[Wound healing of the oral mucosa: process, factors affecting healing and complications]. / Wondgenezing van het mondslijmvlies: het proces, factoren die van invloed zijn op de genezing en complicaties.

The oral mucosa is made up of an epithelium supported by the lamina propria and the submucosa. When the mucosa is damaged, wound healing is characterized by distinct, sequential phases. How does the healing process proceed? Both primary and secondary wound healing, encompasses haemostasis, inflammation, proliferation, and remodelling. Secondary healing also involves a granulation phase to cover the wound. Saliva and the oral microbiome play a role in the healing process, too. Smoking, certain systemic disorders and medication can have a negative effect on the healing process.

[Loss of an eye as a result of an odontogenic infection]. / Oogverlies als gevolg van een dentogene infectie.

A 50-year-old woman presented at the outpatient clinic of the department of oral and maxillofacial surgery with a severe swelling around the left eye 1 week after removal of the second molar in the upper jaw. Despite administration of antibiotics 2 days after the removal of the molar because of periorbital swelling, the inflammation spread to the intraorbital space with eventual loss of the left eye. Timely recognition of the symptoms of (the onset of) an orbital infection after dental treatment and immediate referral to an oral and maxillofacial surgeon and/or ophthalmologist for adequate treatment can be vision-saving. Fortunately, orbital infections with an odontogenic cause are rare.

Comparison of the long-term clinical performance of a biodegradable and a titanium fixation system in maxillofacial surgery: A multicenter randomized controlled trial.

BACKGROUND: Biodegradable fixation systems could reduce or eliminate problems associated with titanium removal of implants in a second operation. AIM: The aim of this study was to compare the long-term (i.e. >5 years postoperatively) clinical performance of a titanium and a biodegradable system in oral and maxillofacial surgery. MATERIALS AND METHODS: The present multicenter Randomized Controlled Trial (RCT) was performed in four hospitals in the Netherlands. Patients treated with a bilateral sagittal split osteotomy (BSSO) and/or a Le Fort-I osteotomy, and those treated for fractures of the mandible, maxilla, or zygoma were included from December 2006 to July 2009. The patients were randomly assigned to either a titanium (KLS Martin) or a biodegradable group (Inion CPS). RESULTS: After >5 years postoperatively, plate removal was performed in 22 of the 134 (16.4%) patients treated with titanium and in 23 of the 87 (26.4%) patients treated with the biodegradable system (P = 0.036, hazard ratio (HR) biodegradable (95% CI) = 2.0 (1.05-3.8), HR titanium = 1). Occlusion, VAS pain scores, and MFIQ showed good and (almost) pain free mandibular function in both groups. CONCLUSION: In conclusion, the performance of the Inion CPS biodegradable system was inferior compared to the KLS Martin titanium system regarding plate/screws removal in the abovementioned surgical procedures. TRIAL REGISTRATION: http://controlled-trials.com ISRCTN44212338.

Cost-Effectiveness of a Biodegradable Compared to a Titanium Fixation System in Maxillofacial Surgery: A Multicenter Randomized Controlled Trial.

BACKGROUND: Biodegradable fixation systems could reduce/delete the problems associated with titanium plate removal. This means less surgical discomfort, and a reduction in costs. AIM: The aim of the present study was to compare the cost-effectiveness between a biodegradable and a titanium system in Maxillofacial surgery. MATERIALS AND METHODS: This multicenter RCT was performed in the Netherlands from December 2006 to July 2009. Included were 230 patients who underwent a bilateral sagittal split osteotomy (BSSO), a Le Fort-I osteotomy, or a bi-maxillary osteotomy and those treated for fractures of the mandible, maxilla, or zygoma. The patients were randomly assigned to a titanium group (KLS Martin) or to a biodegradable group (Inion CPS). Costs were assessed from a societal perspective. Health outcomes in the incremental cost-effectiveness ratio (ICER) were bone healing (8 weeks) and plate removal (2 years). RESULTS: In 25 out of the 117 patients who were randomized to the biodegradable group, the maxillofacial surgeon made the decision to switch to the titanium system intra-operatively. This resulted in an Intention-To-Treat (ITT-)analysis and a Treatment-Received (TR-) analysis. Both analyses indicated that operations performed with titanium plates and screws had better health outcomes. In the TR-analysis the costs were lower in the biodegradable group, in the ITT-analysis costs were lower in the titanium group. CONCLUSION AND DISCUSSION: The difference in costs between the ITT and the TR analyses can be explained by the intra-operative switches: In the TR-analysis the switches were analysed in the titanium group. In the ITT-analysis they were analysed in the biodegradable group. Considering the cost-effectiveness the titanium system is preferable to the biodegradable system in the regular treatment spectrum of mandibular, Le Fort-I, and zygomatic fractures, and BSSO's, Le Fort-I osteotomies and bimaxillary osteotomies. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN 44212338.

Comparison of the long-term skeletal stability between a biodegradable and a titanium fixation system following BSSO advancement - a cohort study based on a multicenter randomised controlled trial.

Biodegradable fixation systems could reduce or eliminate the problems associated with removal of titanium plates. A multicenter randomised controlled trial (RCT) was performed in the Netherlands from December 2006-July 2009, and originally 230 injured and orthognathic patients were included. The patients were randomly assigned to either a titanium control group (KLS Martin) or to a biodegradable test group (Inion CPS). The aim of the present study was to compare the long-term skeletal stability of advancement bilateral sagittal split osteotomies (BSSO) of a biodegradable system and a titanium system. Only patients from the original RCT who were at least 18 years old and who had a BSSO advancement osteotomy were included. Those who had simultaneous Le Fort I osteotomy or genioplasty were excluded. Analysis of skeletal stability was made by digital tracing of lateral cephalograms. Long-term skeletal stability in BSSO advancement did not differ significantly between patients treated with biodegradable plates and screws and those treated with titanium plates and screws. Given the comparable amount of relapse, the general use of Inion CPS in the treatment of BSSO advancement should not be discouraged. On the basis of other properties a total picture of the clinical use can be obtained; the short-term stability, the intraoperative switches, the number of plates removed and cost-effectiveness. Trial registration of original RCT: http://www.controlled-trials.com; ISRCTN 44212338.

Decision-making considerations in application of biodegradable fixation systems in maxillofacial surgery--a retrospective cohort study.

In a recent RCT comparing biodegradable (Inion CPS) with titanium (KLS Martin) plates and screws for fixation of osteotomies or fractures, we found that in 21% of the cases the surgeon decided intra-operatively to switch from biodegradable to titanium. The aim of the current retrospective cohort study was to analyse the reasons for these switches in order to find predictor variables that may be helpful in the decision to use biodegradable devices or not. The surgeons' opinion about the biodegradable system, and if there was a learning curve in the application of the biodegradable system were also investigated. All variables were assessed during the original RCT by using a questionnaire that was completed by the OMF surgeon directly post-operatively. For the outcome variable "surgeons' opinion" a separate questionnaire was used. Regarding the predictor variables a mandibular fracture had a higher risk of switching compared to a BSSO. However, looking at the reasons for these switches no firm conclusions can be drawn. There was a subjective learning curve to acquire the application-skills for the biodegradable system. There were no changes in isolated Le-Fort-I osteotomies despite the fact that the biodegradable system seems more difficult to apply in the midface. Inadequate stability was the main reason for switching. This can be material-related, or related to inexperience with or lack of confidence in the system, or impatience of the surgeon. A learning curve and personal preferences probably play an important role in the decision to switch. We think that with more patience and more experience it should be possible to increase both user comfort and confidence in the biodegradable system of Inion CPS, which likely will decrease the number of intra-operative switches.

Comparison of biodegradable and titanium fixation systems in maxillofacial surgery: a two-year multi-center randomized controlled trial.

Biodegradable osteosynthesis could reduce/delete the problems associated with titanium plate removal. The aim of the present study was to compare the clinical performance in the first 2 post-operative years between a biodegradable and a titanium system in oral and maxillofacial surgery. The multicenter randomized controlled trial (RCT) was performed in the Netherlands from December 2006 to July 2009. Included were 230 patients who underwent a bilateral sagittal split osteotomy (BSSO) and/or a Le Fort-I osteotomy and those treated for fractures of the mandible, maxilla, or zygoma. The patients were randomly assigned to a titanium group (KLS Martin) or to a biodegradable group (Inion CPS). Plate removal was necessary in 16 of the 134 patients (11.9%) treated with titanium and in 21 of the 87 patients (24.1%) treated with the biodegradable system within the first 2 post-operative years [p = .016, HR biodegradable (95% CI) = 2.2 (1.1-4.2), HR titanium = 1]. Occlusion, VAS, and MFIQ scores showed that both groups had good mandibular function and were (almost) free of pain 1 and 2 years post-operatively (http://controlled-trials.com ISRCTN 44212338).

Bilateral sagittal split osteotomy in cadaveric pig mandibles: evaluation of the lingual fracture line based on the use of splitters and separators.

OBJECTIVE: To analyze the splitting pathways of the (lingual) fracture lines during a bilateral sagittal split osteotomy (BSSO) in cadaveric pig mandibles. STUDY DESIGN: A BSSO was performed using splitters and separators. Special attention was paid to end the horizontal medial cut at the deepest point of the entrance of the mandibular foramen. RESULTS: Of all lingual fractures, 95% ended in the mandibular foramen. Forty percent of these fractures extended through the mandibular canal and 40% extended inferiorly along the mandibular canal. CONCLUSION: Almost all lingual fracture lines ended in the mandibular foramen, most likely due to the placement of the medial cut in the concavity of the mandibular foramen. The mandibular foramen and canal could function as the path of least resistance in which the splitting pattern is seen. We conclude that a consistent splitting pattern was achieved without increasing the incidence of possible sequelae.

A randomized clinical trial of biodegradable and titanium fixation systems in maxillofacial surgery.

Biodegradable fixation systems could reduce or delete the problems associated with metallic systems, since removal is not necessary. The aim of this study was to establish the effectiveness and safety of biodegradable plates and screws as potential alternatives to metallic ones. This multi-center randomized controlled trial was conducted from December 2006 to July 2009. Included were patients who underwent mandibular and/or Le Fort I osteotomies and those with fractures of the mandible, maxilla, and zygoma. The patients were assigned to a titanium control group (KLS Martin) or to a biodegradable test group (Inion CPS). The primary outcome measure was 'bone healing 8 weeks post-operatively'. The Intention-To-Treat (ITT) analysis of 113 patients in the titanium group and 117 patients in the biodegradable group yielded a significant difference (p < 0.001), primarily because in 25 patients (21%) who were randomized to the biodegradable group, the surgeon made the decision to switch to titanium intra-operatively. Despite this 'inferior' primary outcome result, biodegradable plates and screws could be safely used when it was possible to apply them. The benefits of using biodegradable systems (fewer plate removal operations) should be confirmed during a follow-up of minimally 5 years (Controlled-trials.com ISRCTN number 44212338).

[A toxic reaction of the oral mucosa to alendronate (Fosamax)]. / Een toxische reactie van de mondmucosa op orale bisfosfonaten.

A 90-year old woman attended a department of Oral and Maxillofacial Surgery with a tongue that had been painful for at least 3 months. Clinical examination revealed extensive bullous and ulcerative lesions located on the tongue, the oral vestibule and the buccal mucosa on both sides. A variety of diseases may be causative of ulcerative stomatitis: autoimmune diseases (like Pemphigus vulgaris, Erosive Lichen Planus, SLE or M. Crohn), or a viral, bacterial or mycotical infection, vitamin deficiency, a toxic reaction to medication or an immune deficiency. After an extensive, clinical examination, a definitive diagnosis still had not been achieved. The patient suffered from osteoporosis, for which she used alendronate (Fosamax). A study of the literature described a possible relationship between the occurrence of oral ulcers and the use of oral biphosphonates. Since a toxic reaction to alendronate was suspected, the use of Fosamax tablets was suspended. Three months later a complete recovery of the oral mucosa was observed.

[Fracture healing of the face. General principals]. / Fractuurgenezing van het aangezicht. Algemene principes.

To obtain good and uncomplicated primary fracture healing, anatomical repositioning, direct bone apposition and stable fixation are mandatory. The course of primary fracture healing starts with acute inflammation (cellular and vascular), stabilization (formation of new bone), and remodeling. Besides good fixation, local factors such as age and type of fracture will influence the healing. If good reposition, apposition or adequate stabilization of the bony fragments are not achieved, the bone healing will be secondary. In secondary healing fracture repair and stabilization occurs through the formation of callus.

In vivo degradation and biocompatibility study of in vitro pre-degraded as-polymerized polyactide particles.

The degradation of high molecular weight as-polymerized poly(L-lactide) (PLLA) is very slow; it takes more than 5.6 yr for total resorption. Moreover, the degradation products of as-polymerized PLLA bone plates, consisting of numerous stable particles of high crystallinity, are related with a subcutaneous swelling in patients 3 yr postoperatively. In order to avoid these complications, polymers were developed that are anticipated to have comparable mechanical properties but a higher degradation rate and do not degrade into highly stable particles that can induce a subcutaneous swelling. On chemical grounds it can be expected that copolymerization of PLLA with 4% D-lactide (PLA96) or by modifying PLLA through cross-linking (CL-PLLA) will lead to less stable particles and a higher degradation rate. To evaluate the long-term suitability of these as-polymerized polymers, the biocompatibility of the degradation products should be studied. Considering the very slow degradation rate of as-polymerized PLLA, in vitro pre-degradation at elevated temperatures was used to shorten the in vivo follow-up periods. In this study, the biocompatibility and degradation of as-polymerized PLLA, PLA96 and CL-PLLA were investigated by implanting pre-degraded particulate materials subcutaneously in rats. Animals were killed after a postoperative period varying from 3 to 80 wk. Light and electron microscopical analysis and quantitative measurements were performed. The histological response of all three pre-degraded materials showed a good similarity with in vivo implanted material. Pre-degraded PLLA induced a mild foreign body reaction and showed a slow degradation rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Biocompatibility study of as-polymerized poly(L-lactide) in rats using a cage implant system.

To evaluate the biocompatibility of in vitro predegraded as polymerized poly(L-lactide) (PLLA), a cage implant system was used to investigate white cell and enzyme concentrations with time. The use of a cage permits in a serial fashion a quantitative and qualitative measurement of exudate components formed around an implant. Subcutaneously in rats, caped cages manufactured from stainless-steel mesh were implanted with in vitro predegraded, as-polymerized PLLA, as-polymerized PLLA cylinders, and empty cages serving as controls. In vitro predegradation was used to simulate the degradation products of long-term in vitro degradation. Predegraded PLLA particles were obtained by in vitro hydrolysis at elevated temperatures. The first 7 days of implantation were characterized by an acute inflammatory reaction; the exudate extracted from the cages showed predominantly neutrophils for all types of implants. After day 7, there was a more chronic inflammatory reaction with predominantly macrophages and lymphocytes. There were no significant differences in the total leukocyte concentration or macrophage concentration for any of the cages in the period from 10-21 days. Extracellular enzyme activity also did not show any significant differences among the three types of cages. A possible explanation for the absence of any significant differences could be that the in vitro predegraded particles were sieved before implantation, thus eliminating all small particles (< 70 microns) that are probably mandatory to provoke an increased cellular reaction.

Late degradation tissue response to poly(L-lactide) bone plates and screws.

Patients with fractures of the zygomatic bone were treated with high molecular weight poly(L-lactic) acid (PLLA) bone plates and screws. Three years after implantation four patients returned to our department with a swelling at the site of implantation. At the recall of the remaining patients we found an identical type of swelling after the same implantation period. To investigate the nature of the tissue reaction, eight patients were reoperated for the removal of the swelling. The implantation period of the PLLA material varied from 3.3 to 5.7 years. Microscopic evaluation and molecular weight measurements were performed. The excised material showed remnants of degraded PLLA material surrounded by a dense fibrous capsule. Ultrastructural investigation showed crystal-like PLLA material internalized by various cells. The results of this investigation suggest that the PLLA material slowly degrades into particles with a high crystallinity. The intra- and extracellular degradation rate of these particles is very low. After 5.7 years of implantation, these particles were still not fully resorbed.