A two-probe laser Doppler flowmetry assessment as an exclusive diagnostic device in a long-term follow-up of traumatised teeth: a case report

Transient apical breakdown of a discoloured maxillary central incisor during orthodontic treatment: A case report

Transient apical breakdown (TAB) appears to be a repair process taking place in the pulp and periapical area of traumatised teeth which may display crown discoloration and have no responses to pulp sensitivity tests. Few TAB cases induced by orthodontic forces have been reported so far. Presented is a case report in which TAB occurred on the maxillary right central incisor during orthodontic treatment. The affected tooth suddenly displayed crown discoloration and had no response to pulp testing at 6 weeks after the placement Invisalign Clear Aligner appliances. Condition of the discoloured tooth was monitored by periodic recall examinations without any active treatment. Six months after the occurrence of discoloration, the affected tooth recovered to its original shade and responded normally to pulp sensitivity tests.

Present status and future directions: Root resorption

Root resorption is the loss of dental hard tissue because of odontoclastic action. In permanent teeth, it is undesirable and pathological in nature. Root resorption may occur on the inner aspect of the root canal (internal root resorption) or on the outer aspect of the root (external root resorption). Regardless of its location, root resorption is irreversible, and may result in discomfort for the patient, requires management and/or, in some cases, results in the premature loss of the affected tooth. Root resorption is often challenging to accurately diagnose and manage. The aim of this narrative review is to present the relevant literature on the aetiology, pathogenesis, diagnosis and management, as well as discuss the future directions of diagnosis and management of root resorption.

The Decisive Role of Laser Doppler Flowmetry for Pulp Preservation in Discolored Traumatized Teeth

Objective: It has been stated that blood pigments within discolored teeth may interfere with Laser Doppler Flowmetry (LDF) measurements. The aim of this study was to assess pulp vitality with LDF in a cohort of discolored traumatized teeth referred for endodontic treatment or where the referring dentist had doubts regarding maintained tooth vitality. Background: Discoloration of teeth is a common sequel of dental trauma. Still today, it is taken as an indicator for root canal treatment. Transient apical breakdown (TAB) is confused with apical periodontitis, although it is a sequel of dental trauma in young mature teeth and will result in revascularization and dissolution of the apical radiolucency. Methods: A total of 26 patients with 28 discolored teeth, belonging to a cohort of referred patients with traumatized teeth referred for root canal treatment and/or pulp vitality assessment were screened on color with photographs by three investigators, with traditional sensibility tests and with a Moor VMS II LDF meter. Results: The color of the intrinsically discolored teeth was grayish in 58% of teeth, blue 20%, pink/crimson 12%, and yellow 4%. Eighty-five percent were central maxillary incisors, 11% were mandibulary incisors. Thanks to LDF, 43% of the trauma cases in this small cohort with discoloration underwent root canal treatment instead of 70% with traditional sensibility tests as indicator. TAB was found in 11%. Conclusions: LDF was decisive in diagnosing vitality of discolored teeth and there was no negative impact of tooth discoloration on LDF measurements.

The Efficacy of Laser Doppler Flowmetry, Electric Pulp Test and Cold Test in Diagnosing Revascularization of Extrusively Luxated Immature Maxillary Incisors

Objective:

To evaluate the effect of extrusion on immature permanent tooth PBF values during a 6-month post-trauma period and to compare the accuracy of cold tests on pulp sensibility of traumatized teeth with that of electric pulp tests (EPT).

Methods:

The study group comprised of 26 extruded immature maxillary incisors in 25 trauma patients. The respective contralateral homologous teeth (n=25) were included as a positive control group. Teeth in the study group were treated by repositioning and splinting. Pulp vitality readings for traumatized and control teeth were taken with LDF, EPT and cold test on the day of splint-removal (2-3 weeks after trauma–T1) as well as 6 weeks (T2), 3 months (T3) and 6 months (T4) post-trauma. Student t and Mann-Whitney U-tests were used to compare data among groups. Statistical significance was set at P< 0.05.

Results:

LDF gave positive vitality readings (>4.5 PU) in all patients from T1 to T4 (with the exception of 1 patient at T1).

Conclusions:

LDF was able to accurately identify vitality in traumatized immature teeth even during the first few weeks following trauma, whereas conventional sensibility tests were unable to accurately recognize vitality shortly after trauma.

Detection of Pulpal Blood Flow In Vivo with Pulse Oximetry in Dogs

Objective

The aim of the present study was to investigate the ability of pulse oximetry to detect blood flow within the canine tooth of dogs.

Materials and methods

Dogs aged 18–138 months presenting for oral treatment and meeting the inclusion criteria underwent pulse oximetry evaluation of at least one canine tooth. Oxygen saturation (SpO₂) and pulse rate values were acquired from vital canine teeth of 38 clinical patients (representing 40 total teeth) with a handheld pulse oximeter and compared to a control area. SpO₂ values from the tooth and control area were recorded every 5 s for three 60-s intervals. The sensors were repositioned after each 60-s interval.

Results

The vital teeth consistently recorded SpO₂ values significantly lower than the control area. The mean vital tooth SpO₂ was 85.9% (median = 87%; SD = 8.6), and the mean control area SpO₂ was 97.7% (median = 98%; SD = 1.8). An age-related significant difference was noted in vital tooth SpO₂ values.

Conclusion

In conclusion, the present data support the possible use of pulse oximetry to detect blood flow in canine teeth. However, there was no significant correlation between SpO₂ values in the vital tooth and in the control areas. Additionally, the results were not definitive, and validation of the modality with additional studies of non-vital canine teeth is needed before clinical use can be recommended.

Pulp sensibility and vitality tests for diagnosing pulpal health in permanent teeth: a critical review

The aim of this review was to critically appraise the literature related to pulp vitality and sensibility testing in order to determine the diagnostic accuracy of pulp tests with reference to a gold standard or control group. Implications of the results for research and clinical practice are also explored. The MEDLINE (Ovid), MEDLINE (PubMed), Embase and Cochrane databases were searched for English-language clinical trials in humans in which in vivo studies were designed to evaluate or compare the accuracy of selected pulp sensibility and pulp vitality tests in determining the state of pulpal health in permanent teeth. Studies were included only if the results were compared to a control group or to a valid gold or reference standard. Eight studies were identified. Shortcomings in research design were found to influence the findings. The limited number of studies investigating pulp vitality tests was insufficient to answer the research question. It was concluded from this critical appraisal of the literature that laser Doppler flowmetry appeared to be the most accurate method for diagnosing the state of pulpal health and came closest to serving as a gold standard. Pulp vitality tests proved superior to pulp sensibility tests for early and accurate assessments of the pulpal health of traumatized teeth. When accurately used and interpreted, pulp sensibility tests provide valuable diagnostic information, particularly when an electric pulp test is used in combination with either CO₂ snow or Endo-Ice.

Laser physics and a review of laser applications in dentistry for children

AIM

The aim of this introduction to this special laser issue is to describe some basic laser physics and to delineate the potential of laser-assisted dentistry in children.

REVIEW

A brief review of the available laser literature was performed within the scope of paediatric dentistry. Attention was paid to soft tissue surgery, caries prevention and diagnosis, cavity preparation, comfort of the patient, effect on bacteria, long term pulpal vitality, endodontics in primary teeth, dental traumatology and low level laser therapy. Although there is a lack of sufficient evidence taking into account the highest standards for evidence-based dentistry, it is clear that laser application in a number of different aetiologies for soft tissue surgery in children has proven to be successful. Lasers provide a refined diagnosis of caries combined with the appropriate preventive adhesive dentistry after cavity preparation. This will further lead to a new wave of micro-dentistry based on 'filling without drilling'.

CONCLUSION

It has become clear from a review of the literature that specific laser applications in paediatric dentistry have gained increasing importance. It can be concluded that children should be considered as amongst the first patients for receiving laser-assisted dentistry.

Assessment of pulp blood flow in primary and permanent teeth using pulse oximetry

Pulse oximetry (PO) is a well-accepted non-invasive method for assessing vascular health, based on oxygen saturation (SaO(2) ) measurements. The objectives of this study were to design and build a custom-made PO dental sensor holder, to evaluate the effectiveness of PO in determining pulp blood flow in primary and permanent teeth, and to compare the SaO(2) levels obtained in teeth and on the little finger of patients. The PO sensor adapted to the custom-made sensor holder is termed as a device to position and hold the PO sensor. This study evaluated SaO(2) readings obtained in the pulp of 123 teeth of 84 children aged 4-13years. The teeth were divided into three groups: group I - primary teeth: 23 central incisors and 28 canines; group II - permanent teeth: 25 central incisors and 28 canines; and group III - endodontically treated teeth (control): 12 permanent central incisors and seven primary central incisors. The pulp blood flow and SaO(2) were measured and were compared with readings of the patient's finger. Data were analyzed by paired t-tests and Pearson's analysis method. The PO was able to identify all the clinically normal pulps contained in the sample, and all the endodontically treated teeth (controls) showed no response. The mean SaO(2) values were 85.27% in the teeth and 92.85% in the fingers. In conclusion, PO readings were effective in determining pulp blood flow in primary and permanent teeth. However, there was no correlation between the SaO(2) values in the fingers and in the teeth of the patients (P<0.05).

Pulpal blood flow changes due to rapid maxillary expansion

OBJECTIVE

To determine the pulpal blood flow (PBF) changes in anchorage teeth associated with the high forces of a rapid maxillary expansion (RME) appliance.

MATERIALS AND METHODS

The study was performed with 14 girls and 7 boys for a total of 21 patients between 10 and 15 years of age (mean, 13.1 +/- 1.39 years). A modified acrylic bonded RME appliance was used as an expansion appliance. Laser Doppler flowmetry was used for the pulpal perfusion measurements. Records were taken from 42 upper central incisors, 28 canines, and 42 first molars at the following time intervals: just before expansion (T1); at the first week of expansion (T2); at the end of the expansion process (T3); and at the third (T4), seventh (T5), and 12th weeks of retention (T6). The data gained were statistically evaluated by parametric tests.

RESULTS

PBF values of the anchorage teeth were doubled at the first week of expansion; however, these values began to decrease because of separation of the median palatal suture. PBF values tended to reach their initial values during the retention period. Pulpal perfusion changes of all examined anchorage teeth were similar to each other from the beginning to the end of the evaluation.

CONCLUSION

PBF changes that occur with RME are reversible.

Pulpal blood flow changes in abutment teeth of removable partial dentures

The purpose of this study was to investigate the effect of tooth supported (TSD) and tooth-tissue supported (TTSD) removable partial denture wearing on pulpal blood flow (PBF) of the abutment teeth by using Laser Doppler Flowmeter (LDF). Measurements were carried out on 60 teeth of 28 patients (28 teeth and 12 patients of TTSD group, 32 teeth and 16 patients of TSD group) who had not worn any type of removable partial dentures before, had no systemic problems and were non smokers. PBF values were recorded by LDF before insertion (day 0) and after insertion of dentures at day 1, day 7 and day 30. Statistical analysis was performed by student t test and covariance analyses of repeated measurements. In the group TTSD, the mean values of PBF decreased statistically significantly at day 1 after insertion when compared with PBF values before insertion (p<0,01). There was no statistically significant difference among PBF mean values on 1st, 7th and 30th day. However, in the group TSD, there was no statistically significant difference among PBF mean values before insertion and on 1st, 7th and 30th day. In other words, PBF mean values in group TSD continued without changing statistically significant on 1st, 7th and 30th day.TTSD wearing may show negative effect on the abutment teeth due to decreasing basal PBF.

The use of likelihood ratio methodology to find predictors of treatment outcome in patients with dental injury diagnoses

The purpose of this prospective, cohort study of patients with dental injuries was to develop prediction rules to predict treatment response related to the management of dental injuries. The study comprised of 130 patients with a single permanent incisor affected by a dental displacement (n = 100) or fracture injury (n = 30). Laser Doppler flowmetry (LDF) measurements of pulpal blood flow (PBF) were taken 6 and 18 weeks after dental injury Treatment response (success or failure) was categorized based on findings of clinical and radiographical evaluation after 9 months. Forty-four (34%) subjects were categorized as treatment success (absence of loss of sensitivity, periapical radiolucency and grey discolouration of crown), 43 (33%) as treatment failures (loss of sensitivity, and periapical radiolucency and/or grey discolouration of crown) and 43 (33%) as acceptable outcome (loss of sensitivity). After using univariate analysis to determine the association between potential clinical and LDF predictor variables and treatment response status, preliminary prediction rules were developed for prediction of success [positive likelihood ratio (LR), 29.0; 95% confidence interval (CI), 1.7-496.4] and failure (negative LR, 0.55; CI, 0.4-0.7). The most important variables were subluxation, root fracture, baseline PBF level and change in PBF level at 3-month follow-up. Outcome following the management of dental injuries may be predicted from variables collected from LDF and physical examination. Predictive modelling may provide clinicians with the opportunity to identify 'at-risk' patients early and initiate specific treatment approaches.

Dental pulp testing: a review

Dental pulp testing is a useful and essential diagnostic aid in endodontics. Pulp sensibility tests include thermal and electric tests, which extrapolate pulp health from sensory response. Whilst pulp sensibility tests are the most commonly used in clinical practice, they are not without limitations and shortcomings. Pulp vitality tests attempt to examine the presence of pulp blood flow, as this is viewed as a better measure of true health than sensibility. Laser Doppler flowmetry and pulse oximetry are examples of vitality tests. Whilst the prospect is promising, there are still many practical issues that need to be addressed before vitality tests can replace sensibility tests as the standard clinical pulp diagnostic test. With all pulp tests, the results need to be carefully interpreted and closely scrutinised as false results can lead to misdiagnosis which can then lead to incorrect, inappropriate, or unnecessary treatment.

Outcomes of dental fracture injury as related to laser Doppler flow measurements of pulpal blood-flow level

Laser Doppler flowmetry (LDF) is a non-invasive method to assess pulpal blood flow (PBF). Dental fracture injuries have been associated with significant PBF reduction The purpose of this study was: (i) to evaluate whether the severity of outcomes of dental fracture injuries may be related to LDF measurements of PBF, and (ii) to investigate whether outcomes of dental fracture injuries may predict PBF levels. The relationship between outcomes and PBF measurements was analyzed in 72 permanent maxillary incisors of 52 consecutive dental trauma patients. The diagnostic outcome group comprised 72 incisors with a type I (absence of sensitivity, periapical radiolucency, and grey discoloration of crown) (n = 42), type II (loss of sensitivity) (n = 16), or type III (loss of sensitivity, periapical radiolucency, and/or grey discoloration of crown) diagnosis. At each session, when an injured permanent maxillary incisor was recorded, a contralateral homologous tooth was used as a control. An ordinal stepwise regression was completed to assess the degree of association between PBF measurements and diagnostic outcomes. A logistic regression analysis was used to compute the odds ratios for the outcome features for incisor non-injury controls vs two outcome groups: type II (n = 16) and type III (n = 14). PBF measurements that were significantly associated with more severe outcome were PBF levels of <or=6 perfusion units (PU) (106.70 odds ratio) (P = 0.000). Significant increase in the risk of a PBF level of <or=6 PU occurred with a type III outcome (32.49 odds ratio) (P = 0.004). PBF measurements were related to the severity of adverse outcomes. Diagnoses of treatment outcomes predicted the presence of specific PBF levels.

Late term complications of intruded permanent incisors: 2 case reports

This report describes 2 cases of intrusive luxation injuries of maxillary immature permanent central incisors. In both cases, intruded teeth were left for spontaneous re-eruption. During periodic follow-ups for up to 2 years the teeth did not show any sign, clinically or radiographically, of pulp necrosis with apical periodontitis. However, in the first case tenderness to percussion and periapical radiolucency developed after 2.5 years and endodontic treatment was started. In the second case, the patient returned after 2 years 9 months with complaint and periapical radiolucency was observed radiographically. Endodontic therapy was performed. These late-term complications highlight the need for regular long-term follow-up in cases of intrusive luxation in permanent teeth.

Possible application of transmitted laser light for the assessment of human pulp vitality. Part 2. Increased laser power for enhanced detection of pulpal blood flow

The purpose of this study was to investigate the effect of an increase in laser power on the transmitted laser signals from vital and non-vital teeth, in the hope of achieving a better assessment of human pulp vitality with the transmitted laser-light flowmeter. The experiments were carried out on total of 61 vital teeth with no restoration (19 upper central incisors, 16 upper lateral incisors, 16 upper canines, and 10 first premolars) and five non-vital upper central incisors (the root canals of which were filled with gutta-percha) in 15 subjects aged 22-28 years. For use with transmitted laser light, the fibers within the probe of a conventional laser Doppler flowmeter (LDF) apparatus were used, one for transmitting light onto the labial surface, the other for receiving it at the palatal surface of the same tooth, as reported previously. Laser output power was set at the original 2 mW and also at 5, 7, and 10 mW. The number of vital teeth displaying a blood flow (BF) signal at each laser power setting was: 1) 12/19 central incisors at 2 mW, 19/19 at 5, 7, and 10 mW, 2) 19/19 lateral incisors at 2, 5, 7, and 10 mW, 3) 0/16 canines at 2 mW, but eight, 12, and 14 at 5, 7, and 10 mW, 4) 0/10 first premolars at 2, 5, 7, and 10 mW. Thus, an increase in laser power increased BF detection from the thicker teeth (but not from premolars). In addition, clearer BF signals synchronized with heart rate, and greater passive BF changes secondary to blood pressure (BP) changes were observed at higher laser settings. In non-vital teeth, no signals synchronized with heart rate or BP changes were observed, indicating that no BF signal of non-pulpal origin was ever monitored with this ballistic light even when the laser power was increased. These results indicate that high-powered transmitted laser light could be a useful tool both for monitoring pulpal BF and for the assessment of tooth-pulp vitality.

Use of laser Doppler flowmetry to predict vitality of luxated or avulsed permanent teeth

OBJECTIVE

Splinting of traumatically displaced or avulsed permanent teeth has been described as an effective modality in the treatment of patients with dental injuries. The purpose of this study was to investigate whether laser Doppler flowmetry (LDF) measurements of pulpal blood flow (PBF) and/or dental injury type may predict treatment outcome of splinting of permanent maxillary incisors.

STUDY DESIGN

The study comprised 64 patients undergoing dental trauma splinting, who were characterized by the presence of a single permanent maxillary incisor affected by a subluxation, luxation, or avulsion type injury. Perfusion units (PU) were taken in 2 sessions, on the day of splint removal (6 weeks after trauma; session I) and 12 weeks after splint removal (session II). At each session, when an injured permanent maxillary central incisor was recorded, the respective contralateral homologous tooth was used as a control. An adverse outcome occurring 36 weeks after splint removal was defined as the presence of "periapical radiolucency and/or grey discoloration." A multiple logistic regression analysis was used to compute the odds ratio for session-related PBF characteristics and dental injury type for adverse outcome (n=22) versus nonadverse outcome (n=42).

RESULTS

There was a significant increase in PBF values from session I to session II (P=.047) for teeth without an adverse outcome, whereas teeth affected by an adverse outcome showed a significant decrease in PBF values (P=.001). PBF measurements did not change over time for the control group of contralateral incisors (P=.185). For the outcome criterion of "presence of periapical radiolucency and/or grey discoloration," there was a significant association between the treatment outcome groups and the variables of dental injury type (P=.049), session-related PBF difference (P=.000), and session II-related PBF level (P=.000). Significant increase in risk of an adverse outcome occurred with a session-related PBF difference (PBF(Session I) - PBF(Session II)) of >/=0 PU (8.6 odds ratio) (P=.014), and a session II-related PBF level of </=2.8 PU (20.2 odds ratio) (P=.030).

CONCLUSION

The data suggest the LDF test to be a valuable diagnostic adjunct for luxated teeth showing signs of adverse outcomes. Predictive modeling may provide clinicians with the opportunity to identify "at-risk" teeth early and initiate specific treatments.

Laser Doppler flow measurements of pulpal blood flow and severity of dental injury

AIM

To evaluate laser Doppler flowmetry (LDF) measurements of pulpal blood flow (PBF) and severity of dental injury.

METHODOLOGY

The relationship between adverse outcomes and PBF measurements was analysed in 94 permanent maxillary incisors of 71 consecutive dental trauma patients. The diagnostic adverse outcome group was comprised of 72 incisors in 52 patients with a type I (loss of sensitivity), type II (loss of sensitivity and periapical radiolucency), or type III (loss of sensitivity, periapical radiolucency and grey discoloration of crown) diagnosis. The nonadverse outcome group consisted of 22 incisors in 19 patients with the finding of an absence of an adverse outcome. At each session, when an injured permanent maxillary incisor was recorded, a contralateral homologous tooth was used as a control. An ordinal stepwise regression was completed to assess the degree of association between PBF measurements and adverse outcomes

RESULTS

Using chi-square analysis for pairwise comparison, a significant relationship between PBF measurements and types of adverse outcomes (chi(2) =119.635, d.f. = 12, P = 0.000) was observed. PBF measurements that were significantly associated with more severe outcome were PBF levels of </=3 perfusion units (PU) (119.1 odds ratio) (P = 0.000), and those of >3 PU and </=6 PU (12.7 odds ratio) (P = 0.000).

CONCLUSIONS

PBF measurements were related to the severity of adverse outcomes. Further studies are required to evaluate whether PBF measurements can predict dental injuries that progress to adverse treatment outcomes.

Transient apical breakdown following tooth luxation

Transient apical breakdown is a sequelae of certain dental traumatic injuries where the injured tissues undergo a spontaneous process of repair with no permanent damage to the pulp. Misdiagnosis of this condition may result in unnecessary endodontic treatment. Presented is a case of transient apical breakdown following a subluxation injury of a maxillary central incisor in a 15-year-old girl. Four months after injury, coronal discoloration, periapical radiolucency as well as negative pulp responses to cold and electric tests were still recorded. Subsequently, the tooth spontaneously regained its original shade and the pulp responded normally to pulp sensitivity tests. Methods for early diagnosis of transient apical breakdown are discussed.