Clinical retrospective study of dental implant removal: do patients who require implant removal desire implant prosthesis again?

BACKGROUND: This study investigated the causes of dental implant removal due to complications, and examined whether patients who had dental implant removal desired re-implant prosthesis treatments. MATERIAL AND METHODS: A retrospective case-control study was conducted on patients who had their dental implants removed. We investigated whether the removed dental implant was replaced with other implant prostheses. Age, sex, diabetes, smoking, implant site distribution, reason for implant removal, and blade and root-form implants were categorized as predictive variables. The outcome variable was desire for re-implantation or use of other prosthetic methods after implant removal. A logistic regression model was created to identify patient factors that could predict the re-implantation of dental prostheses after implant removal. RESULTS: A total of 215 dental implants were removed from 143 patients. The most common reason for implant removal was peri-implantitis that was identified in 165 implants. After implant removal, re-implantation was performed in 98 implants (45.6%). Bivariate analyses showed that age, diabetes, implant type, and reason for implant removal were associated with the desire for re-implanted prostheses. The multiple regression model revealed that age, implant type, and reason for implant removal were associated with an increased desire for re-implant prostheses after implant removal. CONCLUSIONS: Re-implantation of prostheses after the removal of dental implants was desired by patients who were younger, had implants placed in the root form, and had implants removed due to prosthetic-related complications.

What are the risk factors for postoperative infections of third molar extraction surgery: A retrospective clinical study?

BACKGROUND: This study aimed to identify (1) the predilection site of postoperative infection after third molar extraction surgery, (2) risk factors associated with postoperative infection, and (3) the cause of the difference between delayed- and early-onset infections. MATERIALS AND METHODS: This retrospective study included 1010 patients (396 male, 614 female) who had ≥1 third molars extracted (2407; 812 maxilla, 1595 mandible). The risk factors were classified as attributes, general health, anatomic, and operative. Outcome variables were delayed- and early-onset infections. RESULTS: Postoperative infection was completely absent in the maxilla, and all infections occurred in the mandible, with a probability of 1.94% (31/1595). Bivariate analysis for postoperative infection showed depth of inclusion and intraoperative hemostatic treatment to be significantly associated with the development of infections. Bivariate analysis for delayed- and early-onset infections showed simultaneous extraction of the left and right mandibular third molars to be prominent risk factors. CONCLUSIONS: Postoperative infection occurs mainly in the mandible, and that in the maxilla is very rare. The risk of postoperative infection in the mandible was found to be related to the depth of inclusion and intraoperative hemostatic treatment. Simultaneous extraction of the left and right mandibular third molars appear to increase the risk of delayed-onset postoperative infection.

Is the removal of osteosynthesis plates after orthognathic surgery necessary? Retrospective long-term follow-up study.

The removal of titanium miniplates is a controversial topic in oral and maxillofacial surgery. This retrospective study examined the timing of and reasons for titanium plate removal after orthognathic surgery. The study included 240 orthognathic surgery patients (71 male, 169 female; age range 16-55 years, mean 25.0±8.8 years) who had maxillofacial osteosynthesis plates inserted or inserted and then removed at the Division of Oral and Maxillofacial Surgery, Kagawa Prefectural Central Hospital, between April 2003 and March 2017. During the study period, a total of 717 miniplates were inserted in the 240 patients, and 71 of the patients (29.6%) had 236 plates (32.9%) removed. Ten patients (14.1%) had their plates removed within a year due to early complications. Although no patient had their plate removed due to complications at 1-5 years postoperative, a further 14 patients (19.7%) had their plates removed after more than 5 years of long-term follow-up due to plate-related complications. Complications requiring plate removal were evidently biphasic, occurring within 1 year after the operation and at ≥5 years after the operation. Therefore, after confirming postoperative bone healing, it is necessary to explain to patients the risks of plate removal and the importance of long-term follow-up.

Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics.

OBJECTIVES: The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. METHODS: A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. RESULTS: 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. CONCLUSIONS: Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture.

The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures.

We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results.

Endotracheal tube stabilization using an orthodontic skeletal anchor in a patient with facial burns.

Stabilizing the endotracheal tube is of vital importance in patients suffering facial burns or trauma in the intensive care unit, as well as during a general anaesthetic procedure. Here is presented a secure method using a simple orthodontic skeletal anchorage system on the maxilla and 0.4-mm stainless steel wire that does not require any work or place any burden on the teeth or gingival tissue, and does not require extensive surgery.

Overcorrection in vertical alveolar distraction osteogenesis for dental implants.

A decrease in bone height following alveolar distraction osteogenesis (DO) before implant placement is common, and can be severe when alveolar DO is performed soon after surgical intervention. The aim of this study was to investigate the decrease in bone height after vertical alveolar DO and determine the need for overcorrection with implant placement. Thirty-five patients (17 males and 18 females, mean age 43.9 years) underwent 38 procedures with successful placement of 141 dental implants. Alveolar ridge height was evaluated using digital orthopantomographic radiographs taken shortly after the end of distraction, at consolidation and before implant placement. The mean distraction was 9.7 mm. The total vertical alveolar bone decrease was 2.1mm (21%) during the consolidation period and 3.6mm (37%) at implant placement. Although the 20 sites with a healthy alveolus (surgery >6 months) had bone reductions of 1.5 and 2.5mm (15 and 25%) the 18 sites at which alveolar DO was performed within 6 months (mean 3.0) of surgical intervention had much greater bone loss of 2.7 and 4.8mm (28 and 50%), respectively ((**)P<0.01). These results indicate that any alveolar DO protocol should include a waiting period after the surgical intervention, as well as consider an overcorrection of more than 25% within the limits of the applied surgical protocol.

Corticotomy and compression osteogenesis in the posterior maxilla for treating severe anterior open bite.

A new technique is described for outpatient treatment of anterior open bite. The compression osteogenesis method with a two-stage corticotomy was used in the posterior maxilla to treat a woman with severe anterior open bite. Three-week post-surgical compression using anchor plates and elastics repositioned the posterior maxillary bone/teeth segments by 7 mm to the ideal superior position. The patient had a stable skeletal position of the maxilla at 14-month follow-up with satisfactory results and no complications after orthodontic treatment. This technique appears to be an efficient option for treating patients with anterior open bite.

A radiographic study of recurrent unicystic ameloblastoma following marsupialization. Report of three cases.

OBJECTIVES: To study the radiographic sequence in the recurrence of unicystic ameloblastoma following marsupialization. MATERIALS AND METHODS: Retrospective analysis of three cases of uncystic ameloblastoma. RESULTS: Six distinct stages were identified in all three cases: bone regeneration starting at the periphery of the cavity; appearance of a diffusely sclerotic band; appearance of scalloping; expansion of scalloping; formation of a multilocular pattern; and enlargement of the cystic lesion. CONCLUSION: The first radiographic sign of recurrence is scalloping of the sclerotic margin of the regenerated bone.

Image salvage in panoramic radiography using histogram optimization.

Optical density and contrast recovery from poor quality panoramic radiographs was studied using the histogram modification technique. A series of experimental images of varying density and contrast were obtained by exposing a phantom in 4 kV steps between 50 and 94 kV. A standard of good image quality was selected by 10 observers grading the radiographs. Images were processed using the histogram specification technique and re-evaluated. All the processed images were found to be of acceptable quality. This technique was also shown to be applicable for salvaging unacceptable clinical radiographs.

[Scoring system for screening of patients with endometriosis in infertile clinic].

An outpatient department screening method for endometriosis was prepared by designing a scoring system in a retrospective study. We compared the incidence of 21 characteristic symptoms and the finding of endometriosis in 39 infertile women with endometriosis diagnosed by laparoscopy or laparotomy and 21 women without it. A table for diagnostic scoring composed of 11 items was accomplished. The feasibility of this diagnostic scoring system was then examined in a prospective study of 72 women with endometriosis and 47 without it. The results were as follows. 1. In the retrospective study, all the women with 10 or more points had had endometriosis. Fifteen out of 20 women with -20 points or less had been without endometriosis and the remaining 5 with endometriosis (4 minimal and 1 mild stage according to AFS classification). 2. In the prospective study, a 94.5% (52/55) incidence of endometriosis was found in women with 10 or more points and 66.7% (10/15) of women with -20 points or less were without endometriosis. 3. This diagnostic scoring system, in which women with endometriosis score 10 or more points and women without it -20 points or less, has 91.2% sensitivity, 76.9% specificity, 94.5% positive predictive value and 66.7% of the negative predictive value. It is concluded that this scoring system has clinical diagnostic value in screening for endometriosis in infertile women at the outpatient department.

[BANA hydrolase and DNP peptidase activities in the ovulatory process of PMS-hCG treated immature rat].

To investigate the roles of collagenolytic enzymes in the ovulatory process of PMS-hCG treated immature female rats (22 days old), we measured the activities of two of them in the ovary by the using synthetic substrates alpha-N-benzoyl-DL-arginine-2-naphthylamide HCl (BANA) (a collagenolytic cathepsin) and dinitrophenol-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg OH (DNP peptide) (a neutral collagenase). BANA hydrolase activities significantly began to increase after the hCG injection, reaching a peak 8-9 hours later, and then decreased sharply 10 hours later. There was also a significant increase in DNP peptidase activities 7-10 hours after the hCG injection and a significant decrease 12 hours after the injection. The present study has shown that BANA hydrolase and DNP peptidase appear during the ovulatory process of PMS-hCG-treated immature female rats, and that their significant preovulatory increases are contributory to collagenolysis in follicle rupture.

Substrates for adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase in the rat pituitary gland.

1. Substrates for cAMP-dependent protein kinase were investigated in anterior, intermediate, and neural lobes of the rat pituitary gland. In a cell-free assay system, cAMP increased phosphorylation of 17 K, 33 K, and 60 K macromolecules of the anterior lobe, 17 K, 33 K, 60 K, and 80 K macromolecules of the intermediate lobe, and 60 K, 80 K, and 85 K macromolecules of the neural lobe. 2. Other nucleotides were tested in the intermediate lobe; 8 Br-cAMP mimicked cAMP, cGMP was much less effective than cAMP or 8 Br-cAMP, and 5'-AMP showed no significant effect. The purified catalytic subunit of cAMP-dependent protein kinase evoked the same phosphorylation pattern as the endogenous kinase. 3. Maximum cAMP-dependent phosphorylation occurred at between 1 and 2 min of incubation; after 20 min, phosphorylation was reduced by 80%. This suggests the presence of phosphatase activity in the intermediate lobe. 4. When tested upon dispersed intermediate lobe cells permeabilized by high-voltage electrical discharges, cAMP increased phosphorylation of the 17 K and 33 K macromolecules.

Radiographic characteristics of the calcifying odontogenic cyst.

4 additional cases of calcifying odontogenic cysts (COC) were reported, together with the radiographic interpretation of 138 cases from the literature. From the review of the literature and of our own cases, the root resorption is one of the most common diagnostic findings as is cystic radiolucency accompanied by radiopacities. Other radiographic characteristics, such as loculation, tooth divergency and bone resorption were emphasized.

Alpha-melanocyte-stimulating hormone secretion from permeabilized intermediate lobe cells of rat pituitary gland. The role of guanine nucleotides.

The non-hydrolyzable GTP analogue, guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and cyclic AMP potentiated the Ca2+-evoked secretion of alpha-melanocyte-stimulating hormone (alpha-MSH) from permeabilized neurointermediate lobe (IL) cells of rat pituitary gland. The enhancement by Mg-GTP gamma S (100 microM) and cyclic AMP (1 microM) depended on the intracellular Ca2+ concentration (EC50 = 4.8 +/- 1.8 and 4.6 +/- 1.7 microM; mean +/- SE, with and without Mg-GTP gamma S and cyclic AMP, respectively). A similar effect was observed with guanine nucleotide triphosphate (GTP and GppNHp). Mg was absolutely required for this event. Neither Mg-GTP gamma S nor cyclic AMP alone was effective in potentiating alpha-MSH secretion. GDP beta S blocked the Mg-GTP gamma S (100 microM) and cyclic AMP augmented secretion of alpha-MSH. Neither neomycin (which affects the process of inositol 1,4,5-triphosphate-mediated Ca2+ mobilization) or colchicine (which influences microtubule assembly) had an effect on the cyclic AMP and Mg-GTP gamma S potentiation of alpha-MSH secretion. These data suggest that the GTP-binding protein may be involved in the regulation of alpha-MSH secretion after Ca2+ entry into the cells, since the intracellular environment is controlled in the permeabilized cells.