Umeå universitets logga

AIM: To assess the accuracy of panoramic radiography and spiral or computed tomography for the localisation of the mental foramen.

MATERIALS AND METHODS: The distance from the alveolar crest to the mental foramen was measured from panoramic radiographs, spiral tomograms and CT scans. The same distance was measured during implant surgery using a specially designed caliper.

RESULTS: Panoramic radiography showed more deviation (+0.6 mm) from the perioperative measurements than either spiral or computed tomography (+0.4 and -0.3 mm respectively). The difference was significant (P<0.05). In general, distances were overestimated on the panoramic radiographs.

CONCLUSIONS: Cross-sectional imaging techniques are recommended for the pre-operative planning of implants in the posterior mandible.

Aim: To gain insight into the decision processes of dentists when requesting a cone beam computed tomography (CBCT) examination in endodontic settings.

Methodology: Fourteen dentists (eight female) 33-58 years of age (mean = 44) practising in Sweden were interviewed. Ten of the dentists were specialists in Endodontics. The absolute inclusion criterion was experience of referring patients for CBCT for endodontic reasons. The included dentists comprised a strategically selected diverse sample in terms of gender, age, work experience, educational background, location of practice, service affiliation and accessibility to CBCT. Data were obtained through semistructured interviews exposing the context of their last three self-reported referrals. Dentists were encouraged to describe their experiences of the circumstances in their own words, aided by the interviewer's open-ended questions. The interviews were audio-recorded and transcribed verbatim. The text was analysed by qualitative content analysis.

Results: The manifest content was organized into three categories that were defined as visualization as a desire, facilitating tough decisions and allocating responsibility.

Conclusion: An overall theme (covering the latent content) was identified: A balance between clinical common sense and a 'better safe than sorry' attitude guides the use of CBCT in endodontic settings. Informants had high clinical standards, knowledge concerning radiation risks and good sense, which could compensate for their lack of knowledge of guidelines. The national radiation regulatory system was perceived to work as a slightly porous gatekeeper for over-usage.

Aim To determine whether the outcome of cone beam computed tomography (CBCT) examinations performed in accordance with the European Commission guidelines in a clinical setting has an impact on choosing diagnoses in endodontics. Methodology A prospective observational study was conducted. Fifty-three consecutive patients (81 teeth) from two different endodontic specialist clinics in Sweden were followed. After performing a thorough clinical examination (based on the history, clinical findings, and diagnostic tests such as intra-oral radiography), the examiner wrote down a preliminary diagnosis before CBCT examination. After the CBCT examination, a new diagnosis was made by the same examiner. Both the pre- and the post-CBCT examination diagnoses were plotted according to patients and teeth. The CBCT examinations were performed using similar equipment and protocols that were standardized amongst the clinics. Results The diagnoses were changed for at least one tooth in 22 patients (41%); overall, the diagnoses were changed for 28 teeth (35%). Conclusion CBCT has a substantial impact on diagnostic thinking in endodontics when used in accordance with the European Commission guidelines.

The clinical success of 85 Screw Vent and 107 Brånemark implants, consecutively installed in a private periodontal clinic under the same conditions and by the same operator, is compared. Mobile implants were removed and considered as failures. Intra-oral radiographs were assessed for the presence of peri-implant radiolucencies and for analysis of bone loss after functional loading. 85 Screw Vent implants were installed in 31 patients. Of 23 implants installed in 9 mandibles, none failed after 16.8 (range 12-25) months of function. Of 62 Screw Vent implants installed in 23 maxillae, 6 failed at abutment connection, 1 failed after 2 months and 2 after 13 months of function. The absolute failure rate after 13.2 (range 6-24) months was 9/62. Mean loss of bone was 1.47 mm (-1.0- +4) after 12 months of functional loading. 107 Brånemark fixtures were installed in 25 patients. Of 51 fixtures inserted in 12 mandibles, none failed; of 56 fixtures installed in 13 maxillae 1 failed before and 2 failed during abutment connection. The absolute failure is 3/56. All remaining fixtures were immobile after loading. 13 fixtures were more than 6 months in function. Only short-term comparison between both systems is possible because the observation time is longer for the Screw Vent implants. In the 1st year, only 1 implant system was available to the periodontist. Short-term comparison reveals 11.3% versus 5.3% of cumulative failure after 6 months for the Screw Vent and Brånemark implants, respectively. The results indicate that clinical efficacy is as effectively obtained with Screw Vent as with Brånemark implants in the mandible. The outcome of treatment with Screw Vent implants in the maxilla seems less predictable.

AIM: To re-examine a population after 20 years and evaluate changes in prevalence of endodontic treatment and apical periodontitis, as well as the technical quality of root fillings.

METHODOLOGY: One hundred and fifteen out of an original 200 patients living in the northern part of Sweden were re-examined with a full mouth radiographic survey after 20 years. Frequencies of root canal treated teeth, apical periodontitis and quality parameters of root fillings were registered.

RESULTS: The frequency of root canal treated teeth increased significantly (P < 0.05) from 13.9% at the first investigation to 17.7% after 20 years. There was also a statistically significant increase (P < 0.05) in teeth with apical periodontitis from 3.3% to 6.8%. Apical periodontitis both in connection with root canal treated teeth and teeth without endodontic treatment, had increased during the follow-up period. Even though the quality of the root fillings had improved, there was no corresponding improvement of the apical status in teeth with root fillings.

CONCLUSIONS: There is still a great need for endodontic treatment in the Swedish population, and no improvement in apical health was found during this 20-year follow up.

I fem autopsistudier undersöktes humana käkledspreparat med tomografi (skiktröntgen), makroskopiskt (inspektion) och mikroskopiskt för förekomst av degenerativa (nedbrytande) förändringar. Speciellt undersöktes förekomst av erosiva förändringar i benet samt förändringar i den förkalkade broskzonen (skiktet mellan mjukbrosk och ben). Det förkalkade brosket var i normala fall avgränsat mot överliggande mjukbrosk av en jämn basofil vågig linje, den s.k. tidemark. Avgränsningen mot benet var oregelbunden. Ett samband fanns mellan tjockleken på det "mjuka" brosket och det förkalkade brosklagret. Detta tyder på att den förkalkade broskzonen är en biologiskt aktiv zon även hos vuxna individer. Två typer av erosiva benförändringar kunde urskiljas. En typ där det överliggande brosket var intakt och en typ där det överliggande brosket var s.g.s. helt bortskalat. Den senare typen av förändring fanns i större antal i condylen (käkledshuvudet), medan förändringarna i den temporala ledkomponenten (ledhålan i skallbasen) oftare var av den första typen och mindre utbredda. Detta kan tyda på en skillnad i biologisk reaktion mellan de båda ledkomponenterna. Skiktröntgen undervärderade både antalet och utbredningen av de erosiva förändringarna. Positiva prediktiva värden (d.v.s. sannolikheten att ett röntgenfynd av en erosion verkligen motsvaras av en erosion) var 70% i kondylen och 91% i den temporala komponenten. Negativa prediktiva värden (d.v.s. sannolikheten att ytor som ser friska ut på röntgen verkligen är det) var 83% i condylen och 68% i den temporala komponenten. Tre olika tekniker för benvolymsbestämning med hjälp av databaserad bildanalys utvärderades, en automatisk, en manuell och en semi-automatisk. Den semi-automatiska tekniken gav en god reproducerbarhet och liten variation när man använde sig av endast en operatör. Den semi-automatisk tekniken användes för att mäta benvolymen i käkledspreparaten. Käkledskondyler med erosiva förändringar visade sig generellt vara tätare i benet än käkleder utan förändringar. Detta talar för att bentätheten spelar en roll i uppkomsten av erosiva förändringar i käkleden. I en klinisk studie undersöktes ledvätskan från patienter som fick käkledsdisken bortopererad. Prover på käkledsvätskan togs dels vid operationen och 6 månader efter operationen. Proverna analyserades avseende förekomst av fragment av två olika broskmolekyler Aggrecan och COMP. Dessa molekylerna finns normalt i ledbrosket och "läcker ut" i ledvätskan när brosket skadas. Det visade sig att ration (förhållandet) mellan Aggrecan/COMP var högre i alla ledvätskorna vid 6-månaderskontrollen. Vid denna kontroll uppvisade dessutom samtliga leder benförändringar av degenerativ karaktär (på röntgen). Detta talar för att man eventuellt kommer att kunna spåra tidiga broskskador i käkleden genom att analysera ledvätskan. Tekniken måste dock först förfinas både vad avser provtagning och den biokemiska analysen.

Background: Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has been proven to be a good method to detect distant spread of head and neck cancer (HNC). However, most prior studies are based on Asian populations and may not be directly transferable to western populations.

Purpose: To investigate the frequency and distribution of distant metastases and synchronous malignancies detected by PET/CT in HNC in a northern Swedish population.

Material and Methods: All primary whole-body FDG-PET/CT examinations performed on the suspicion of HNC (n = 524 patients) between 1 January 2013 and 31 December 2016 at Umeå University Hospital in Sweden were retrospectively reviewed . After the exclusion of 189 examinations without evidence of primary HNC, 335 examinations were analyzed.

Results: Distant metastases were detected in 10 (3%) patients, all with advanced primary tumors corresponding to TNM stage 3–4, most frequently in salivary gland adenocarcinoma, where 50% of patients had distant spread. Four patients had metastases below the diaphragm, representing 20% of the salivary gland malignancies. In the remaining six patients, metastases were supraphrenic, of which all but one were identified by CT alone. Synchronous malignancies were discovered in 14 (4.2%) patients, of which five were below the diaphragm.

Conclusion: The overall frequency of distant spread and synchronous malignancy in primary HNC was generally low. However, the risk for distant metastases below the diaphragm was relatively higher in salivary gland adenocarcinoma, supporting whole-body FDG-PET/CT in the primary diagnostic work-up in these patients.

Background: The value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for TN staging in head and neck cancer (HNC) has been proven in numerous studies. A few studies have investigated the value of FDG-PET/magnetic resonance imaging (MRI) in the staging of HNC; the combined results indicate potential for FDG-PET/MRI, but the scientific evidence remains weak.

Purpose: To compare performance of FDG-PET/CT and FDG-PET/MRI for locoregional staging in patients with oropharyngeal carcinomas.

Material and Methods: Two radiologists independently of each other retrospectively reviewed primary pre-therapeutic FDG-PET/CT and FDG-PET/MRI examinations from 40 individuals with oropharyngeal carcinomas. TN stage and primary tumor size were noted. The results were compared between observers and modalities and against TN stage set at a multidisciplinary conference.

Results: For nodal staging, PET/MRI had slightly higher specificity and accuracy than PET/CT for the most experienced observer. Both methods demonstrated excellent sensitivity (≥ 0.97 and 1.00, respectively), as well as high negative predictive values (≥ 0.95 and 1.00, respectively). No significant differences were found for tumor staging or measurement of maximum tumor diameter. There was a weak agreement (κ = 0.35–0.49) between PET/CT and PET/MRI for T and N stages for both observers. Inter-observer agreement was higher for PET/MRI than for PET/CT, both for tumor staging (κ = 0.57 vs. 0.35) and nodal staging (κ = 0.69 vs. 0.55). The agreement between observers was comparable to the agreement between methods.

Conclusion: PET/MRI may be a viable alternative to PET/CT for locoregional staging (TN staging) and assessment of maximal tumor diameter in oropharyngeal squamous cell cancer.

The aim was to compare the trabecular bone volume (TBV) and the total bone volume (TOBV) of human temporomandibular joints (TMJ) with erosive changes with those of joints without erosive changes. We examined 35 TMJ autopsy specimens from 19 individuals aged 66 88 years. Sagittal sections of the joints were analyzed microscopically for erosive hard-tissue changes. The TBV and the TOBV of the sections were assessed with the aid of computerized image analysis. A significant increase in trabecular and total bone volume was found in condyles with erosive changes (TBV = 21%, TOBV = 54%) as compared with condyles without erosive changes (TBV = 15%, TOBV = 40%). The trabecular bone volume of the temporal component was also increased (TBV = 24%) in joints with erosive changes in the condyle as compared with joints with unaffected condyles (TBV = 16%). The findings indicate that the relative bone mass may play a role in the development of erosive changes in the TMJ.