Three-dimensional dento-skeletal effects of mandibular midline distraction and surgically assisted rapid maxillary expansion:A retrospective study

It was the aim of the study to provide a three-dimensional evaluation of dento-skeletal effects following bone-borne vs tooth-borne mandibular midline distraction (MMD) and tooth-borne surgically assisted rapid maxillary expansion (SARME). A retrospective observational study was conducted. Cone beam computed tomography (CBCT) records were taken pre-operatively (T1), immediately post-distraction (T2) and 1 year post-operatively (T3). All included 30 patients had undergone MMD (20 bone-borne MMD; 10 tooth-borne MMD). A total of 20 bone-borne MMD and 8 tooth-borne MMD patients had simultaneously undergone tooth-borne SARME. At T1 vs T3, canine (p = 0.007; 26.0 ± 2.09 vs 29.2 ± 2.02) and first premolar (p = 0.005; 33.8 ± 2.70 vs 37.0 ± 2.43) showed significant expansion on the tip level for tooth-borne MMD. This was no significant on the apex level, indicating tipping. Bone-borne MMD showed a parallel distraction gap, whereas tooth-borne MMD showed a V-shape. There was a significant (p = 0.017; 138 ± 17.8 vs 141 ± 18.2) inter-condylar axes increase for bone-borne MMD. In conclusion, bone-borne vs tooth-borne MMD and tooth-borne SARME showed stable dento-skeletal effects at 1 year post-operatively. Bone-borne and tooth-borne MMD seemed not to be superior to each other. The choice of distractor type therefore depends more on anatomical and comfort factors.</p

Safety and morbidity of intra-oral zygomatic bone graft harvesting : Development of a novel bone harvesting technique

AbstractThis study focuses on the development of a bone collecting device for intra-oral bone harvesting and on the introduction of a new bone graft donor site, zygomatic bone.A bone collector was constructed and tested in vitro. This bone collector is suitable and efficient in dental implant related bone grafting surgery. It was also found to be more efficient and with a larger capacity in bone harvesting when compared to the two commercially available bone collectors. A zygomatic bone harvesting technique is introduced in this study. The safety and morbidity of the method was assessed in a cadaver and a prospective clinical study. In the cadaver study, 40 procedures were performed. The complications during the cadaver harvesting included 15 perforations into the maxillary sinus and 7 perforations into the infratemporal fossa. The only intra-operative complication in 32 clinical operations was perforation of the maxillary sinus in 33% of the zygomatic sites. None of these patients experienced any post-operative problems related to the perforation. Patients needed pain medication for a mean time of four days and they did not demonstrate any paresthesias or altered sensations in the donor area.The yield of the bone graft from zygomatic bone was quantified in cadaver and clinical studies. In the cadaver study, the average yield of the graft was 0.59 ml. In the clinical study the average graft volume was 0.90 ml. The required reconstructions were accomplished in all clinical cases.In the prospective clinical study, the bone grafts from the zygomatic bone were used simultaneously with one-stage dental implants placement. Bone grafting was employed at 72 of the 82 implant sites. Two of the bone grafted implants failed, yielding a survival rate of 97.2% for bone grafted implants and 97.6% for the whole study group. Grafted sites healed remarkably well, and no obvious signs of graft resorption were noted during the 26.9 months follow-up period.The bone collector developed in this study is an effective instrument in intra-oral bone harvesting. The zygomatic bone can be regarded as a safe bone harvesting donor site and the yield of bone graft from this area is sufficient for moderate defects in resorbed alveolar ridges.Academic Dissertation to be presented with the assent of the Faculty of Medicine, University of Oulu, for public discussion in Auditorium 1 of the Institute of Dentistry, on October 29th, 2004, at 12 noon.Abstract This study focuses on the development of a bone collecting device for intra-oral bone harvesting and on the introduction of a new bone graft donor site, zygomatic bone. A bone collector was constructed and tested in vitro. This bone collector is suitable and efficient in dental implant related bone grafting surgery. It was also found to be more efficient and with a larger capacity in bone harvesting when compared to the two commercially available bone collectors. A zygomatic bone harvesting technique is introduced in this study. The safety and morbidity of the method was assessed in a cadaver and a prospective clinical study. In the cadaver study, 40 procedures were performed. The complications during the cadaver harvesting included 15 perforations into the maxillary sinus and 7 perforations into the infratemporal fossa. The only intra-operative complication in 32 clinical operations was perforation of the maxillary sinus in 33% of the zygomatic sites. None of these patients experienced any post-operative problems related to the perforation. Patients needed pain medication for a mean time of four days and they did not demonstrate any paresthesias or altered sensations in the donor area. The yield of the bone graft from zygomatic bone was quantified in cadaver and clinical studies. In the cadaver study, the average yield of the graft was 0.59 ml. In the clinical study the average graft volume was 0.90 ml. The required reconstructions were accomplished in all clinical cases. In the prospective clinical study, the bone grafts from the zygomatic bone were used simultaneously with one-stage dental implants placement. Bone grafting was employed at 72 of the 82 implant sites. Two of the bone grafted implants failed, yielding a survival rate of 97.2% for bone grafted implants and 97.6% for the whole study group. Grafted sites healed remarkably well, and no obvious signs of graft resorption were noted during the 26.9 months follow-up period. The bone collector developed in this study is an effective instrument in intra-oral bone harvesting. The zygomatic bone can be regarded as a safe bone harvesting donor site and the yield of bone graft from this area is sufficient for moderate defects in resorbed alveolar ridges

CT Scanning

Since its introduction in 1972, X-ray computed tomography (CT) has evolved into an essential diagnostic imaging tool for a continually increasing variety of clinical applications. The goal of this book was not simply to summarize currently available CT imaging techniques but also to provide clinical perspectives, advances in hybrid technologies, new applications other than medicine and an outlook on future developments. Major experts in this growing field contributed to this book, which is geared to radiologists, orthopedic surgeons, engineers, and clinical and basic researchers. We believe that CT scanning is an effective and essential tools in treatment planning, basic understanding of physiology, and and tackling the ever-increasing challenge of diagnosis in our society

Periodontal impact of surgically induced dental lesions in mandibular osteodistraction: an animal study.

AIM: The objective of the study was to evaluate the impact of dental lesions on the periodontium, in a canine model of mandibular osteodistraction. MATERIAL AND METHODS: In six adult male Beagle dogs, an osteotomy was made between the right second lateral incisor and canine, and a distraction device placed. The roots adjacent to the osteotomy were deliberately damaged by the reciprocating saw and chisel, with preservation of the attached gingiva. The osteodistraction protocol used was: latency of 7 days, rate of distraction 1mm per day, and rhythm once a day for 5 days. Vital staining was carried out with tetracycline, Xylenol Orange and Calcein Green. The dogs were sacrificed after 12 weeks of consolidation and the specimens were evaluated with light microscopy (native, polarized light, fluorescence, and after toluidin blue staining). RESULTS: The periodontal ligament (PDL) regeneration was observed in the 2500 slices examined. Cementum and dentine lesions were repaired by cellular cementum. Loose dentine and cementum-dentine fragments were embedded in regenerated PDL and their surface repaired by cementum. By means of light microscopic examination and within the limited observation time, no degenerative pulpal changes were found, when the pulp canal was not entered. Extensive pulp exposure and destruction resulted in ingrowth of the PDL and bone-like tissue. In that case, cellular cementum also lined the dentine surface of the pulp canal. CONCLUSION: Although there was an extensive reparative response to the para-pulpal lesions, none of the changes observed showed evidence of a loss of functional integrity of the periodontium at the distraction site. The fate of the tooth with exposed pulp canal remains uncertain

Prospektive Studie über dentale und skelettale Veränderungen durch mediane Unterkieferdistraktion

Wachstumsbedingte Missverhältnisse zwischen Knochen- und Zahnangebot führen im Unterkiefer zu frontalem Engstand oder Protrusionsstellung der Incisivi. Die Extraktion von Zähnen kann das Missverhältnis ausgleichen. Zum Erhalt der Zähne ist aber auch eine Vergrößerung des Kieferkörpers durch mediane Unterkieferdistraktion möglich. Die eng stehenden oder protrudierten Frontzähne werden mit kieferorthopädischer Hilfe zu einem normalen Zahnbogen ausgeformt. Mit dieser Methode wird auch eine Vergrößerung der Eckzahndistanz erreicht. Bei 16 weiblichen und 14 männlichen Patienten im Alter von 10 bis 51 Jahren wurden in Allgemeinnarkose mediane Unterkieferdistraktionen mit einem bukkal applizierten, knochenverankerten Distraktor durchgeführt. Die dentalen und skelettalen Veränderungen wurden mit Hilfe von Modellanalysen, Röntgenbildern und parodontalen Messungen untersucht, dokumentiert und statistisch ausgewertet. Die Untersuchungszeitpunkte waren präoperativ (T1), nach Ende der Distraktion (T2) und am Ende der kieferorthopädischen Ausformung des Zahnbogens (T3)