Effects of the highly COX-2-selective analgesic NSAID etoricoxib on the rate of orthodontic tooth movement and cranial growth.

BACKGROUND: NSAID analgesics have found widespread use in the treatment of pain, inflammation and fever. The highly COX-2-selective NSAID etoricoxib has shown a favorable side effect profile and excellent analgesic efficacy, particularly for dental and orthodontic pain, surpassing the current standard analgesic in orthodontics, acetaminophen. However, potential side effects on the rate of orthodontic tooth movement (OTM) and cranial growth, relevant for clinical usability during orthodontic treatment, have not yet been investigated. MATERIAL AND METHODS: 40 male Fischer344 rats were randomly assigned to 4 groups (n=10) - controls receiving only 1.5ml tap water per day by oral gavage for a total of 5 weeks (1) as well as rats receiving an additional daily normal etoricoxib dosage of 7.8mg/kg for 3d (2) and 7d/week (3) and a high dosage of 13.1mg/kg for 7d/week (4) with serum bioavailability assessed by liquid chromatography-mass spectrometry. After one week of premedication, the first upper left molars (M1) were moved orthodontically in anterior direction for 4 weeks using a closed NiTi coil spring (0.25N) and OTM as well as sagittal cranial growth were quantified cephalometrically by CBCT imaging at the start and end of OTM. RESULTS: OTM, quantified as anterior metric tipping of M1, was significantly inhibited by about 33% only in rats receiving high-dose etoricoxib 7d/week (p=0.046) with a respective, but insignificant tendency also detectable for the normal dosages, whereas sagittal cranial growth was by tendency slightly increased with rising etoricoxib dosages, reflected by corresponding steady-state serum concentrations, confirming etoricoxib bioavailability. CONCLUSIONS: An etoricoxib-induced clinically relevant deceleration of OTM is not to be expected at dosage regimens used in clinical practice to treat dental or orthodontic pain in contrast to a continuously administered high dosage. Due to its favorable side effect profile and higher analgesic efficiency regarding dental and orthodontic pain, etoricoxib should be a clinically valid alternative to the current standard orthodontic analgesic acetaminophen with its associated higher risk profile.

Interactive effects of periodontitis and orthodontic tooth movement on dental root resorption, tooth movement velocity and alveolar bone loss in a rat model.

BACKGROUND: Many adult orthodontic patients suffer from chronic periodontitis with recurrent episodes of active periodontal inflammation. As their number is steadily increasing, orthodontists are more and more frequently challenged by respective treatment considerations. However, little is currently known regarding interactive effects on undesired dental root resorption (DRR), tooth movement velocity, periodontal bone loss and the underlying cellular and tissue reactions. MATERIAL AND METHODS: A total of 63 male Fischer344 rats were used in three consecutive experiments employing 21 animals each (A/B/C), randomly assigned to 3 experimental groups (n=7, 1/2/3), respectively: (A) CBCT; (B) histology/serology; (C) RT-qPCR-(1) control; (2) orthodontic tooth movement (OTM) of the first/second upper left molars (NiTi coil spring, 0.25N); (3) OTM with experimentally induced periodontitis (cervical silk ligature). After 14days of OTM, we quantified blood leukocyte level, DRR, osteoclast activity and relative gene expression of inflammatory and osteoclast marker genes within the dental-periodontal tissue as well as tooth movement velocity and periodontal bone loss after 14 and 28 days. RESULTS: The experimentally induced periodontal bone loss was significantly increased by concurrent orthodontic force application. Periodontal inflammation during OTM on the other hand significantly augmented the extent of DRR, relative expression of inflammatory/osteoclast marker genes, blood leukocyte level and periodontal osteoclast activity. In addition, contrary to previous studies, we observed a significant increase in tooth movement velocity. CONCLUSIONS: Although accelerated tooth movement would be favourable for orthodontic treatment, our results suggest that orthodontic interventions should only be performed after successful systematic periodontal therapy and paused in case of recurrent active inflammation.

Impact of radiotherapy on implant-based prosthetic rehabilitation in patients with head and neck cancer: A prospective observational study on implant survival and quality of life-Preliminary results.

PURPOSE: To study implant-based prosthetic rehabilitation of head and neck cancer patients with focus on implant survival and quality of life. MATERIALS AND METHODS: The prospective observational study presents preliminary results of 29 edentulous head neck cancer patients (20 patients after radiotherapy) with 165 OsseoSpeed implants. Implant success after 1-year follow-up was evaluated by means of the Albrektsson criteria. Quality of life was analysed with the EORTC QLQ-C30, QLQ-H&N35, and OHIP 14 questionnaires. RESULTS: The overall implant survival rate after 1 year was 95.2% (157/165). Implant success measured by the Albrektsson criteria showed a lower success rate of 86.7% (143/165), mainly because of peri-implant marginal bone loss with a mean of 0.8 mm after 1 year. Xerostomia (p = 0.008), implant insertion within the radiation target volume (p = 0.09), implantation in transplanted bone (p = 0.05), and smoking (p = 0.041) were the main reasons for implant failure, followed by D4 bone quality, maxillary implant site, and insufficient primary stability. Speaking, swallowing, eating, as well as social integration and individual self-confidence had considerably improved 1 year after denture placement compared to before treatment. CONCLUSION: Implant-based prosthetic rehabilitation of head and neck cancer patients is possible at a calculable risk and significantly improves patients' quality of life.

Can dental panoramic radiographic findings serve as indicators for the development of medication-related osteonecrosis of the jaw?

OBJECTIVES: The purpose of this case-control study was to find a correlation between certain imaging findings in dental panoramic radiographs and the risk for developing a medication-related osteonecrosis of the jaw (MRONJ) in patients taking antiresorptive therapy (AT). METHODS: Randomized and blinded dental panoramic radiographs of 60 patients undergoing antiresorptive drug treatment (36 patients with MRONJ, 24 patients without MRONJ) and of 60 patients without AT were analyzed by 3 experts for the following signs: sequestrum, osteosclerosis, difference in sclerosing of alveolar process and body of mandible, visible alveolar socket, enhancement and loss of lamina dura, enhancement of the oblique ridge, enhancement of the mandibular canal, proliferative periostitis and osteolytic processes at the cortex. RESULTS: Signs were seen significantly more often in patients undergoing AT than in the control group (CG) (osteosclerosis p-value = 0.019, visible alveolar socket p-value = 0.001, enhancement of lamina dura p-value < 0.001, enhancement of the mandibular canal p-value = 0.025, proliferative periostitis p-value = 0.05 and osteolytic processes at the cortex p-value < 0.001). While there is no significant difference between the CG and the group of patients with AT without manifest MRONJ for any sign, the significance increases when taking the group of patients under AT with manifest MRONJ into consideration. In addition, if medication was administered for malignant reasons, the signs visible alveolar socket, enhancement of the lamina dura and the enhancement of the mandibular canal were seen significantly more often. CONCLUSIONS: The radiographic findings mentioned above are not indicators for the development of MRONJ, as they are seen only in patients with manifest osteonecrosis. However, these findings could be important to assess the dimension and potency of a MRONJ.

Strontium ranelate improved tooth anchorage and reduced root resorption in orthodontic treatment of rats.

The anchorage mechanisms currently used in orthodontic treatment have various disadvantages. The objective of this study was to determine the applicability of the osteoporosis medication strontium ranelate in pharmacologically induced orthodontic tooth anchorage. In 48 male Wistar rats, a constant orthodontic force of 0.25 N was reciprocally applied to the upper first molar and the incisors by means of a Sentalloy(®) closed coil spring for two to four weeks. 50% of the animals received strontium ranelate at a daily oral dosage of 900 mg per kilogramme of body weight. Bioavailability was determined by blood analyses. The extent of tooth movement was measured both optometrically and cephalometrically (CBCT). Relative alveolar gene expression of osteoclastic markers and OPG-RANKL was assessed by qRT-PCR and root resorption area and osteoclastic activity were determined in TRAP-stained histologic sections of the alveolar process. Compared to controls, the animals treated with strontium ranelate showed up to 40% less tooth movement after four weeks of orthodontic treatment. Gene expression and histologic analyses showed significantly less osteoclastic activity and a significantly smaller root resorption area. Blood analyses confirmed sufficient bioavailability of strontium ranelate. Because of its pharmacologic effects on bone metabolism, strontium ranelate significantly reduced tooth movement and root resorption in orthodontic treatment of rats. Strontium ranelate may be a viable agent for inducing tooth anchorage and reducing undesired root resorption in orthodontic treatment. Patients under medication of strontium ranelate have to expect prolonged orthodontic treatment times.

Differentiated analysis of orthodontic tooth movement in rats with an improved rat model and three-dimensional imaging.

Rat models currently available for analysis of orthodontic tooth movement often lack differentiated, reliable and precise measurement systems allowing researchers to separately investigate the individual contribution of tooth tipping, body translation and root torque to overall displacement. Many previously proposed models have serious limitations such as the rather inaccurate analysis of the effects of orthodontic forces on rat incisors. We therefore developed a differentiated measurement system that was used within a rat model with the aim of overcoming the limitations of previous studies. The first left upper molar and the upper incisors of 24 male Wistar rats were subjected to a constant orthodontic force of 0.25 N by means of a NiTi closed coil spring for up to four weeks. The extent of the various types of tooth movement was measured optometrically with a CCD microscope camera and cephalometrically by means of cone beam computed tomography (CBCT). Both types of measurement proved to be reliable for consecutive measurements and the significant tooth movement induced had no harmful effects on the animals. Movement kinetics corresponded to known physiological processes and tipping and body movement equally contributed to the tooth displacement. The upper incisors of the rats were significantly deformed and their natural eruption was effectively halted. The results showed that our proposed measurement systems used within a rat model resolved most of the inadequacies of previous studies. They are reliable, precise and physiological tools for the differentiated analysis of orthodontic tooth movement while simultaneously preserving animal welfare.

Implant-supported fixed dental prostheses in an edentulous patient with dystrophic epidermolysis bullosa.

PURPOSE: This clinical report describes the use of implant-supported fixed dental prostheses (ISFDPs) in a severe case of dystrophic epidermolysis bullosa. MATERIALS AND METHODS: The patient's appearance was characterized by reduced corporal growth and severe mutilation of the hands and feet. He was first examined at age 20. The severely decayed residual dentition had already been extracted by the time of examination. Conventional dentures were not possible due to severe microstomia and the fragility of the denture-bearing tissues. Even a modest manual touch was very painful and detached the epithelium of the oral mucosa. The first treatment was only possible under general anesthesia. To allow some prospect for oral rehabilitation, four implants were inserted in the maxilla and three in the mandible. Several years of steroid treatment had weakened the bony structures. Therefore, the diameter of the last drill used to prepare the bone for implant insertion was smaller than the diameter of the implants to improve primary stability. Complete FDPs with a shortened dental arch design served as superstructures. Several fractures in the screw-designed titanium abutments in the mandible necessitated insertion of three additional implants and an ISFDP with two occlusal units, which was screwed horizontally to a milled bar mesostructure. RESULTS: Despite multiple fractures of the acrylic resin veneers caused by severe bruxism and the small occlusal surface, this rehabilitation proved successful until the patient died at age 25, as a consequence of his hereditary disease. CONCLUSION: This treatment greatly improved the patient's oral function, nutrition, and psychosocial well-being. Int J Prosthodont 2010;23:42-48.

Primary stability of a conical implant and a hybrid, cylindric screw-type implant in vitro.

PURPOSE: The differences with respect to primary stability between 2 Camlog implants, a conical implant, and a hybrid cylindric screw-type implant, were investigated in vitro. The effect of underdimensioned implant bed preparation was also studied for both implant designs. MATERIALS AND METHODS: In an in vitro model the stability of different implants in fresh porcine iliac bone blocks was measured using torque moment values, the Periotest, resonance frequency analysis, and push-out testing. RESULTS: The conical implant showed significantly higher primary stability than the cylindric hybrid implant using the insertion torque, Periotest, and push-out tests. For both types of implants, the torque moment values following under-dimensioned preparation were significantly better than those obtained following the standard drilling protocol (Conical: 25.00 vs 11.00 Ncm; Cylindrical: 11.75 vs. 5.75 Ncm). For the cylindric implant, significantly better results following under-dimensioned implant bed preparation were observed only with the insertion torque and the pushout testing values. The mean ISQ values for all groups were between 55 and 57; no statistical differences with respect to ISQ could be found. CONCLUSION: In this in vitro model conical implants showed higher primary stability than cylindric implants. The procedure of under-dimensioned drilling seemed to increase primary stability for both types of implants; however, the effect was only observable using insertion torque. RFA and Periotest, the noninvasive, clinical methods tested, did not clearly demonstrate this difference.

Reconstruction of mandibular defects following tumor ablation by vertical distraction osteogenesis using intraosseous distraction devices.

OBJECTIVES: Distraction osteogenesis has recently evolved a challenging technique to overcome major drawbacks of conventional augmentation procedures. We, therefore, report the application of miniaturized intraosseous distraction devices for the rehabilitation of mandibular defects due to ablative tumor surgery. METHODS: In 10 patients who had undergone box-shaped or segmental resections, augmentation of the residual mandibular bone or of full thickness iliac crest grafts was performed by intraosseous implant-shaped distractors. Distraction and reconsolidation was monitored by ultrasonography. Implants were inserted within 1 week after active distraction. Median follow-up after implant insertion was 38 months. RESULTS: On average, a vertical gain of 7.3 mm was obtained by distraction. Except for one case (local infection), all distraction zones showed complete ossification by radiologic and ultrasonographic evaluation. Overall 28 implants were placed in the distracted bone. Two implants were lost at 2.4 and 22 months after placement. The estimated 4-year implant survival rate in this population was 90%. For the endpoint 'bone loss' (>1.5 mm in the first and >1 mm in following years), the estimated 4-year success rate was 59% with four out of seven events occurring in a single patient (patient No. 1 of this series). CONCLUSION: Vertical distraction by means of implant distractors could be performed with reasonable success in tumor patients with box-shaped resection defects or undercontoured bone grafts. Overall morbidity was very low. Even though blood supply is continuously maintained in distraction osteogenesis, bone resorption remains a critical issue for this reconstruction technique too.

The use of implant-supported prostheses in the functional and psychosocial rehabilitation of tumor patients.

PURPOSE: The present study investigated the residual functional constraints as well as the psychosocial rehabilitation of tumor patients following prosthetic treatment with implant-supported dentures. MATERIALS AND METHODS: A clinical examination and semistructured interview were performed in 66 of 132 consecutive patients who underwent tumor resection and subsequent implant-supported restoration between 1985 and 1997. RESULTS: Functional and psychosocial constraints were improved by between 91% (general comfort) and 47% (social reintegration) of all cases, but these constraints were never fully compensated for. Restrictions in tongue mobility, loss of sensation, and radiotherapy-induced hyposalivation led to problems in chewing and swallowing, which were hardly improved by prosthetic rehabilitation. The best subjective assessments referred to appearance, followed by masticatory improvement and denture retention. CONCLUSION: Functional impairment cannot be fully compensated by implant-supported prosthodontic reconstructions, but such treatment contributes essentially to general well-being and relief of disease-related social restrictions.