In situ endoscopic analysis of bone microstructure and vascularization in post-extraction sites immediately after a minimally invasive vertical tooth extraction in teeth with different periodontal status / Análisis endoscópico in situ de la microestructura ósea y vascularización en alvéolos post-extracción inmediatamente después de una extracción dental mínimamente invasiva en dientes con diferente estado periodontal

SUMMARY: The aim of this study was to perform an in situ endoscopic analysis of the vascularization of post-extraction sites immediately after a non-traumatic extraction in terms of the number of blood vessels per field (NBV), relative area of blood vessels (RABV) and relative area of unmineralized bone (RAUB) in teeth with different periodontal status (PS). This assessment was performed using short distance support immersion endoscopy (SD-SIE). Ten patients (4 men/ 6 women, aged between 25 and 44) were selected. From them, 10 teeth were extracted due to periodontal reasons or other motives. These teeth were then categorized into 2 groups according to their PS, either as periodontally compromised (PC) (clinical attachment loss (CAL) > 7 mm and probing depth (PD) > 5 mm) or periodontally healthy (PH) (CAL < 7 mm and PD < 5 mm, without bleeding or suppuration during periodontal probing), and mobile (M) (> 1 mm horizontally) or immobile (I) (< 1 mm horizontally). The minimally invasive vertical tooth extractions were performed using the Benex ® extractor. Immediately after extraction, a rigid immersion endoscope with a diameter of 2.7 mm was introduced, and a video-alveoloscopy was carried out. This video was analyzed by ImageJ software for the quantification of NBV, RABV and RAUB per field of the post-extraction sites with different PS (PC, PH, M, I) were quantified. In the PC group, significantly greater values for RAUB were observed (33.45 %) compared to those from the PH group (19.65 %). Compared with the M group, the I group did not show significant differences in terms of RAUB or RABV. There were also no differences in NBV in both groups (Means: 33.8 vs. 30.5, respectively).

RESUMEN: El objetivo de este estudio fue realizar un análisis endoscópico in situ de la vascularización de los alvéolos post-extracción inmediatamente después de una extracción atraumática en términos de número de vasos sanguíneos por campo de observación (NBV), área relativa de vasos sanguíneos (RABV) y el área relativa de espacios no mineralizados (RAUB) en dientes con diferente estado periodontal (PS). Esta evaluación se realizó mediante endoscopía de inmersión de corta distancia (SD-SIE). Se seleccionaron diez pacientes (4 hombres / 6 mujeres, con edades comprendidas entre 25 y 44). De ellos, se extrajeron 10 dientes debido a razones periodontales u otros motivos. Estos dientes se clasificaron en 2 grupos según su PS, ya sea como periodontalmente comprometidos (PC), los que presentaban un nivel de inserción clínica (CAL) ≥ 7 mm y una profundidad de sondaje (PD) ≥ 5 mm; o periodontalmente sanos (PH) (CAL <7 mm y PD <5 mm, sin sangramiento o supuración durante el sondaje periodontal). También se categorizaron según su movilidad como móvil (M) (≥ 1 mm horizontalmente) o inmóvil (I) (<1 mm horizontalmente). Las extracciones verticales mínimamente invasivas se realizaron con el extractor Benex ®. Inmediatamente después de la extracción, se introdujo un endoscopio rígido de inmersión con un diámetro de 2.7 mm, con el cual se realizó una video-alveoloscopía. Este video fue analizado por el software ImageJ para la cuantificación de NBV, RABV y RAUB por campo, de los alvéolos post-extracción con diferente estado periodontal. En el grupo de dientes PC, se observaron valores significativamente mayores para RAUB (33.45%) en comparación con los del grupo PH (19.65 %). En comparación con el grupo M, el grupo I no mostró diferencias significativas en términos de RAUB o RABV. Tampoco hubo diferencias en el NBV en ambos grupos (Media: 33.8 frente a 30.5, respectivamente).

Effect of CBX7 deficiency on the socket healing after tooth extractions.

CBX7 is shown to down-regulate the expression of osteopontin (OPN) that is associated with osteoblast function. Here, we studied the role of CBX7 in the wound healing of tooth extraction socket in which osteoblast activity is critical via comparison between CBX7-knockout (CBX7-/-) mice and their wild-type (WT) counterparts of 6 weeks old with maxillary first molar extracted. Mice were euthanized at 7, 14, and 21 days after extractions, and alveolar sockets were assessed by semi-quantitative histomorphometry for hard tissue healing, including new bone fill (Masson's trichrome staining), osteoblast activity (OPN/osterix, Osx), osteoclast activity (tartrate-resistant acid phosphatase, TRAP), and for soft tissue healing, including blood vessels (alpha smooth muscle actin, α-SMA). Also, the bone microarchitecture was evaluated by micro-CT. In radiological analysis, CBX7-/- mice increased bone mass significantly more than WT mice did. Consistently, both the amount of new bone fill and OPN/Osx-immunopositive cells in the extraction sockets were significantly increased in CBX7-/- mice at each time point with respect to their WT siblings, while osteoclast number exhibited a trend of more increase in CBX7-/- mice at all time points as well. In agreement with enhanced bone formation during socket healing, significantly elevated α-SMA-immunopositive area was noted in CBX7-/- mice in contrast to WT mice. Taken together, these data suggest that CBX7 deficiency has a positive effect on tooth extraction socket healing.

Delayed Socket Healing After Dental Extraction in Patients Undergoing Myelosuppressive Chemotherapy for Hematological Malignancy: Incidence and Risk Factors.

PURPOSE: The purpose of this study was to measure the frequency and identify factors associated with delayed socket healing after dental extraction in patients undergoing myelosuppressive chemotherapy for hematologic malignancy. MATERIALS AND METHODS: This prospective cohort study focused on delayed healing after extraction in patients with hematologic malignancy. Sockets with delayed healing were defined as those with intense pain and bone exposure 1 week postoperatively. Patients with and without delayed socket healing were compared using the Fisher exact test and Mann-Whitney U test with some variables. Receiver operating characteristics curve analysis was conducted to define cutoff values for delayed healing. RESULTS: One hundred ninety-four dental extractions in 93 patients (median age, 64 yr; range, 20 to 85 yr) were analyzed. The incidence of delayed socket healing was 7.5% (7 of 93 patients). There was no postoperative bleeding. Older age, type of hematologic malignancy (acute leukemia), shorter time from dental extraction to initiation of chemotherapy, low platelet count or hemoglobin level, requirement for red blood cell concentrate or platelet transfusion, and use of an absorbable hemostatic agent were statistically associated with the occurrence of delayed socket healing. Platelet and hemoglobin cutoffs were 4.6 × 104/µL and 7.7 g/dL, respectively. CONCLUSIONS: Although dental extraction can be safely performed in patients undergoing myelosuppressive chemotherapy for hematologic malignancy, oral surgeons should understand the potential risk for delayed socket healing. When considering dental extraction, patients with hematologic malignancy and low hemoglobin or platelet levels should be informed about the possibility of delayed socket healing.

Support Immersion Endoscopy in Post-Extraction Alveolar Bone Chambers: A New Window for Microscopic Bone Imaging In Vivo.

Using an endoscopic approach, small intraoral bone chambers, which are routinely obtained during tooth extraction and implantation, provide visual in vivo access to internal bone structures. The aim of the present paper is to present a new method to quantify bone microstructure and vascularisation in vivo. Ten extraction sockets and 6 implant sites in 14 patients (6 men / 8 women) were examined by support immersion endoscopy (SIE). After tooth extraction or implant site preparation, microscopic bone analysis (MBA) was performed using short distance SIE video sequences of representative bone areas for off-line analysis with ImageJ. Quantitative assessment of the microstructure and vascularisation of the bone in dental extraction and implant sites in vivo was performed using ImageJ. MBA revealed bone morphology details such as unmineralised and mineralised areas, vascular canals and the presence of bleeding through vascular canals. Morphometric examination revealed that there was more unmineralised bone and less vascular canal area in the implant sites than in the extraction sockets.

Soft tissue healing in alveolar socket preservation technique: histologic evaluations.

After tooth extraction, 14 alveolar sockets were grafted with porous bovine bone mineral particles and covered with non-cross-linked collagen membrane (test group), and 14 alveolar sockets were left uncovered. At 5 and 12 weeks, microvascular density (MVD), collagen content, and amount of lymphocytes (Lym) T and B were analyzed in soft tissue. At 5 weeks, MVD was significantly lower and Lym T was significantly higher in tests than in controls (P < .05). At 12 weeks no differences were found. Placement of resorbable membrane seems to induce an initial and transient modification of the normal wound healing process of the soft tissue.

TGF-ß1 and BMP-4 carried by liposomes enhance the healing process in alveolar bone.

OBJECTIVE: In this work we evaluated the bone-forming potential of BMP4, TGFß1 and BMP4/TGFß1 mixed by performing histological and morphometric analysis. We also evaluated the immunolabelling of fibronectin (FN) and collagen type III (Col III), two determinant proteins for the early phase of bone repair. DESIGN: Histological, histomorphometric and immunohistochemistry analysis were used to evaluate new bone and blood vessels formation as well as fibronectin and collagen type III expression. 112 male Wistar rats weighing 250-300g had their maxillary second molar extracted. Sockets filled with blood clot (BC) or treated with L (empty liposome), P (PBS), BP (BMP-4 in PBS) and TP (TGF-ß1 in PBS), as well as with BL (BMP-4 in liposome) and TL (TGF-ß1 in liposome) administered isolated or in association (BTL) were obtained. The animals were sacrificed at 3, 7, 14 and 21 days after surgery. RESULTS: An increased percentage of bone trabeculae, and a higher number of blood vessels were observed in groups BL or TL administered isolated or in association when compared to groups BC, L, P, BP and TP. Fibronectin and collagen type III analysis revealed enhanced expression firstly detected at 3 days followed by a peak at 7 days. Lower levels of immunoreactivity were observed in the sockets filled with blood clot, and treated with L, P, BP and TP when compared with sockets from groups BL, TL and BTL. CONCLUSION: The present study indicates growth factors carried by liposomes, either in isolated or associated forms, as successful enhancers of the healing process in rat tooth sockets. We also conclude that the expression of fibronectin and collagen type III increases during the early phases of bone repair.

Bone physiology in human grafted and non-grafted extraction sockets--an immunohistochemical study.

PURPOSE: The aim of the present immunohistological investigation was to define and compare the osteogenic potential with the vascularization of the provisional matrix in grafted and ungrafted extraction sockets after 4 and 12 weeks of healing. METHODS: A total of 33 Patients (15 women, 18 men) with 65 extraction sites with a mean age of 54.4 years (30-73 years) participated in this study. After tooth extraction, the sockets were augmented with Bio-Oss collagen or non-augmented. At implant placement after 4 or 12 weeks bone biopsies were obtained. Within the specimens the osteogenic and endothelial potential of mesenchymal cells was analyzed in the provisional matrix using immunohistochemical analysis with three monoclonal antibodies Cbfa1/Runx2, Osteocalcin (OC), and CD31. Statistical analysis was performed using Mann-Whitney U-test, Spearman's rank-order correlation coefficient, and the two-factorial analysis for repeated measurements. RESULTS: Of the 65 extraction sockets, 25 (13 non-augmented, 12 augmented) sites after 4 weeks healing time and 40 (19 non-augmented, 21 augmented) sites after 12 weeks healing time were involved in the study. No signs of acute or chronic inflammation were noted in any specimens. After 4 weeks, a median amount of 56% (10-85%) of Cbfa1 positive cells and a median amount of cells expressing OC of 21% (5-42%) were measured. A median CD31 score of 5 was observed. After 12 weeks, a median amount of 61% (19-90%) positive cells expressed by Cbfa1/Runx2 staining a median amount of OC positive cells of 9% (2-17%) was measured. The results at 12 weeks revealed a median score of CD31 positive cells of 3. DISCUSSION: Osteoblastic activity in the provisional matrix was highest after 4 weeks of healing period. The active zone of bone formation is found in the apical region of the extraction socket during the early healing phase, shifting to the coronal region after 12 weeks. A peak of osteoblast activity within the first weeks is followed by a reduction in mature osteoblasts with osteoblasts remaining in an inactive stage. The vascularity changed in likewise fashion to the maturation of osteoblasts within the observation period. The results have shown that with increasing age a decreasing endothelial potential was observed not after 4 weeks, but after 12 weeks, thus it suggests that angiogenesis is diminished in older patients in the later phase of healing in extraction sockets.

N-butyl-2-cyanoacrylate (NBCA) tissue adhesive as a haemostatic agent in a venous malformation of the mandible.

Cyanoacrylate tissue glue has many uses. We describe a case involving a 27-year-old man with a low-flow venous malformation that affected the right side of his face including the mandible. After extraction of the lower right eight, torrential haemorrhage was successfully arrested using N-butyl-2-cyanoacrylate (NBCA) glue. We think that it may be of use not only in the management of patients with vascular malformations, but also in the treatment of recalcitrant haemorrhage after dentoalveolar surgery.

Particle embolization of the bilateral superior and inferior alveolar arteries for life threatening dental socket hemorrhage.

Particle embolization for epistaxis and intra-oral hemorrhage are performed on an as needed basis by neurointerventionalists. A case is presented of massive oral hemorrhage associated with end stage liver disease coagulopathy after tooth extraction of bilateral maxillary and mandibular molars. A man in his fifties with end stage liver disease who presented for evaluation of a syncopal episode was determined to be in hemorrhagic shock from 2 days of persistent oral bleeding after elective tooth extractions. Conservative management with multiple blood transfusion products, packing and vasoconstrictive spray was ineffective. Microcatheter angiograms of the alveolar arteries demonstrated blood and contrast pooling within the sockets of the extracted teeth. Selection of the bilateral supplying alveolar and inferior alveolar artery branches was achieved followed by polyvinyl alcohol particle embolization (250-355 µm). Polyvinyl alcohol particle embolization of dental socket hemorrhages is technically feasible and effective.

Unilateral variation in the origin of the inferior alveolar and buccal arteries: a case report / Variación unilateral en el origen de las arterias alveolar inferior y bucal: reporte de un caso

The maxillary artery (MA) is one of the terminal branches of the external carotid artery (ECA) and is located in the infratemporal fossa (IF). Some of the branches in this region are the inferior alveolar artery (IAA) and the buccal artery (BA), both descending branches. Here, we report an unusual unilateral origin of the IAA and the BA from a common trunk directly from the ECA. We conducted a routine dissection of both IF in a 54-year-old hispanic male cadaver. Fixed with Universidad de los Andes® conservative solution and red latex for vascular filling. On each side, the MA is observed superficially located over the lateral pterygoid muscle. On the right side, the IAA and the BA originate from a common trunk from the ECA approximately 5 mm prior to the bifurcation into their terminal branches. On the left side, the IAA originates from the MA that is immediately next to its origin, making a common trunk with the pterygoid branches. Knowing the morphology of the MA and its branches at the IF is important for oral and maxillofacial surgery procedures; and any variation in the origin or course of these arteries may result in the patient's increased morbidity during some invasive procedure in the area.

La arteria maxilar (AM) es una rama terminal de la arteria carótida externa (ACE), y se ubica en la región infratemporal (RI). Algunas de sus ramas en esta región son la arteria alveolar inferior (AAI) y la arteria bucal (AB), ambas ramas descendentes. En este trabajo informamos de un inusual origen unilateral de la AAI y de la AB a partir de un tronco común desde la ACE. Se realizó una disección de rutina de ambas regiones infratemporales en un cadáver de 54 años, sexo masculino, caucásico. Fijado con solución conservadora Universidad de los Andes® y repleción vascular con látex rojo. A cada lado, se observa la AM en ubicación superficial sobre el músculo pterigoideo lateral. Al lado derecho, la AAI y la AB se originan de un tronco común desde la ACE aproximadamente 5 mm antes de la bifurcación en sus ramas terminales. Al lado izquierdo la AAI se origina de la AM inmediato a su origen, formando un tronco común con los ramos pterigoideos. El conocimiento de la morfología de la AM y de sus ramas en la RI es de importancia en procedimientos odontológicos, de cirugía oral y maxilofacial. Por lo que cualquier variación en el origen o trayecto de estas arterias puede predisponer a un paciente a una mayor morbilidad durante algún procedimiento invasivo en la zona.

An extraction socket classification developed using analysis of bone type and blood supply to the buccal bone in monkeys.

Bone modeling and remodeling following tooth extraction has been studied extensively. The reason for bone loss during the remodeling process is multifactorial, and the primary reason for this loss is still yet to be determined. The aim of this study was to examine the type of bone and the blood supply to the buccal bone in monkeys. Six maxillary arches from six monkeys were used. The arches were divided into three sections: right posterior, anterior from canine to canine, and left posterior. Blocks were decalcified and prepared for histologic processing and examination. Modified Masson trichrome and retic staining were used. Histologic sectioning demonstrated that the blood supply to the buccal bone came from the inner (socket) side of the alveolus, the periodontal ligament, the adjacent interdental bone, and the supraperiosteal vessels emanating from the covering gingiva or mucosa. Histologic examination showed that the buccal bone was composed of bundle and cortical bone. The thickness of the buccal bone was not uniform coronoapically, and the thinnest area of buccal bone was the coronal portion.

Effects of alendronate on bone healing after tooth extraction in rats.

OBJECTIVES: Tooth extraction has been identified as an important risk factor for bisphosphonate-induced osteonecrosis of the jaw. Therefore, the main goal of this study was to determine the effects of alendronate on healing of the extraction socket and on interdental alveolar bone after tooth extraction in rats. MATERIALS AND METHODS: Animals were injected subcutaneously with vehicle or alendronate for 3-4 weeks before the first mandibular molar was extracted and these treatments were continued during post-extraction periods of 10, 21, 35 and 70 days. Mandibles were processed to evaluate healing of the extraction socket and adjacent alveolar bone by assessing bone formation, bone resorption and vascularity by histomorphometric techniques. RESULTS: Alendronate decreased new woven bone formation, blood vessel area, perimeter and number in the extraction socket at 10 days postextraction, but not at later time points. Furthermore, alendronate-treated rats had increased interdental alveolar bone volume and height only at 10 days postextraction. In addition, a 2.5-fold increase in the percentage of empty osteocyte lacunae was found in alveolar bone of alendronate-treated rats only at 10 days postextraction. CONCLUSIONS: Alendronate transiently decreases bone formation and vascularity in the extraction socket and delays the removal of interdental alveolar bone after tooth extraction in rats.

Vascular endothelial growth factor (VEGF) response to dental trauma: a preliminary study in rats.

BACKGROUND: Successful periodontal healing and pulpal revascularization after trauma may be age-related. After dental trauma, age-related impaired angiogenesis may play a role in the revascularization rate during the healing process. OBJECTIVES: The aim of the present preliminary in vivo study was to detect the presence of vascular endothelial growth factor (VEGF) in venous and whole blood from the alveolar socket immediately post-tooth extraction. MATERIALS AND METHODS: The study consisted of 16 Wistar rats divided into two groups: eight young (6 weeks) with incomplete root development and open apices, and eight adult (4 months) with complete root development. One first mandibular molar was extracted and whole blood from the alveolar socket collected immediately and at 5, 10 and 15 min post-extraction. Venous blood samples were collected immediately pre- and 24-h post-extraction. All samples were tested for VEGF. RESULTS: Increased VEGF levels were found in the venous blood 24 h post-extraction, with a significant difference in the young rats (P < 0.05). The increased VEGF serum concentration in the young rats was significantly higher (12.2 +/- 4.6 pg ml(-1), median 12.1) than that in the adult rats (7.6 +/- 3.8 pg ml(-1), median 6.7) (P = 0.037). VEGF at the extraction site was not significantly different at 15 min post-extraction. At the extraction site, there was no significant difference of VEGF concentration between young and adult rats. CONCLUSIONS: Young rats had higher post-extraction serum VEGF levels, which may contribute to the healing process after dental trauma.

Estudio Descriptivo Macro y Mesoscópico de la Irrigación de Piezas Dentarias Superiores en Perro (Canis familiaris) Mediante Repleción con Tinta China / Macro and Mesoscopical Study About the Irrigation of the Upper Teeth in Dogs (Canis familiaris) through Repletion With Chinese Ink

Se describe macro y mesoscópicamente la irrigación de piezas dentarias superiores en su tercio rostral (incisivos y canino) en perro, mediante repleción con tinta china. Se utilizaron 30 cabezas de cadáveres de perro, divididas en tres grupos de igual número. El grupo I fue inyectado con tinta china azul vía arteria facial, el grupo II con tinta amarilla vía arteria maxilar y el grupo III con tinta azul y amarilla vía arteria facial y arteria maxilar respectivamente y en forma simultánea. En las cabezas, ya fijadas y conservadas, se analizó macroscópicamente la llegada del color de la tinta china inyectada a nivel de la gíngiva asociada a dientes incisivos y canino superior derecho. Posteriormente, las cabezas se congelaron para realizarles cortes transversales, los que fueron analizados mesoscópicamente, donde se observó la llegada de la tinta china, a nivel de los alvéolos y cavidad pulpar de las piezas dentarias en estudio. La presente investigación demostró que la arteria facial se distribuye hacia tejidos profundos como gíngiva, alvéolos y pulpa de los dientes incisivos y canino superior derecho en perro, por lo tanto, estaría aportando a su irrigación complementaria; se reafirmó la participación de ramas de la arteria maxilar en la irrigación de estos mismos tejidos y finalmente se demostró que ramas de las arterias facial y maxilar se anastomosan para irrigar tejidos en común, como los ya mencionados. Estos resultados permiten conocer el origen de la revascularización de piezas dentarias superiores y periodonto en perro, luego de procedimientos quirúrgicos que pudiesen dañar ramas de la arteria maxilar. Debido a la similitud anatómica de la cavidad oral entre el perro y el humano, los resultados descritos se podrían utilizar como referencia para explicar el origen de la revascularización de piezas dentarias superiores y periodonto, luego de la cirugía ortognática.

The irrigation of upper teeth is described macro and mesoscopically in their facial third (incisive and canine teeth) through repletion with Chinese tint. Thirty heads of corpses of dogs were used, which were divided in three equal groups. Group I was injected with blue Chinese ink via facial artery, group II with yellow Chinese ink via maxillary artery, and the group III with blue and yellow Chinese ink via facial and maxillary artery respectively and simultaneously. In the heads, already fixed and conserved, the arrival of the colour of the injected ink was macroscopically analyzed up to the level of the gingiva associated to the upper right incisive and canine teeth; subsequently, the heads were frozen to make them cross sections, which were analyzed mesoscopically, where the arrival of the injected ink was observed up to the level of the alveolus and pulpar cavity of the teeth under study. The present research demonstrated that the facial artery is distributed to deep-lying tissues such as gingiva, alveolus, and pulpar cavity of the upper right incisive and canine teeth in dogs; therefore, it would be contributing to its complementary irrigation, the participation of the branches of the maxillary artery in the irrigation of these tissues, and, finally, it demonstrated that the branches of the facial and maxillary artery anastomose themselves to irrigate tissues they have in common, as the ones that were already mentioned. These results allow us knowing the origin of the revascularization of the upper and periodontal teeth in dogs, after surgical procedures that could damage some branches of maxillary artery. Due to the anatomic similarity of human being's oral cavity and the oral cavity of dogs, the already described results could be used as reference to explain the origin of the revascularization of upper and periodontal teeth, after orthognathic surgery.

Effects of an intravenous infusion of Ringer's solution on eruption rates of incisor teeth in anesthetized rats.

OBJECTIVE: The vasculature within the socket is reportedly involved in determining the position of continuously erupting teeth. Thus, loss of body fluid in anesthetized rats, which would affect the vascular physiology, should influence tooth movement. We investigated the effects of an infusion of Ringer's solution on the systemic arterial blood pressure, regional blood flow at the base of the incisor, and axial tooth movement in anesthetized rats to determine the cause of tooth displacement. MATERIAL AND METHODS: In the experimental group, the animals received intravenous infusions of Ringer's solution at 27 microl/min for 13 h. In the control group, the animals did not receive the infusion. RESULTS: The infusion of Ringer's solution suppressed an increase of the mean arterial blood pressure from 86 to 80 mmHg and a decrease of the regional blood flow from 170 to 217 mV, and increased the eruption rate from 267 to 361 microm/13 h during the experimental period. There was a positive correlation between the eruption rate and regional blood flow, and a negative correlation between the blood pressure and regional blood flow. CONCLUSIONS: These results suggest that an infusion of Ringer's solution can cause an increase in the regional blood flow, resulting in increased fluid volume, elevated intra-socket pressure, and increased eruptive movement. It is possible that the regional vascular volume and/or pressure within the socket play an important role in determining the position of the incisor.

Ultrastructural changes in postcapillary-sized venule morphology in aged mouse periodontal ligament.

The aim of this study was to compare the postcapillary-sized venule (PCV) morphology of four young ALCA mice (35 days) and four colony-related aged mice (365 days) using the transmission electron microscope (TEM). Right and left mandibular first molar mesial roots with associated periodontal ligament (PDL) and bony socket, were used for TEM assessment. Five PCV profiles were selected at each 160 microm interval, from the alveolar crest to the tooth apex. PCV profile dimensions were measured on standardised micrographs magnified x2900. Age affects were tested using multiple regression analysis. The number of PCV profiles in the tooth third of the PDL was higher in aged mice (p < 0.01) and comprised predominantly apericytic vessels (p < 0.001). The number of PCV profiles increased significantly (p < 0.001) in aged mice in the PDL middle circumferential third halfway down the molar root. Age had no significant affect on PCV diameter. Aged PDL permeability studies are needed to investigate whether the changes in aged PCV profile number are associated with functional modification of the PDL microvasculature.

Dental extraction wound management: medicating postextraction sockets.

The rather impressive percentage of extraction sites undergoing clot loss and deranged healing results in significant morbidity for the patient and frequent visits to the surgeon to effect relief of discomfort, most often by the use of anodyne dressings. The amount of work lost by patients needing such palliative treatment, and loss of productive time for the surgeon, translate into an unknown, but potentially large, economic loss to society. This would mandate that economical methods of ensuring normal extraction socket healing with minimal morbidity be developed. The most useful socket medicaments to prevent socket healing derangements would include broad-spectrum antibiotics, specifically clindamycin and tetracycline. Not discussed in this article, but possibly germane to the subject of clot stabilization and healing, is consideration of resorbable substances such as gelatin sponge, polylactic acid, and methylcellulose as clot-stabilizing socket implants. The record of such substances in preventing AO is mixed, but the combinations of these inexpensive materials with topical socket medicaments may yield a decreased tendency for clot lysis and greater mechanical strength to the bulk blood clot, as has been demonstrated with difficult mandibular third molar impactions in one study involving polylactic acid, tetracycline, and hydrocortisone.