing was observed for the antimicrobial agents in a direct exposure test with the reference strain S. moorei CCUG39336. Concentrations of ≥0.5% tea tree oil caused decreases in viability of >5 log colony forming units/ml even after short incubation periods, while bacterial viability was less affected by alpha-bisabolol. The combination of 0.1% alpha-bisabolol plus 0.05% tea tree oil showed a synergistic effect on S. moorei strain CCUG39336 and on two of the four clinical S. moorei isolates tested. However, incubation of S. moorei with a sublethal concentration of 0.1% alpha-bisabolol for three days prior to the administration of 0.05% tea tree oil did not enhance the antibacterial effect of tea tree oil. CONCLUSION Halitosis-associated bacterium S. moorei is susceptible to the antimicrobial agents tea tree oil and alpha-bisabolol, suggesting that these compounds might be beneficial in oral healthcare products.

Patient assessment and diagnosis in implant treatment

As in any dental treatment procedure, a thorough patient assessment is a prerequisite for adequate treatment planning including dental implants. The literature was searched for references to patient assessment in implant treatment up to September 2007 in Medline via PubMed and an additional handsearch was performed. Patient assessment included the following aspects: (1) evaluation of patients history, his/her complaints, desires and preferences; (2) extra-and intra-oral examination with periodontal and restorative status of the remaining dentition; (3) obligatory prerequisites were a panoramic radiograph and periapical radiographs (at least from the adjacent teeth) for diagnosis and treatment planning. Additional tomographs are required depending on the anatomic situation and the complexity of the planned restoration; (4) study casts are needed especially in more complex situations also requiring a diagnostic set-up, which can be tried-in and transferred into a provisional restoration as well as into a radiographic and surgical template. The current review clearly revealed the necessity for a thorough, structured patient assessment. Following an evaluation, a recommendation is given for implant therapy or, if not indicated, conventional treatment alternatives can be presented.

Detection of peri-implant bone defects with different radiographic techniques – a human cadaver study

OBJECTIVES Two- and three-dimensional radiographic techniques are available to determine peri-implantitis-related bone loss around dental implants. PURPOSE To compare the performance of detecting different peri-implant bone defects in intraoral radiography (IR), panoramic radiography (PR), Cone Beam Computer Tomography (CBCT) and Computer Tomography (CT). MATERIAL AND METHODS Six implants were inserted under ideal conditions into the lower jaw of an edentulous human cadaver. IR, PR, CBCT and CT were performed. Two-wall, three-wall and four-wall defects with 1 mm depth were artificially created around two of the implants (one anterior and one posterior), and radiographies were repeated. The identical set-up was used for 3-mm-deep bone defects. All images were presented to seven observers. Sensitivity (SN) and specificity (SP) were determined for each modality, defect type and depths, and likelihood ratios were calculated. RESULTS The highest sensitivity was found with IR and CBCT for 1 mm (0.67; 0.68) and 3-mm defects (0.81; 0.79). The highest specificity was found with IR for both defect depths (0.51). The best classification of defect type revealed PR for both 1-mm and 3-mm-deep defects. Both likelihood ratios (LR+ and LR-) were best for IR with 1-mm (1.37 and 0.65) and with 3-mm defects (1.65 and 0.37). CONCLUSIONS IR should still be recommended as favourable method evaluating bone loss around dental implants, while CT demonstrated the lowest performance in detecting peri-implant bone defects.

Intraosseous temperature changes during the use of piezosurgical inserts in vitro

This study concerns intraosseous temperature changes during the use of piezosurgical inserts. On six fresh pig jaws heated to body temperature (36°C), osteotomies and osteoplasties were performed in vitro with the Piezosurgery(®) 3 device (Mectron, Carasco, Italy) and various inserts. The intraosseous temperature increases were measured at a depth of 3mm and at a distance of 1mm from the working site using nickel-chromium/nickel temperature sensors. 20°C Ringers solution was used for cooling in an initial test series and 10°C Ringers in a second series. The processed bone was examined using digital volume tomography images to determine the ratio of cortical to cancellous bone thickness. Mean temperature increases of 4.4-10.9°C were found; maximum temperature peaks were over 47°C for an average of only 8.5 s. The type of piezosurgical insert had a marked influence on intraosseous temperature generation (p=0.026); the thickness of the cortical bone and the temperature of the coolant did not. Coolant temperature had an influence on the bone cooling time (p=0.013). The results show that correct use of the piezosurgery device does not give rise to prolonged temperature increases over 47°C and hence does not cause any irreversible thermal damage in the bone.

Methicillin-resistant Staphylococcus aureus (MRSA) among dental patients: a problem for infection control in dentistry?

We assessed the frequency of carriers of methicillin-resistant Staphylococcus aureus (MRSA) among 500 dental patients of a university clinic. From each participant, two specimens were taken from the anterior nares and the pharynx and analysed by culture. The participants completed a questionnaire on possible risk factors of MRSA infection. Two hundred ten individuals carried S. aureus, 90 in the nares only, 51 in the throat only and 69 in nares and throat. Isolates of 208 patients were methicillin-sensitive; two isolates were methicillin-resistant, both carried in the throat exclusively. In conclusion, the frequency of nasal and/or throat carriers of MRSA among dental patients was low and suggests few opportunities of exposure in the dental clinic assessed.

Practicability of a tooth rescue concept--the use of a tooth rescue box.

Healing following replantation of avulsed teeth is dependent upon short unphysiologic periods during the extraalveolar phase. A commercially available tooth rescue box was developed and distributed at schools in Hessen, a state in Germany. Aim of the study was to evaluate the availability times of rescue boxes and the storage periods of rescued teeth within the boxes. Two thousand one hundred tooth rescue boxes together with a questionnaire were distributed predominantly at schools. In case of usage of a box, the questionnaire should be filled out by patients and dentists and sent back for evaluation. One hundred seventy-two (8.2%) questionnaires were sent back. Eighteen questionnaires were incomplete. In the remaining 154 tooth rescue boxes, a total of 201 avulsed teeth and tooth crown fragments were rescued. When accidents occurred near a stored rescue box, the availability time was short (median: 5 min). It was significantly longer (median: 35 min) when the location of the accident was distant to a stored box. Storage of avulsed teeth in the tooth rescue box was longer (median: 2 h) than storage of fractured crown fragments (median: 1 h). Lay people (teachers, pupils) used the rescue boxes correctly without professional help or even advice through telephone. The usage of the tooth rescue box seemed to be self-explanatory and plausible to lay persons, very short availability times resulted when accidents occurred near stored boxes. Thus, an excellent healing prognosis can be anticipated after replantation. The storage periods of avulsed teeth before the commencement of treatment exceed by far the periods that are acceptable for alternative but unphysiologic media (saline, saliva, milk). It is concluded that tooth rescue boxes should be distributed at locations prone to tooth traumas (schools, kindergartens, sporting facilities, public pools) to enhance the prognosis of avulsed teeth. Emergency units (hospitals, ambulances) should be equipped with tooth rescue boxes as well as every dentist. Tooth rescue boxes are recommended for families with children.