NKX3.1 Expression and Molecular Characterization of Secretory Myoepithelial Carcinoma (SMCA): Advancing the Case for a Salivary Mucous Acinar Phenotype.

BACKGROUND: Secretory myoepithelial carcinomas (SMCA) are rare, mucinous, signet ring predominant tumors with primitive myoepithelial features. While many mucinous salivary gland tumors have now been molecularly characterized, key drivers in SMCA have yet to be elucidated. Recently, NKX3.1, a homeodomain transcription factor implicated in salivary mucous acinar development was also shown in a subset of salivary mucinous neoplasms, salivary intraductal papillary mucinous neoplasms (SG-IPMN). To date, NKX3.1 expression has not been characterized in other mucinous salivary lesions. Here, we report molecular and extended immunophenotypic findings in SMCA and NKX3.1 expression in the context of other head and neck lesions. METHODS: We retrieved 4 previously reported SMCA, performed additional immunohistochemical and targeted next-generation sequencing (NGS). We also investigated the use of NKX3.1 as a marker for SMCA in the context of its prevalence and extent (using H-score) in a mixed cohort of retrospectively and prospectively tested head and neck lesions (n = 223) and non-neoplastic tissues (n = 66). RESULTS: NKX3.1 positivity was confirmed in normal mucous acini as well as in mucous acinar class of lesions (5/6, mean H-score: 136.7), including mucinous adenocarcinomas (3/4), SG-IPMN (1/1), and microsecretory adenocarcinoma (MSA) (1/1). All SMCA were positive. Fluorescence in situ hybridization for SS18 rearrangements were negative in all successfully tested cases (0/3). NGS was successful in two cases (cases 3 and 4). Case 3 demonstrated a PTEN c.655C>T p.Q219* mutation and a SEC16A::NOTCH1 fusion while case 4 (clinically aggressive) showed a PTEN c.1026+1G>A p.K342 splice site variant, aTP53 c.524G>A p.R175H mutation and a higher tumor mutation burden (29 per Mb). PTEN immunohistochemical loss was confirmed in both cases and a subset of tumor cells showed strong (extreme) staining for P53 in Case 4. CONCLUSION: Despite a partial myoepithelial phenotype, SMCA, along with mucinous adenocarcinomas/SG-IPMN and MSA, provisionally constitute a mucous acinar class of tumors based on morphology and NKX3.1 expression. Like salivary mucinous adenocarcinomas/SG-IPMN, SMCA also show alterations of the PTEN/PI3K/AKT pathway and may show progressive molecular alterations. We document the first extramammary tumor with a SEC16A::NOTCH1 fusion.

An atypical presentation of a Respiratory Epithelial Adenomatoid Hamartoma, a case report.

INTRODUCTION: Respiratory Epithelial Adenomatoid Hamartoma (REAH) is a benign disease that can resemble other malignant entities. Thus, it is essential to diagnose it accurately as the treatment approach differs, from radical surgeries in malignant cases, to a simple excision in hamartoma. We present an unusual case of bilateral REAH that was misdiagnosed, and hence it was treated aggressively. CASE REPORT: A 57-year-old male patient presented with anosmia, 2-years history of bilateral nasal obstruction, and was accompanied with a moderate headache. An impression of olfactory neuroblastoma was made after history taking physical examination, and imaging studies. The patient underwent Functional Endoscopic Sinus Surgery (FESS), excisional biopsy of the cribriform plate mass bilaterally, and superior septectomy. Histopathologic examination of the bilateral masses showed sinonasal polyposis with crypting of surface mucosa and pseudoglandular formation. A diagnosis of sinonasal polyps with REAH was established. The patient's nasal obstruction improved, with no recurrence of sinusitis ±â€¯polyposis. However, he still complains of anosmia after 2-years follow-up. CONCLUSION: Although REAH is a benign disease, it is critical to reach the correct diagnosis, in order to avoid aggressive treatment. Unfortunately, the preoperative investigations were not consistent with REAH, thus it was misdiagnosed and treated aggressively.

Diffuse Neurofibroma in a Patient with Unknown History of NF1.

Malignant peripheral nerve sheath tumor (MPNST) is a rare disease in the parotid gland with a poor prognosis in most cases. The disease most often develops in the setting of neurofibromatosis type 1 (NF1) but can also occur sporadically. Herein, we report a rare case of MPNST in the parotid gland, in a patient with no previous history of NF1. Initial investigations of the patient, which consisted of laboratory investigations, ultrasound imaging of the swelling, fine-needle aspiration (FNA), computed tomography (CT) scan, and magnetic resonance imaging (MRI) of the neck and swelling, were compatible with a benign pleomorphic adenoma of the parotid gland. However, intraoperatively, the dissection was challenging as the tumor was adherent to the neighboring tissue. A diagnosis of MPNST arising from a diffuse neurofibroma was established based on clinicopathologic features of the disease. The patient, who exhibited clinical features compatible with (NF1), proceeded for radiotherapy following surgery to continue his treatment.

Necrotizing tonsillitis caused by group C beta-hemolytic streptococci.

Tonsillitis and pharyngitis are among the most common infections in the head and neck. Viral tonsillitis is usually caused by enterovirus, influenza, parainfluenza, adenovirus, rhinovirus and Epstein-Barr virus (causing infectious mononucleosis). Acute bacterial tonsillitis is most commonly caused by group A beta-hemolytic streptococci. On the other hand, pseudomembranous and necrotizing tonsillitis are usually caused by fusiform bacilli and spirochetes. Here we report what is, to our knowledge, the first case of necrotizing tonsillitis caused by group C beta-hemolytic streptococci.

A Subset of Sinonasal Non-Intestinal Type Adenocarcinomas are Truly Seromucinous Adenocarcinomas: A Morphologic and Immunophenotypic Assessment and Description of a Novel Pitfall.

While sinonasal intestinal type adenocarcinoma (ITAC) is defined by an intestinal phenotype, non-intestinal type adenocarcinoma (non-ITAC) is traditionally viewed as a diagnosis of exclusion, despite previous implication of a seromucinous phenotype and similarity to sinonasal seromucinous hamartomas (SSH). We performed a comparison of clinicopathologic and immunophenotypic features of ITAC, non-ITAC and SSH using traditional discriminatory markers and new markers of seromucinous differentiation. Twenty-three non-ITAC, 17 ITAC, and 5 SSH were retrieved (1987-2014). As expected, ITAC occurred predominantly in the nasal cavity in elderly patients (mean age 65 years) with a striking male predilection (15:2). Regardless of grade/subtype, all ITAC were invariably CK20 and CDX2 positive, and many (11/15) showed some CK7 positivity. Non-ITAC occurred in younger individuals (mean age 51 years) with a slight female predilection (male to female ratio: 10:13) and showed diverse morphologic patterns and grades, some with morphologic similarity to SSH. SSH occurred in younger individuals (mean age 33 years). Non-ITAC and SSH were invariably CK7 positive and CK20 negative, however, 4/22 non-ITAC and 2/5 SSH showed squamoid morular metaplasia that aberrantly expressed CDX2 and co-expressed nuclear ß-catenin. Markers of seromucinous differentiation (S100, DOG1, and SOX10) were essentially absent in ITAC, but present to varying degrees in the majority of non-ITAC and all SSH. Thus, the term 'seromucinous adenocarcinoma' is the more appropriate designation for non-ITAC. Squamoid morules in non-ITAC and SSH may be an immunophenotypic pitfall given the aberrant CDX2 expression.

Secretory myoepithelial carcinoma: a histologic and molecular survey and a proposed nomenclature for mucin producing signet ring tumors.

Signet ring cell (mucin producing) adenocarcinoma is a rare low grade salivary gland malignancy. While currently designated as an adenocarcinoma, myoepithelial differentiation has been implied in previously reported cases. We herein perform a survey of our cases of signet ring cell adenocarcinoma and review the literature in order to refine categorization of this rare tumor. Five cases were retrieved. One was reclassified as a mammary analogue secretory carcinoma, leaving four that fulfilled the criteria for signet ring cell adenocarcinoma: the presence of prominent signet ring or vacuolated cells arranged in islands, interconnecting strands, cords or sheets in a myxoid or hyaline stroma, or pools of mucin. An extensive panel of histochemical and immunohistochemical stains and fluorescence in situ hybridization (FISH) (modeled after common phenotypes and molecular alterations seen in signet ring and myoepithelial tumors at other sites) was performed. The male-to-female ratio was 3:1. The mean age was 56 years (range 18-81). Sites involved included buccal mucosa (2), soft palate (1) and deep parotid (1). Perineural and angiolymphatic invasion were present in three and two cases respectively. One patient was lost to follow up and the remainder were alive and without disease at time of last follow up (mean 38 months). All cases showed mucicarmine positive vacuolated/signet ring cells embedded in a myxoid stroma. Three cases showed at least focal p63 staining and two cases showed positivity for calponin. Membranous E-cadherin was retained in all cases. FISH was negative for ETV6, EWSR1, and ALK1 rearrangements in all four cases. Based on the current series and the previously reported cases, it is evident that signet ring adenocarcinomas have a dual secretory and myoepithelial phenotype and thus as a whole more appropriately designated as 'secretory myoepithelial carcinoma.' They behave in a fairly indolent fashion and do not share the major molecular alterations seen in other signet ring and myoepithelial tumor types.

Primary sclerosing paraganglioma of the thyroid gland: a case report.

OBJECTIVES: Paragangliomas are neuroendocrine tumors derived from extra-adrenal paraganglionic cells of the autonomic nervous system. Paragangliomas of the thyroid are rare, with only 28 cases reported in the literature. The sclerosing paraganglioma variant, characterized by marked stromal sclerosis and hyalinization, has scarcely been reported. METHODS: A 36-year-old woman with a history of a 1-cm vagal schwannoma followed with serial magnetic resonance imaging presented with a new solitary 2.5-cm enhancing soft tissue mass in the left thyroid. RESULTS: Ultrasound examination of the thyroid revealed a hypoechoic, hypervascular, malignant-appearing mass. Two fine-needle aspirations were insufficient for diagnosis, and the mass was deemed a lesion of undetermined significance with subsequent indeterminate molecular testing. A diagnostic left thyroid lobectomy was performed, and pathologic examination revealed a lesion consistent with a sclerosing paraganglioma. CONCLUSIONS: Sclerosing paragangliomas are rare tumors, and only 1 case involving a primary thyroid mass has been reported in the literature. Although the sclerosing variant has features suggestive of malignancy, the true incidence of malignancy is unknown, given the rarity of its presentation. However, given the overall benign nature of paragangliomas, the sclerosing variant is also likely benign, despite its malignant features on ultrasound and histopathologic examination.

Barriers to seeking preventive dental care by Kuwaiti adults.

OBJECTIVE: The aim of this study was to assess the prevalence of preventive dental visits and to identify self-reported barriers for this practice among Kuwaiti adults. MATERIALS AND METHODS: A self-administered, anonymous, structured questionnaire was distributed to a random sample of Kuwaiti nationals 18 years of age or older recruited from all six health districts of Kuwait. A total of 2,400 questionnaires were distributed. Multiple logistic regression analysis was performed to identify factors independently associated with not having a preventive dental visit for more than 1 year. RESULTS: Of the 2,400 questionnaires, 1,925 (80.2%) were completed. Of these, 620 (32.2%) had a dental visit within the previous 6 months, 504 (26.2%) between 6 and 12 months and 801 (41.6%) more than 12 months ago. The most common reasons for the last dental visits were pain or a dental emergency, need for restorative treatment, and an examination/prophylaxis. The strongest factors for not having preventive visits were not using a mouthrinse daily, flossing less than once a day, dental fear, belief that there is no need for visits unless pain was present, brushing the teeth less than twice a day, and believing that appointments are too far ahead. Also older respondents (>30 years), female gender, and those having only high school education or less were less likely to visit a dentist for preventive reasons. CONCLUSION: More than half of the studied population reported not having had a preventive visit for more than 1 year. Unfavorable self-care habits, dental fear and belief that visiting a dentist is necessary only for pain relief were the strongest factors for the nonattendance behavior.

Gender differences in oral health knowledge and behavior of the health science college students in Kuwait.

Dental caries and periodontal diseases have been declining in most industrialized countries, but this positive trend has not been seen in the Middle East. This study aimed to determine oral health knowledge and behavior of the students at the Health Sciences College in Kuwait as well as possible associated factors. This study was first conducted at the college of the male students (n = 153) during the autumn semester in 2001. A similar questionnaire study was then conducted at the college of the female students (n = 547) during the spring semester in 2002. The samples were merged for this study, for a total sample of 700 students. The response rate was 84% (n = 128) among the male students and 73% (n = 400) among the female students. Most of the students had visited a dentist during the past year, and quite a high proportion was seen for an examination or prevention. Female students reported twice-a-day tooth-brushing frequency much more often than did male students. They also used fluoride toothpaste more often than male students. Oral health knowledge (as a summary variable) was statistically significantly higher among the female students than among the male students. It was also strongly associated with the older age among the female students. The knowledge and oral health behavior of the Health Sciences College students in Kuwait, especially among the male students, seems to be poor and calls for an urgent improvement of health education programs.

Self-reported oral hygiene habits and oral health problems of Kuwaiti adults.

OBJECTIVE: The aims of this study were to examine self-reported oral hygiene habits and oral health problems of a sample of adult Kuwaitis. MATERIALS AND METHODS: A self-administered, anonymous, structured questionnaire was distributed to 2,400 adult Kuwaiti nationals from all 6 governates of Kuwait assessing socio-demographic variables, oral hygiene habits, and oral health problems. RESULTS: Of the 2,400 questionnaires, 1,925 (80.25%) responded. Of these, 62% reported brushing their teeth at least twice daily, while daily use of dental floss was uncommon (11.8%). Adequate toothbrushing habits were significantly associated with female gender, educational level, non-smoking status, and history of recent preventive dental visits (p = 0.001). The majority of subjects reported multiple oral health problems (64.7% with 2 or more and 41.8% with 3 or more). Factors associated with multiple oral health complaints included younger age, smoking, not having a recent preventive dental visit, and brushing the teeth less than twice daily. CONCLUSIONS: Less than two-thirds of the sampled adult Kuwaitis followed the recommended toothbrushing frequency of twice daily or more, and the majority of subjects have not had a preventive dental visit in the previous 6 months. Furthermore, most subjects reported multiple oral health problems that are mostly preventable through adequate oral hygiene habits and regular preventive dental visits.

Reasons for tooth extraction in Kuwait.

OBJECTIVES: To investigate reasons for tooth extraction and its association with age and gender in Kuwait. SUBJECTS AND METHODS: A record of all tooth extractions performed in 21 general dental practice centers during a 1-month period was logged on specially designed study forms. The patient's age and gender, number of teeth extracted, and the reason(s) for the extraction were recorded. RESULTS: A total of 2,783 teeth were extracted in 1,604 patients (1.73 +/- 0.07 teeth per patient). Caries and periodontal disease were responsible for 43.7 and 37.4% of extractions, respectively. Caries was the principal cause for extraction in patients < or =40 years old (60.7%), while periodontal disease was the main cause of extractions in patients > or =40 years of age (63.0%). Extractions for caries and orthodontic reasons were more common in females, while extractions for periodontal disease were more prevalent in males. Molars and maxillary premolars were more commonly extracted due to caries, while mandibular premolars, and maxillary and mandibular anterior teeth (canines and incisors) were more commonly extracted due to periodontal disease. CONCLUSIONS: The data show that caries is the principal cause for extractions in younger patients, while periodontal disease accounts for the majority of tooth extractions in patients older than 40 years. Furthermore, this study indicates that more teeth per patient are lost to periodontal disease than for any other reason.

Association of periodontal disease severity with diabetes duration and diabetic complications in patients with type 1 diabetes mellitus.

OBJECTIVES: The association between periodontal disease severity and diabetes complications and duration in patients with type 1 diabetes mellitus (DM) was investigated in this comparative cross-sectional study. MATERIALS AND METHODS: Twenty-nine patients with type 1 DM of < or = 5 years duration were compared with 43 patients with > 5 years duration of DM. Complete medical history and examination and assessments of retinopathy, neuropathy, and nephropathy were performed, followed by assessments of the plaque index (PI), pocket depth (PD), clinical attachment level (CAL), and the number of missing teeth by one examiner masked to the diabetic status of the patients. RESULTS: The number of missing teeth (4 versus 0) and CAL (2.88 vs 2.56 mm) were significantly higher in patients with longer DM duration (p < 0.05). For patients with > or = 5 years DM duration, periodontal disease severity was also greater in patients with one or more DM complications, as assessed by the number of missing teeth (17 vs 0; p < 0.001) and CAL (4.74 vs 2.81 mm; p < 0.01). Stepwise multiple regression analysis associated the presence of > or = 1 DM complications and smoking history with severe attachment loss (CAL > or = 7 mm; p < 0.001). CONCLUSION: Periodontal disease severity is associated with both DM duration and the presence of DM complications in this sample of type 1 DM patients.

Dietary habits of the primary to secondary school population and implications for oral health.

Surveys have shown increases in dental caries in young persons in Kuwait. Intake of sugar and carbohydrates has increased, as has the incidence of obesity. The objective of this study was to identify dietary practices and the potential for dental disease in primary, intermediate, and secondary school students in a health region. A random sample of 600 students aged 8, 13, and 17 yrs in 12 schools (6 boys' schools and 6 girls' schools) received a questionnaire. Responses were analyzed by age group, gender, and dietary practices at home and in school. The dietary composition of meals tended to be similar at all ages and in both genders. A total of 97% of 8-yr-old, 96% of 13-yr-old, and 92% of 17-yr-old students reported snacking at school. Sugar intake from identified snacks alone was calculated as 193.8 g/day or the estimated equivalent of 746 calories, and daily fat intake was 70.17 g. A total of 88.6% of respondents (56.6% of all children) used fluoridated toothpaste; 44.4% of all children (22.6% of 8-yr-old, 14.1% of 13-yr-old, and 7.7% of 17-yr-old students) reported brushing their teeth three times per day. Use of school snacks increased with age, while use of a toothbrush decreased. Fundamental oral hygiene procedures such as brushing and use of fluoridated toothpaste appear to have been implemented. Health workers need to provide new and pertinent oral health messages, nutrition counseling, attention to diet, and reinforcement with parents, food preparers, health facilities, and intermediate and secondary schools.

Implant recommendation as a replacement option after tooth loss for periodontal reasons.

PURPOSE: The aim of this study was to examine the frequency of implant recommendation by general dental practitioners to patients who had extractions as a result of periodontal disease and factors that influenced their decisions. MATERIALS AND METHODS: Dentists in each of 20 general dental practice centers in Kuwait were asked to document replacement options given to patients after all tooth extractions performed for periodontal reasons within a 30-day period. The association of demographic and medical/dental history variables with the decision to recommend an implant was statistically tested. RESULTS: A total of 711 patients with a mean age +/- of 47.34 +/- 0.45 years (range 18-96) had 2202 teeth extracted for periodontal reasons during the study period. Only 21 implants for 12 patients were offered as a replacement option (1.7%). Factors significantly associated with a less likelihood of implant recommendation included older age, male gender, diabetes mellitus, inadequate compliance with regular periodontal maintenance visits, inadequate oral hygiene practices, and anterior tooth types (P < 0.05; chi test). CONCLUSION: Dental implants were rarely recommended to patients losing their teeth for periodontal reasons by general dentists in Kuwait.

Dental patient awareness of smoking effects on oral health: Comparison of smokers and non-smokers.

OBJECTIVES: The negative effects of cigarette smoking on oral health are well established, yet few studies assessed patient awareness of such effects. The aim of this study was to examine differences in dental patient knowledge and awareness of the effects of smoking on oral health between smokers and non-smokers. METHODS: Adult patients from 12 dental centers in Kuwait were asked to complete a 14-point self-administered structured questionnaire on the effects of smoking on oral health in this cross-sectional survey. Significant associations between oral health knowledge, smoking status, and sociodemographic variables were examined with univariate analysis and logistic regression. RESULTS: A total of 1012 subjects participated (response rate = 84.3%). The prevalence of smoking was 29.3%. Fewer smokers than non-smokers thought that oral health and smoking are related (92.2% vs. 95.8%; P = 0.020), and that smoking affected oral cancer (52.4% vs. 66.8%; P < 0.001), periodontal health (72% vs. 78%; P = 0.040), or tooth staining (86.1% vs. 90.9%; P = 0.018). Logistic regression analysis showed smokers to be significantly less aware of the oral health effects of smoking than non-smoking patients (OR=1.51; 95% CI: 1.05-2.16; P = 0.025). CONCLUSION: Smoking dental patients are significantly less aware of the oral health effects of smoking than non-smokers. Comparative studies in other populations may be warranted to ascertain the validity of these results.

Factors associated with self-reported halitosis in Kuwaiti patients.

OBJECTIVES: Oral malodor is a common complaint of dental patients, yet limited data is available on the actual prevalence of this condition. The aim of this study was to assess the prevalence and factors associated with self-reported halitosis in Kuwaiti patients. METHODS: This was a cross-sectional study of Kuwaiti adults using a 19-point self-administered structured questionnaire on self-perception of halitosis. Significant associations between self-reported oral malodor and sociodemographic, medical history, and oral hygiene variables were examined with multiple logistic regression analysis. RESULTS: A total of 1551 subjects participated (response rate=86.2%). The prevalence of self-reported halitosis was 23.3%. Use of the toothbrush less than once daily was the factor most strongly associated with self-perceived halitosis (OR=2.68; 95% CI=1.83-3.92; p<0.001). Other factors significantly associated with self-perceived halitosis included current or past smoking (OR=2.51), female gender (OR=1.54), being 30 years of age or older (OR=1.35), having high school education or less (OR=1.41), history of chronic sinusitis (OR=1.58) or gastrointestinal disorders (OR=1.73), never using miswak (OR=1.56), and never using dental floss (OR=1.33). CONCLUSION: Inadequate oral hygiene practices were the factors most strongly associated with self-reported oral malodor in this sample of Kuwaiti patients. Other factors with significant associations included history of gastrointestinal tract disorders, chronic sinusitis, older age, female gender, and lower education levels.

Risk indicators for tooth loss due to periodontal disease.

BACKGROUND: Several risk indicators for periodontal disease severity have been identified. The association of these factors with tooth loss for periodontal reasons was investigated in this cross-sectional comparative study. METHODS: All extractions performed in 21 general dental practice clinics (25% of such clinics in Kuwait) over a 30-day period were recorded. Documented information included patient age and gender, medical history findings, dental maintenance history, toothbrushing frequency, types and numbers of extracted teeth, and the reason for the extraction. Reasons were divided into periodontal disease versus other reasons in univariate and binary logistic regression analyses. RESULTS: A total of 1,775 patients had 3,694 teeth extracted. More teeth per patient were lost due to periodontal disease than for other reasons (2.8 +/- 0.2 versus 1.8 +/- 0.1; P <0.001). Factors significantly associated with tooth loss due to periodontal reasons in logistic regression analysis were age >35 years (odds ratio [OR] 3.45; 95% confidence interval [CI] 2.79 to 4.26), male gender (OR 1.42; 95% CI 1.17 to 1.73), never having periodontal maintenance (OR 1.48; 95% CI 1.23 to 1.78), never using a toothbrush (OR 1.81; 95% CI 1.49 to 2.20), current or past smoking (OR 1.56; 95% CI 1.28 to 1.91), anterior tooth type (OR 3.23; 95% CI 2.57 to 4.05), and the presence of either of the following medical conditions: diabetes mellitus (OR 2.64; 95% CI 2.19 to 3.18), hypertension (OR 1.73; 95% CI 1.41 to 2.13), or rheumatoid arthritis (OR 4.19; 95% CI 2.17 to 8.11). CONCLUSION: Tooth loss due to periodontal disease is associated with the risk indicators of age, male gender, smoking, lack of professional maintenance, inadequate oral hygiene, diabetes mellitus, hypertension, rheumatoid arthritis, and anterior tooth type.

Factors associated with implant recommendation for single-tooth replacement.

The use of dental implants for single-tooth replacement has been established as a predictable treatment option; yet, limited data are available as to how frequently this option is recommended to patients. The aim of the present study was to examine the frequency of implant recommendation by general dental practitioners after single-tooth extraction and factors influencing their decision to recommend an implant. All single-tooth extractions performed in 26 general dental practice clinics in Kuwait over a 30-day period were examined. Dentists in these centers used the study form to record demographic data, the type of tooth extracted, reason for extraction, and replacement options presented to the patients. Univariate and logistic regression analyses were used to examine associations between background factors and decisions to recommend implant therapy. A total of 1367 patients (mean age, 37.9 +/- 11.8 years) had an extraction of one tooth during the study period. Forty-three patients were offered implants as a replacement option (3.3% of the total sample; 8.6% of patients who were offered tooth replacement options). Factors associated significantly with the recommendation of an implant by Kuwaiti dentists to their patients included younger age, regular dental maintenance visits, and adequate oral hygiene practices (P < 0.05; binary logistic regression). Dental implant recommendation for single-tooth replacement in the present sample of dentists was low. Factors associated significantly with dentist recommendation of an implant for single-tooth replacement included age, history of dental maintenance, and oral hygiene practices.

Biomechanical analysis of the effect of varying suture pitch in tendon graft fixation.

The purpose of this study was to biomechanically assess the effect of varying suture pitch on the holding power of the Krackow suture technique for tendon graft fixation. Seven pairs of rabbit Achilles tendons were sutured with single No. 5 Ti-Cron suture using the Krackow technique. One tendon from each pair was sutured using a 0.5-cm suture pitch (half-pitch group) while the contralateral tendon from each pair was sutured with a 1.0-cm suture pitch (one-pitch group). The tendons were loaded to failure using a servohydraulic materials test system at a loading rate of 0.5 mm/sec. There were no statistically significant differences noted in suture slippage at failure (1.58 cm for half pitch versus 1.45 cm for one pitch) or maximal force to failure (158.5 N for half pitch versus 168.2 N one pitch) between the two treatment groups. However, the construct with the 1-cm suture pitch was significantly stiffer than the construct with the 0.5-cm suture pitch, with stiffness values of 106.2 N/cm and 91.4 N/cm, respectively. The most common mechanism of failure was slippage of the suture at the first suture throw and tearing of the first knot through the most distal portion of the tendon. Four constructs failed by suture rupture, two from each experimental group.