Displacement of oropharyngeal structures during suction-swallowing cycles.

Suction ability plays an important role in supporting oral nutrition and needs special care following neurological disorders and tumor-associated defects. However, the details of suction are still poorly understood. The present study evaluates displacement of orofacial structures during suction and deglutition based on manometric controlled MRI. Nine healthy subjects were scanned wearing an intraoral mouthpiece for water intake by suction and subsequent swallowing. Suction-swallowing cycles were identified by intraoral negative pressure. Midsagittal MRI slices (3 T; temporal resolution 0.53 s) were analyzed at rest, suction and pharyngeal swallowing. The mandibular displacement was measured as the distance between the anterior nasal spine and the inferior point of the mandible. Following areas were defined: subpalatal compartment (SCA), retrolingual (RLA), epipharyngeal (EPA) and mouth floor area (MFA). During rest, an average distance of 7 cm was observed between the mandibular measurement points. The measured SCA was 3.67 cm(2), the RLA 6.98 cm(2), the EPA 9.00 cm(2) and the MFA 15.21 cm(2) (average values). At the end of suction, the mandibular distance reduces (to 6.88 cm), the SCA increases significantly (to 5.96 cm(2); p = 0.0002), the RLA decreases (to 6.45 cm(2)), the EPA increases (to 10.59 cm(2)) and the MFA decreases (to 15.02 cm(2)). During deglutition, the mandible lifted significantly (to 6.81 cm; p = 0.0276), the SCA reduced to zero, the RLA was not measurable, the EPA reduces significantly (to 3.01 cm(2); p < 0.0001) and the MFA increases (to 16.36 cm(2)). According to these observations, a combined displacement of the tongue in an anteroposterior direction with active tongue dorsum-velum contact appears to be the predominant activity during suction and responsible for the expansion of the subpalatal area.

An appraisal of the current and potential value of web 2.0 contributions to continuing education in oral implantology.

OBJECTIVE: To systematically assess the informational value, quality, intention, source and bias of web 2.0 footage whose aim is peer-to-peer education about oral implantology. METHODS: YouTube (http://www.youtube.com) was scanned on 15 October 2010 for oral implantology-related videos using an adequately pre-defined search query. Search results were filtered with the system-generated category 'education' and the additional criterion 'most viewed'. Only those videos with at least 1000 views were included (total 124, of which 27 were excluded because they were not related to implantology). Filtered videos were discussed and rated with particular regard to the educational needs of potential groups of addressees [(i) undergraduates and laymen, (ii) dentists without or currently undergoing a specialisation in oral implantology and (iii) dentists who have completed a specialisation in the field of oral implantology] by a jury consisting of (i) an accredited post-graduate university instructor with 22 years of professional teaching experience in the field of implantology, (ii) a university lecturer in dentistry/orthodontics with 10 years teaching experience and (iii) a university haematologist/oncologist. They were required to fill out a questionnaire for each video. The data were statistically analysed using non-parametric ANOVA (α = 5%) and a sign test (α = 0.05/3 = 0.017). RESULTS: The YouTube scan produced 1710 results in the category 'EDU'. The analysis revealed that there is a wide range of instructional footage on this topic, but with highly variable range in quality and informational value. Footage intention was to large proportions (47.4%) a mixture of education and advertisement. Its usefulness differed significantly for the three groups of addressees, offering greater novelty to undergraduates and post-graduates. CONCLUSION: YouTube and similar social media websites may have a potential capacity and value in complementing continuing education in the technique of oral implantology. As a means of achieving an acceptable level of knowledge about the topic when used alone, it should not be considered to be suitable at this point in time.

Tongue position after deglutition in subjects with habitual open-mouth posture under different functional conditions.

OBJECTIVE: To test the null hypothesis of no significant differences in (1) the duration of the post-deglutory, cranial tongue rest position (CTP) between different functional orofacial conditions and (2) the presence or absence of an oral screen (OS) in subjects with a habitual open-mouth posture. SUBJECTS: Twenty-nine subjects (aged 6-16; mean: 9.69 years; 13/16 girls/boys) were selected according to the inclusion criterion of a habitual, daytime open-mouth posture. METHODS: Deglutition was screened at baseline during resting respiration using orofacial polysensography and simultaneous assessment of tongue-to-palate position and nasal airstream, during five functional intervals of 8 min each: F1 without instruction (RR); F2 the same, but including an oral screen (RROS); F3 with OS and the instruction to maintain a tongue-to-palate contact (IROS); F4 with OS and the instruction to perform tongue repositioning manoeuvres at the time of spontaneous swallowing (TRMOS); and F5 corresponds to F3 omitting OS (IR). Duration and frequency of deglutition were analysed descriptively as well as by anova and subsequent multiple comparisons, and the CTP was evaluated with chi-square tests and paired comparisons at a significance level of 5%. RESULTS: Of 542 identified swallowing acts, 75% were accompanied by a post-deglutory CTP. Mean duration of CTP increased for functional conditions RR/1.01s > RROS/2.56s > IR/3.21s > IROS/6.53s > TRMOS/6.58s. The null hypothesis (1) was rejected in comparison of resting respiration (F1, F2) with IROS and TRMOS, whereas the use of an oral screen alone did not significantly prolong the duration of CTP.

Comparative study using video analysis and an ultrasonic measurement system to quantify mandibular movement.

OBJECTIVES: This study provides a direct comparison between two registration systems used in quantifying mandibular opening movements: two-dimensional videography and electronic axiography, which is used as a reference. METHOD: A total of 32 volunteers (age: 27.2 ± 6.8 - gender: 17 F - 15 M) participated in the study and repeated a characteristic movement, the frontal Posselt, used in the clinical evaluation of the temporomandibular joint. RESULTS: Frontal Posselt diagrams were reconstructed with the data gathered from both systems, which yielded acceptably similar data. Three commonly assessed parameters were obtained from each diagram and compared. These parameters were: maximum opening, right laterotrusion and left laterotrusion. Both descriptive statistics and the ANOVA test suggested that there was no significant difference between the estimated maximum opening parameter and the reference system (p = 0.217, 95% confidence). Laterotrusion values, on the other hand, appear to be overestimated by videography system and to show greater variability. DISCUSSION: Two-dimensional videography appears to be a suitable tool with resolution that is adequate for tracing mandibular movements - and opening values, in particular - for screening purposes, long-term observation, and as a quick check for dysfunction as far as frontal plane trajectories are concerned. CONCLUSION: Reliability and acceptable quality of 2D videography data, acquired in this work, show that it has clear advantages for its wide application in the dental office due to simplicity and low cost for maximum opening measurement given the usefulness of this parameter in the detection of temporomandibular disorders.

Must radiation dose for CT of the maxilla and mandible be higher than that for conventional panoramic radiography?

We evaluated the feasibility of performing preoperative spiral CT of the maxilla and mandible with a radiation dose similar to that used for conventional panoramic radiography. The skin entrance doses of radiation used for spiral CT (collimation, 1 mm; pitch, 2; tube voltage, 80 kV; tube current, 40 mA) and for panoramic radiography (75 kV, 8 mA, 15 seconds) were measured in one patient by using thermoluminescent dosimeter chips. Results were 0.56 +/- 0.06 mGy for CT and 0.59 +/- 0.04 mGy for radiography. Image quality was adequate for preoperative implant planning. Spiral CT of the mandible and maxilla may therefore be feasible with a radiation dose of similar magnitude as that used for conventional panoramic radiography.

Alveolar reconstruction with splitting osteotomy and microfixation of implants.

This report describes a surgical technique for reconstruction of the buccolingually reduced alveolar process. The technique involves the preparation of an artificial socket with immediate implant placement, which reduces total treatment time compared with two-stage procedures. Alveolar preparation comprises lamellar cortical splitting of the alveolus, interlamellar implant placement, and primary stabilization based on a microfixation technique. It was used for a wide range of indications involving single and multiple alveoli related to the partially dentate and the edentulous alveolar process. The results of 24 Branemark standard implants and 97 ITI implants with 44 consecutively treated patients have been reviewed with a mean observation time of 34.3 months (range 6 to 68 months). The main indicator for alveolar reconstruction was the narrow anterior maxillary arch. The 5-year cumulated success rate was 86.2%. Twelve implants failed during the observation period. The mean marginal bone loss was 1.7 mm (range 0 to 7.5 mm). There was a low infection rate compared with membrane-based GTR techniques. Treatment costs were low as a result of shorter treatment time.

Complications following arthroscopy of the temporomandibular joint: analysis covering a 10-year period (451 arthroscopies).

451 arthroscopies of the temporomandibular joint (TMJ) have been performed on 373 patients during 10 years of clinical experience. The complication rate was low (1.77%). Most complications were transient, consisting mainly of temporary deficits of the 5th and 7th cranial nerves. No patient required arthrotomy because of complications, but one patient had to undergo angiography and embolization of a traumatic aneurysm of the superficial temporal artery secondary to arthroscopy.

Loose bodies in the temporomandibular joint. The advantages of arthroscopy.

Loose bodies are a rare cause of temporomandibular joint symptoms. Their main source is synovial chondromatosis. We report on clinical findings, diagnostic methods, treatment choices and outcome following the removal of loose bodies in 10 patients. Seven patients were evaluated and treated by means of arthroscopy, while in three patients open arthrotomy was performed. In five patients, no diagnostic imaging technique had demonstrated the presence of loose bodies prior to arthroscopy. In six patients, histology revealed synovial chondromatosis. In four patients, osteochondral fragments alone were found. Until now, the recommended treatment of choice for the removal of all loose bodies and of affected synovial tissue required open arthrotomy. We conclude that the advantages of arthroscopy consist in locating loose bodies that are not detectable radiologically and in reducing operative trauma.

Diagnostic accuracy of TMJ arthroscopy in correlation to histological findings.

From 1987-1993, 356 arthroscopic examinations of the temporomandibular joint were performed on 295 patients. During 69 examinations, biopsies were obtained to correlate arthroscopic findings with histology. In the overall group, histology confirmed in 78.9% the arthroscopic findings. Correlation was better in joints with degenerative changes (81.5%) than in those with a synovitic/hyperaemic appearance (61.5%). Chondroid metaplasia, detritus synovitis and synovial chondromatosis were additional diagnoses given by histological examination. In 11 joints, open arthrotomy was performed after arthroscopy with biopsy was carried out. The excised tissue was also investigated microscopically and correlates to the biopsy-result. Because no different pathological changes were found, it is concluded that biopsies performed during arthroscopy of the temporomandibular joint are representative for histological investigation. An additional perforation for introducing the biopsy forceps is not necessary, because results obtained with different techniques appeared to be equally accurate.

Real-time endoarticular ultrasound imaging of the TMJ--a new diagnostic possibility? A cadaver study.

Recent advances in ultrasound imaging suggested endoarticular ultrasound imaging of the temporomandibular joint (TMJ) in combination with TMJ-arthroscopy as a new diagnostic method. Our investigations were performed on human cadavers, in combination with traditional TMJ-arthroscopy. During our investigations, the main articular structures were identified: the glenoid fossa of the temporal bone, articular disc, condyle of the mandible, and retrodiscal tissue. The combination of arthroscopy and ultrasound imaging provides more information on position, movement, and pathological changes in joint structures. Although all of the advantages, disadvantages, indications, and complications of this new diagnostic procedure are not yet clear, the authors consider this new method a useful diagnostic procedure for TMJ imaging.

Implant position following HA-augmentation of the mandible.

The transverse inclination, height and width of 20 lingually placed hydroxylapatite (HA) implants, to augment the atrophic mandibular ridge, were examined using computed tomography of cross sections through the first molar region. Favourable prosthetic conditions are achieved if the HA-implants are placed in a lingual position. This is the case when the transverse inclination varies from 65 to 85 degrees.

Preoperative imaging in a case of molar retention.

The use of high resolution spiral computed tomography with additional 2-D reconstruction is demonstrated for a patient with a deeply impacted first mandibular molar. The precise anatomical localization enabled us to remove the tooth without damaging the inferior alveolar nerve.

Autotransplantation of immature third molars into edentulous and atrophied jaw sections.

The aim of the present study was to assess the results after transplantation of 85 immature third molars. Recipient site conditions varied and different surgical techniques were used. The long-term results after preparation of a new alveolus, splitting osteotomy of the alveolar process or use of free bone autografts were compared with the results after transplantation into a fresh extraction site (control group). Transplantations into prepared sockets showed equal results to the control group (94% respectively). Transplantations in connection with free bone autografts (84%) or after splitting osteotomy of the alveolar process (63%) showed poorer success rates, the differences between the latter and the control group being statistically significant. A possible correlation to revascularization disturbances of the pulp due to an insufficiency of the recipient site or to postoperative infection is suspected. The results show that transplantation of immature third molars is a safe, useful procedure when appropriate conditions of the recipient site are present. Where the alveolus is atrophic, a splitting osteotomy should be performed only in exceptional cases and preference should be given to alternative methods such as primary bone augmentation or bone-regenerative procedures.

Endoscopic and ultrasonographic evaluation of the maxillary sinus after combined sinus floor augmentation and implant insertion.

OBJECTIVE: The aim of our study was a radiographic, endoscopic, and ultrasound follow-up of the maxillary sinus comparing 2 techniques of sinus floor augmentation. STUDY DESIGN: Sonograms, radiographs (Waters' view) of the sinuses, and endoscopy served before and during surgery to evaluate the maxillary sinus. One week after the operation, ultrasound and radiograph follow-up (Waters' view) were carried out. Six months after the operation, we performed an ultrasound follow-up along with uncovering the implants. If any pathologic condition was found, we took another x-ray film of the sinuses, performed another endoscopic examination, or both. RESULTS: In 23 of 63 patients, healing was uneventful. Waters' view revealed opacification of the maxillary sinus 1 week after surgery in 40 cases when the "window technique" was used. Sinusitis occurred 3 times, as a result of migration of bone chips in 2 patients. We lost 11 of 132 inserted implants during the healing and loading periods. CONCLUSION: Endoscope-controlled sinus floor augmentation may lower the complication rate in a remaining height of the jaws between 4 and 8 mm. In our group of patients, we proved by endoscopic examination that migration of cancellous bone sequestra was the reason for sinusitis. In case of infected bone grafts with antral symptoms, sinoscopy allowed debridement and removal of a sequestrum.

[Are additional filters made of niobium superior to the copper filter in dental radiology?]. / Sind Zusatzfilter aus Niobium in der zahnärztlichen Radiologie dem Kupferfilter uberlegen?

At a dental X-ray unit the effect of an additional filter made of niobium has been tested in the molar region of the mandible with respect to dose reduction. It has been compared against the effect of an additional filter made of copper. With regard to the same dose at the film, radiation dose at the surface of the patient proved to be slightly more reduced after application of the copper filter than after application of the niobium filter. Radiographs have been made by exposure of intraoral dental films (Kodak film Ultra Speed D) together with a hydroxyapatite step-wedge. Measurements of optical density resulted in the same values after application of the copper filter and the niobium filter, respectively. Reduced image contrast due to application of one of these additional filters proved to be helpful. In short, an additional copper filter placed in the X-ray beam shows identical or better results when compared against an additional filter made of niobium.

Clinical comparison of patients with osteonecrosis of the jaws, with and without a history of bisphosphonates administration.

This retrospective study aimed to evaluate the role of bisphosphonates in jaw osteomyelitis. 29 patients were included: 18 had been treated with bisphosphonates (12 with multiple myelomas, 3 with breast carcinomas, 2 with prostate carcinomas, and 1 with osteoporosis). Of 11 control patients, 2 had breast carcinomas, 2 had bronchial carcinomas, and 7 had no cancer. Descriptive and statistical evaluations were conducted to investigate the influence of chemotherapy, corticosteroids, stem cell transplantation, and bisphosphonates on the development and clinical picture of osteomyelitis. Both groups had similar disease histories, clinical pictures, treatment methods, and outcome. Wound dehiscence frequencies were also similar (Mann-Whitney rank sum test 1.66±1.5 vs. 1.45±2.0 p=0.393). Chemotherapy, steroid therapy, stem cell transplantation, or bisphosphonate administration did not correlate with the clinical picture. Neither the duration of therapy nor the type of bisphosphonate influenced the clinical picture (negative Fisher's tests). The bisphosphonate group showed a characteristic settlement of Actinomyces in the exposed bone (positive Fisher's test, p=0.021). These results suggested that osteomyelitis developed as a consequence of the simultaneous, cumulative action of many factors. Bisphosphonates played a role comparable to other predisposing features. Coating the jaws with bisphosphonates could promote the settlement of Actinomyces.

Remoción de terceros molares mandibulares con asistencia endoscópica: nota técnica de un nuevo procedimiento quirúrgico para prevenir lesiones del NAI y formación de defectos óseos / Removal of mandibular third molars with endoscopic approach. Technical note of a new surgical procedure to avoid IAN damage and bone defect formation

La variada posición anatómica de los terceros molares mandibulares presenta importantes desafíos asociados a su profundidad y grado de inclinación. Las complicaciones más habituales del procedimiento quirúrgico convencional de extracción se relacionan con la extensa osteotomía y poca visualización del sitio quirúrgico, que pueden generar consecuencias post-quirúrgicas como inflamación, dolor, trismus, lesiones reversibles e irreversibles del nervio alveolar inferior (NAI) o nervio lingual, riesgo de fractura y formación de defectos periodontales del segundo molar. La implementación de soportes rígidos en la óptica endoscópica ha permitido utilizar esta tecnología para realizar abordajes mínimamente invasivos para remover terceros molares mediante accesos flapless con una mínima osteotomía de la zona oclusal, conservando la pared bucal y lingual a través de la visualización directa y magnificada del sitio quirúrgico, adaptable a los movimientos del paciente durante la intervención. En este reporte se presenta un nuevo procedimiento quirúrgico mínimamente invasivo a través de asistencia endoscópica para la conservación ósea en la remoción de terceros molares mandibulares con riesgo de lesión del nervio alveolar inferior.

Anatomic variability of the position of mandibular third molars represents significant challenges associated with its depth and angulation. The most common complications of conventional surgical procedure are related to extensive osteotomy and poor visualization, which can cause postsurgical effects such as inflammation, pain, trismus, reversible and irreversible lesions of the inferior alveolar nerve (IAN) or lingual nerve, fracture risk and formation of a deep periodontal defect on the distal aspect of the second molar. The implementation of rigid endoscopy in optics has allowed to use this technology via a minimally invasive approach to remove third molars by a minimally occlusal flapless ostectomy, preserving the buccal and lingual walls through direct and magnified visualization of the surgical site, adaptable to the patient’s movements during the surgery. In this report, we present a new and minimally invasive procedure through endoscopic assistance for bone conservation in the removal of third molars at risk of inferior alveolar nerve injury.