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Biomedical subjects

N Hardt

Publications and source records attributed to N Hardt.

At least 19 recordsLinked to original sources
PubMed1998

[Results of transcranial and subcranial management of fractures of the naso-ethmoid-orbital system in complex midfacial fractures].

Injuries of the nasoethmoid-orbital (NEO) region are associated with midfacial fractures or fractures of the frontobase in over 90% of all cases. In up to 70% fractures of the skull base run through the roof of the ethmoidal bone or the lamina cribrosa. There are different surgical approaches for the treatment of these complex fractures. Between 1990 and 1997 50 patients with midfacial fractures in association with NEO fractures were treated in the Klinik für Mund-, Kiefer- und Gesichtschirurgie, Kantonsspital Luzern, Switzerland. Of these, 25 had suffered midfacial fractures combined with fractures of the nasoethmoid-orbital and frontobasal region and were treated via a transcranial approach. The other 25 patients with midfacial and NEO fractures without involvement of the frontobasis were managed by subcranial incisions. A total of 47 patients were followed up for up to 4 years. The results were reevaluated retrospectively. There was no case of secondary liquorrhea, intracranial or ethmoidal infection. Our therapeutic concept of transcranial and subcranial management of NEO fractures in combination with frontobasal and midfacial fractures is demonstrated.

Adolescent↗
PubMed1998

Localized ridge augmentation using a micro titanium mesh: a report on 27 implants followed from 1 to 3 years after functional loading.

The present paper describes the clinical and radiographic healing results of 27 implants followed from 1 to 3 years after functional implant loading. Prior to implant placement, alveolar ridges with insufficient bone volume were augmented using autogenous bone grafts and a micro titanium mesh for graft stabilization. After a mean interval of 5.2 months implants were installed. Following an osseointegration period of on average 7.2 months, implants were supplied with suprastructures. The mean loading period for the 27 implants was 21 months. All implants exhibited ankylotic stability and healthy peri-implant soft tissues. The detailed analysis of clinical parameters (probing depth, level of mucosal margin, attachment level, modified plaque and sulcus bleeding indices) and radiographic measurements (crestal bone level), revealed findings similar to those at implants placed into non-augmented bone. Peri-implant bone resorption was calculated to be 1.0 mm for the 1st year after implant loading and 0.1 mm for the following year. Pain, suppuration or semilunar bone defects were absent at all implants. It was concluded that loaded dental implants which have been inserted into an augmented alveolar ridge using autogenous bone grafts and a micro titanium mesh for graft stabilization, demonstrate clinical and radiographic findings similar to those of implants placed into a pristine ridge.

Adult↗
PubMed1998

Preliminary results and analysis of a new set of sonic instruments for root-end cavity preparation.

The introduction of microinstruments for root-end cavity preparation has clearly improved the surgical technique in periradicular surgery with apicectomy. The new generation of sonic and ultrasonic root-end preparation devices, usually termed 'retrotips', has simplified the preparation of a sufficiently deep cavity that follows the original path of the root canal. The present paper describes the use of a new set of diamond-surfaced retrotips driven by a sonic handpiece. For clinical evaluation a prospective study was carried out, with assessment of pre-, intra- and postoperative data in 50 teeth (43 patients). This paper analyses: (i) the applicability of the new retrotips; (ii) the quality of the root-end filling assessed radiographically; (iii) the immediate postoperative course. Access with the retrotips to the resected root-end was found to be excellent in 80% of the treated teeth. The postoperative radiographs showed a root-end filling of at least 3 mm in 70% of the resected teeth. Healing was uneventful in all cases and most patients presented without any symptoms after 5 days and 10 days. The long-term treatment outcome will be reported in a future paper.

Adolescent↗
PubMed1997

[Synovial chondromatosis of the temporomandibular joint with invasion into the middle cranial fossa].

Synovial chondromatosis of the temporomandibular joint is a rare occurrence. Resorption of the floor of the skull base caused by the tumour with invasion into the middle cranial fossa has only been described a few times. We report on diagnosis, histologic examination and therapy of a patient with synovial chondromatosis in the articular tubercle of the right temporomandibular joint invading the middle and cranial fossa. After tumour exstirpation the defect in the floor of the middle cranial fossa was reconstructed using a split-skull graft via an intracranial approach.

Adult↗
PubMed1997

Results of a modified staircase technique for reconstruction of the lower lip.

Our experience with a modified staircase technique for closure of lower lip defects is reported. The procedure is based on the original technique of Johanson et al. (1974). However, the integrity of the orbicularis oris muscle is respected when advancing lower lip flaps. Twenty patients with squamous cell carcinoma of the lower lip were treated using this modified reconstruction technique. The size of the defects ranged from 30-60% of lower lip width. No recurrences were observed during a 3-year to 5-year follow-up. All patients showed symmetrical lip movement, an adequate buccal sulcus and intact labial commissures. No symptomatic microstomia was seen and the aesthetic results were excellent. The surgical technique is explained in detail. Four types of flap are presented according to the size and location of lip defects. Lower lip defects up to 60% of the lip width can be closed easily, with good aesthetic results. The technique is also applicable to upper lip reconstruction.

Carcinoma, Squamous Cell↗
PubMed1997

Treatment of severe peri-implant bone loss using autogenous bone and a resorbable membrane. Case report and literature review.

Clinical case reports and animal studies have demonstrated that the principle of guided bone regeneration can be applied for surgical treatment of moderate to profound peri-implant bone loss (peri-implantitis). However, the degree of bone regeneration within the peri-implant osseous defect was reported to be variable depending on different clinical factors and on the postoperative course. Most papers dealing with surgical treatment of peri-implantitis advocate the use of a non-resorbable ePTFE membrane for secluding the peri-implant bone defect enabling bone regeneration. Additionally some surgeons fill the defects with allografts or alloplasts. The present case report demonstrates another surgical approach by using autogenous cancellous bone for grafting into the peri-implant bone defect and placing a bioresorbable polylactide membrane as a matrix barrier. The successful outcome of this modified surgical approach enabled the patient to maintain the implant for prosthetic reconstruction after early but severe bone loss.

Absorption↗
PubMed1996

The use of micro-titanium mesh for maxillary sinus wall reconstruction.

Operations on the maxillary sinus can lead to extensive bony defects of the facial and laterodorsal walls of the sinus. If there is no autogenous bone material available, the problem is to find a suitable substitute for reconstruction. We examined the suitability of micro-titanium mesh for reconstruction of the walls of the maxillary sinus. In 13 adult patients large defects of the walls of the maxillary sinus were reconstructed using micro-titanium mesh. Indications for operation were tumours, large dental-type cysts, traumatic bone loss and chronic inflammation in sinuses which had been previously operated on. Clinical and radiological examinations were carried out immediately after surgery and after a 3 months interval. Control by sinuscopy was performed in all patients. Great importance was attached to the following aspects: 1. correctly shaped reconstruction of the maxillary sinus 2. prevention of soft tissue prolapse into the sinus 3. aeration of the maxillary sinus 4. preservation of the facial contour

Adolescent↗
PubMed1996

[Results of follow-up of temporomandibular joint fractures in 30 children].

Disturbances of facial growth and occlusion as well as temporomandibular joint dysfunction are possible sequelae of temporomandibular joint fractures in children. In a follow-up study we examined 30 children with conservatively treated condylar fractures of the mandible (age at time of accident from 9 months to 13 years) regarding dysfunction or growth disturbances within the stomatognathic system. The mean interval between the accident and the follow-up was 4 years and 11 months. We found 6 cases with tilted occlusional planes in the 'en face' analysis, 3 of them with bilateral condylar fractures. There was only one case with a facial asymmetry. The interincisive distance was never below 35 mm. Only 3 patients, all of them with bilateral condylar fractures, had a restricted mobility of the mandible. Remodelling of the condylar head was good in 92% of the cases. Two patients with bilateral fractures showed formation of a bifid condyle without ankylosis. Deviation of the ascending ramus in the horizontal plane was observed radiographically in 21% of the cases with unilateral fractures and in 33% with bilateral fractures respectively and always in a medial direction. Measurement of the length of the Processus articularis in the orthopantomogramm showed a shortening in 70% of the cases on the fracture side. The radiographic evaluation of facial asymmetry after Ricketts and Mulick only revealed an angle difference of more than 5 degrees in some cases.

Adolescent↗
PubMed1995

[Effect and sequelae of supernumerary tooth in the premaxilla].

Although uncommon, anterior maxillary supernumerary teeth (mesiodentes) are the most frequent supernumerary teeth. A disturbed or delayed eruption of the adjacent permanent incisors may be due to a mesiodens and should lead to a further radiographic examination. In some cases the exact radiographic location of the mesiodens may prove difficult. The surgical removal of mesiodentes is especially difficult in extreme cranial displacement. The records of 90 patients with 113 mesiodentes are discussed with special reference to their degree of retention, topographical location, width of pericoronal space and surgical removal, and incidence of retention and malposition of the adjacent permanent incisors, respectively.

Adolescent↗
PubMed1995

[The resistance spectrum and antibiotic therapy in progressive infections in the mouth, jaw and face areas].

Assessing the surgically treated progressive abscesses of the head and neck from 1991 to 1993 at our clinic of maxillofacial surgery, a surprising percentage of the microbiologically isolated germs showed resistance against the recommended antibiotics of first choice. The location of the abscesses, the microbiological spectrum and the clinical course are analysed and compared with the literature. Preventing possible severe complication of progressive abscesses of the head and the neck an additional parenteral antibiotic therapy in high doses combined with the surgical treatment is recommended. Common dentoalveolar infections without progressive tendency are sufficiently treated surgically without administration of antibiotics.

Abscess↗
PubMed1994

[Temporomandibular joint fractures in children. A clinical and radiological follow-up in 30 patients].

Disturbances of facial growth, occlusion and temporomandibular joint function respectively are all possible sequelae of condylar fractures in children. In this study 30 children (age at accident from 9 months to 14 years, mean 6 years and 9 months) were reexamined who had sustained conservatively treated condylar fractures. Dysfunction and disturbances within the stomathognathic system were assessed by a clinical and radiographic examination. The mean interval between the accident and the follow-up study was 4 years and 11 months. The maximal interincisive distance was always better than 35 mm. The "en face" analysis revealed 6 cases with an inclined occlusion plane referring to the horizontal plane. Only 3 patients, all with bilateral condylar fractures, showed a restricted mandibular mobility. Remodelling of the condylar head was very good in 77% of the cases. In the frontal plane, 21% of the unilateral cases and 33% of the bilateral cases respectively had a persistent medial inclination of the condyle. The measured difference in length of the processus articularis showed the highest correlation to the previous condylar fracture. The radiological evaluation after Ricketts (1960) and Mulick (1965) to assess facial asymmetry revealed six cases (20%) with a relevant angle difference of more than 5 degrees.

Adolescent↗
PubMed1994

[Results of various reconstructive procedures in defects of the fronto-facial area].

Small calvarial defects may be recontoured by Gore-Tex membranes or by micro burr hole covering plates in combination with bone dust. In extended defects the best primary and secondary results are obtained with splitted calvarium grafts due to their stabilizing and esthetic features. Micromeshes prevent contour disturbances in the contact zone of the transplants.

Bone Transplantation↗
PubMed1993

The treatment of mandibular fractures in children.

92 children with mandibular fracture were treated at our hospital between 1980 and 1989. Distribution and treatment of the fractures focus on a new classification based upon the stage of the dentition, site of the fracture and displacement of the tooth-bearing part of the mandible. The treatment rationale includes intermaxillary fixation by specially designed mini-arch bars with acrylic resin stiffening in cases with undisplaced fractures in the early stages of the dentition. With the help of this technique, invasive procedures for fracture immobilization become less common. The indication for miniplate osteosynthesis is limited to displaced or multiple fractures of the tooth-bearing part of the mandible. The combination of miniplates and monomaxillary splinting with mini-arch bars allows a shorter duration of intermaxillary fixation and hence early functional treatment of additional condylar fractures. Correctly applied miniplates neither injure the tooth germs nor lead to growth disturbances of the mandible. The classification and treatment of mandibular fractures in children are discussed.

Bone Plates↗