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Biomedical subjects

Thomas von Arx

Publications and source records attributed to Thomas von Arx.

At least 19 recordsLinked to original sources
PubMed2007

Periapical surgery and the maxillary sinus: radiographic parameters for clinical outcome.

OBJECTIVE: To find out whether conventional periapical radiographs can be used to determine the risk of creating an oroantral communication (OAC) while performing periapical surgery on maxillary premolars and molars. STUDY DESIGN: One hundred thirteen periapical radiographs of maxillary premolars and molars with periapical radiolucencies indicating chronic apical periodontitis were retrospectively analyzed and classified. The surgery reports were evaluated for occurrence of perforation of the maxillary sinus and postoperative complications. RESULTS: Perforation of the sinus membrane (also referred to as the Schneiderian membrane) occurred in 12 cases (9.6%). Exposure of the membrane without rupture occurred in 15 cases (12%). It was found that the distance between the apex or the periapical lesion and the sinus floor did not serve as a predictor of a possible sinus membrane rupture. On the other hand, if the radiograph showed a distinct distance between the lesion and the sinus floor, there was an 82.5% probability that OAC would not occur. Additionally, a blurred radiographic outline of the periapical lesion did not indicate an increased risk of sinus membrane rupture. CONCLUSION: Conventional periapical radiographs cannot be used as predictors for perforation of the maxillary sinus during periapical surgery. However, radiographs with a specific distance between the periapical lesion and the sinus floor point toward a very low risk of accidental sinus perforation during periapical surgery.

Adult↗
PubMed2006

Horizontal ridge augmentation using autogenous block grafts and the guided bone regeneration technique with collagen membranes: a clinical study with 42 patients.

OBJECTIVE: To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with an organic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. MATERIAL AND METHODS: In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. RESULTS: Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2-7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. CONCLUSIONS: The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure.

Adolescent↗
PubMed2006

Treatment of replacement resorption by intentional replantation, resection of the ankylosed sites, and Emdogain--results of a 6-year survey.

The present clinical study investigated the outcome of intentional replantation using resection of the ankylosed sites of the root, extraoral endodontic treatment using titanium posts and Emdogain for periodontal healing following trauma-related ankylosis. During an evaluation period of 6 years, 16 ankylosed teeth affected by replacement resorption were treated as described. Evaluation parameters before treatment and during the follow-up period included Periotest scores, percussion sound and periapical radiographs. All findings were compared to those of the adjacent teeth. In a second accident, one tooth was lost after 7 months and was excluded as a dropout. Ankylosis did not recur in seven replanted teeth, which were observed for an average of 52.3 months (range: 24-68 months). Ankylosis recurred in eight teeth after an average period of 12 months (range: 4-26 months). An infraocclusion, normal or only slightly reduced Periotest scores and normal percussion sound were preoperatively found in six of seven successfully replanted teeth, which corresponded to a relatively small area of ankylosis. The majority of the teeth showing recurrent ankylosis preoperatively presented with normal position, negative Periotest scores and a high percussion sound which corresponded to an extended area of ankylosis. Statistically significant relationship between preoperative findings and the treatment outcome (P = 0.031) have become apparent. The results indicate that the treatment of minor areas of ankylosis by intentional replantation, resection of the ankylosed sites and Emdogain appeared to prevent or delay the recurrence of ankylosis in 7 of 15 teeth.

Adolescent↗
PubMed2006

Orofacial/cerebral injuries and the use of mouthguards by professional athletes in Switzerland.

The objective of the present study was to measure the occurrence of orofacial and cerebral injuries in different sports and to survey the awareness of athletes and officials concerning the use of mouthguards during sport activities. Two hundred and sixty-seven professional athletes and 63 officials participating in soccer, handball, basketball and ice hockey were interviewed. The frequency of orofacial and cerebral trauma during sport practice was recorded and the reason for using and not using mouthguards was assessed. A great difference in orofacial and cerebral injuries was found when comparing the different kinds of sports and comparing athletes with or without mouthguards. 45% of the players had suffered injuries when not wearing mouthguards. Most injuries were found in ice hockey, (59%), whereas only 24% of the soccer players suffered injuries when not wearing mouthguards. Sixty-eight percentage of the players wearing mouthguards had never suffered any orofacial and cerebral injuries. Two hundred and twenty-four athletes (84%) did not use a mouthguard despite general acceptance by 150 athletes (56%). Although the awareness of mouthguards among officials was very high (59%), only 25% of them would support the funding of mouthguards and 5% would enforce regulations. Athletes as well as coaches should be informed about the high risk of oral injuries when performing contact sports. Doctors and dentists need to recommend a more intensive education of students in sports medicine and sports dentistry, and to increase their willingness to become a team dentist.

Adult↗
PubMed2005

Neurosensory disturbances following bone harvesting in the symphysis: a prospective clinical study.

OBJECTIVE: To analyse the occurrence and resolution of neurosensory disturbances following bone harvesting from the symphysis. MATERIAL AND METHODS: In 30 patients, skin sensitivity of the chin/lower lip area and pulp sensitivity of all mandibular anterior teeth were assessed preoperatively, at the time of suture removal, at 6 and 12 months postoperatively. In addition, bone defect dimensions of the donor site were measured intraoperatively, and distances from defect margins to adjacent anatomical structures, such as root apices, mental foramen and inferior border of mandible, were assessed postoperatively on a panoramic radiograph. RESULTS: Pulp sensitivity changes were found in 18.6% of adjacent teeth at the time of suture removal. At the 6-month follow-up, 8.1% of teeth, and at the 12-month re-examination, 0.6% of teeth presented with altered sensitivity. This decrease over time of the number of affected teeth per patients with sensitivity changes was significant (P=2.35e-007). Lower lip hypaesthesia was only observed in one patient postoperatively, with complete resolution at the 6-month follow-up. Radiographic measurements of distances between donor defect and adjacent anatomical structures only reached significant difference for one parameter in patients with sensitivity changes compared with patients without sensitivity changes. CONCLUSIONS: Patients must be informed about possible transient and long-term sensitivity changes of adjacent teeth and soft tissues following bone harvesting from the chin. However, by correctly placing mucoperiosteal incisions and bone cuts, the risk of sensitivity changes can be minimized.

Adolescent↗
PubMed2005

Replantation of 45 avulsed permanent teeth: a 1-year follow-up study.

Thirty-four patients with 45 avulsed and replanted permanent teeth were followed for 1 year. All teeth were soaked in tetracycline before replantation. In addition, enamel matrix derivative was used in teeth with dry storage times exceeding 30 min. Splinting was carried out with a non-rigid titanium splint and was limited to 7-10 days. Within that period, root canal treatment was begun in all teeth with a closed apex, whereas teeth with an open apex and ideal post-traumatic storage were not instrumented. All patients were given tetracycline systematically for 10 days. The survival rate of replanted avulsed permanent teeth was 95.6% at the 1-year follow-up. In 82.2%, root canal treatment was performed. Pulp survival was never observed, but three teeth had pulp canal obliteration. Normal periodontal healing was observed in 57.7% of teeth; 42.3% of teeth showed external root resorption (28.9% replacement resorption, 6.7% infection-related resorption, 6.7% surface resorption). The occurrence of replacement resorption correlated with the period of extraoral dry storage. Compared with other clinical studies on avulsed and replanted teeth, the present study reports a higher percentage of periodontal healing. The favorable treatment outcome may be associated with a strict protocol to enforce endodontic treatment, the use of topical and systemic tetracycline, and the relatively high number of ideally stored teeth following avulsion. In contrast, the present study has a follow-up period limited to 1 year.

Adolescent↗
PubMed2005

The use of guided tissue regeneration principles in endodontic surgery for induced chronic periodontic-endodontic lesions: a clinical, radiographic, and histologic evaluation.

BACKGROUND: Chronic periodontic-endodontic lesions are not uncommon in clinical practice and their regenerative capacity has long been questioned. However, there are no published studies investigating the application of guided tissue regeneration techniques in combination with endodontic surgery using an induced perio-endo defect model. This study evaluated the clinical, radiographic, and histologic outcomes of three surgical procedures used to treat induced perio-endo lesions. METHODS: Pulpal necrosis was induced in foxhounds along with surgical removal of radicular buccal bone. After 4 weeks, chronic lesions were clinically and radiographically assessed. Treatment surgery consisted of apicoectomy, root canal instrumentation, and retrofilling with mineral trioxide aggregate. Teeth were then assigned to one of the following treatment groups: open flap debridement only (OFD), OFD with bioabsorbable porcine-derived collagen membrane (BG), or OFD with BG and anorganic bovine bone matrix (BO/BG). Clinical parameters and standardized radiographs were assessed at defect creation; treatment surgery; and at 1, 2, 4, and 6 months. Animals were sacrificed at 6 months and specimens prepared for histometric analysis. RESULTS: Clinical and radiographic conditions improved during the study period. Mean epithelial attachment was similar between all groups. Mean connective tissue attachment for groups OFD, BG, and BO/BG was 3.79 mm, 2.63 mm, and 1.75 mm, respectively, and mean radicular bone height was 2.16 mm, 3.24 mm, and 3.45 mm, respectively. Statistically significant increases in the amount of new cementum were observed in groups BG and BO/BG when compared with OFD (P <0.05). CONCLUSIONS: Treatment of combined induced perio-endo lesions using bioabsorbable collagen membranes alone or in combination with anorganic bovine bone matrix resulted in increased amounts of bone, periodontal ligament, and significant increases in the amount of new cementum when compared to open flap debridement in a canine model.

Absorbable Implants↗
PubMed2005

[Laser Doppler flowmetry for vitality testing of traumatized maxillary incisors].

Pulp sensitivity and vitality changes were evaluated in 69 traumatized maxillary incisors and in 38 control teeth during a follow-up period of 20 months. Examinations included thermal testing using carbon dioxide snow (CO2) and the laser Doppler flowmetry (LDF). These measurements were compared to the clinical and radiological findings. In 47.8% of the traumatized teeth and in 55.3% of the control group the three LDF measurements corresponded with the sensitivity testing using CO2 and with the clinical and radiological findings. In 31.9% of the traumatized teeth and in 7.9% of the control group the LDF-measurements differed from the CO2-measurements, but were in agreement with the other clinical and radiographic findings. The information obtained by laser Doppler flowmetry is of additional importance for the treatment planning. Since the clinical examination of traumatized teeth is sometimes inconclusive, the laser Doppler flowmetry is a further diagnostic tool but it cannot replace the radiological or clinical examination.

Adolescent↗
PubMed2005

[Injuries to permanent teeth. Part 1: diagnosis of the tooth injury].

Diagnostic and therapeutic interventions following dental injuries are not part of the routine practice in the dental office. Quite often, these patients are emergency cases who seek treatment after normal office hours. The objective of this and the future papers is to present the current treatment concepts in dental traumatology at the School of Dental Medicine, University of Berne. The fruitful cooperation in the field of dental traumatology between the Department of Oral Surgery and Stomatology, and the Department of Conservative Dentistry (including pediatric dentistry and endodontology), is based on the interdisciplinary approach that has been established four years ago. Following discussion and evaluation of such treated cases, and considering current clinical and experimental references, the said concepts have been worked out. The present paper describes the diagnostic measures following injuries to the permanent teeth. Subsequent papers will illustrate our therapeutic concepts of injuries to the periodontal and dental hard tissues of permanent teeth.

Adult↗
PubMed2005

Splinting of traumatized teeth with focus on adhesive techniques.

Splinting of traumatized teeth is an important step in the treatment of periodontally injured teeth and a precondition of healing of the periodontal tissues. Although it has been shown in animal experiments that replanted teeth without splinting showed analogous healing outcomes compared to splinted teeth, the placement of a splint in dental trauma situations is warranted for medico-legal reasons, for the comfort of the patient, and for the avoidance of additional trauma during periodontal healing. Ideally, the splinting of traumatized teeth should be an easy and fast procedure for the dentist. Trauma splints should be comfortable and easy to keep clean for the patient. The splint should allow some physiologic mobility to promote healing of the periodontal tissues. The widely used and recommended wire-composite splint, with material variations, meets the ideal requirements of current splinting concepts in dental traumatology. Times of using destructive tissue-coverage splints are definitely gone. They are too rigid, compromise periodontal and gingival healing, and are uncomfortable to the patient. The objective of this article is to present the current concepts in splinting of traumatized teeth. The given recommendations about splinting techniques and splinting periods are based on experimental and clinical studies.

Composite Resins↗
PubMed2005

[Periotest-analysis in penradicular surgery: preliminary results of a clinical-prospective study].

The two objectives of the present study were: to assess the healing after periradicular surgery using the Periotest device, and to compare the recorded Periotest values with the healing category determined after a one-year follow-up using radiographic and clinical criteria. In 43 patients with periradicular surgery, Periotest values could be recorded pre- and postoperatively, as well as after six and twelve months. Cases with a successful healing, as determined at the one-year follow-up, demonstrated a continuous decrease of the Periotest values over time, whereas one-year failures showed increasing Periotest values over the study period. In control teeth, the Periotest values remained unchanged for the whole study period. It appears that the Periotest measurements correlate with the postoperative healing mode following periradicular surgery, and therefore, allow an additional assessment of the healing outcome.

Adult↗
PubMed2005

[Injuries to permanent teeth. Part 2: Therapy of avulsion].

The present paper describes the current treatment philosophy of dislocated or avulsed permanent teeth at our school. Splinting and medication (root canal treatment, systemic antibiotics, etc.) are targeted to minimize the initial inflammatory reaction and to reduce post-traumatic complications such as pulp necrosis and/ or external root resorption.

Adolescent↗
PubMed2005

[The Retroplast Technique. Retrograde obturation with composite and adhesive technique in endodontic surgery].

Endodontic surgery, and in particular periapical surgery, has seen a significant development in the last few years, mainly following the introduction of microsurgical principles and the use of magnification devices. The successful outcome of periapical surgery, however, is based on the quality of the root-end obturation that should prevent any reinfection originating from the root canal. Since amalgam as a root-end sealing material was abandoned many years ago, a great diversity of obturation techniques and materials have been described. Besides the standard root-end cavity preparation with microtips, the author today has a preference for the Retroplast-technique. The paper describes this technique in detail and reports the possibilities and limits of this obturation method.

Apicoectomy↗
PubMed2003

["Esthetic plus"-ITI-implants (TPS): a prospective clinical study].

The purpose of this prospective study was to examine the influence of a 1 mm lengthening of the rough surface (TPS) of "esthetic plus"-ITI-implants on the periimplant soft and hard tissues. Twenty-one "esthetic plus" ITI-implants were inserted into the maxilla in an esthetically critical zone of 12 patients with sufficient alveolar bone. Clinical and radiographic examinations were performed after ten and 32 months. The mean DIB-score (DIB = distance between implant shoulder and first implant-bone contact) was 2.19 mm after 32 month. The average DIB-score of implant sites adjacent to natural teeth was 1.90 mm, there only 0.1 mm of the rough surface did not have bone contact. However, the average DIB-scores of implant sites adjacent to other implants (2.63 mm) or distal extension situations (2.79 mm) were much higher. This means that the coronal part of the rough surface had no radiographic bone contact with 0.83 mm (to other implants) and with 0.99 mm (to distal extension situations), what should be taken into consideration when using an "esthetic plus"-ITI-implant. As a consequence a standard ITI-implant with a smooth neck of 2.8 mm would be indicated. The results of the present study indicate, that not only the shortening of the smooth implant neck to 1.8 mm but also the adjacent structures influence the periimplant soft and hard tissues.

Adult↗
PubMed2003

[Frequency and nature of anterior tooth injuries and the use of mouth protectors in sports clubs in Bern].

Tooth injuries are frequently associated with sports injuries. Most of them could be minimized or prevented by the use of a mouthguard. The present study investigated the occurrence of tooth injuries and the attitude of athletes of Bernese sports clubs towards mouthguards, by means of a questionnaire and clinical examination. A total of 172 out of 200 athletes from six sports clubs, who were contacted directly at the sports fields, returned the questionnaire. Fifty of them owned a mouthguard (= 29.1%) and 54 reported having suffered dental trauma. The majority of athletes did not wear a mouthguard, despite acknowledging its usefulness. Even after a dental injury, the rate of mouthguard-acceptance increased just marginally; only 38.9% of all injured athletes were wearing a mouthguard after dental trauma. Most of the athletes had not considered wearing a mouthguard at all. For many of them, impairment of speech and breathing and discomfort were reasons not to wear a mouthguard. Of the 54 reported athletes with dental trauma, 48 were examined clinically. The upper central incisors were by far the most frequently injured teeth. The clinical examination used an injury severity index (NIDR-Index, National Institute of Dental Research) ranging from grade 0 (no visible damage), to grade 6 (loss of tooth). The most common finding was grade 4 (injuries that were treated by reconstruction). In conclusion there is a need to optimize information for athletes concerning mouthguards and sports injuries. Providing such information is not only the responsibility of coaches and trainers, but also of dentists.

Athletic Injuries↗
PubMed2003

Healing of periapical lesions with complete loss of the buccal bone plate: a histologic study in the canine mandible.

This study evaluated periapical healing of induced apical lesions with concomitant loss of the buccal bone plate in a dog model using four foxhounds. In an initial surgery, pulp cavities of mandibular premolars were exposed to induce apical lesions. In the same session, the cortical bone covering the buccal root surfaces was surgically removed to simulate buccal bone loss. After radiographic confirmation of the development of apical lesions, sites were reentered for surgical treatment. Following apical and buccal debridement, root-end resection, and root-end filling, sites were subjected to three different treatment modalities: (1) flap readaptation (controls); (2) placement of a collagen membrane covering the apical defect and denuded root surface; or (3) placement of an anorganic bovine bone filler into the apical defect and onto the exposed buccal root surface, with additional application of a collagen membrane. Animals were sacrificed 7 months following the second surgery. Step sections were analyzed histometrically and morphometrically for periapical healing. Sites with membrane + filler showed a statistically significantly lower mean percentage of new bone formation within the former defect compared to both membrane-alone and control sites. No significant differences were found for tissue components deposited on the cut root face across treatment groups. Formation of a continuous thin layer of new cementum covering the exposed dentin surface and root-end filling material was a frequent finding. Analysis of the tissue regeneration on the buccal root aspect as well as the clinical periodontal parameters will be presented in a separate article.

Absorbable Implants↗
PubMed2003

[Periradicular surgery with and without endoscopy: a prospective clinical comparative study].

A total of 129 teeth with periradicular surgeries (apicoectomies) were analyzed in a prospective clinical study. In the test group including 62 teeth, an endoscope (Tele-Otoscope with a 70 degrees viewing angle) was used as an intraoperative visualization aid to monitor the following surgical steps: root-end resection, root-end cavity preparation and retrograde root-canal obturation. In the control group including 67 teeth, intraoperative diagnostics were carried out using micromirrors. Fifty-four and 61 teeth could be re-examined after one year. Based on the clinical and radiographic findings they were categorized as success, uncertain healing or failure. In the test group with endoscopy, the success rate was 88.9%, whereas in the control group it was only 75.4%. However, statistically no significant difference was found between the two groups. Additional experimental and clinical studies will show if endoscopy will improve the success rates in periradicular surgery any further.

Apicoectomy↗