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T von Arx

Publications and source records attributed to T von Arx.

At least 19 recordsLinked to original sources
PubMed2003

Diagnostic accuracy of endoscopy in periradicular surgery - a comparison with scanning electron microscopy.

AIM: To compare the accuracy of endoscopic diagnostics with the scanning electron microscope (SEM) in evaluating elements of periradicular surgery. METHODOLOGY: The material consisted of 22 extracted human molars, which were subjected to the following treatments: orthograde root-canal obturation, root-end resection and root-end cavity preparation with diamond-coated sonic microtips. After each step, the cut root face was inspected with an endoscope, and subsequently, the roots were duplicated for SEM evaluation. Endoscope findings were compared to those obtained with SEM serving as the 'gold standard' with a blinded observer. The presence of the following structures was assessed including specificity and sensitivity: isthmuses, accessory canals, obturation gaps, microfractures and chipping of cavity margins. RESULTS: The specificity and sensitivity of the identification of isthmuses or accessory canals was 100% each for the endoscope compared to SEM. The sensitivity of identification of obturation gaps, crack formation or chipping ranged between 73 and 95% (except intradentine cracks with only 36% sensitivity). The specificity of the same parameters ranged between 77 and 100% for the endoscope compared to SEM. CONCLUSIONS: With the exception of intradentine cracks, the endoscope accurately identified microstructures following root-end resection and root-end preparation. The endoscope could be considered for use during intraoperative diagnostics in periradicular surgery.

Apicoectomy↗
PubMed2002

Evaluation of a prototype trilayer membrane (PTLM) for lateral ridge augmentation: an experimental study in the canine mandible.

The objective of this animal study was to evaluate a biodegradable/bioresorbable prototype trilayer membrane (PTLM) consisting of two collagen layers and an internal polylactide layer for lateral ridge augmentation in conjunction with two different bone grafting materials: particulate autograft or deproteinized bovine bone mineral (DBBM). In four mongrel dogs, two lateral bone defects per side were created in the mandible. The four defects per dog were randomly subjected to the following grafting treatments 3 months later: 1. PTLM+DBBM, 2. PTLM+particulate autograft, 3. ePTFE membrane+DBBM, 4. ePTFE membrane+particulate autograft. After a healing period of 4 1/2 months, the dogs were sacrificed for histological and histomorphometrical analysis. Percentage calculations for areas showing bone regeneration within the former defect outline were 56.8% for PTLM+DBBM, 85.2% for PTLM+autograft, 52.3% for ePTFE+DBBM, and 96.9% for ePTFE+autograft (differences between autograft and DBBM sites were significant at P<0.01 to P<0.05). Measurements of ridge enlargement (horizontal bone gain) were also significantly better for autograft+ePTFE sites compared to the other three grafting treatments. Histology demonstrated for most PTLM sites a moderate infiltration of lymphocytes and plasma cells adjacent to empty spaces corresponding to polylactide fragments. In addition, these reactions appeared to provoke subsequent resorption of newly formed bone. No such findings were seen in ePTFE sites. The tested prototype membrane cannot be recommended for clinical application.

Absorbable Implants↗
PubMed2001

Lateral ridge augmentation using different bone fillers and barrier membrane application. A histologic and histomorphometric pilot study in the canine mandible.

Lateral ridge augmentation has become a standard treatment option to enhance the bone volume of deficient recipient sites prior to implant placement. In order to avoid harvesting an autograft and thereby eliminating additional surgical procedures and risks, bone grafting materials and substitutes are alternative filler materials to be used for ridge augmentation. Before clinical recommendations can be made, such materials must be extensively studied in experimental models simulating relevant clinical situations. The present pilot study was conducted in three dogs. Different grafting procedures were evaluated for augmentation of lateral, extended (8 x 10 x 14 mm) and chronic bone defects in the mandibular alveolar ridge. Experimental sites received tricalcium phosphate (TCP) granules or demineralized freeze-dried bone allograft (DFDBA) particles. Barrier membranes (ePTFE) were placed for graft protection. These approaches were compared to ridge augmentation using autogenous cortico-cancellous block grafts, either with or without ePTFE-membrane application. After a healing period of six months, the sites were analyzed histologically and histomorphometrically. Autografted sites with membrane protection showed excellent healing results with a well-preserved ridge profile, whereas non-protected block grafts underwent bucco-crestal resorption, clearly limiting the treatment outcome. The tested alloplastic (TCP) and allogenic (DFDBA) filler materials presented inconsistent findings with sometimes encapsulation of particles in connective tissue, thereby reducing the crestal bone width. The present pilot study supports the use of autografts with barrier membranes for lateral ridge augmentation of extended alveolar bone defects.

Alveolar Process↗
PubMed2001

Decoronation of an ankylosed tooth for preservation of alveolar bone prior to implant placement.

A 12-year-old patient sustained avulsions of both permanent maxillary central incisors. Subsequently, both teeth developed replacement resorption. The left incisor was extracted alio loco. The right incisor was treated by decoronation (removal of crown and pulp, but preservation of the root substance). Comparison of both sites demonstrated complete preservation of the height and width of the alveolar bone at the decoronation site, whereas the tooth extraction site showed considerable bone loss. In addition, some vertical bone apposition was found on top of the decoronated root. Decoronation is a simple and safe surgical procedure for preservation of alveolar bone prior to implant placement. It must be considered as a treatment option for teeth affected by replacement resorption if tooth transplantation is not feasible.

Alveolar Process↗
PubMed2001

Treatment of replacement resorption with Emdogain--preliminary results after 10 months.

Ankylosis of traumatized teeth in children and adolescents may inhibit further development and growth of the corresponding jawbone. Therefore, ankylosed teeth should be removed. As an alternative treatment option to autotransplantation of a premolar, intentional replantation using Emdogain may be considered, provided the ankylosis is detected at an early stage or has only affected a small area of the root. Eleven ankylosed teeth presenting with replacement resorption were treated as follows: after tooth extraction, the root canal was treated extraorally and obturated by retrograde insertion of a titanium post. Emdogain was applied to the root surface and into the extraction socket with subsequent replantation of the tooth. During a mean follow-up period of 6.3 months, no signs of recurrence of ankylosis were noted. The horizontally and vertically measured Periotest scores were identical to those obtained on the adjacent teeth. These results suggest that intentional replantation using Emdogain may prevent or delay ankylosis of these replanted teeth.

Adolescent↗
PubMed2001

Splinting of traumatized teeth with a new device: TTS (Titanium Trauma Splint).

Displacement injuries of permanent teeth are an increasing emergency in the dental office. Children and adolescents are particularly prone to dental trauma due to participation in risky activities. Repositioning or replantation with subsequent stabilization by a dental splint is the standard of care for most displaced or avulsed permanent teeth. Non-rigid fixation allowing physiologic tooth mobility has been shown to be desirable for periodontal healing. A flexible splint of short duration appears to reduce the risk of dentoalveolar ankylosis or external replacement resorption. Different splinting techniques are currently recommended for stabilization of repositioned or replanted teeth, including a wire-composite splint, an orthodontic bracket splint or a resin splint. Each splinting option has its specific advantages and shortcomings. This paper describes a new splinting technique which offers improved comfort and handling to the patient and dentist alike.

Adult↗
PubMed2001

Comparison of a new dental trauma splint device (TTS) with three commonly used splinting techniques.

Splinting is the standard of care for stabilization of replanted or repositioned permanent teeth following trauma. The present experimental study compared four dental trauma splints in 10 volunteers. The evaluated splints included a wire-composite splint (WCS), a button-bracket splint (BS), a resin splint (RS), and a new device (TTS=Titanium Trauma Splint) specifically developed for splinting traumatized teeth. All splints were bonded to the labial surfaces of the maxillary lateral and central incisors. Splints were left in place for 1 week. After splint removal, the next splint was placed after a 1-week rest period. The sequence of splint application was randomized for each individual. The following parameters were assessed: tooth mobility with horizontal and vertical Periotest values (PTV) before and after splint application and splint removal, respectively; probing depths, plaque and bleeding on probing indices before splint application and removal, and chair time needed for splint application and removal. After splint application, horizontal PTV were significantly lower in central incisors for BS compared to TTS (P=0.04), and for RS compared to TTS (P=0.005) and to WCS (P=0.006). Reduction of lateral tooth mobility (=splint effect) expressed by the difference between horizontal pre- and postoperative PTV was significantly greater in RS compared to TTS and WCS (P<0.05) for central as well as for lateral incisors. However, changes of vertical tooth mobility were not significant across the splinting techniques. Periodontal parameters remained unchanged, reflecting the excellent oral hygiene by the study subjects. The chair time needed for splint application was significantly shorter for TTS (P<0.01). In conclusion, all tested splints appeared to maintain physiologic vertical and horizontal tooth mobility. However, the latter was critically reduced in RS splints.

Acrylic Resins↗
PubMed2001

Periradicular surgery of molars: a prospective clinical study with a one-year follow-up.

AIM: The purpose of this prospective clinical study was to evaluate the outcome of periradicular surgery of molars after one year. METHODOLOGY: The material consisted of 25 molars with 39 roots demonstrating periradicular lesions of endodontic origin. Surgical treatment included root-end resection, root-end preparation with sonic microtips, and root-end filling with Super-EBA cement. At the one-year follow-up examination, healing was evaluated clinically and radiographically. Healing was assigned to three categories: (i) success (ii) improvement, and (iii) failure using well defined criteria. RESULTS: Eighty-eight per cent of the surgically treated molars showed successful healing. In 8%, the healing was rated as improved and only 4% were failures. CONCLUSIONS: The outcome of the present study and data of recently published studies show that periradicular surgery may result in a predictable treatment outcome in molars with persistent periradicular lesions.

Adult↗
PubMed2001

Rationale for the application of the GTR principle using a barrier membrane in endodontic surgery: a proposal of classification and literature review.

Periradicular surgery has become an established treatment option in endodontic surgery. The major objective of this surgery is to obtain periradicular tissue regeneration, including the formation of a new attachment apparatus, by exclusion of any potentially noxious agent within the physical confines of the affected root. However, in a substantial number of cases, the endodontic lesion has a concomitant marginal periodontal lesion that may complicate the healing success. In periodontology, the guided tissue regeneration (GTR) principle using a barrier membrane has been extensively studied and successfully used, and thus may become an adjunct in endodontic surgery. This article presents a classification system of endodontic and periodontal lesions with respect to the application of the membrane technique and reviews the pertinent literature based upon this classification system.

Alveolar Bone Loss↗
PubMed2000

Basic surgical principles with ITI implants.

The basic surgical principles governing the placement of ITI implants are based on research-oriented developments in harmony with evidence-based and outcome-oriented clinical procedures. In the past 15 years, the range of implant indications has been significantly widened, and partially edentulous patients clearly represent the majority of patients seeking treatment with dental implants today. An important aspect of the successful rehabilitation of patients with ITI implants is the careful selection of implant candidates with respect to systemic and local risk factors. These factors are presented based on current knowledge. Today, solid-screw implants in various screw dimensions and neck configurations comprise the ITI Dental Implant System. These different implant types are necessary to handle the full range of implant indications, in particular in partially edentulous patients. The main clinical factors are presented for the selection of the appropriate implant type, length and diameter. These implants are utilized both in a non-submerged and in a submerged approach. The main goal of surgical therapy is low trauma and the least demanding surgical procedure for patient and clinician to optimize the cost-effectiveness of implant therapy. Hence, a non-submerged approach is preferred in all sites without esthetic priority, such as in fully edentulous patients or in posterior sites of partially edentulous patients. These indications clearly represent the majority of implant patients. In esthetic sites, a submerged approach is utilized to satisfy the specific esthetic demands. The possibility to successfully utilize short implants (6 and 8 mm) and a reduced healing period of 3 months are further advantages of ITI implants due to favorable properties of the rough TPS surface. With the introduction of the microrough SLA surface, a reduction of the healing period to 6 weeks facilitates further progress towards simplification of implant therapy. In summary, the ITI Dental Implant System represents a scientifically well-documented, complete implant system for the treatment of fully and partially edentulous patients, offering straightforward surgical concepts based on predictable treatment outcome and excellent cost-effectiveness.

Antibiotic Prophylaxis↗
PubMed2000

Surgical procedures in partially edentulous patients with ITI implants.

Today, partially edentulous patients represent the majority of patients seeking treatment with implant-supported prostheses. This chapter presents the specific aspects of the surgical handling of partially edentulous patients with either single-tooth gaps, extended edentulous spaces or distal extension situations. Due to differences in treatment objectives, a distinction is made between sites without esthetic priority (non-esthetic sites) and with esthetic priority (esthetic sites). In non-esthetic sites, the primary goal of the surgical therapy is to achieve a predictable hard and soft tissue integration of the implant to re-establish function with the implant-supported prosthesis. In esthetic sites, the goal of surgical therapy is to achieve successful tissue integration and to obtain esthetic soft tissue contours to re-establish both function and esthetics. Therefore, the surgeon must have a clear understanding of the specific needs in a given situation, and must master the necessary surgical techniques concerning a correct implant placement and a correct soft tissue handling to achieve the treatment objectives. In non-esthetic sites, a non-submerged approach is clearly preferred, thus avoiding a second-stage procedure for abutment connection. If a soft tissue correction is necessary to re-establish keratinized peri-implant mucosa, this is done at the time of implant placement with mucogingival surgery. In esthetic sites, a submerged implant placement is preferred to achieve esthetically pleasing soft tissue contours. If a soft tissue augmentation is necessary, this is done at the time of implant placement with connective tissue grafts. Thus, the second surgical procedure after 8-10 weeks of healing is reduced to a mucosaplasty like a punch biopsy, avoiding an open flap procedure. Based on favorable properties of the TPS surface, short implants (6 or 8 mm) and short healing periods of 3-4 months have been successfully utilized in partially edentulous patients in the last 14 years. The introduction of the SLA surface allows a further reduction of the healing period to 6 weeks of healing in all sites with normal bone density (class I-III). In summary, the ITI philosophy offers straightforward surgical concepts to predictably achieve the treatment objectives with the least demanding surgical protocol, reducing the related chairtime and costs for the patient and the clinician.

Dental Abutments↗
PubMed2000

Microsurgical instruments for root-end cavity preparation following apicoectomy: a literature review.

Root-end cavities have traditionally been prepared by means of small round or inverted cone burs in a micro-handpiece. Since sonically or ultrasonically driven microsurgical retrotips became commercially available in the early 1990s, this new technique of retrograde root canal instrumentation has been established as an essential adjunct in periradicular surgery. At first glance, the most relevant clinical advantages are the enhanced access to root ends in limited working space and the smaller osteotomy required for surgical access because of the various angled designs and small size of the retrotips. However, a number of experimental studies comparing root-end preparations made with microsurgical tips to those made with burs have demonstrated other advantages of this new technique, such as deeper cavities that follow the original path of the root canal more closely. The more centered root-end preparation also lessens the risk of lateral perforation. In addition, the geometry of the retrotip design does not require a beveled root-end resection for surgical access thus decreasing the number of exposed dentinal tubules. A controversial issue of sonic or ultrasonic root-end preparation is the formation of cracks or microfractures, and its implication on healing success. The present paper reviews experimental and clinical studies about the use of microsurgical retrotips in periradicular surgery and discusses many issues raised in previous papers.

Apicoectomy↗