Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man

A total of 2895 threaded, cylindrical titanium implants have been inserted into the mandible or the maxilla and 124 similar implants have been installed in the tibial, temporal or iliac bones in man for various bone restorative procedures. The titanium screws were implanted without the use of cement, using a meticulous technique aiming at osseointegration--a direct contact between living bone and implant. Thirty-eight stable and integrated screws were removed for various reasons from 18 patients. The interface zone between bone and implant was investigated using X-rays, SEM, TEM and histology. The SEM study showed a very close spatial relationship between titanium and bone. The pattern of the anchorage of collagen filaments to titanium appeared to be similar to that of Sharpey's fibres to bone. No wear products were seen in the bone or soft tissues in spite of implant loading times up to 90 months. The soft tissues were also closely adhered to the titanium implant, thereby forming a biological seal, preventing microorganism infiltration along the implant. The implants in many cases had been allowed to permanently penetrate the gingiva and skin. This caused no adverse tissue effects. An intact bone-implant interface was analyzed by TEM, revealing a direct bone-to-implant interface contact also at the electron microscopic level, thereby suggesting the possibility of a direct chemical bonding between bone and titanium. It is concluded that the technique of osseointegration is a reliable type of cement-free bone anchorage for permanent prosthetic tissue substitutes. At present, this technique is being tried in clinical joint reconstruction. In order to achieve and to maintain such a direct contact between living bone and implant, threaded, unalloyed titanium screws of defined finish and geometry were inserted using a delicate surgical technique and were allowed to heal in situ, without loading, for a period of at least 3--4 months.

Platelet gel: an autologous alternative to fibrin glue with applications in oral and maxillofacial surgery

The preparation and use of platelet gel, an autologous formulation of fibrin glue, are described. The unique features of this biologic sealant are that it is derived from autologous blood collected in the immediate preoperative period by the anesthesiologist, it contains a high concentration of platelets, and it can be used in patients who are not candidates for blood bank donation. Platelet gel has been used successfully in the area of reconstructive oral and maxillofacial surgery in conjunction with ablative surgery of the maxillofacial region, mandibular reconstruction, surgical repair of alveolar clefts and associated oral-antral/ oral-nasal fistulas, and adjunctive procedures related to the placement of osseointegrated implants.

Distraction osteogenesis in maxillofacial surgery using internal devices: review of five cases

PURPOSE

The purpose of this report is to show the feasibility and potential advantages of using internal devices for distraction osteogenesis in the management of maxillofacial skeletal deficiencies.

PATIENTS AND METHODS

Distraction osteogenesis was used to correct a variety of maxillofacial skeletal deformities in five patients. One patient underwent bilateral Le Fort III advancement aided by distraction, three patients underwent mandibular ramus lengthening, and one patient underwent segmental alveolar reconstruction by distraction. The devices were activated by either a transcutaneous or transmucosal pin. After achievement of the desired skeletal transport, the activating pins were disengaged and removed from the distraction device. This allowed the distraction device to remain submerged and to stabilize the site of the consolidating bone.

RESULTS

All patients achieved lengthening of their jaws. However, premature consolidation was noted in two patients, and one patient had significant relapse.

CONCLUSIONS

Development of internal distraction devices is important to address the limitations of currently available biphasic systems. Potential benefits of internal devices include 1) elimination of skin scarring caused by translation of transcutaneous fixation pins, 2) improved patient compliance during the fixation or consolidation phase because there is no external component, and 3) improved stability of the attachment of the device to the bone.

The importance of incisor positioning in the esthetic smile: the smile arc

The smile arc is defined as the relationship of the curvature of the incisal edges of the maxillary incisors and canines to the curvature of the lower lip in the posed smile. The ideal smile arc has the maxillary incisal edge curvature parallel to the curvature of the lower lip. Evaluation of anterior smile esthetics must include both static and dynamic evaluations of profile, frontal, and 45 degrees views to optimize both dental and facial appearance in orthodontic planning and treatment. This article presents the concept of the smile arc and how it relates to orthodontics-from the recognition of its importance, to its impact on orthodontic treatment planning, to how procedures and mechanics are adapted to optimize the appearance of the smile. Three cases are used to illustrate how treatment is directed, emphasizing how facial and smile goal setting go hand in hand.

Restoration of masticatory function by microsurgically revascularized iliac crest bone grafts using enosseous implants

Forty-one free osteomyocutaneous groin flaps were used for osteoplastic reconstruction of the mandible (n = 36) or maxilla (n = 5) following tumor resection or, less often, chronic osteomyelitis or traumatic bone loss. Nineteen grafts were transplanted into a preirradiated area. No total loss of a transplant or pseudoarthrosis was observed. Plates were used for graft fixation. Free grafting was necessary in two patients, who developed partial bone loss because of infection. Four patients showed partial loss of the skin part of the myocutaneous flap. Improvement of the preprosthetic situation was achieved by a total of 38 enosseous aluminium oxide implants into the vascularized bone grafts. All showed primary healing and successful integration in prosthetic rehabilitation, maximum follow-up time being 30 months.

Changes in temporomandibular joint dysfunction after orthognathic surgery

PURPOSE

We sought to evaluate the effects of orthognathic surgery on temporomandibular joint (TMJ) dysfunction in patients with known presurgical TMJ internal derangement who underwent double-jaw surgery for the treatment of dentofacial deformities.

PATIENTS AND METHODS

Treatment records of 25 patients with magnetic resonance imaging and clinical verification of preoperative TMJ articular disc displacement who underwent double-jaw surgery only were retrospectively evaluated, with an average follow-up of 2.2 years. Signs and symptoms of TMJ dysfunction, including pain, range of mandibular motion, and presence/absence of TMJ sounds, were subjectively (visual analog scales) and objectively evaluated at presurgery (T1), immediately postsurgery (T2), and at longest follow-up (T3). Surgical change (T2-T1) and long-term stability of results (T3-T2) were calculated using the superimposition of lateral cephalometric and tomographic tracings.

RESULTS

Presurgery, 16% of the patients had only TMJ pain, 64% had only TMJ sounds, and 20% had both TMJ pain and sounds. Postsurgery, 24% of the patients had only TMJ pain, 16% had only TMJ sounds, and 60% has both TMJ pain and sounds. Thus, presurgery 36% of the patients had TMJ pain, and postsurgery, 84% had pain. Average visual analog scale pain scores were significantly higher postsurgery and none of the patients with presurgery TMJ pain had relief of pain postsurgery. In addition, 6 patients (24%) developed condylar resorption postsurgically, resulting in the development of Class II open bite malocclusion.

CONCLUSIONS

Patients with preexisting TMJ dysfunction undergoing orthognathic surgery, particularly mandibular advancement, are likely to have significant worsening of the TMJ dysfunction postsurgery. TMJ dysfunction must be closely evaluated, treated if necessary, and monitored in the orthognathic surgery patient.

Bioactive glass particulate material as a filler for bone lesions

Calcium-phosphate ceramic particulates are often used as filler material for enhanced repair of dental bone defects. Although evidence of bone ingrowth in the scaffold of these particles has been described, it is not observed consistently. Fibrous tissue often encapsulates these particles, which can subsequently become dispersed into the surrounding tissues or even exfoliated. The aim of the present study was to evaluate bioactive glass granules (Biogran) as a filler for osseous lesions, and to compare them with two commercially available Hydroxylapatite (HA) granules. The particulates were implanted in the jaws of five beagle dogs, resected and evaluated after 1, 2, 3, 6 and 12 months of implantation. Histological analysis revealed an improvement in repair of all the lesions. A massive osteoconductive bone growth was seen near the walls of the bony cavities, but in greater amounts around the bioactive glass granules than around the HA materials. On top of this massive growth a trabecular bone growth was observed in the centre of the bony cavities. These trabeculae were associated with the glass particles, which exhibited osteophilic properties, while fibrous tissue separated the bone tissue from the HA particles. The centres of many of the particles are excavated, and are subsequently filled by newly formed bone tissue. This internally formed bone tissue is not necessarily connected to the surrounding bone tissue, and functions as a nucleation site for further bone repair. For the mesenchymal cells within the eroded glass particles this inner environment acts as a stimulus to differentiate into osteoblasts and to start their osteogenetic potential. This phenomenon was not observed around the HA materials. If the latter were surrounded by fibrous tissue, disintegration of the surface by giant cells was observed.

The use of hyperbaric oxygen therapy in bony reconstruction of the irradiated and tissue-deficient patient

Eighteen bony reconstructions of the mandible or maxilla using a newly defined and specific hyperbaric oxygen protocol are reported. Eleven of 12 grafts in irradiated tissue met six rigid criteria for a 91.6% rate of success. All six grafts into scarred and deficient tissue beds also met the same criteria, for an overall success rate of 94%. The rationale for emphasizing preoperative tissue preparation using hyperbaric oxygen is discussed, as are the mechanisms of action of hyperbaric oxygen on a biochemical, cellular, and tissue level. Neovascularity and neocellularity are demonstrated histologically by human biopsy specimens, and this is suggested as being the reason for the excellent results of reconstruction in irradiated and/or deficient tissue beds.

Obstructive sleep apnea syndrome: a surgical protocol for dynamic upper airway reconstruction

A surgical protocol for dynamic upper airway reconstruction in the treatment of obstructive sleep apnea syndrome is presented. Two hundred thirty-nine consecutively treated patients were evaluated. All patients underwent a presurgical evaluation that included a physical examination, fiberoptic pharyngoscopy, cephalometric analysis, and polygraphic monitoring. The goal of the presurgical evaluation was to document sleep apnea and isolate the area of obstruction. The treatment was then directed to the obstructive site. The surgical protocol included two phases. Phase 1 was a conservative approach and included uvulopalatopharyngoplasty and/or mandibular osteotomy with genioglossus advancement-hyoid myotomy and suspension. Polysomnography was repeated at 6 months and patients with unsuccessful surgical results were offered maxillary-mandibular advancement osteotomy. Results were based on the postoperative polysomnograms, and included assessing changes in both sleep architecture and sleep-disordered breathing. The surgical results were compared with results in patients who were using nasal continuous positive airway pressure. The surgical success rate for the 239 patients entered into phase 1 therapy was 61% (145 patients). Twenty-four patients who failed phase 1 treatment elected phase 2 treatment. The surgical success rate of this phase was 100%.

Psychologic changes in orthognathic surgery patients: a 24-month follow up

This report describes the final, two-year follow up in a longitudinal study of 74 patients who underwent orthognathic surgery for developmental deformities. Data for all six measurement periods were available for 46 patients. Complaints of functional problems decreased significantly from before surgery to 24 months after, although 49% of the patients continued to report lip paresthesia. The incidence of postsurgical problems had no effect on the satisfaction expressed with surgical outcomes, which remained high throughout the postoperative course. Self-esteem appeared to rise in anticipation of surgery, only to decline significantly at nine months after surgery, to rise again by 24 months (but not as high as before surgery). In some components, self-esteem remained significantly lower after surgery than before. Body image also showed a decline at nine months, although overall body image and profile image 20-26 months after surgery were significantly more positive than before surgery. These results point to the importance of continued contact with orthognathic surgery patients by surgeons and orthodontists for at least two years after surgery, particular attention being paid to the intermediate stages (six to 12 months) after surgery. This period of psychologic upheaval appears to be related to the patient's desire to complete postsurgical orthodontics.

Heat generation during implant drilling: the significance of motor speed

PURPOSE

The purpose of this study was to measure the heat generated from 3 drilling speeds (1,225, 1,667, and 2,500 rpm) using the armamentarium of 4 implant systems.

MATERIALS AND METHODS

The mean rise in temperature, the time of drilling, and the time needed for pig jaw bone to return to the baseline temperature were monitored using 4 thermocouple technology.

RESULTS

The mean rise in temperature, the time of drilling, and the time needed for the specimens to return to the baseline temperature were lower at 2,500 rpm than at 1,667 or 1,225 rpm (P < or =.05), regardless of the system used. The rpm also directly correlated to the amount of time the bone remained at an elevated temperature.

CONCLUSION

From a heat generation standpoint, we conclude that preparing an implant site at 2500 rpm could decrease the risk of osseous damage, which may affect the initial healing of dental implants. This may decrease the devital zone adjacent to an implant after surgery and be most advantageous in immediate load application to dental implants.

Rapid protyping technology in medicine--basics and applications

Using medical models built with Rapid Prototyping (RP) technologies represents a new approach for surgical planning and simulation. These techniques allow one to reproduce anatomical objects as 3D physical models, which give the surgeon a realistic impression of complex structures before a surgical intervention. The shift from the visual to the visual-tactile representation of anatomical objects introduces a new kind of interaction called 'touch to comprehend'. As can be seen, from the presented case studies of maxillo-cranio-facial surgery, the RP models are very well suited for use in the diagnosis and the precise preoperative simulation of skeleton modifying interventions.

The temporalis muscle flap in oral reconstruction. A cadaveric, animal and clinical study

The possibility of rotating the temporalis muscle down into the mouth, after division of the zygomatic arch and base of the coronoid, was studied in cadaver material and in the rhesus monkey. Six human subjects are described in whom this muscle flap was employed successfully in oral reconstruction after either hemimandibulectomy or hemimaxillectomy. The flap remained viable in all subjects, and in six experimental monkeys. It proved useful in contour restoration, repair of the palate and of the floor of mouth. Further work is being undertaken on combination with skin grafts and myocutaneous flaps.

Manufacturing splints for orthognathic surgery using a three-dimensional printer

OBJECTIVE

A new technique for producing splints for orthognathic surgery using a 3D printer is presented.

STUDY DESIGN

After 3-dimensional (3D) data acquisition by computerized tomography (CT) or cone-beam computerized tomography (CBCT) from patients with orthognathic deformations, it is possible to perform virtual repositioning of the jaws. To reduce artifacts, plaster models were scanned either simultaneously with the patient during the 3D data acquisition or separately using a surface scanner. Importing and combining these data into the preoperative planning situation allows the transformation of the planned repositioning and the ideal occlusion. Setting a virtual splint between the tooth rows makes it possible to encode the repositioning. After performing a boolean operation, tooth impressions are subtracted from the virtual splint. The "definitive" splint is then printed out by a 3D printer.

CONCLUSION

The presented technique combines the advantages of conventional plaster models, precise virtual 3D planning, and the possibility of transforming the acquired information into a dental splint.

Comparison of actual surgical outcomes and 3-dimensional surgical simulations

PURPOSE

The advent of imaging software programs has proved to be useful for diagnosis, treatment planning, and outcome measurement, but precision of 3-dimensional (3D) surgical simulation still needs to be tested. This study was conducted to determine whether the virtual surgery performed on 3D models constructed from cone-beam computed tomography (CBCT) can correctly simulate the actual surgical outcome and to validate the ability of this emerging technology to recreate the orthognathic surgery hard tissue movements in 3 translational and 3 rotational planes of space.

MATERIALS AND METHODS

Construction of pre- and postsurgery 3D models from CBCTs of 14 patients who had combined maxillary advancement and mandibular setback surgery and 6 patients who had 1-piece maxillary advancement surgery was performed. The postsurgery and virtually simulated surgery 3D models were registered at the cranial base to quantify differences between simulated and actual surgery models. Hotelling t tests were used to assess the differences between simulated and actual surgical outcomes.

RESULTS

For all anatomic regions of interest, there was no statistically significant difference between the simulated and the actual surgical models. The right lateral ramus was the only region that showed a statistically significant, but small difference when comparing 2- and 1-jaw surgeries.

CONCLUSIONS

Virtual surgical methods were reliably reproduced. Oral surgery residents could benefit from virtual surgical training. Computer simulation has the potential to increase predictability in the operating room.

Osseointegrated implants in irradiated bone: a case-controlled study using adjunctive hyperbaric oxygen therapy

PURPOSE

The current investigation was undertaken to study whether osseointegration of implants in irradiated tissues is subject to a higher failure rate than in nonirradiated tissues. It further aimed to study whether hyperbaric oxygen treatment (HBO) can be used to reduce implant failure.

PATIENTS AND METHODS

Seventy-eight cancer patients who were rehabilitated using osseointegrated implants between 1981 and 1997 were investigated. Three groups of patients were compared: irradiated (A), nonirradiated (B), and irradiated and HBO-treated (C). In addition, 10 irradiated patients who had lost most of their implants received new ones after HBO treatment. These were compared as a case-control group.

RESULTS

Implant failures were highest in group A (53.7%). Implant failure was 13.5% in group B and 8.1% in group C. The difference between group A and the other two groups was statistically significant (P = .001 to .0023, Mantell's test). HBO significantly improved implant survival in the case-control group from 34 of 43 implants lost to 5 of 42 lost (P = .0078).

CONCLUSIONS

Implant insertion in irradiated bone is associated with a higher failure rate. Adjuvant HBO treatment can reduce the failures.

Effects of cervical anchorage during and after treatment: an implant study

Two groups of ten patients with postnormal molar relation, identical as regards facial morphology and dental stage, were treated for 8 months with cervical traction of the Kloehn type. The extraoral arch of the headgear was tilted upward in relation to the occlusal plane in one group and downward in the other. The local tooth movements were measured and related to metal implants inserted in the jaws. The movement of the implants in relation to the anterior cranial base expressed the amount and direction of the sutural and condylar growth. It was shown that a normal molar relationship was established in the shortest time with a downward tilt of the extraoral bow. A pronounced distal tipping of the molars was observed in these patients. The growth direction of the maxilla during cervical treatment was downward and backward and the mandible rotated posteriorly. The children were observed again 7 to 8 years after treatment, and it appeared that the influence of the headgear on the growth pattern of the facial skeleton was reversible, as a pronounced anterior direction of growth of the maxilla as well as of the mandible was observed in all but two subjects.

Orthognathic surgery: patient expectations; psychological profile and satisfaction with outcome

61 orthognathic surgery patients were studied (39% male, 61% female). It confirms that the group of patients we see in the West of Scotland are well adjusted psychologically and that the majority seek orthognathic surgery for aesthetic reasons. The degree of satisfaction is high (87%). Dissatisfaction is not related to sex, age or procedure. Patients who were dissatisfied tend to have higher neuroticism scores on the Eysenck Personality Inventory and those patients who had had unreal expectations of post surgical pain, numbness and swelling, were likely to express dissatisfaction with the outcome in the early stages. Several patients initially expressed some dissatisfaction with the outcome after 3 months then went on to increase their score and by 12 months became satisfied with the procedure. The authors outline the importance of adequate patient preparation prior to surgery and the use of printed literature is recommended.

Autogenous bone chips: influence of a new piezoelectric device (PiezosurgeryR) on chip morphology, cell viability and differentiation

AIM

The aim of the present study was to investigate the influence of a new piezoelectric device, designed for harvesting autogenous bone chips from intra-oral sites, on chip morphology, cell viability and differentiation.

METHODS

A total of 69 samples of cortical bone chips were randomly gained by either (1) a piezoelectric device (PS), or (2) conventional rotating drills (RD). Shape and size of the bone chips were compared by means of morphometrical analysis. Outgrowing osteoblasts were identified by means of alkaline phosphatase activity (AP), immunhistochemical staining for osteocalcin (OC) synthesis and reverse transcriptase-polymerase chain reaction phenotyping.

RESULTS

In 88.9% of the RD and 87.9% of the PS specimens, an outgrowth of adherent cells nearby the bone chips was observed after 6-19 days. Confluence of cells was reached after 4 weeks. Positive staining for AP and OC identified the cells as osteoblasts. The morphometrical analysis revealed a statistically significant more voluminous size of the particles collected with PS than RD.

CONCLUSION

Within the limits of the present study, it may be concluded that both the harvesting methods are not different from each other concerning their detrimental effect on viability and differentiation of cells growing out of autogenous bone chips derived from intra-oral cortical sites.

Pharyngeal airway space changes after counterclockwise rotation of the maxillomandibular complex

The purpose of this study was to evaluate the effects of double-jaw surgery with counterclockwise rotation of the maxillomandibular complex on the pharyngeal airway space and velopharyngeal anatomy in patients with high occlusal plane facial morphology. Fifty patients (22 men, 28 women) with high occlusal plane facial morphology underwent double-jaw surgery with counterclockwise rotation of the maxillomandibular complex. The patients were divided into 2 groups: group 1, 30 patients (8 men, 22 women) who underwent maxillary and mandibular advancement and group 2, 20 patients (14 men, 6 women) who underwent maxillary advancement and mandibular setback. Presurgery and postsurgery lateral cephalometric radiographs were analyzed to correlate changes in pharyngeal airway space dimensions and velopharyngeal anatomy with maxillary and mandibular positional changes. The calibration showed a more than 0.94 correlation for both intra- and interoperator error. The average follow-up time was 29.6 months in group 1 and 22.2 months in group 2. Mean maxillary surgical change at point A was 4.15 mm in group 1 and 2.5 mm in group 2. Mean mandibular surgical change at the genial tubercles was 7.5 mm in group 1 and -4.95 mm in group 2. After surgery, group 1 patients had an increase in pharyngeal airway space of 47% at the soft palate and 76% at the base of the tongue relative to the amount of mandibular advancement. Group 2 patients had a decrease in pharyngeal airway space of 47% at the soft palate and 65% at the base of the tongue relative to the amount of mandibular setback. Double-jaw surgery with counterclockwise rotation of the maxillomandibular complex significantly affects the pharyngeal airway space and velopharyngeal anatomy in patients with high occlusal plane facial morphology, with both mandibular advancement and setback.

Distribution of bone quality in patients receiving endosseous dental implants

Knowledge of the distribution of bone quality in the various jaw regions assists the clinician in dental implant treatment planning. Bone quality was assessed with radiographs and tactile sensation for 2,839 implants at the time of placement into four anatomic regions of the jaw. The Lekholm-Zarb classification system was used. Overall, bone quality types 1 and 4 were found much less frequently than types 2 and 3. Although variations in density existed in each region, quality 2 bone dominated the mandible, and quality 3 bone was more prevalent in the maxilla. For both anterior and posterior jaw regions, types 2 and 3 bone predominated. The anterior mandible had the densest bone, followed by the posterior mandible, anterior maxilla, and posterior maxilla.

Fusion of computed tomography data and optical 3D images of the dentition for streak artefact correction in the simulation of orthognathic surgery

OBJECTIVE

To determine the limits of accuracy of fusion of optical three-dimensional (3D) imaging and computed tomography (CT) with and without metal artefacts in an experimental setting and to show the application of this hybrid system in 3D orthognathic surgery simulation.

METHODS

Ten plaster casts of dental arches were subjected to a CT scan and optical 3D surface imaging. Subsequently, the first molars in the plaster casts were supplied with metal restorations, bilaterally, and new CT scans and optical surface images were assessed. The registration of the surface data of the two imaging modalities of the study models without and with metal restorations was carried out. The mean distance between the two data sets was calculated. From a patient a CT scan of the skull as well as optical 3D images of plaster casts of the dental arches were acquired. Again the two imaging modalities were registered and virtual orthognathic surgery simulation was carried out.

RESULTS

The mean distance between the corresponding data points of CT and optical 3D surface images was 0.1262+/-0.0301 mm and 0.2671+/-0.0580 mm, respectively, for the plaster casts without and with metal restorations. The differences between these data were statistically significant (P<0.0005). For the patient case a mean difference of 0.66+/-0.49 mm and 0.56+/-0.48 mm for mandible and maxilla, respectively, was calculated between CT and optical surface data.

CONCLUSION

The accuracy of the fusion of 3D CT surface data and optical 3D imaging is significantly reduced by metal artefacts. However, it seems appropriate for virtual orthognathic surgery simulation, as post-operative orthodontics are performed frequently.

Human demineralized freeze-dried bone: inadequate induced bone formation in athymic mice. A preliminary report

The purpose of this study was to test the osteoinductive properties of demineralized freeze-dried bone (DFDBA) randomly purchased from four commercial bone banks. Twenty-five (25) milligrams of bone from each of the banks was implanted into the hindquarter muscles of athymic mice. Two samples from each of the banks were compared with samples from the other banks. A total of 16 implants were grafted into 8 mice. Two additional mice served as controls. One mouse received an implantation of deactived human cortical bone matrix (DBM) (negative control). The other mouse received an implant of human bone morphogenetic protein/non-collagenous proteins (hBMP/NCP) infused to surface demineralized human cortical bone (positive control). At 21 days the mice were killed, the hindquarters were photographed, and the tissues were prepared for histologic evaluation. Of the 16 commercial DFDBA implants, 12 were available for histologic evaluation. There was no radiographic evidence of bone formation for the DFDBA implanted mice or the DBM implants. Small bone ossicles were scarcely visible in the hindquarters of the mouse which received the hBMP/NCP infused bone. Histomorphometric analysis was used to determine the percentage of new and dead bone. The bone was measured in pixels. The predominant histologic feature of the DFDBA implants was non-vital bone chips with minimal amounts of new bone. The average amount of non-vital bone ranged from 78.4% to 92.5%. There was no evidence of bone formation for the DBM implants. The average amount of bone for the mouse which received hBMP/NCP was 96%. The results of this pilot study indicate that commercially-available DFDBA induced clinically insignificant amounts of bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic validity (or acuity) of 2D CCD versus 3D CBCT-images for assessing periodontal breakdown

OBJECTIVE

The objective of this study was to compare 2-dimensional intraoral digital images with 3-dimensional cone beam CT (CBCT) in assessment of periodontal bone levels and defects.

METHODS

Thirty periodontal bone defects of 2 adult human skulls (with soft tissue or substitute) were evaluated by using intraoral digital radiography and CBCT. Digital radiographs were made with a size #2 CCD sensor and a 60-kV DC x-ray unit, with 0.28, 0.42, or 0.56 mAs as respective exposure settings. For CBCT, jawbone images were obtained at 120 kV and 23.87 mAs. Periodontal bone levels and defects on both imaging modalities were assessed and compared to the gold standard. Delineation of lamina dura, crater defect, furcation involvements, contrast, and bone quality were also analyzed.

RESULTS

Linear measurement deviations of periodontal bone levels from the gold standard ranged from 0.19 to 1.66 mm for intraoral radiography versus 0.13 to 1.67 mm for CBCT. Accuracy was not significantly different between both imaging modalities (P = .161). Intraoral radiography scored significantly better for contrast, bone quality, and delineation of lamina dura, but CBCT was superior for assessing crater defects and furcation involvements (P = .018).

CONCLUSIONS

CBCT images allowed comparable measurements of periodontal bone levels and defects as intraoral radiography. CBCT images demonstrated more potential in the morphological description of periodontal bone defects, while the digital radiography provided more bone details. These findings may offer perspectives for further studies on periodontal diagnostics, prognostics, and presurgical planning with CBCT.

Maxillofacial surgery and nasal CPAP. A comparison of treatment for obstructive sleep apnea syndrome

Nasal continuous positive airway pressure (CPAP) is the primary therapy for obstructive sleep apnea syndrome (OSAS). Recent reports have indicated, however, that there is a small but significant number of failures related to patient compliance. Primary surgical treatment, which has been uvulopalatopharyngoplasty (UPPP), has declined because of poor results. A reviewed of UPPP failures has shown that while UPPP eliminated palatal obstruction, it failed to eliminate base of tongue obstruction. Maxillofacial surgery has been reported as treatment of OSAS by correcting base of tongue obstruction. Thirty patients with severe OSAS were evaluated to compare nasal CPAP and maxillofacial surgery. The goal was to determine if our surgical protocol was as effective as nasal CPAP. All patients initially underwent baseline diagnostic polysomnography to document OSAS. A nasal CPAP study was performed to determine the appropriate positive end-expiratory pressure. The patients in this study were using nasal CPAP, but they found it unacceptable as long-term treatment and elected surgery. Maxillofacial surgery consisted of maxillary, mandibular, and hyoid advancement. Polysomnography was performed six months following surgery and compared with the night 2 CPAP results. The parameters included in the investigation were the respiratory disturbance index (RDI), lowest SaO2, number of SaO2 falls below 90 percent, total sleep time (TST), REM sleep percent, stage 3-4 sleep percent, and wake after sleep onset. The mean RDI before treatment was 72.0 (SD 25.7). After completing therapy, the RDI from surgery and CPAP was 8.8 (SD 6.0) and 8.6 (SD 4.1), respectively. The mean low SaO2 prior to treatment was 61.0 (SD 13.5), and the CPAP results and postsurgical results were 86.2 (SD 5.5) and 86.1 (SD 4.2), respectively. An analysis of variance was used to examine the results, and there was no statistical difference between nasal CPAP and surgery for all respiratory variables.